Eardrums & loudspeakers Right & Wrong!

"Unique" has almost become a tired old cliché in the world of high end AV. Every man and his passive crossover are claiming "unique this" and "unique that". The sad truth is that 99.9999 (yes six nines!) of all the loudspeakers in the world are all using exactly the same, fatally flawed, 100 year old technology that does not work! Pistonic motion (cones, domes, ribbons and panels, yes including Quads!) and passive crossovers (inductors, capacitors and resistors) were first used in audio in the early 1900's! They didn’t work then and they still don’t work today, here are the two reasons why.
Timing, Timing and Timing & Speed, Speed and Speed . Please be patient, read on and allow me to explain this radical but true statement. OK, hold on to your preconceptions cause this is really going to put the hungry cat among the fat pigeons!
Timing first;
The human (and all the other land based mammals) ear does not care what a sound is, what a sound sounds like or if a sound is pleasant or unpleasant. All that matters is where a sound is coming from in three dimensional space. All mammals ear brain mechanisms were developed to locate prey or flee from predators. In mammals the primary trigger for the fight or flight response is aural. When our primate ancestors detected a noise they instantly bolted in the opposite direction, away from the source of the noise. They may have been 10 meters into their flight response before they correctly identified the sound and realised it was as a false alarm… like a falling coconut. Or they may have identified a snapping twig as a predator was about to strike, then they looked back and thought that was close!
Natural selection ensured the survival of the creatures with the most accurate spacial location hearing mechanism not the most accurate tonal identification mechanism. So how does this well documented and accepted science & biology affect you and me in today's audio world?
To answer that we must first take a brief look at the mechanics of our ears and how they work, how they don't work and how fast they work.
Fact, our ears do not use pistonic motion!
Our ears use a rippling (or bending wave) principle to decode sounds. The outer ear channels sound waves (a series of compression and rarefactions in the air) down the ear canal onto the centre of the ear drum (imagine dropping a small pebble into the centre of a calm pool of water) which then ripples in response to this sound energy hitting its centre. Various tissues & tiny hairs and nerves located all around the edges of the ear drum (imagine how a spider uses its legs to detect the movement of struggling prey in its web) convert this movement, Kinetic energy, into electrical energy, and these impulses are then sent to the brain for decoding.
Now speed.
The ear drums response time is critical. How quickly the ear drum starts and stops the rippling motion determines the accuracy and effectiveness of our ears. Mother nature addressed this mechanical limitation by evolving the fastest possible energy conversion system, the rippling or bending wave ear drum motion. Pistonic motion is far too slow. The reason the ear drum does not work like a cone loudspeaker driver (a mass on the end of a spring) is because it would be in constant oscillation as it wobbles in and out never having enough time to settle back to its neutral or starting point. This would send a constant stream of "ghost echoes" to our brains which would be impossible to decode quickly and accurately.
Our ears are incredibly sensitive and specialised devices which are designed to detect where sounds are located (spacial information) in a fraction of the time it takes to identify what a sound is (tonal information).
The point to note here is that our hearing mechanism is ultra sensitive to time domain distortions. So the fundamental prerequisite in order for any loudspeaker to reproduce life like accurate sound is that its response time (speed) has to match or exceed that of the human ear.
Someone with average hearing can detect time domain errors down to an incredible 25uS or even less if your hearing is very good. The very best ribbon drivers covering 2KHz & above settle in an average of 100uS, the best dome tweeters have a settling time of between 140uS and 180uS, ultra fast midrange units need over 450uS to settle in the 500Hz to 2KHz band and a typical high end 12" bass driver can continue to oscillate and resonate for nearly a second after the initial musical note or impulse stops.
There is a driver which covers the entire 300Hz to 30 KHz band with a blindingly fast rise time of 13uS and does so without any of the ghost echoes and distortions caused by sluggish pistonic drivers slow settling times. It covers 90% of the audible frequency range with both rise and settling times that average over twenty five times faster than the very best pistonic drivers. Even more startling is the fact that this driver is so fast, the 13uS rise time is undetectable by the human ear, even a very good one! How is this possible I hear the sceptical voice cry?!
By refined the worlds only true rippling or bending wave loudspeaker system incorporating linear phase (time and phase coherent) digital crossovers and a genuinely unique cabinet material.
All full range loudspeaker systems are a combination of three equally important components; the driver, the cabinet and the crossover. In a world obsessed with measurements and statistics its easy to forget that it is more important how music sounds than how it measures.
A loudspeaker cabinet is not a passive box. Regardless of its material & construction techniques, a loudspeaker cabinet must be viewed as an active component which is equally important to the overall sound as the driver and crossover. The cabinet is an active energy conversion system, its job is to contain and convert energy, it must deal with the sonic back wave produced by the drivers it houses. Remember that the back wave disappearing into the cabinet is just as loud as the sound flowing into your room!
Creative engineering solutions can convert the kinetic (sound waves) energy of the back wave into heat energy by utilising proprietary viscoelastic materials and techniques.
MDF, plywood, hard wood, phenolic resin or plastic simply can not approach the energy conversion characteristics of this new unique 16 layer Self Damping Compound (SDC).
In acoustics the most important law of physics is, "for every action there is an equal and opposite reaction", so for all the musical sound you hear filling your listening room there is exactly the same amount of sound energy bouncing around inside the speaker cabinet! How can you convert this sound into heat before it bounces back out through the driver diaphragm out of phase!?
The only answer is…. ?

To close this opening article a big thanks to all the other guys who have asked questions and offered constructive criticism, I hope I can respond soon.
For the benefit of the "all mental one", see you did read all the way to the end, you can do it when you try! I will answer your questions;

" I'd be curious to find out how DEQX fixes your THD problems. That's my point. Why you would use DEQX with those drivers is beyond me. "
And
" I think they're full of a lot of BS, especially our sensitivity to time/phase. I also don't see how cutting out the LF will solve the Manger's distortion components at 2kHz, for example."

The reason crossing over the Manger at 300Hz with a 66 decibel or 96 decibel per octave slope eliminates THD throughout the entire bandwidth is that all the "hard work" or X-MAX consuming power bandwidth has been removed from the driver. It is "relieved of duty" so to speak and the driver is free to "rise and settle" midrange and high frequencies at maximum speed without having to reproduce the lower frequencies which require larger diameter points of energising. i.e. the starting diameter of the ripples required are larger the lower the frequency generated. Crucial vocal and string harmonics which all have fundamentals down to 300Hz benefit by an order of magnitude decrease in THD. This has never been done before and this is part of the reason why all previous tests and measurements are irrelevant to our application.
You can hear a similar effect (i.e. lower midrange and upper frequency distortion and greater power handling) when you take a standard two way bass mid cone and dome speaker and add an active 12 inch sub woofer. If you use an active filter to cut off the bass at say 100Hz to the two way speaker and direct all frequencies below 100Hz to the 12 inch sub woofer. Suddenly the little 8 inch bass/mid driver is free to concentrate on the easy (low X-MAX consuming) work and can play louder with lower distortion across its entire bandwidth. In addition the reason the tweeter and high frequencies benefit is the bass/mid driver now does a better job at the crossover point. Or to be more accurate at the crossover point plus and minus one or two octaves each side of the crossover point. This is due to the "barn door overlap" inherent in all passive crossovers (and actually analogue active crossovers with 24Db or less slopes) where there is no crossover "point" at all only a "region" of overlap and transition, but that’s another story.
So, all metal jacket, there you go its actually very simple, basic design and now you can use little nugget of wisdom (think of it as a friendship gift!) to sell more of your cone and dome /passive crossover kit and your customers will be sooo impressed at your design knowledge and experience!
I won't tell anyone if your nice to me! Can we be friends now have a latte & talk about football?

Big Hug
Derek.

Derek

Please don't take to heart anything that Alimentall heretofore has posted. Discount everything he says. He has NEVER heard a high end system and is nothing more than a troll here. I would love to hear your speakers. Let me know when it is possible here in the SF Bay are. Everyone here (I would bet will agree with me that Alimentall is nothing more than a scab on the a$$hole of we here) :)

I only posted this 30 seconds ago!
Thanks I was begining to wonder if I had enterd the Hotel California!
As you can tell from my last few coments to all metal friend I was having a laugh and I am guessing that he is one alpha male that is rather easy to make bark!
I do have a lot of good audio stuff too but I love the debates as well!

Thanks again and I better go now as Petra (my better half and golden ears who voices our speakers) and I have just been blessed with twin sons and they need feeding and changing.
There is a cute photo on our News & Events page if its ok to mention that!

Cheers
Derek & Petra.

Your speakers look great and I look forward to auditioning them

The sad truth is that 99.9999 (yes six nines!) of all the loudspeakers in the world are all using exactly the same, fatally flawed, 100 year old technology that does not work!
Derek.

Thanks for clarifying. I guess all of those speakers and amps I've been installing for years do nothing and the sound that we're hearing is due to my ability to cast mass hypnosis over everyone in the building?

Talk about the Emperor's New Clothes!

I say, give the guy a chance

Let's hear them before all of you condemn them

"Unique" has almost become a tired old cliché in the world of high end AV. Every man and his passive crossover are claiming "unique this" and "unique that".

"Unique" is a more accurate word than "holy grail"

The sad truth is that 99.9999 (yes six nines!) of all the loudspeakers in the world are all using exactly the same, fatally flawed, 100 year old technology that does not work!

See, this is why I have a problem here. "Fatally flawed"?!? "Does not work"?!? Actually, it does work and will be around for decades more. Sheer hyperbole.

Pistonic motion (cones, domes, ribbons and panels, yes including Quads!) and passive crossovers (inductors, capacitors and resistors) were first used in audio in the early 1900's! They didn’t work then and they still don’t work today, here are the two reasons why.
Timing, Timing and Timing & Speed, Speed and Speed .

The human (and all the other land based mammals) ear does not care what a sound is, what a sound sounds like or if a sound is pleasant or unpleasant. To answer that we must first take a brief look at the mechanics of our ears and how they work, how they don't work and how fast they work. Fact, our ears do not use pistonic motion! Our ears use a rippling (or bending wave) principle to decode sounds.

Your first premise completely contradicts your second. The ear "doesn't care"(!) how the sound is produced, only if it is realistic. If a driver is high distortion, the ear will hear it *no matter what the technology*.

Pistonic motion is far too slow.

That's completely without merit. By definition, if a speaker is pistonic within its range, it is plenty fast enough.

Our ears are incredibly sensitive and specialised devices which are designed to detect where sounds are located (spacial information) in a fraction of the time it takes to identify what a sound is (tonal information).
The point to note here is that our hearing mechanism is ultra sensitive to time domain distortions. So the fundamental prerequisite in order for any loudspeaker to reproduce life like accurate sound is that its response time (speed) has to match or exceed that of the human ear. Someone with average hearing can detect time domain errors down to an incredible 25uS or even less if your hearing is very good. The very best ribbon drivers covering 2KHz & above settle in an average of 100uS, the best dome tweeters have a settling time of between 140uS and 180uS, ultra fast midrange units need over 450uS to settle in the 500Hz to 2KHz band and a typical high end 12" bass driver can continue to oscillate and resonate for nearly a second after the initial musical note or impulse stops.
There is a driver which covers the entire 300Hz to 30 KHz band with a blindingly fast rise time of 13uS and does so without any of the ghost echoes and distortions caused by sluggish pistonic drivers slow settling times. It covers 90% of the audible frequency range with both rise and settling times that average over twenty five times faster than the very best pistonic drivers.

Can you post independent spectral decay plots of the Manger to verify this please?

The reason crossing over the Manger at 300Hz with a 66 decibel or 96 decibel per octave slope eliminates THD throughout the entire bandwidth is that all the "hard work" or X-MAX consuming power bandwidth has been removed from the driver. It is "relieved of duty" so to speak and the driver is free to "rise and settle" midrange and high frequencies at maximum speed without having to reproduce the lower frequencies which require larger diameter points of energising. i.e. the starting diameter of the ripples required are larger the lower the frequency generated. Crucial vocal and string harmonics which all have fundamentals down to 300Hz benefit by an order of magnitude decrease in THD. This has never been done before and this is part of the reason why all previous tests and measurements are irrelevant to our application.

I know how DEQX works and a 300Hz crossover won't alleviate a 2kHz distortion peak that is inherent to the driver.

So, all metal jacket, there you go its actually very simple, basic design and now you can use little nugget of wisdom (think of it as a friendship gift!) to sell more of your cone and dome /passive crossover kit and your customers will be sooo impressed at your design knowledge and experience!

They already are, I don't need to add ********** to my inventory, thank you.

Derek

Please don't take to heart anything that Alimentall heretofore has posted. Discount everything he says. He has NEVER heard a high end system and is nothing more than a troll here. I would love to hear your speakers. Let me know when it is possible here in the SF Bay are. Everyone here (I would bet will agree with me that Alimentall is nothing more than a scab on the a$$hole of we here) :)

I find the irony of you defending this guy absolutely hysterical. He just said your speakers are overpriced, antiquated, "fatally flawed" and "don't function". I say anything 1/10th as strong and you're all over me.

He has NEVER heard a high end system and is nothing more than a troll here. I would love to hear your speakers.

You're right, all those $15K-$45K speakers I've sold were just crap. :rolleyes:

Or do by "high-end" you simply mean overpriced and underperforming? I've heard plenty of those too, I just didn't sell it.

Hi All,

First of all I do want to apologise to Curt Palm and believe it or not to Alimental as well!
Regarding my postings attitude of "I am right everyone else is wrong".
Even if I am right (a demonstration is the only true proof) I am wrong to be so brash in my "First contact" with all you AVS guy's.
With the benefit of hindsight it would have been better to just make some low kew postings and then let anyone who is interested find my website and take it from there.
Anayway all is well that ends well and I have learned a valuable lesson in diplomacy (or my lack of it!) and I sincerely believe I have much to contribute on a technical level to your excellent forum. Lastly I think you guys are actually very well behaved. I have looked at some forums and not even bothered making a posting at all.
I will answer the last few questions from Alimental in a separate posting as I want to keep this one brief (makes a pleasant change!)

All the best

Derek.

Hello Alimental,

I'll answer what I can, your first two points are yours to make.

Your third point is difficult because you have cut & pasted some of my text and missed out the midsection so it actually does not make sense to me or other readers. But reading between your lines I think your question relates to my statements about "the ear does not "care" about sound quality..."
This relates to the evloutionary biology of how mammals ear brains mechanisms developed to prioritise spacial location information over sound identification. I think it is clearly explained in the post but I did have to edit it all down from the main document on my website to remove any sales pitch or names so maybe I have cut out some salient information from the original. Sorry if it was confusing.
You are correct about our ears detecting driver distortion, my point is that when implemented correctly, the Manger has in fact the lowest time domain distortion of any driver currently available.
Regarding time domain distortion, spacial (spatial) detection and phase coherence that is a big subject.
In summary (I am working on a white paper on this one but its going to be over 10 pages long!) all the biology proves our ear brain gives priority to decoding spacial information over decoding identification of sounds.ie Where the sound is comming from is more important than what the sound is. You can try a fun experiment to prove the theory.
Sit blind folded on a chair in the middle of a heavily furnished room with a thick carpet or floor rug. The room needs to be very quiet. Now ask a friend (whom you trust!) to walk slowly and very quietly all around you whilst occasionally snapping their fingers. The finger snapping should be as consistant as possible in "volume" randomly moving in very close and then walking right back to the walls. The point is you (the blindfolded one in the chair) will be able to pinpoint with great accuracy where the finger snapping (the potential predator or prey; note no capital P's!) is comming from.
Now compare this ability to our inability to seperate closley spaced frequencies ie in test CD'S try running up from 20Hz to 20KHz and see how big a "jump" in frequency bands you need to tell them apart.
If you go to the Manger web site there is a series of graphs and test results showing the "perfect" step response and ultra clean water fall plots.
I have already explained how a "brick wall" filter de-stresses a driver when you remove the low frequency work load. Just to repeat the point there is no inherent distortion in the Manger driver at 2KHZ or at any other point above 300 Hz.
Your quote : "That's completely without merit. By definition, if a speaker is pistonic within its range, it is plenty fast enough. "
This one is good even by your standards! Sorry but there is just no point in replying to this one.
Regarding your last quote ;
"They already are, I don't need to add ********** to my inventory, thank you"
As you think my explanation of how adding an active sub woofer will affect the performance of a typical two way speaker (see last paragraph in posting Eardrums & speakers above) is BS please do enlighten us all to YOUR views on the subject.
Lastly I do want to put the record straight on value for money, IMO!
The best value for money in MINSTREAM audio loudspeakers at this moment is DIY CONES & RIBBONS! When ever I get customers who cant justify spending £20K on speakers I give them this advice. Find a good joiner (or buy the tools and wood and DIY) to build up the cabinets of an off the shelf DIY kit from Wilmslow Audio (UK) or Madisound (USA).
You can get fantastic sound out of a simple design. I am going to publish details of two DIY kits designs in the spring. One is open bafflle the other is sealed box, both have active analogue crossovers as standard but can be upgraded to DSP crossover. The kits will retail at approx 3K so most movie and music lovers will be able to enjoy 90% (IMO!) of what many flagship cone and dome systems offer.
As far as true high-end audio is concerned I really believe I have something new and exciting in value for money terms. As well as taking a big step (giant leap?) towards reproducing natural time coherent sound with low distortion life-like dynamics.

" Time will tell " !!!

All the best

Derek.

You are correct about our ears detecting driver distortion, my point is that when implemented correctly, the Manger has in fact the lowest time domain distortion of any driver currently available.

This is true based on everything I've heard, but it is also something that humans really aren't that susceptible to as you imply. Besides, since DEQX fixes time domain distortion, you could have inserted other drivers just as easily and have gotten the same or similar result.

If you go to the Manger web site there is a series of graphs and test results showing the "perfect" step response and ultra clean water fall plots.
I have already explained how a "brick wall" filter de-stresses a driver when you remove the low frequency work load. Just to repeat the point there is no inherent distortion in the Manger driver at 2KHZ or at any other point above 300 Hz.

Well, I guess I'd have to see that in an independent test because Tom and others say there is. Implementation? Maybe. If this the Manger is so good, why isn't it on dozens of companies' speakers? The only other major company to use it seems to have replaced it with conventional drivers. Have you sent a pair of speakers to Soundstage or Stereophile? I'm prepared to eat my words if necessary!

Your quote : "That's completely without merit. By definition, if a speaker is pistonic within its range, it is plenty fast enough. "
This one is good even by your standards! Sorry but there is just no point in replying to this one.

Your statement is that pistonic drivers can't reproduce a waveform properly because they don't have fast enough rise time. That isn't the case because if they didn't, you would see a rolloff at that frequency. A woofer can be very slow, yet properly reproduce a bass note.

As you think my explanation of how adding an active sub woofer will affect the performance of a typical two way speaker (see last paragraph in posting Eardrums & speakers above) is BS please do enlighten us all to YOUR views on the subject.

Well, adding in a crossover will lower distortion below the crossover dramatically. It may even have a smaller effect on distortion levels above the crossover because it keeps the driver in a zone where it's more linear. But it's not going to turn a 10% distortion peak at 2kHz and turn it into .5%.

As far as true high-end audio is concerned I really believe I have something new and exciting in value for money terms. As well as taking a big step (giant leap?) towards reproducing natural time coherent sound with low distortion life-like dynamics.

Well, the Manger driver has been around for 20 years now, correct? While adding DEQX is a nice touch, it should have been unnecessary given the time/phase/frequency accuracy of the driver. So what is it about this old driver that is so special if it's made virtually no inroads into the industry? Why are you the odd man out? Keep in mind, I love new technological advancements, but I also find that most of them come with 90% hype and 10% substance. So, the less hype there is, the more you get a chance to look at the substance.

First of all I do want to apologise to Curt Palm and believe it or not to Alimental as well!

I don't think I need an apology as I wasn't actually offended (annoyed, yes, offended, no), but I appreciate it nonetheless. I'm a big believer in DSP, especially DEQX (since I've sold DEQX and sell NHT's version of it). And I think DSP will replace passive crossovers as fast as people are ready for it because the advantages are massive. And I think you'll still see a wide variety of drivers attached to this DSP. Some will still use soft domes or dipoles or ribbons or line arrays or horns, no matter how I may think that is not the best way to go. And I think DSP will make the most of all these concepts and the entire playing field will be elevated by it, but remain just as diverse with just many different tastes. When Xd came out, I felt it was a landmark product because it first combined a lot of advanced new technology and also did it at a ridiculously low price. But it could be a rather mundane, even overpriced, product in 5 or 6 years if every other company starts using DSP as the price to do so comes down.

Keep in mind, you don't have to have "the best" product to have a home run, you just have to have a unique one and there's nothing at all wrong with unique.

On a side note, time/phase really isn't a huge deal also because most recordings have been so processed that all sense of time/phase was purged before it was even mastered. And even a pristine mic recording of an orchestra is rife with all kinds of time/phase issues because the instruments are not co-located. So while it doesn't hurt to have good time/phase behavior, it's not really necessarily audibly helpful in the end, partially because it's hard to hear, partially because we wouldn't have good source material if it weren't.

Hi John,

I totally agree with your statement;
"And I think DSP will replace passive crossovers as fast as people are ready for it because the advantages are massive."
You will know better than most (because you are at the "sharp end" in retail sales) that introducing something as radical as a DSP which digitises all the "pure sweet" analogue is incredibly difficult. Especially since most really good analogue sources still have some sonic advantages over most really good digital sources.
SIDE BAR SUBJECT: I have recently heard some prototype solid state (flash drive not hard disk based servers) memory devices loaded with 24bit 96KHz music recorded live and burned straight onto the memory device. WOW! I really must have one of them. Not only did it out perform any source as we know it in retail, it was sonically invisable back in the studio when we were mastering the recording.Using a high speed 1 or 2 inch (I cant remember
but I think it was a Tascam or Studer deck) we could not tell when the memory chips were in or out of the loop. Even on a live feed with no recording equipment in the loop the vocalists and drummer said it was impossible to detect when the chips were switched in and out of the loop.
BACK TO TOPIC.
Back to your other points, I am actually going to head out for while to walk the dog and think how best to try and explain what is going on with our implementation of the Manger driver as your points are all valid and warrant a well thought out reply!
I may not have been thinking as clearly as normal over the last 3 weeks due to lack of sleep with the new born (26th Sept) twins, but they are soooo cute we love them to bits already!

Cheers

Derek.

I also have an argument that the more idealized you make a speaker, the more hampered it is by stereophonic reproduction. Until we well-mixed music for 3 or 5 front channels, true realism will elude us, no matter how "realistic" people dream their systems are. Too many arrival times for the same instruments to sound natural. I'd rather have 5x $1000 speakers in front with the proper multi-channel source than 2 x $10,000 speakers with stereo.

Come to think of it, if our ear/brain was so adept at picking up small time/phase differences, stereo imaging wouldn't work at all, would it? ;)

Derek,

I don't know how good your speakers are or aren't, but in my opinion you're treading down the well-worn high-end path of offering enthralling subjectivism mixed with unfounded technical claims that create a nonexistent problem for which you then offer a solution.

I'm not saying the deception is intentional; maybe you believe all this yourself.

If pistonic transducers were as bad as you say, there wouldn't be speakers using them that produce a few % distortion and have inspired reviewers to call them a window on the sound.

I only read far enough on your site to get to the part about the aerodynamics of a cone, i.e. 85% vs. 15% flow resistance on one side vs. the other, and the asymmetry causing distortion.

This completely misunderstands the situation; the cone is not traveling through the air, it oscillates in a fixed baffle.

Again, even if it was that significant, conventional woofers wouldn't be capable of producing less than 1% distortion (within their magnetic and mechanical linear ranges).

Derek, I didn't take offense either, I just tend not to believe wild claims as per your first posts..:)

Send a pair of your speakers to Mike Lavigne in Seattle. I've been meaning to go down to his place to check out his system, and from an objective and subjective point of view, he seems to be well grounded, even if he and I don't always see eye to eye.

Just so you know, I'm not a high end audiophile guy, but I have spent 22 years installing pro/commercial sound systems in the Vancouver area. I'm a board level tech, so I jump into discussions here from a very objective point of view, and throw around technical terms every once in a while to throw people off..

Hi All,

Well between you all I have my work cut out just to answer the quetions never mind add any of my own ideas!
I am on baby feeding duty right now but I will be thinking of how best to explain my answers as I feed the twins!
Give me a few hours and I'll do my best to respond.

Cheers

Derek.

The Prey

Why is this coming up now, this "star" driver is old news.

Morning John, Noah, Curt & Blueray

Lot's to say in order to do all your questions justice so I'll have to answer one at a time to try and keep each one as brief as I can other wise everyone else gets bored and don’t read any of it!
(1) How important is time distortion?
Imagine a live band playing in front of you, say, a vocalist, upright bass, drummer piano and Sax. Lets say the are using the very best studio grade mics, the best amplifiers and any one of the top ten speaker brands in the world.
Now imagine the mixing engineer starts to delay (with DSP or if you prefer analogue delay the vocal track on replay when mixing down) the vocalist (or bass or drums etc) by say 10 uS (ten, one millionth's of a second) we cant detect this so what we cant hear wont hurt. OK. Now keep adding more and more delay, 50uS, 100Us 100ms (100, one thousands of a second) until the poor girl is singing 10 seconds behind the band! Its the same effect as when you get the picture lagging behind the sound on your home cinema systems. OK so can we all agree it is important to get the timing accurate? The question remains just HOW accurate does it need to be?!
SIDE BAR : Also please remember that phase and time are NOT the same thing. You can have two signals in phase (the peaks of the wave form aligned) but one can be delayed in time by any amount. This is one of the unavoidable effects of passive crossovers.
BACK TO TIMING.
There is a raft of scientific data and a complete consensus among the experts that our hearing is ultra sensitive to time domain errors. I have done my best to reproduce some on material my website and some as the first post in this thread, but really it's up to you guys to surf and Google the subject. Only then might you believe me! The whole issue of jitter (time domain distortion) in digital repay is all about timing and its taken 22 years of measuring CD players to even discover the problem!

John, you already acknowledge that you have heard and enjoy the benefit of the DEQX fixing SOME (I'll come back to this one!) of the time distortions in various cone, dome, ribbon and panel speakers. The DEQX does this by measuring the sound waves timing errors generated by any loudspeaker compared to its own pure signal generator. IE the DEQX inputs a pure sine wave sweep from 20Hz to 20KHz and then compares that to the disjointed sound waves as reproduced by the various loudspeaker drivers (and passive crossovers if the DEQX is not been run in full active mode)
This is a big step forward (a giant leap if you ditch the passive crossovers and go fully active in Bi or Tri amp mode) and I have upgraded some big flagship (Avalon, Wilson, Apogee, etc) just by bypassing the passive crossovers and adding two extra power amps. If any of you guys have bought big speakers on the used or grey market or your warranty has expired, I can highly recommend going active, DSP or analogue, it is a huge and easy upgrade.
Now imagine that effect (benefit) increased by a factor of ten! This is accomplished by addressing BOTH the rise time and the SETTLING time of the drivers. To explain this in detail requires that we look at a simplified model of how we are attempting to reproduce sound waves with loudspeakers.
THE PISTONIC THEORY.
Imagine looking side on at a clear plastic tube containing a ping pongl ball with copper wire wound around the balls circumference. The ping pong ball has a piece of elastic fixed to it and the other end of the elastic is fixed to one end of the tube. At the end of the tube where the elastic is fixed there is a ring of magnets around the outside of the tube. Lets assume the magnets are powerful and can fill the whole tube with a perfectly symmetrical magnetic field and the elastic is also 100% Linear in its operation. (Big assumptions but pistonic theory needs all the help it can get!)

This is our pistonic driver! All it lacks is the paper cone around the ping pong ball, but I'll come back to that later when I address the question of aerodynamics. So we pass an electric current through the wire that's around the ball and hey presto the ball shoots forward inside the tube! Now this bit is important. If all our musical signals were continuous sine waves we would be home and dry! But music signals are all about transients, amplitude and ….Timing! All "real" (i.e. not signal generators and sine waves) sounds musical or snapping twig etc are formed by an initial transient of air pressure and then a decay back to ambient pressure.
So lets play some music through our ping pong ball speaker! First up one single drum strike. Bang, the ball shoots forward causing a compression of the air in front of it (yes it does have to move through the air and yes aerodynamics do come into play!) it is propelled forward by the electrical impulse and simultaneously it is being retarded by the elastic band (the spider, surround and suspension) which is now storing this kinetic energy as potential energy. So when the ball reaches the end of its forward motion it is now pulled backwards by the elastic band, the ball will overshoot its original starting point (carried past the start position by its own momentum) it behaves exactly as the laws of physics dictate, a mass on the end of a spring. It will oscillate! Back and forward until it disputes all the energy in the elastic band. These oscillations because ghost echoes i.e. instead of the one clean drum strike you get one clean strike followed by a slowly diminishing number of ghost strikes. This is what is wrong or unnatural about pistonic motion speakers. The degree to which it is wrong varies from driver to driver but it is none the less wrong! Suspension non linearity's, material and component tolerances, heat and humidity, glue joint integrity, mechanical assembly tolerances magnetic field symmetry, X-MAX limitations BL to MMS ratio driver loading, air volume etc. they all are variable and have an effect.
Now start to factor in real music i.e. before the driver has stopped oscillating from the first strike, bang here comes another and another and now a double bass and look out here comes the piano…! You get the picture, it’s the compounding of errors one on top of the next which never allows the cone or dome to actually start and stop on its marks.
Just briefly on the aerodynamics, our ping pong ball is symmetrical so it is aerodynamically balanced, all cones are out of balance to some degree depending on profile. The fact that the drivers are only moving back and forward a short distance (plus and minus half an inch or half a millimetre it makes no difference) it’s the huge acceleration and deceleration that magnifies the effect. IE at walking pace the wind on your face is not noticeable, but at 100 miles per hour it will distort your cheeks! The fact that the distances and times are small makes no difference; the speakers must move and re-move the air mass in front and behind the cones hundreds and thousands of times per second. The air mass in front of all cone drivers is actually measured and recognised by ALL driver manufacturers already. The MMS (expressed in grams) specification given for all drivers is the total weight of all the moving mass of the driver PLUS the weight of air in the cone profile. The manufactures know the problem is there but can't figure out (yet!) how to get round it.

I will address the other points in my next post as duty calls me to nappy changing the twins again!

Cheers

Derek.

Just a quick thought and a fun experiment.

Instead of comparing our systems to one another or to a "reference" system, try this test.
Take a track consisting of lead and backing vocals, acoustic instruments ie piano, drums, upright bass, Sax and anything else you enjoy hearing live.
Now sit in the hot seat and imagine there are 20 bags on the floor in front of you, each bag contains $10,000! You have a chance to win all of them!
Hit the play button and start listening to your track.
The first second you get a clue that you are listening to a hifi and not the live musicians in your the room stop the CD or record. You have just won the first bag of $10K! Now press play and continue, how many bags will you win per track?
My point is the ONLY reference is live unamplified music and vocals.
If you could have a giant revolving stage (like the one Harman International use to do A / B comparisons with different speakers) at the end of your room and there was your ultimate dream team hifi playing a recording of your favourite artists on one side and on the other side of the stage were the actual live musicinans how easy would it be to win all twenty bags of cash?!
This is the truth we are a long, long, long way from not being able to win any bags of cash in live versus hifi.
I believe a very large part of the blame for this is becuse pistonic motion loudspeakers are failing to create acurate preasure transients in the air. ie they are not linear pistons starting and stopping exactly as their manufactures would like you believe. They are in fact a mass on the end of a spring ocilating out of control.

"Time Will Tell"

Cheers
Derek.

Now press play and continue, how many bags will you win per track?
My point is the ONLY reference is live unamplified music and vocals.

So how meaningful is this for people who listen to amplified music? Even acoustic bands are miked usually, and orchestras as well in many venues nowadays!

Hello QueueCumber,

By targetting or voicing an audio system 100% on natural (unamplified) vocals and instruments we can be sure that it is starting from a correct and neutral position.
Just as we have the internationally accepted pantone colours and colour charts for calibrating video screens.
What works for international picture calibration would and should work for audio.
This would enable us (or any other company who uses the Conductor or a high end DSP) to then add more bass more top, more whatever at the end user stage to fine tune the system according to room acoustics and the sonic preferences of the customer(end user). Again when you buy your high end plasma or screen it is individually callibrated to suit your room and your taste.

In an ideal scenario all recordings and studio mastering of movie sound tracks would be created and monititored using an identical and internationally accepted "reference" system.
Maybe one day,

" Time Will Tell "

Cheers

Derek.

Derek,

I'm sorry, but you come across as though someone at Manger spoon fed you selective data and you're repeating it.

Pistonic drivers work very well in acoustic suspension cabinets because the air chamber creates a counter force to the the mass of the driver. This is very simple to tune so that the desire to overshoot is negated.

Now, try this. Take an old fashioned saw, our "bending wave" driver and start it vibrating. It doesn't stop instantaneously either. It has resonances in it that keep going. This is the type of thing that would cause harmonic distortion. This is why I can barely stand the sound of a B&W speaker, especially the FST designs. They are rippling much like a Manger driver, but adding tons of audible distortions that cloud the sound.

So, each driver is going to have some issues, no driver is perfect. Perhaps a Manger driver can stop and start at low frequencies faster than a conventional driver *but* I also bet it has lots of harmonics added (hence the measurable HF distortions) that a pistonic driver will not. And low frequency distortions are much less audible than high frequency distortions.

Derek,

You haven't addressed how, if pistonic drivers are so bad, how they work so well.

Your description is also misleading in that it describes an underdamped mechanical system, which in any case is mostly irrelevant above the resonant freq.

Hi Noah,

My post about comparing live acoustic instruments and vocals to any current flagship cone and dome speakers system says it all.
With cones and we are still a million miles away from reproducing the real thing, so after nearly 100 years of barking up the wrong tree maybe we could try an alternative.
Also please remember Manger is one small family run business, a life long passion and dream that has only had (so far) the R&D resource of the Manger family.
What state of development would it have reached had it had the combined might of 2800 speaker companies pouring in R&D for 30 years?

Regarding the damping issue and my simplified "ping pong ball" speaker,
The model accuratly describes the actual practical application as well as the mathematical formula of sealed box cone and dome drivers be they tweeters, midrange, bass / midrange and bass speakers. The only thing that varies is the scale of the design ie the mass and movement of a silk dome tweeter is obviously miniscule compared to a 12 inch bass driver but the formula and equations to describe the function is the same.
The volume of sealed air helps the siuation but driver overshoot is a well recognised and acknowledged problem.
An under damped box design is simply even worse.

Regarging Johns point;
"Now, try this. Take an old fashioned saw, our "bending wave" driver and start it vibrating. It doesn't stop instantaneously either. It has resonances in it that keep going. This is the type of thing that would cause harmonic distortion."
Your analogy is not valid because
(1) The saw is metal. Metal is the worst material to use for any speaker diaphram. All the metal dome (Titainium or aluminium) tweeters and bass drivers ring like bells!
(2)Your bent saw is under tension.
A fundamental part of the bending wave principal is that the radiating membrane must be free of all tension. In addition the membrane must be inherantly self damping, hence the use of several advanced polymers combined to make a membrane which has remarkable close acoutic properties to the human ear drum.

I really dont want to come accoss as a smart ass with answer to everything or some guy who is simply repeating the physics from the Manger website.
I am genuine in my own belief that I have taken the basic Manger driver and for the first time ever, the true potential of this driver has been released.
I have deliberatly not used any of the Manger website text or images on my own site in order to avoid looking like a copy cat.
I know that I am swimming against the flow but sometimes when you go with the flow you just end up washed up on the beach with all the other dead fish!

Cheers

Derek.

My post about comparing live acoustic instruments and vocals to any current flagship cone and dome speakers system says it all.

No, it doesn't.

With cones and we are still a million miles away from reproducing the real thing, so after nearly 100 years of barking up the wrong tree maybe we could try an alternative.

We could, but that wouldn't necessarily better. Besides, we've been barking up the Manger tree for 20 years with little consequence.

Also please remember Manger is one small family run business, a life long passion and dream that has only had (so far) the R&D resource of the Manger family.

According to the Manger website, the driver is so perfect that no further evolution is possible. Sounds like a dead end to me.

What state of development would it have reached had it had the combined might of 2800 speaker companies pouring in R&D for 30 years?

Apparently nothing according to the website.

Regarding the damping issue and my simplified "ping pong ball" speaker,
The model accuratly describes the actual practical application as well as the mathematical formula of sealed box cone and dome drivers be they tweeters, midrange, bass / midrange and bass speakers. The only thing that varies is the scale of the design ie the mass and movement of a silk dome tweeter is obviously miniscule compared to a 12 inch bass driver but the formula and equations to describe the function is the same.
The volume of sealed air helps the siuation but driver overshoot is a well recognised and acknowledged problem.
An under damped box design is simply even worse.

Regarging Johns point;
"Now, try this. Take an old fashioned saw, our "bending wave" driver and start it vibrating. It doesn't stop instantaneously either. It has resonances in it that keep going. This is the type of thing that would cause harmonic distortion."
Your analogy is not valid because
(1) The saw is metal. Metal is the worst material to use for any speaker diaphram. All the metal dome (Titainium or aluminium) tweeters and bass drivers ring like bells!
(2)Your bent saw is under tension.
A fundamental part of the bending wave principal is that the radiating membrane must be free of all tension. In addition the membrane must be inherantly self damping, hence the use of several advanced polymers combined to make a membrane which has remarkable close acoutic properties to the human ear drum.

The above is simply the same as a conservative not understanding liberalism or vice versa. You say my analogy isn't valid, but yours is. That is not the case. Bending wave transducers are not all you claim them to be, nor are pistonic drivers as bad as you claim them to be.

I really dont want to come accoss as a smart ass with answer to everything or some guy who is simply repeating the physics from the Manger website.
I am genuine in my own belief that I have taken the basic Manger driver and for the first time ever, the true potential of this driver has been released.

Well, let me ask you this - in what field do you have a degree? It surely isn't engineering. Philosophy? Religion? Sales?

I have deliberatly not used any of the Manger website text or images on my own site in order to avoid looking like a copy cat.

And yet you quote it as though you wrote it yourself.

I know that I am swimming against the flow but sometimes when you go with the flow you just end up washed up on the beach with all the other dead fish!

Or you end up being eaten by a shark.

Hello John,

..... & you were doing so well for a couple of posts you actually raised some valid points.
Have you forgotton to take your medication again?
You know how angry matron will be...!

Big Hug

Dr Derek.

Derek,

I'm going to conclude then that you're not an engineer, just a "designer". And that is fine to an extent, but your technical descriptions come across as hackneyed and borrowed, designed to deal with less astute potential customers. The whole "we do it right, everyone does it wrong" thing has been done to death. I also came to this conclusion because you've jumped on DEQX so quickly. This allows anyone to design and build a competent speaker, whereas designing an analog crossover is very difficult and painstaking. Simply follow the instructions for a proper box size and measure, voila!

So, can you explain to me why the Manger driver has failed commercially if it is so far ahead of everything? I'm fairly sure that you're not the only one that can figure out that it needs to be crossed over above 300Hz or so. How is it that a 20 year old driver is suddenly the only right way of doing things? Why did Audio Physic replace this driver with a conventional coaxial design with all of their known problems?

You can't just toss out simplistic analogies and get people here to nod in agreement. You're going to have to step up your game. Unfortunately, I don't think that will be possible with the gear you're trying to sell. You can't just pretend away the problems of the Manger driver.

Derek, do you have supporting data for the various claims you made regarding the Manger driver? Also, what is your Doctorate in?

Apart from some cowbell (underdamped obviously! ;)) this thread needs a certain Dr. from livermore...

Hello Chu Gai,

My story and our team are similar to most small niche manufacturers, a short summary as follows.
I am a humble engineer, OK an engineer! School, trade, job, no degree in the subject I now study for a living, just hard work. Prior to 2001 I had been in telecoms for over 10 years and when the 'Coms bubble burst in 2001 I decided to pursue my life long dream of running my own audio design company. It has taken me nearly seven years to find the right team, all of whom are vastly experienced within their particular area of expertise, and now we are a solid unit.
I do all the design and Petra the voicing, we always use live vocals and acoustic instruments played by friends as the ultimate test and reference.
My electronics designer, Bob, is a genius I was very lucky enough to meet him and he is now also a parner in Overkill Audio.
We have spent a lot of time and effort (ie money!) finding the absolute best OEM team for CNC routing, metal work, industrial design, and finishing. When you get up close to our products they really do comand respect.
As an example of this I will be publishing some more photographs on the website next month that show the multi-layered internal construction of our 2004Encore bass cabinets. You will see exactly where several of the current conteders got "their unique" designs from!
We rely primarily on our ears, guided by the application of basic physics and well grounded construction and engineering. We do use a selection of the usual suspects when it comes to test and measurement software and hardware, including CLIO V7,(not sure yet about V8) Earthworks Mics, Prisim Sound DA Analyzer and the very good SMAART LIVE V5, it's Real Time Transfer and FFT are the best by a mile. They actualy agree with our ears!
The reason we (and many other manufacturers) dont show graphs and publish our results is we instantly get bombarded with the DIY guys saying" "your wrong , my CLIO suite gives XYZ results" and we get into arguments over control conditions. Also the reviewers results are the only ones people believe as you guys already said!
You guys are all quite right to be sceptical and I look forward to meeting you all in person at an Overkill Vs the best (of the rest!) audio shoot out and then you can judge for yourselves if I am "full of it" or not!

All Mental, have you taken your pills yet?
Will they taste better than your words...!
I hope you sell a lot of kit and earn alot of money in the next year cause you will need to be rich to afford the Finale system!

Cheers

Derek.

Hello NHT Killer, (Love the name!)

I to get out more, cause I think this is fun!

I do enjoy trying to answer serious questions and valid points from any one of the AVS members, even the mental one when he is on his meds, and even although I have only been posting here for a few days (or is it a week?) I have already recieved some very reasuring private mails. Thanks.

I do want to continue this thread and I will check back to see if I have missed any serious questions and I will answer them as soon as I can.
However I have an idea for a new thread.... How about a look at the pricing and mark-up structure from factory to end user / customer of say the top 5 contenders in loudspeakers?
Component & labour cost from manufacture, through distributors and onto retailers and then customers. That should be fun, what do you think?
I would like to call it "Costing the Emperor's clothes!"

Cheers

Derek.

Thanks Derek,

I think that would be a fun thread, doomed to be shutdown by the moderators though....I think. I am sure John would be happy to give you all the information on B&W's pricing and mark up structure, since he knows all about B&W's costs and things. Heck he has even taken the tour at the B&W factory in England....Oh wait...That was just another one of his lies, my bad.

Seriously though, I do want to hear this speaker, hope it comes to my town someday. I always like new things & try all types of cool stuff. Don't knock it till you try it, right?

Hi Mike,

Good point, I would really be putting my neck on the line if I reveal all the dirty little secrets of the pricing and mark up structure.

Well to be honest I think most people are aware of the true value and there are so many internet based sources where you buy all the big names brand new but described as previously owned; "boxed", "mint", "crated" ,"un wanted gift" ( I love that one!) at 40% to 50% discount.
The true value is well known.

We have a different business model which allows us to miss out the distributor stage altogether.
In fact it is almost Factory to customer but we need some (about 6 in the USA) dealers to stock a demo system which they keep long term and use only to demonstrate how it all sounds. Any customer orders are shipped directly from the UK to the customer. I then I fly out to do the set up. So the dealer has no shipping costs, no delivery and installation costs, and no warranty costs as Overkill pays for all of that.
This means that the dealer can still get a good profit margin for finding the customer and making the sale but all the hassle has been taken out of the process. We dont offer the dealer the typical 100% mark up or 50% discount from an artificially inflated retail price ie buy it for $50K sell it at $100K).
The bottom line is that we can sell our equipment at less than half the price compared to the traditional business model.

Anyway until we get the first early adopter its all hypothetical but I really am looking forward to doing some USA demonstrations.

All the best

Derek.

Overkillaudio do you have any THD numbers for your driver?

Hi Blu Ray,

With a 96dB slope the THD remains below 0.5% at 95dB @1m up to 23KHz, the accurate limit on our Earthworks mic. The B&K mic measurement peaks at 0.8 % at 550 Hz andaverages 0.6% up to 22KHz, again the top end accurate limit.
The manger falls apart if you use a 6dB or 12 dB passive crossover at 140 Hz, we get nearly 7% distortion at 95dB 550Hz and we actally blew a driver trying to get 98dB with the passive xover. Any low midrange or upper bass kills the abilty of the bending wave principal.
If you carefully read Professor Manfred Heckle's mathematical study of the Manger driver ( a PDF on the Manger site under the research heading) he states in his assumptions"....above 300Hz..." is the zone where it all works. We agree!
With our Conductor we can run at huge SPL's ie 118dB peaks with the Finale system.

I hope this helps,

Derek.

Derek, when will Stereophile and Soundstage review one of your systems so we can see independent measurements to back up your claims? Then we can see how the systems function as far as distortion, dispersion, accuracy, spectral decay, etc. If the speaker is truly superior, it will measure better in every way than anything previously measured.

Personally, I think that everyone with a new idea, no matter how wacky, should be able to build it and try to sell it. HOWEVER, when there are claims of absolute superiority over everything else with little or nothing to back it up combined with over the top guerilla marketing, well, I don't know why you wouldn't expect to be challenged.

posts deleted

reopened: personal attacks are unacceptable

"Personally, I think that everyone with a new idea, no matter how wacky, should be able to build it and try to sell it. HOWEVER, when there are claims of absolute superiority over everything else with little or nothing to back it up combined with over the top guerilla marketing, well, I don't know why you wouldn't expect to be challenged."


Ultra hi end cables, anyone? anyone?

With a 96dB slope the THD remains below 0.5% at 95dB @1m up to 23KHz, the accurate limit on our Earthworks mic. The B&K mic measurement peaks at 0.8 % at 550 Hz andaverages 0.6% up to 22KHz, again the top end accurate limit.

If this is actually the case, then this would be able to do something that I've never seen any driver do, especially at 95dB. So, while I'm open to that possibility, it seems very unlikely, especially given that Tom Danley is a very smart guy who knows how to measure a driver. He must have said half a dozen times that the Manger is a great driver in many ways, except for its high THD. <.5% at all ranges above 300Hz at 95dB isn't just low, it's almost impossibly low.

One thing about settling time. You can't compare a midrange or treble driver to a woofer as did 6moons. It seems that is what is regularly done with the Manger driver. It, as a driver, is compared to a complete system with a 12" or so woofer which will naturally have a decay time in the 3-5ms range. So, what I'm seeing here is often a "game" where the Manger driver is portrayed on an uneven playing field to make it look better than it is.

Ultra hi end cables, anyone? anyone?

http://www.avsforum.com/avs-vb/showthread.php?t=918365

<.5% at all ranges above 300Hz at 95dB isn't just low, it's almost impossibly low.

For the manger or all speakers? Because most speakers can hit low THD numbers.

.5%? Not that many. And we're talking drivers with excursion to spare. Look at www.speakermeasurements.com and I don't recall too many (if any at all) that hit, what, 46dB below signal levels at 95dB at all frequencies above 300Hz.

Edit - well, PSB T6s are less than .5% distortion over about 300Hz. NHT's Xd do that except for a few blips. But those are both ultra-low distortion speakers. Again, not impossible, just strange that Tom would constantly refer to the driver as relatively high in distortion and others showed up to 10% distortion in the upper midrange.

I hope there's more to a speaker than just low distortion numbers.

.5%? Not that many.

No, I would say most speakers can best that.

http://www.hometheaterhifi.com/volume_14_3/earthquake-2515-speaker-minime-subwoofer-9-2007-part-3.html

Earthquake Sound PN-2515 LCR Speakers at $599 each can hit "At 1 kHz, still measuring from the mid/woofers, THD+N was only 0.22%" and "And, at 10 kHz, measuring from the tweeter, also a very low amount 0.24 of THD+N."

The THD is higher when you are dealing with low bass.

Hi All,

It was fun while it lasted but after being advised by other members private mail, public mail and advice from the forum moderators
This is both a blessing and a curse because he will of course claim "I cant handle the truth"! Blah blah etc etc.
But on balance I believe it to be the correct thing to do.
Until I have an Overkill system in the USA I must rely on giving detailed and accurate answers to all valid and genuine questions.
I can't do that, with limited posting time, when I am trying to shelter from the snow storm (avalanche!) of mis-representations and fiction

Of course I am happy to still answer any of his Valid questions which are posted by any third parties.
I hope you all understand and thanks for your support, it is not easy swimming upsream all the time!

All the best

Derek Wilson
Overkill Audio.

No, I would say most speakers can best that.

Not if you go by Soundstage's measurements! Very few can. Of course, I'm not an expert on distortion measurement techniques, by any stretch.

I hope there's more to a speaker than just low distortion numbers.

Of course, but that is supposedly the Manger's weak spot.

Now, I can say that I've heard speakers that have very low distortion figures that still sound resonant and forward and hard on the ears, so obviously there's more to it. I haven't quite figured out what measurement consistently coincides with an aggressive sound.

Not if you go by Soundstage's measurements! Very few can. Of course, I'm not an expert on distortion measurement techniques, by any stretch.

And it differs how?

Hi Bluray and Chu Gai,

I hope the following new perspective helps clarify a couple of points on the THD driver distortion front.
If we look at the whole audio chain from source to drivers and look at the audio signal as one continous signal does it really matter where the distortion occurs?
If the true and total accumulative THD of the signal was measured from source through to the output of the loudspeaker drivers, could we measure or hear if the distortion was all in the source, all in the amps or all in the speakers?
If the total system THD figure was say 3% could we tell if each component in the chain added 1% or was the source "perfect" and the amp a super clean 0.0007% so it had to be the fault of the speakers?
Why are some of the worst measuring digital sources (Zanden and most NOS DAC players) reviewed and acclaimed by buyers as the most natural and life-like sounding?
Ditto SET amplifiers and valve pre amps, many exhibit over 1% distortion in real load measurements yet they are again bought and treasured as the most natural sounding. How can they be even close to in performance terms, never mind the prefered choice over many of the "so low its basically zero" distortion amps?
My last question is do we actualy believe that if we replay the most perfect high resolution recording of a powerfull piece of music on a $Million system made up of a THD 0.5 % source, a THD 0.5% amplifiers and a THD 0.5% pair of speakers that our ears will agree and tell us "yes that is 98.5% indistinguishable and a 98.5% perfect reproduction of the live event?
No way on gods green earth!
With current technology, we are obviously a million miles away from being able to reproduce the power and complexity of real music.
My point is this; Our current obsessive "tunnel vision" with THD is focused on the wrong distortion. THD is Total HARMONIC Distortion we need to measure
Total Signal Integrity Distortion (TSID).
This is what I have been focussing on for the last 6 years.
Please take a look at some of my previous postings on the importance of Time coherence in the audio signal for more background on this.

In summary current THD only measures amplitude and frequency errors ie THD is two dimensional!
Despite the smoke and mirrors marketing of conventional speaker manufacturers, the very pretty 3 D waterfall plots from speaker measurement software are still only 3D representations of a two dimensional event.
I hope this is of interest and helps further the debate.

"Time Will Tell"

All the best

Derek/

And it differs how?

You can look at the distortion elements at all frequencies, not just one or two.

You can look at the distortion elements at all frequencies, not just one or two.

And I doubt the distortion is going to change from 5KHz to 10KHz. How many tests do you want them to do.

Why wouldn't it? Besides, it's more to do with having the measurements done exactly the same way as different techniques and gear will have different results.

I was thinking about suing Cerwin Vega.

Why wouldn't it? Besides, it's more to do with having the measurements done exactly the same way as different techniques and gear will have different results.

THD will only increase when you are pushing a driver to its limits so if the tweeter can do 10k with ease then 5k should be easy. Are you saying that they "rigged" these tests to show low THD numbers for these speakers? Go through the reviews on that site and you will see that most speakers have no problem getting low THD numbers.

Most of the speakers seem to have 1%-10% distortion peaks in the midrange that I see, even some very expensive ones, especially at 95dB.

Most of the speakers seem to have 1%-10% distortion peaks in the midrange that I see, even some very expensive ones, especially at 95dB.

Then that says a lot about who makes those speakers since a basic speaker can trump those numbers. Do you have a link to those high distortion numbers?

I gave it to you several times. There are lots of examples there.

If we look at the whole audio chain from source to drivers and look at the audio signal as one continous signal does it really matter where the distortion occurs?
Well, it's relatively easy to get benign and inaudible distortion from amplifiers that still remain benign and inaudible as the power output increases. With speakers a signficant amount is non-linear distortion that is amplitude related. But to focus on a single number, THD, without consideration of the distortion spectrum and other aspects is misleading. Further,in order to reliably measure exceedingly low levels of distortion in speakers requires that the inherent noise of the measuring system be even lower and have sufficient bandwidth. Do the microphones you use meet that criteria?

Why are some of the worst measuring digital sources (Zanden and most NOS DAC players) reviewed and acclaimed by buyers as the most natural and life-like sounding? Focussing on a small, but vocal minority of reviewers and buyers with questionable standards who review and buy products with poor manufacturing standards as the arbiters of either high-end or hi-fi is laughable. Mostly these people thoroughly relish the smell of a ripe and juicy fart as it wafts through a room like a low level fog and comment favorably upon it.

Ditto SET amplifiers and valve pre amps, many exhibit over 1% distortion in real load measurements yet they are again bought and treasured as the most natural sounding. How can they be even close to in performance terms, never mind the prefered choice over many of the "so low its basically zero" distortion amps?
Opinion stated as fact.

My last question is do we actualy believe that if we replay the most perfect high resolution recording of a powerfull piece of music on a $Million system made up of a THD 0.5 % source, a THD 0.5% amplifiers and a THD 0.5% pair of speakers that our ears will agree and tell us "yes that is 98.5% indistinguishable and a 98.5% perfect reproduction of the live event?
No way on gods green earth!
Of course not and that is in juxtaposition to your earlier focussing on distortion. Most of the earth is blue. I saw it from space photographs.

THD is Total HARMONIC Distortion we need to measure Total Signal Integrity Distortion (TSID).
Do we really need another contrived term that isn't properly specified and correlatable?

Hello Chu Gai,

Re your quote ;
"With speakers a signficant amount is non-linear distortion that is amplitude related."
I 100% agree, this is the very point I have been trying to make in a lot of my previous posts about the fundamental failings in all pistonic drivers. To make the point in another way here is a real controversial Overkill quote :
" All loudspeakers sound and measure 100% identically the same...when they are not doing any work!!!"
Its only when you start to turn up the volume can you begin to hear or measure any signal at all, never mind differences between drivers and speakers. All THD distortion is simply a measure of how non-linear, non-pistonic, or un-even a cone / dome becomes as it starts to any "work"
They all fall apart because the mechanical principal if wrong, it's just a matter or quickly and how far do they fall.
All the "spectrum" of the THD is the breakdown of the harmonics (the "H" in THD) IE first, second, third, odd or even.) Its all still just two dimensional (see my previous post) and does not measure true time domain distortion.

Re your other valid question yes our software, hardware and mics are all of a very high standard, I have previously posted details of some of our test &measurement kit.

I hope this helps.

"Time Will Tell"

Derek Wilson
Overkill Audio.

http://www.avsforum.com/avs-vb/showthread.php?t=918365

What are your thoughts on this?

Hi Mike,

Without delving in too deep here are two ways to describe my mind set and attitude towards this subject.

" we should understand that there is still much we don't understand "

"That which was "Black magic" yesterday is accepted science today and what we cant explain today will be well understood tomorrow"

As always take care and "Time Will Tell"

Derek.

What are your thoughts on this?

Much ado about nothing, really. I don't think it would change much either way. I don't hear huge differences in cables and sometimes wonder if I hear the small ones or just think I do, but don't really care because I've got some basic Nordost cables and am perfectly happy with the price/performance regardless.

I have no doubt that wires make a difference, I have first hand experience (many times) with this. I am no one to be criticizing expensive speakers cables (I have about $3500 in speaker cables on my main system alone. In my basement system I have on vintage tube preamp that you can pick up on audiogon for $150 and I have about $600 in interconnects on it) but I do believe that there comes a point where there are diminishing returns or sometimes no difference at all.

Much ado about nothing, really. I don't think it would change much either way. I don't hear huge differences in cables and sometimes wonder if I hear the small ones or just think I do, but don't really care because I've got some basic Nordost cables and am perfectly happy with the price/performance regardless.

Must say I agree with this. The only time I have every really heard a big difference was when I first switched from lamp cord to Audioquest type 2 back in the day. The second time was when I removed some silver interconnects between my turntable and replaced them with copper ones then back again. The silver was far more open sounding. Even the girlfriend heard a difference. I don't know if it was as simple as they were better cables or there was some other stuff going on there, but I did hear it.

Well, at this stage of the game, your speakers haven't been heard by any signficant amount of people that I'm aware of but I thoroughly welcome new players into the game. Competition at all price points is a good thing and I hope your offering lives up to your claims of sound quality with commensurate reliability. Perhaps you can work out some sort of cross promotional thing with other companies where they can feature your speakers with their offerings.

The second time was when I removed some silver interconnects between my turntable and replaced them with copper ones then back again. The silver was far more open sounding. Even the girlfriend heard a difference. I don't know if it was as simple as they were better cables or there was some other stuff going on there, but I did hear it.
Among other things, you changed the capacitance loading on the cartridge. Next time, if you're a DIY type person, experiment with one cable, but different lengths to find what sounds good to you.

Among other things, you changed the capacitance loading on the cartridge. Next time, if you're a DIY type person, experiment with one cable, but different lengths to find what sounds good to you.


I left something out. The cables I changed were between my phone preamp & my preamp.

Hi Guy's

My cable experiments all ended in 2003 when I discovered DIY solid core silver,Teflon tubing and heatshrink.
It is possible to make a full suite of DIY power cords, interconnects and speaker cables for an average of £40 per meter that are so good they will never be the weakst link in the system until you get up to the real big £50K plus level. Even at the very highest level the cost only rises to an average of £100 per meter.
You can extract a few more % out of them by going crazy with some exotic dielectric materials.
The most important things are ;
(1) use ultra pure silver, not jewelery or Sterling silver.
(2) use 0.5mm single strand for interconects.
(3) use multiple runs of same to increase gauge to appropriate level for bass, mid and top.
(4) use high quality heat shrink to cover over the Teflon dielectric, the full length must be covered.
(5) use good outer braiding to cover full length of power cords over and above the teflon and heatshrink.
(6) Never mess with mains power cables unless you really know exactly what you are doing!
(7) All multi starnded cables have electrical characteristics that make them unsuitable for real high end AV use.
(8) All cable effects are subtle in isolation but are progressivly more apparant the more you replace in the system. IE If you open up all the elecronics and speakers and replace all the internal cable with solid core silver and replace all the external cable suite with matching solid core silver the total difference is worth 10 times the cost of materials and time. But in isolation you may not hear any real benefit if you replace only one part of the chain.
(9) Minimum mass conectors are very good. Heavy "medallion man" connectors are bad.
(10) All solder is very, very very bad! Use cold weld or crimp where possible, when forced to use solder make metal to metal contact with appropriate preasure and the cover or seal with high quality silver solder.
Try using a few meters of solder (carefull not to short out anything!)as speaker cable and interconnects and listen to hells fire burning your music!!

All of this cable stuff is important in well balanced high end systems but will be lost in many exotic "big rigs" that are not fully "tuned in"

Resonance control and clean mains are equally important but often neglected. Over priced "isolation" stands are very common, they dont work but they do sell! Mains conditioners... another time!

All the best

Derek.

Resonance control and clean mains are equally important but often neglected. Over priced "isolation" stands are very common, they dont work but they do sell! Mains conditioners... another time!
.

You need to meet ValhallaPC one day..;)

Hi Curt,

I do like the power Nordost power cords, individualy isolated solid core silver(like the DIY £50 per meter) is always going to perform really beautifully. As all muilti stranded cables are flawed, most of the competion are more "tunning devices" than neutral signal transmission devices as all cables should be.
My only experience with Nordost power cords in a controled test (not just swapping cables in an unfamiliar room / system or show scenario) resulted in 3 out of 4 listeners unable to form a preference between the DIY cables and the Nordost. The one listener who did pick out her favourite said it was very close but the cable 3 (the Nordost) was her choice.
All our listening tests are done blind with no shared verbal or (body language!) clues shared until the end of the testing session when the written notes are collated.
The only real difference is the Nordost spiral winding, geometry does make a difference so it could be the thing that seperates them from the crowd.
I have yet to find a sytem where spending $20K on the Nordost (or any other brand) cables gives a $18K upgrade over and above the 95% as good $2K DIY silver cables. I have heard a few systems where $20K of Nordost gives a great value for money upgrade over any brand (at any price) of multi stranded "hose pipe" monsters. But the DIY silver cables easily out perform any mega buck multi stranded hose pipes as well, then the customer can save a fortune and be able to afford more CD's! Or buy better amps, speakers a rack or whatever.

So thats my take on Nordost so far.

Hope it is of interest.

Cheers

Derek.

Well Derek, I'm known as one of the objectivists here, so statements like 'all multistranded cables are flawed' go against what I learned in college, but also really don't faze me, as I believe that a $.25/ft generic 14 gauge cable sounds as good as the highest esoteric one, as long as things like the resistance of the cable is observed when running long lengths.

;)

I've come to expect that as the prices of certain devices move upwards, and I don't know where that cutoff is, there becomes a need to attract a greater audience who might be predisposed to buy the product. Part of that audience is the one who suscribes to various products that are more grounded in pseudo-science and embraces personal experiences without qualification. Hence, what Derek says kind of goes with the territory for me. I don't like it, but I understand it from a marketing perspective.

Hi Chu & Curt,

There is great book on this subject which you can buy for about $20.
The link is www.vacumestateelectronics.com .

It clearly explains the science behind signal transmission and I really learned a lot from reading it and saved my self of lot of money too!

All the best

Derek.

Above link should be www.vacuumstate.com

[QUOTE=Overkillaudio;11937423]
(10) All solder is very, very very bad! Use cold weld or crimp where possible, when forced to use solder make metal to metal contact with appropriate preasure and the cover or seal with high quality silver solder.
Try using a few meters of solder (carefull not to short out anything!)as speaker cable and interconnects and listen to hells fire burning your music!!

All of this cable stuff is important in well balanced high end systems but will be lost in many exotic "big rigs" that are not fully "tuned in"

QUOTE]

First please elaborate on why you "think" solder is so bad. Also what fool in the first place would use solder for a length of cable? This is typical of snake oil salesmen to get people to do a apples to orange rather than apples to apples.

Second also typical of snake oil is the cable or XYZ jobber is only important in perfect high end systems. If these things truely make a change that can be heard it shouldnt matter if its in Chus Bose system you will hear it and I can measure it.

[QUOTE=Overkillaudio;11937849]
The only real difference is the Nordost spiral winding, geometry does make a difference QUOTE]


Really stop spewing crap and maybe people will not rail on you. Please show us with real science how this spiral winding geometry makes any difference.

It is a simple question it would seem for you to answer.

Speco, it would, as you know, [marginally] lower the resistance to electron flow on the surface of the conductor. The only question really is if you can hear it or not.

Did you wake up on the wrong side of the bed? I mean, hey, if you can't talk about that kind of stuff, then we might as well shut the forum down.

I don't have a problem with Derek saying what he believes, about whatever, I just took issue with the over the top self-marketing hyperbole thing. So, if he wants to be on the forum and discuss audio from his perspective, why not? There's essentially nothing you can say in audio that some other person isn't going to think is "crap". So, you learn to tolerate a little of crap on forums. I think your threshold got set way low this morning or something.

A drop of solder used to mate a cable to a connector impacts nothing in the sound.

Wrong side of the bed? Nope I have ZERO tolerance for the BS. And when someone just spews it with ZERO science to back him up. Then they need to be called on it. I really do want to hear his answers. I dont wish to debate you on how old and grumpy I am. I know I am grumpy and dont really care. I do audio for a living not a hobby and that may be why I have no room for this BS.

And yes there are lots of things in audio you can say that are proven facts not crap. What this person is writing is crap and can be shown to be crap. Audio is not magic it is very real and can be measured.

A drop of solder used to mate a cable to a connector impacts nothing in the sound.

Wrong side of the bed? Nope I have ZERO tolerance for the BS. And when someone just spews it with ZERO science to back him up. Then they need to be called on it. I really do want to hear his answers. I dont wish to debate you on how old and grumpy I am. I know I am grumpy and dont really care. I do audio for a living not a hobby and that may be why I have no room for this BS.

And yes there are lots of things in audio you can say that are proven facts not crap. What this person is writing is crap and can be shown to be crap. Audio is not magic it is very real and can be measured.


WOW! you sure are old and grumpy.

I know of some hi end cable companies that use crimping instead of solder because they feel solder does have a negative affect on the sound.

they feel solder does have a negative affect on the sound.


Great I feel like alot of things. Yet its feel, NOT REAL. Thanks for that insight.

Great I feel like alot of things. Yet its feel, NOT REAL. Thanks for that insight.

Hey anytime! :D

Welding is the way to go.

I glue my connections together ;)

I've done that also using epoxy silver paste. Works great!

FAO Speco - Please keep on topic this is a loudspeaker thread, I only replied to a couple of the guys on cables as they had been generous with their time earlier in the main text. Please read my opening thread and feel free to make any valid points.
I would ask you not to be so "grumpy" in fact is it asking too much from you to be polite from now on?
I suffered 3 days of all mental's abuse before I was advised of the "post blocking" facility and now my screens are free from that stuff, so I dont intend to read any more abuse from anyone.
If you do not know what solder is made from after all your years of soldering up your cones and domes this may shock you... Lead and tin! Plus a wide range (depending on type of solder) of other low melting point metals and impurities such as flux.
Now if you didn't know what solder is consists of I will assume that you might not be aware of the conductivity of these various compounds. Rather than waste everyone elses time listing them, I suggest you Google the subject.
Re cable geometry, I think it's important, every cable manufacurer thinks it's important, every university electronics student can pull out a dozen text books to prove it makes a difference so I will leave it there, again for benefit of others.

Happy surfing.

Derek Wilson.

I suffered 3 days of all mental's abuse before I was advised of the "post blocking" facility and now my screens are free from that stuff, so I dont intend to read any more abuse from anyone.

Goodness, I guess you really are a douche bag, while we're calling names.

I think we were pretty good to suffer through the obnoxious marketing, so maybe you should stop also with the name calling if you want to be taken seriously. I'm sorry I actually tried to be tolerant of you lately.

Goodness, I guess you really are a douche bag, while we're calling names.

I think we were pretty good to suffer through the obnoxious marketing, so maybe you should stop also with the name calling if you want to be taken seriously. I'm sorry I actually tried to be tolerant of you lately.


I don't think he can read you...;)

I've done that also using epoxy silver paste. Works great!


I'm gonna half to look that up.

Well, you might not get the stuff I used to which was used in certain types of circuit attachments. At that time it wasn't something that was sold to the general public.
I worked for a company at one time where they were looking at competitors (don't recall which) and they were doing some product deconstruction. They had various types of silver powders, differing in say particle size and shapes, which were used in the labs to make prototypes. The silver content was quite high with one of the R&D goals being to figure out how one reduces the silver content while still maintaining or improving electrical properties under various environmental, vibration, etc. conditions. For a home audio application, if you also incorporate strain reliefs in your connections, I suspect this would not matter so much.

As long as we are adding .02$ worth, i do have to agree a bit, Overkill, you showed up obviously marketing something that is unknown and unproven. ( a review, a white paper, an AES presentation...) And when you are questioned on it by others you come back with a response that is only repeating marketing dogma. And doing so in a really sarcastic way.

Lets see something original, unbiased, impartial? Anything???

FAO Speco - Please keep on topic this is a loudspeaker thread, I only replied to a couple of the guys on cables as they had been generous with their time earlier in the main text. Please read my opening thread and feel free to make any valid points.
I would ask you not to be so "grumpy" in fact is it asking too much from you to be polite from now on?
I suffered 3 days of all mental's abuse before I was advised of the "post blocking" facility and now my screens are free from that stuff, so I dont intend to read any more abuse from anyone.
If you do not know what solder is made from after all your years of soldering up your cones and domes this may shock you... Lead and tin! Plus a wide range (depending on type of solder) of other low melting point metals and impurities such as flux.
Now if you didn't know what solder is consists of I will assume that you might not be aware of the conductivity of these various compounds. Rather than waste everyone elses time listing them, I suggest you Google the subject.
Re cable geometry, I think it's important, every cable manufacurer thinks it's important, every university electronics student can pull out a dozen text books to prove it makes a difference so I will leave it there, again for benefit of others.

Happy surfing.

Derek Wilson.

You are awesome at cut and paste. Now please answer my questions. What studies do you have to back up the fact you stated that solder has any impact on the sound. If this were indeed the case all the connectors we use everywhere would be crimp only. They are not. How about all that solder in the circuit board on the gear you plug your speakers into?

Also please answer the question about the Power cable geometry you so stated as fact as well. I have never seen or read one electronic text that stated anything about special windings of a power cable for the last 3 feet of line. Every cable manufacture does not think it is important only the ones wishing to dupe the public.I am glad you think its important but you cant seem to tell us why. Block me if you wish and hide in the sand.

If you do not know what solder is made from after all your years of soldering up your cones and domes this may shock you... Lead and tin! Plus a wide range (depending on type of solder) of other low melting point metals and impurities such as flux.
Derek Wilson.

I therefore announce a new breed of audio amps and preamps from my new company, www.allcrimpaudio.com. No solder required.

Derek, I think we're all open to new products and technologies, but between the subjectivists and objectivists, you're going to be under pretty intense scrutiny if you come in here touting all sorts of claims and performance pinnacles without some hard data.

Hi Curt,

Damn, you have registered the domain I was after!!
The whole solder thing is very controversial but many high end manufactures are promoting the sonic benefits of using "point to point wiring" where you eliminate the PCB/ solder mask altogether.
In addition they use the "cold weld" joint technique where the point to point wires meet ie they use (usualy solid core silver) metal to metal join, crmp, and then seal the joint with a small blob of silver solder.
It is very time consuming and expensive to use this technique but it does have major sonic benefits and, as Forest would say....
" Thats all I have to say 'bout solder!!! "

I relish the scrutiny and all qestions are welcome all I ask is that people are polite when doing so, that is what debate ( subjectivists) and peer review(objectivists) are all about. Until I can establish a few early adopter dealers or customers in the USA all I can do is debate with the subjectivists, all you objectivists please be patient!

"Time Will Tell"

Thanks.

Derek.

Hello Dizzman,

We do have a good selection of reviews on our website and if you have a couple of hours to spare there is a lot of independant opinion there for you to read. The latest review ( on two of our systems) from 2007 is just about to go live, two weeks I think, so that will give you all some more up to date independant opinion on the "Predator & Prey" and our other two way system "The Angels".
Also there is already a lot of technical information on the products and the R&D that went into their design on the website, but I have been asked by several interested parties to separate out the sales and marketing text and produce the classic "white papers" which concentrates on the theory testing and results. So I will start work on that in 8 weeks time when everything starts to close down for a few weeks at Christmas & New Year.

I hope this is of interest.

All the best

Derek.

The whole solder thing is very controversial but many high end manufactures are promoting the sonic benefits of using "point to point wiring" where you eliminate the PCB/ solder mask altogether.
Many high end manufacturers don't have sufficient volume to do it the other way so they ask you to direct your attention elsewhere.
In addition they use the "cold weld" joint technique where the point to point wires meet ie they use (usualy solid core silver) metal to metal join, crmp, and then seal the joint with a small blob of silver solder.
A regular crimp is not a cold weld which takes a very rapid application of a large amounts of force. The combination results in sufficiently elevated temperatures to effect the surface welding.

Hello Chu Gai,

You are quite correct re the definition of a cold weld as opposed to a sealed crimp and we use sealed crimp not cold weld. I have never compared the results so I cant say which would be the best sonically.
Re the PCB volume point, I disagree with you on this one.
I can tell you from direct experience dealing with electronics in volumes as low as batches of 10 units, PCB's are very, very low cost indeed.
We have two different OEM companies near Cambridge (the UK silicone valley) who can do PCB layout AND low volume production at low cost.
It would be far cheaper for us to make extensive use of PCB's but we opt to only use them where there is no practical alternative. Where we do use them we pay great attention to detail such as ground plane effect, non resonant boards, dielectric effect of masking and sealing compounds and pure silver traces.
It is far more expensive to pay the high labour costs involved in point to point wiring and crimping (!) than it is to pay for a PCB layout and set of 10 boards.
The savings go way beyond the initial cost comparison due to the space savingsie PCBS are small and light so the casework can be half the size and thats a major saving. The weight is then halved so packaging handling and shipping costs are reduced dramatically. Lastly the retail price is reduced with PCB's so the sales volume can rise which further reduces all costs with the benefit of economy of scale!
So I can promise you that we only choose our "solder free" point to point soilid silver wiring because it has major sonic benefits that only become audible through a high resolution speaker system. For the mass market it would be a non starter.

All the best

Derek.

Hello speco,

Thanks for your re-phrasing of your questions and I will always do my best to respond to any questions asked in this way.
Before I briefly finish with the cables issue please remember I am a loudspeaker and electronics guy first, second and third.
I view cables as a necessary evil and I advise all my customers to save themselves a lot of time and money by using DIY skills (or paying a fair labour charge to a third party) to build superb value for money solid core silver cables.
Re your question regarding solder damaging the sound in high end systems I can only repeat all my previous answers (minus my sarcasm which I only use as a deterent / defense mechanism) and also my reply to Chu Gai above.
Maybe we will just have to be content with our opposing views on this one!

Hello speco,

Thanks for your re-phrasing of your questions and I will always do my best to respond to any questions asked in this way.
Before I briefly finish with the cables issue please remember I am a loudspeaker and electronics guy first, second and third.
I view cables as a necessary evil and I advise all my customers to save themselves a lot of time and money by using DIY skills (or paying a fair labour charge to a third party) to build superb value for money solid core silver cables.
Re your question regarding solder damaging the sound in high end systems I can only repeat all my previous answers (minus my sarcasm which I only use as a deterent / defense mechanism) and also my reply to Chu Gai above.
Maybe we will just have to be content with our opposing views on this one!

Well thanks for nothing. Done with you. You just proved my point.

Great I feel like alot of things. Yet its feel, NOT REAL. Thanks for that insight.

I see you are a bit of a problem, whether someone has a real item that is new..or not.

I'm of the opinion that you might like some of the cable so you can dis them. Read my last comment in the Jame Randi thread, about reviewers with agendas, preconceived notions and glasses coloured exactly the way the given person wants them to be colored. Please don't take it personally. But there isn't much here that tells me in any way, shape or form, that you might even remotely have a fair and balanced opinion on any given audio cable.

Why ask specifically about mine? Do you have an agenda? hmmm? I have nothing to hide, whatsoever. But I don't need a person with such preconceived notions buying a cable just to find a way trash someone. Such a position is neither real, or decent.

As stated, that may not be the case, but after looking at your last 15 posts on this forum as a reference..I think that might be the case. If I am wrong, I would apologize wholeheartedly. But somehow, I don't think that is the case.

The thread you started about asking for a cable from me appears to be seriously disingenuous.

Derek, the vast majority of these so-called objective buffoons have no capacity for balance and basic human credibility within the idea of learning how dismiss themselves from the process of review and analysis, in the course of single cause analysis, or any other method of analysis.

Their attitudes and behaviour show this abundantly. Opinions are like a-holes and they show, sometimes -that they each have many.

After over 7000 post on this forum that make your battle here look like a fart in a windstorm in comparison, I urge you to give up and leave gracefully. The screamy ones ruin it for the folks who have some balance on their side.

The screamy ones fail to understand that the logic we employ is fundamentally correct, fundamentally correctly employed in the ways they desire, but it takes a HUGE amount of our lives and it takes a LIFETIME to master..and that it CANNOT be related in some few posts on a forum.

Yet that is what the screamers demand. Even if you explain bits and tell them that the minutae are the way we make a living, and like any endeavor, we must protect that hard won knowledge..they will still scream at you. Regardless.

Save yourself lots of grief, and Do what I'm about to do, here, again. I'm going disappear for at least a year, again, maybe forever. I've thrown away 7-8 patentable ideas on this forum, likely more, attempting to still their insane rambling. Many ideas ended up being standards in the industry, some were the genesis of actual companies. Still they ask for more blood. I gave them away freely, never even acknowledging that I even gave such away, or pointing such out. I just kept a personal score.

This forum is unfriendly to the innovators who brought the very reason of the forum's existence... to the table in the first place.

Sad, but true. The idiots run rampant. And are allowed to do so.

Such a shame.

Derek, the vast majority of these so-called objective buffoons have no capacity for balance and basic human credibility within the idea of learning how dismiss themselves from the process of review and analysis, in the course of single cause analysis, or any other method of analysis.

Their attitudes and behaviour show this abundantly. Opinions are like a-holes and they show, sometimes -that they each have many.

After over 7000 post on this forum that make your battle here look like a fart in a windstorm in comparison, I urge you to give up and leave gracefully. The screamy ones ruin it for the folks who have some balance on their side.

The screamy ones fail to understand that the logic we employ is fundamentally correct, fundamentally correctly employed in the ways they desire, but it takes a HUGE amount of our lives and it takes a LIFETIME to master..and that it CANNOT be related in some few posts on a forum.

Yet that is what the screamers demand. Even if you explain bits and tell them that the minutae are the way we make a living, and like any endeavor, we must protect that hard won knowledge..they will still scream at you. Regardless.

Save yourself lots of grief, and Do what I'm about to do, here, again. I'm going disappear for at least a year, again, maybe forever. I've thrown away 7-8 patentable ideas on this forum, likely more, attempting to still their insane rambling. Many ideas ended up being standards in the industry, some were the genesis of actual companies. Still they ask for more blood. I gave them away freely, never even acknowledging that I even gave such away, or pointing such out. I just kept a personal score.

This forum is unfriendly to the innovators who brought the very reason of the forum's existence... to the table in the first place.

Sad, but true. The idiots run rampant. And are allowed to do so.

Such a shame.


Delusions of grandeur; belief in the extraordinarily rare possession of a quasi-supernatural skill-set that transcends the cognitive limitations of mere objective mortals, and defies the capacity of any language to articulate, a persecution complex bordering on paranoia, and to top it all off, allusion to messianic self-sacrifice. QQQ was correct in his one word response to an earlier, equally incoherent post, ( that is, if you actually believe any of it ): "Medication.".................... In all seriousness.

I would be curious to hear about the ideas that you've floated that've become standards in the industry, KBK.

I would be curious to hear about the ideas that you've floated that've become standards in the industry, KBK.

Chu, you might have to wait at least a year for an answer.

Oh, you mean like when Ambassador Adlai Stevenson said, "I'm prepared to wait for my answer until hell freezes over if that's your decision." I hope not. The statement generally interests me.

Oh, you mean like when Ambassador Adlai Stevenson said, "I'm prepared to wait for my answer until hell freezes over if that's your decision." I hope not. The statement generally interests me.

Perhaps, but I would have thought it more like when JFK said "We never had a case where it's been quite this--well, it's a goddamn mystery."

AS I would really like some info on these cables. I really would like to hear the breakthrough. KBK seems of no interest to give any info to me on how to get some. We have the second largest Pro Tools rig and recording setup in Las Vegas at our showroom and we would be a great testing ground.

Oh come on now, speco, you no more believe there is a breakthrough here than I do.

Mabie I have no clue, but aren't nearly all microphones 'pistonic'? And, since the microphone has converted the 'true' sound into a 'pistonic' representation, wouldn't a 'pistonic' speaker be able to accurately reverse that process? Just a noobs question.

Chris.

Not in the face of marketing!

Hello Chris,

Sorry about the delay, I have been very busy over the last month or so and forum chat has dropped off the priority list recently!
To answer your question :

"Mabie I have no clue, but aren't nearly all microphones 'pistonic'? And, since the microphone has converted the 'true' sound into a 'pistonic' representation, wouldn't a 'pistonic' speaker be able to accurately reverse that process? Just a noobs question."

No, two wrongs dont make one right.
The problems of pistonic recording mics are very well documented and much discussed. The distortions common to all condenser (the robust live stage type mic) are so severe that no high quality recording studio would use them. The very delicate ribbon type mics (the bulky type usually with a protective cage round them) are better but still have problems.
There is lots to Google on this but here is a starter site on this important subject:
http://arts.ucsc.edu/EMS/Music/tech_background/TE-20/teces_20.html

"Linearity, or Distortion.
This is the feature that runs up the price of microphones. The distortion characteristics of a mic are determined mostly by the care with which the diaphragm is made and mounted. High volume production methods can turn out an adequate microphone, but the distortion performance will be a matter of luck. Many manufacturers have several model numbers for what is essentially the same device. They build a batch, and then test the mics and charge a premium price for the good ones. The really big names throw away mic capsules that don't meet their standards. (If you buy one Neumann mic, you are paying for five!)"

"No mic is perfectly linear; the best you can do is find one with distortion that complements the sound you are trying to record. This is one of the factors of the microphone mystique discussed later"

I hope the above is of interest to you.

All the best

Derek.

All I care to say at this time is, in relation to the original post in this thread, someone has clearly taken the advice to heart.

What advice?

The classic:

"If you can't dazzle them with brilliance, baffle them with bu****it."

That is a truly remarable collection of irrelevancies and marginally related comments strung together to say...well...almost nothing except that ONE guy is right and EVERYBODY ELSE in this multi-BILLION dollar industry is WRONG.


I'm strongly reminded of the argument put forth by some "pseudo-scientists" that the
response curve of a loudspeaker or microphone should match the response curve of the
human ear. Clearly those people failed elementary vector sum math and have no clue
what you get when you stack filter networks. FAIL. Lots and lots of FAIL.

The ear uses bending wave motion?

Cite, please.

It's the fastest way to detect sound?

Cite, please.

And if it's so flipping fast, how come our hearing response is, at best, no greater than 20 KHz? If the response time is in fact 13 microseconds, then our upper hearing limit
would be...according to Nyquist....able to detect signals up to 77 KHz.


Very few things annoy me more than a "pseudo-scientist" who asserts that everybody else is wrong and he alone has the right answer...for a phenomenal price, of course.

That turkey won't fly, not even with a stiff headwind.


CJ

Bingo!

Hello cmjohnson & Dizzman,

http://www.manger-msw.com/en/produkte/index.html

Dear cmjohnson & Dizzman,

Thank you for your comments and I am glad to hear that you both are still open minded and accept that in some areas of science new techniques, applications and materials can be used to improve the current state of the art.

I assume from your previous posts your understanding of the highly complex mathematical models of the only true bending wave driver (ie non tensioned diaphragm as opposed to the failed model of "tensioned petal" see MBL or multi mode NXT panel) is complete. If you have indeed read the various white papers on the Manger web site the only other thing you will need to have is a PHD or preferably a Doctorate in advanced mathematics.
The maths has been proven for over 30 years (since 1978) but the advanced polymer materials have only recently been perfected.

Before I deal with the maths of the Bending Wave Driver I must correct a couple of your more basic statements / misunderstandings.
I,ve no idea why you mention filter networks at this point, the maths behind filter networks is totaly separate ( and much simpler!) from the maths behind the BW driver. Filter networks (stacked or single) are not used by the human ear!
We are discussing the maths behind the BW driver which is very similar to the mathematical model of how the human ear drum "ripples" sound.

Secondly the theory put forward by Nyquist has no relevance to the points under discussion here. The limiting factors involved in the 20KHz limit of the human ear are a matter of well documented biology some of which is repeated on my website. If the human ear drum operated in a pistonic (yo yo ocilation as opposed to precise car piston type accuracy) the human ear could not decode any sounds above 1,000 Hz!

I have copied below the correct and proven mathematical proof which is the answer to your question. Please respond with your model and its assumptions so that I can learn more about this fascinating subject and maybe Dizzman and I can play a game or two of "Bingo" while you do the calculations! Please note the following document is formated as a PDF and it does not display correctly below so please take the time to download the PDF from the Manger site.


" Radiation from a very pliable large plate with circular excitation
1. The problem
We consider a very large plate which is excited along a ring. The excitation
force is uniform along the ring, so that the problem can be regarded as
radially symmetric.
The aim is to determine the sound radiation of such a configuration, with the
time history of the sound pressure being of particular interest.
2. Mathematical model
In order to keep the mathematical effort low, the following assumptions are
made in the calculations:
(a) The plate is large enough and strongly enough damped that the bending
waves excited by the ring do not get reflected by any edge that may be
present. (Because of the high damping of the material, this condition should
be satisfied at least above a few hundred Hertz.)
(b) The motion of the plate can be described by the bending wave equation;
i.e. membrane tensions (which would lead to nonlinearities) must be absent.
(In the present configuration, this condition is probably satisfied.)
(c) The bending wavelength of the plate should be at least 25 kHz below the
sound wavelength in air. (Since the material is very pliable, one can assume
that the bending wavelength is below the sound wavelength by as much as
about 50 kHz.)
(d) In the frequency range of interest, i.e. above about 300 Hz, the radiation
loading by the surrounding air can be neglected. (Since the weight of the
oscillating foil is high compared with that of loudspeaker membranes, this
condition, too, should be satisfied.)
3. Calculation of the sound pressure
3.1. Basic equations
The problem is solved if solutions can be found to the sound wave equation
and the bending wave equation with ring-shaped excitation, under the
assumptions given above. It is known from literature [e.g. Heckl, Acustica 9
(1959), p. 371] that the sound pressure radiated by a very large plane plate is
given for the radially symmetric case by the formula
p r z t ej t p k J k r e k dk d
r r
j k k z
r r
( , , ) = ( , ) ( ) − −r .
∞
−∞
∞
∫ ∫ 1
2 0
0
0
2 2
π
ω �� ω ω (1)
2
r
2 z
F
The following notation has been used:
p(r,z,t)= sound pressure at position r,z at time t
r = perpendicular distance from the symmetry axis which passes
through the centre of the ring
z = distance from the plate
t = time
ω = integration variable (angular frequency)
J0 (..) = Bessel function of order zero
j = − 1
kr = integration variable (wave number)
k0 =
ω
c0
c0 = propagation speed of sound waves in air
�� p
(..) = wave number spectrum of the pressure
If the plate oscillates with the radially symmetric velocity distribution v(r,t) ,
then
�� �� p k v k
k k r r
o
r
( ,ω) ( ,ω) ,
ρ ω
=
− 0
2 2
(2)
with
��v k v r t J k r e rdrdt r r
( ,ω)= ( , ) ( ) −jωt .
∞
−∞
∞
∫ ∫ 0
0
(3)
ρ0 is the density of the air. If the plate is excited by a radial pressure
distribution of the form p r t A( , ), then
��
��
p k
j p k
B k k k k r
A r
r B r
( , )
( , )
( )
ω ,
ω ω
π
ωρ
=
2 4− 4 −
0
0
2 2
(4)
with
�� p
k p r t J k r e rdrdt A r A r
( ,ω)= ( , ) ( ) −jωt .
∞
−∞
∞
∫ ∫ 0
0
(5)
The following notation has been used:
B = bending stiffness of the plate
m' ' = mass per unit area of the plate
kB = 4 ω 2m' '/B = wave number of free bending waves
In the present case of a ring-shaped excitation, pA is given by
p r t
F t
a
r a A( , )
( )
= 0 ( − ),
2π
δ (6)
hence
�� ��
p k
J k a
F t e dt
J k a
F A r
( , ) r j t r
( )
( )
( )
ω ( ).
π π
= − ω = ω
−∞
∞
∫ 0
0
0
0 2 2
(7)
If equation (7) is inserted into (4) and the resulting equation inserted into (1),
one obtains
p r z t
j
B
J k a F
k k k k
r J k r e e k dk d
r B r
r
j k k z j t
r r
( , , ) r
( ) ( )
( )
= ( ) .
− −
∞
−∞
∞
− − ∫ ∫ ρ
π
ω ω
0 ω ω
2
2
0 0
4 4
0
2 2 0
0 4
0
2 2
��
(8)
Because of the assumption (b), we always have k k r B << in the far field, i.e.
for k k0 r > ; therefore
p r z t
j
m
F
k k
J k a J k r e e k dk d
r
r r
j k k z j t
r r
( , , ) r
' '
( )
= ( ) ( ) .
−
− −
∞
−∞
∞
∫ ∫ ρ
π
ω
0 ω ω
2
0
0
2 2 0 0
0 4
0
2 2
��
(9)
3.2. Evaluation of equation (9)
The integral over kr can be obtained from a comparison with the calculation
of the radiation from a small piston membrane, and one can show that
J k a J k r
k k
e kdk
j
r z
r r e
r
j k k z
r r
0 0 r jk r z
0
2 2 2 2
0
0
2 2
0
2 2
2
( ) ( )
.
−
≈
−
+
− − − +
∞
∫ (10)
Strictly speaking, this formula applies only if a is less than half a sound
wavelength; along the symmetry axis, equation (10) also holds for larger
values of a . Substitution of (10) into (9) gives
p r z t
m r z
F e e d
m r z
F t
r z
c
j t
j
c
r z
( , , )
' '
( )
' '
= ( )
+
=
+
−
− + +
−∞
∞
∫ ρ
π
ω ω
ρ
π
ω
ω
0
2 2 2 0
0
2 2 0
2 2
8 4 0
0
�� 2 2
(11)
This surprisingly simple result says that the time history of the sound pressure
near the symmetry axis corresponds exactly to the time history of the force
acting on the plate and hence to the time history of the current in the moving
coil. The time-lag due to sound wave propagation in the air is expressed by
the argument t
r z
c
−
2+ 2
0
.
4. Conclusion
It can be shown theoretically, with the above simplifying assumptions, that the
sound pressure radiated by a large, very pliable, damped plate along the
symmetry axis, has a time history that corresponds to that of the excitation
force in the moving coil (which has to be very light) and hence to the time
history of the coil current. Therefore, time histories of currents with sudden
changes (square wave) are reproduced correctly in the radiated sound
pressure.
The time history of the sound pressure at positions off the symmetry axis can
be obtained from the above equations only after lengthy numerical
evaluations. Presumably, the gradual decay of the function J0 kra ( ) for
increasing arguments causes a "rounding-off of the corners in the time
history" for small distances from the symmetry axis, and a completely
different time history for points further away. "

I hope the above helps you focus on the science and maths of the BW driver
and I look forward to reading your mathematical model of the BW driver and indeed your model of pistonic motion in loudspeaker drivers ( not the maths behind any filters they require!) and how they avoid the mass on the end of a spring overshoot at all frequencies and SPL,s.

All the best

Derek Wilson.

w00t!

Der r a wh0le l0tter b00bz in dat der p0st...

(,)(,)


(...I must be missing a plug-in for a font or something...)

You have the last name Wilson, why not put it to good use and ride the free publicity?

How about calling your company, "The Wilson Audio Group." Then you can refer to yourself as "Wilson Audio" for short! :D

Hi

Sorry about the layout of the mathematical model but I only have it in PDF and it does not copy onto this posting format.
If you follow my link and go to the Prof Manfred Heckl letter in the theory section you will be able to read the full model perfectly.
I love your comment about missing a font! It really looks like that on the posting but as I say please read the PDF.

I think that if I am eventualy proved correct then it will be Dave who will be wanting to use his surname to share in my success.....!!!
Time Will Tell...!

All the best

Derek.

Wow

Sorry about the layout of the mathematical model but I only have it in PDF and it does not copy onto this posting format.
If you follow my link and go to the Prof Manfred Heckl letter in the theory section you will be able to read the full model perfectly.
I love your comment about missing a font! It really looks like that on the posting but as I say please read the PDF.

Yeah, it looks like the spam script kiddies would post on AOL Chat in the old days... With a few (.)(.)'s thrown in! :p

I'm always willing to hear something new in my listening room, but I can never find anyone willing to oblige me...

You'd think with spending winding down and the possibility of a recession looming, that high end dealers would consider it worthwhile to accommodate home demos to prove that what they sell is worth buying...

If you ever find yourself in my area, I'd love to hear them.

Hi CueueCumber,

I have quite a list of interested people in the USA so I hope to be able to find an early adopter dealer or customer who will take the plunge (with the help of an incentive package!) and then .... let the games begin!

I look forward to meeting you one day and playing some music, watch some movies, have some fun and make some money doing it!!

All the best

Derek.

Thanks for the post... i now see where my math was wrong. i aplogize, i will be retracting any previous statements.

Morbius, do you agree?

Hello Dizzman,


Thank you for taking the time to read through the PDF of the maths model, (the "font scrambled" version on my post looks bad!) and with hindsight maybe I should have opened my post with the maths and more technical stuff, but I didnt want to bore forum members by quoting to many equations.

I hope to get some time over Christmas to write a few white papers and incorporate some of the laser interferometry images and graphs onto my website. I will be able to post some on the forum as I would really value the views of the qualified forum members.

I know my full on marketing tends to get a lot of AV guys hackles up, and therefore I am my own worst enemy but I am by nature an "all or nothing" kind of guy and I feel so passionate about bringing music and movies to life that I just have to walk the walk and talk the talk!
In the real world ( not the AV Matrix we are in here!) the majority of UK customers (mostly guys) who can afford the kind of equipment I design look at my website and say :
"well at least I'll go along for a listen and then buy my JBL, Wilson, Krell or whatever".
Often their architect or interior designer makes a "top recomendation" which is of course not influenced by the size of their commission!
As soon as the guys sit down and listen everything changes.... then it only becomes a matter of integration and overall budget.
I really am longing for the oportunity to get a USA showcase system up and running, until then I do offer a $2,000 USA travel package refund against a system purchase to any USA customers who want to spend a few days in beautiful Cambridge England enjoying AV heaven!
I do hope we can meet one day and you can tell me what you really think of the Overkill Audio sound systems!

"Time Will Tell"

All the best

Derek.

Very Simply, this forum does not allow manufacturer marketing and selling. you are blatantly flying in the face of that and i am sure the thread has not been closed due to the fact that nobody has reported it since it is fun listening to you tell folks how every speaker in the world is wrong and your are right.

And all of this with not being able to actually demo the speakers in the US.

I ran into the same thing a few years ago with a friend who was marketing and selling a dodecahedron speaker. And while it was neat, the simple reality is that it like many other designs is great for some apps and not for others. And is not nearly as great as they thought it was and that their white papers suggested.

Instead of you writing more papers, might i suggest you submit it for peer review and get something that actually matters like an AES paper written and submitted. There are lots of folks who are willing to take them in, test and review and submit a paper for you.

In the meantime, i am sorry to say this but for me, this gets filed with exotic cables. looks neat, lots of words on paper, no peer review and no proof of superiority.

Hello Dizman,

I am very keen to start the ball rolling in the USA but the logistics of sending a fully active tri-amp'd system accross the Atlantic for a review only to pack it all up and ship it back are unsustainable financially as well as environmentally.
An overkill system is not just a pair of speakers and a few phone calls. We send one of our own technicians out with the system (between 6 & 12 crates!) and it he takes two days to carry out the full range of room measurements, sound checks and dial in the precise crossover and EQ settings.
I have a number of reviews on my website already and there are two more in the pipe line.
It is not easy to get the major internationally known reviewers interested in carrying out a full review of something as radical as an Overkill system as it takes a lot more time and effort to complete the review.
The reviewer actually has to test 5 components, the speakers, the DAC's, the power amps, the pre-amp the cables plus the complete system performance.
So I hope you can understand that the internet now plays a vital role in spreading the word about new technology start up companies and that AV forum members actually benefit the most if and when the technology gets to market.
If you care to read my opening article on this thread and every one of my replies to the genuine questions as well as the offensive "trolls" as you call them you will notice that I have not listed my website URL or even mentioned one of my products by name. I have acted on advice from the moderators and taken great care to stay well within the guide lines they gave me.
I have written detailed technical descriptions of pistonic motion loudspeaker drivers, both passive and active crossovers, THD distortion measurement techniques, the biology and mechanics of human hearing, supplied independant highly advanced mathematical proof of concept and even offered some DIY cable advice!
I think most members (over 2500 viewings so far on this thread) would say I am indeed making a valid and intersting new contribution to the forum as well as stimulating new debate.
All of this in my first thread. I have had a very good response from over 20 AVS forum members who have emailed requesting more information as well as several private emails offering support, so it appears it is the "silent majority" who read postings and then Google my website who are indeed open minded.

Some people are very insecure and feel threatened by new technology so they respond with anger and abuse so I just block them from my screen and carry on with a smile and a beer!
As always, the "empty vessle" makes the most noise, while the world passes them by.

Cheers

Derek.

As always, the "empty vessle" makes the most noise, while the world passes them by.

The empty vessel also holds the most beer.

Some people are very insecure and feel threatened by new technology so they respond with anger and abuse so I just block them from my screen and carry on with a smile and a beer!


I am not responding with abuse, i am stating a fact. you seem to have no review of substance on your website, most of the people here cannot even hear your system, we are just supposed to take your word that you and you alone have seen the light.

I know very well what it takes to get a system across oceans. I did it when i worked at Kaleidescape and i did it when i worked at Extron Electronics. it is called a Carnet. they are (i seem to recall) about 400$. then shipping.

And when your screen name is overkill audio and the website is http://www.overkillaudio.com/ it is hardly a stretch. Google is not even required.

So before you go getting all indignant and huffy, remember that all we are looking for is substantiative info.

mmmmmmm.... beer!

Hello Dizman,

I have a first class selection of reviews on my website including a very detailed and intensively researched 14 page review by the editor of 6 moons.com which is a hugly successful on line publication. Srajan has established six moons as an international benchmark for on line high end audio reviews and his team now cover 11 different countries and report on all the top international shows.
The latest review (published last month) is by Chris Beeching who is one of the top freelance UK reviewers who has written for a selection of the best UK audio magazines for over 15 years (including 5 years at Hi Fi News) and he is also a skilled musician and audio designer.
Paul Messenger is also an international reviewer who currently writes for both USA (Stereophile) and UK Hi Fi Plus and Hi Fi Critic.
I think the above three are a very solid start.
In addition our fantastic show reports from Robert Harley of The Absolute Sound, Scott Markwell, again Absolute Sound, Clement Perry of the Stereo Times and two best in show awards from Fidelity Magazine Norway and Dr Marj Henk (Dutch reviewer) prove, by independant qualified professionals, we are really on to some thing special.

On the cost of shipping, may I focus your attention on the up to date situation.

I have no idea what type and value of goods you used to ship by "carnet" (whatever that is) but let me update you on some of the costs and procedures involved in shipping and insuring a $109,000 11 crate 580Kg (1,276pounds) Overkill Finale system.
(1) First you have to pay the tooling costs to get all the custom shaped polystyrene foam to line the crates.
(2) Then you have to buy a minimum quantity (£1,000 or $2,000) and provide secure storage for all the extra polystyrene.
(3) Next you have to build the wooden crates to international shipping standards. This now mandates the use of specially heat or chemical treated wood under the 2006 invasive species act. This wood is expensive as is the labour to build the crates.
(4) Now you have to spend two or three days shrink wrapping and itemising every component, packing the crates and then sealing them. Every crate has to have full documentation and be clearly labled.
(5) Now you have to pay Fed Ex, UPS, DHL, or one of the big and reputable (expensive) couriers approx £3,680 ($7,544) to come and collect the shipment with a hydrolic tail lift equiped truck and then fly it all accross the Atlantic and then drive it to the door of the reviewer at the exact time he specifies.
(6) Arrange (pay for) the nesesary man power to be on hand to unpack the system and store the crates.
(7) Pay another £1,000 ($2,000) to fly out an Overkill technician to set up the crossovers and carry out all the sound checks and EQ.
(8)Wait 4 to 8 weeks then pay to have the whole lot packed up and shipped back, another £2,800 (or $5,600) as its actually cheaper comming back into the UK from the USA.
(9) Prey he liked the system!

So Dizman please forgive me if I dont jump to your call for instant gratification via your favourite local reviewer, but as I am sure you now understand, we are not talking about your typical $30,000 or $40,000 cones and domes with a "good old boy muscle amp to drive em".

A small high end niche business needs to operate in a prudent and efficient manor in order to keep the costs within reach of the average millionaire!

Cheers

Derek.

If you were unable to figure out on your own that my use of the reference to filters regarding speakers was intended ONLY as an example of "not getting it", and wasn't intended to be relevant to the subject directly at hand, then you're so disconnected from normal human beings that it may not be possible for us
to have a meaningful conversation.


You have yet to cite your proposition that the eardrum operates in the bending wave mode of operation.

Cite, please. Second request.

You also misunderstood my reference to Nyquist in this context. If the ear can respond to ANY impulse of 13 microseconds duration or less, then I have to
question the definition of the word "response" in this case. Is it PHYSICAL
response of the eardrum to an acoustic signal, or is it PHYSIOLOGICAL response that you're talking about? Physiological response meaning that
sensory cells are actually stimulated enough to generate a neural reaction.

That the input is PERCEIVED by the listener.



Furthermore, even in a dedicated search for any reference to the human eardrum as a bending wave sensory system, I found NO such claims from ANY source other than that of the Manger driver.

The absence of any corroborating evidence simply tells me that you, like so
many others who have hoped to reinvent the wheel in the minds of your
HOPED-FOR CUSTOMERS, have no credibility. The very idea that you
might think that you're right and the rest of the audio industry is wrong,
including such highly intelligent and equally successful loudspeaker designers
as Richard Vandersteen, Michael Kelly, Dan D'Agostino, Dave Wilson, and
many others, makes the very idea nothing short of ludicrous.



CJ

Mr Johnson,

If you Google "human ear biology" you will find 100's of explanations of how the ear / brain functions and try to focus on the ear drum biology.
I will give you a drief description and summary here but to quote your own words
"If you were unable to figure out on your own... insert ...follow a basic biology lesson on line... then you're so disconnected from normal human beings that it may not be possible for us
to have a meaningful conversation."

There are clear explanations of how the sound travels down the ear cannal & hits the centre of the eardrum. This is important.
Second all the sensory detection and transmission systems (nerves hairs and tiny bones) are arranged AROUND THE EDGE of the ear drum NOT above and or below. This is also important. The result is that the sound waves ripple out (imagine dropping a pebble in the centre of a pond and watch the ripples reach the bank) from the centre of the ear drum and they are transmitted by the various nerves, bones, hairs and fluids that are found all around the ear drum. The brain then decodes the sounds as electrical impulses. This is an ultra simplified version but its up to you to Google it in detail as I dont have the time or inclanation to debate accepted science with you.


Regarding your question/statement :
"You also misunderstood my reference to Nyquist in this context. If the ear can respond to ANY impulse of 13 microseconds duration or less, then I have to
question the definition of the word "response" in this case. Is it PHYSICAL
response of the eardrum to an acoustic signal, or is it PHYSIOLOGICAL response that you're talking about? Physiological response meaning that
sensory cells are actually stimulated enough to generate a neural reaction.

That the input is PERCEIVED by the listener. "

I have read this twice and I can't understand what you mean or what you are asking me. Be clear, and specific with your questions and please refrain from yoiur aggressive tone.

Cheers

Derek.

I haven't read all the latest, but has this speaker been brought to the US yet?

I read the reviews, i see lots of rambling hyperbole.

Honestly i pay very little attention to any of the "high end" press. As i said before, something that was an AES peer reviewed paper is of interest to me in this area of audio revolutions.

You don't even have it right about the ear mechanism.

Eardrum, Hammer, stirrup, anvil. Interior anvil pressurizes the fluid in the snail shell-shaped cochlea in response to the sound conducted through the system, and the fluid motion activates the tiny hairs, called cilia, which move, and in doing so, activate sensor nerve cells located in their roots.

Whether or not the eardrum conducts to the hammer bone via pistonic motion or bending wave motion is absolutely IRRELEVANT, as the only difference is in
where the hammer picks up its motional input on the eardrum, and as I stated before, I have found no credible documentation to back up the statement that the ear responds in the bending wave manner.

I understand the bending wave concept, as applied to a speaker, as, in
an idealized form, propagation of the movement of the cone in the manner of an expanding circular wave, which can be visualized as spreading ripples in water in response to an impacting raindrop. I see an immediate problem
with trying to make a speaker that works in this manner. In fact, I see
more than one problem. First, this is HIGHLY prone to the production of
harmonic distortion. I cite most every guitar amplifier's speaker as cases
in point. They DO operate in bending wave mode, and while they ARE
generally quite efficient, as speakers go, they also have HIGHLY colored
tonal response, which is fine for MAKING music, but not good for REPRODUCING it. Second, as the wave motion will complete only
when it's finished propagating through the speaker's cone, transient response
in the cone will be temporally blurred in relation to the motion of the speaker's
voice coil, which will of course be the fastest responding part of the speaker.

Getting an even frequency response will be difficult, too, in a bending wave
speaker design, as the stiffness of the cone is variable in relation to
frequency. At low frequencies, the entire cone will move as a unit,
while at higher frequencies, the flexing of the cone will cause varying
degrees of constructive and destructive interference as there will be
zones that are generating a negative pressure wave while at the same
time other zones are generating a positive pressure wave, or at higher
frequencies still. multiple zones may generate the same type of waves,
causing some serious problems with destructive and constructive interference.


Frankly, it's ridiculous to even want to pursue the idea of an ACCURATE
reproduction via bending wave driver given its many obvious faults,
when it's MUCH easier to design and build a conventional driver that operates
very well in pistonic mode over a reasonably wide frequency range, and as
a result has a more even frequency response due to the lack of the
constructive and destructive interference issues associated with
bending wave operation.



Perhaps I'm completely off base about how your speakers work, so if I am,
please feel free to demonstrate via product photographs, diagrams, and
relatively simple explanations that don't require mathematical skills to understand.

Can I handle the math? Possibly. I'm pretty rusty on the higher functions, though. Should I have to use math to understand a speaker? NO, I do NOT.
Not if the rest of the data is well written, anyway.


If you have to resort to complex math to explain your speakers, you've already lost the debate.


CJ

Hello CJ,

First of all thank you for your detailed reply which you have obviously spent a good deal of time researching, this is what the forum is all about, considered response not "knee jerk" abuse.
I now understand your questions and you do make some valid points. I will do my best to answer them here but I will also need to give you a link to an AES paper by Daniela Manger in order to fully answer your questions.
First of all the biology of the ear, I think we are on the same page now as you have named most of the middle and inner ear organs.
SIDE BAR.
Just before I start my reply in detail here is a fantastic and genuinely amazing piece of science. What is the smallest movement that the human ear drum can possibly move which will result in an audible sound? IE if you are in an anechoic chamber and you drop a pin onto a piece of wood and you can just hear the tiny sound how far has the eardrum moved (or what is the height of the pressure wave as it rides over the ear drum surface)? The answer is the width of a Hydrogen molecule! How incredible is that. We are all blessed with the most astonishingly advanced detection equipment that make any software and microphone package look primitive.
MAIN TOPIC.

Where we differ is the importance of the rippling (bending wave) motion that the ear drum uses to transmit the sound from the receiver (centre of ear drum) to the receptors which are located at the edges of the ear drum.
There are several interesting factors at work here. The ear drum its self is a very highly damped membrane with very low tension, imagine a polo mint with a thin piece of skin grown over the hole in the centre. I know its a weird analogy but you get the picture!
The very high inherent damping of the skin material is important as it allows tiny pressure waves (caused when the sound waves from the ear canal hit the centre of the drum) to radiate out to the edges BUT NOT TO REFLECT BACK towards the centre of the ear drum. This is vital as any reflections bouncing back would cause interference, cancellation and peaks, very bad if you are trying to locate where a sound originates from in 3 dimensional space i.e. where is the snapping twig? time to bolt in the OPPOSITE direction!
Nature had to evolve the fastest possible method of locating where sounds originate from in 3D space i.e. the fight or flight response is triggered by where NOT WHAT! It didn't matter if the monkey was 20 feet away before he realised the sound was a falling coconut and not a predator about to pounce, what mattered is the monkey was still alive!
The fastest and most accurate way to locate the origin of sounds is to decode the initial transient pressure wave (the compression in the air which hits the centre of the ear drum) WITHOUT ANY GHOST ECHO'S. The brain then compares the miniscule time delay difference between the left and right ear and bingo you have located the source. What the brain cant cope with is ghost echo's i.e. if there were false multiple pressure waves bouncing up and down the ear drum the brain could not decode all the data FAST ENOUGH to locate the sound (escape the predator). With a highly damped low tension membrane each and every transient pressure wave is decoded instantly with no ghost echo.
Contrast this with the pseudo pistonic motion of cones domes ribbons and panels as used in conventional loudspeakers. What I mean by pseudo pistonic motion is that it is not actually pistonic at all, it is linear ie along a straight (subject to suspension, spider and assembly tolerances) line but not the beautiful mechanical pistonic motion of say a BMW racing engine piston.
True pistonic motion as in an engine piston has a precise and clearly defined stroke of pistonic motion which the piston never deviates from, regardless of RPM i.e. from idle at a few hundred RPM (Hz in a bass driver!) to 18,000 RPM (Hz in a high frequency driver) the piston will travel exactly the same 215.007mm or whatever the mechanical stroke is because the piston is fixed at one end i.e. NO FLEXIBLE SUSPENSION!!
Contrast this with the "Yo Yo" mass on the end of a spring i.e. the cone or dome with its surround, spider and or suspension and you get the picture.
Even worse is the slow "Yo Yo" settling time causes the dreaded GHOST Echo's i.e. instead of the brain receiving 1 clean sharp pressure wave to decode it gets a whole series of slowly reducing pressure waves. In the case of a musical signal the YO Yo never gets a chance to stop as the next musical impulse comes along before the cone has had a chance to stop at its original starting point!
I hope this is making sense to all the members as its actually very hard to describe in words, an animated film model is far better and easier to understand and I am working on this, I can go into more detail with more precise numbers i.e. the 13 uS (thirteen one millionth's of a second) rise time of the Manger driver with it's corresponding settling time as opposed to the
25 (or more) times slower decay (settling times) of conventional drivers but it's the main principal involved that is really important to understand first.
Does the above make sense?
Here is a beautiful ironic point in a digital age.
Has anyone ever thought about how similar the energy conversion (from Kinetic to Electrical) process is in a moving coil cartridge to the final stage of the inner ear? The nerve endings at the base of the cilia hairs act like the coils/magnet assembly and the tiny cilia hair is like the cantilever!!! Now that really will give all you "valve and vinyl boys something to talk about!

Lastly your point about guitar amps, is very puzzling indeed, to me anyway!
I have built and repaired any number of these from valve to soild state and even a class D model. Each and every one use's a standard 10 12 or sometimes 15 inch cone pistonic driver (YO YO!) ie JBL , Eminence, Marshal etc. I have never seen or heard of any guitar amp / speaker using a bending wave transducer. Please tell me more about your guitar amp experiences!

Cheers

Derek.r

Hello CJ,

I forgot to give you the link to the AES paper you (or was it someone else ?) asked for. I have pasted it below but just like the other mathematical model it does not display correctly on this post.
Go to the Manger website and follor the research link to the two PDF 's.

Below is the "rough copy"

Cheers

Derek.




A sound transducer with a flat, flexible diaphragm working
with bending waves
Daniela L. Manger
Manger Products, Industriestrasse 17, D-97638 Mellrichstadt, Germany
Summary: From the idea to a finally excellent working sound transducer a period of over twenty years was
necessary. Nowadays it is possible to present a wide-band sound transducer working from 100 Hz to 35 kHz. It
follows time-precise without any mechanical energy storage the incoming signal. The special structure of the flat
pliable diaphragm works concentrically only with bending waves. Theoretical equations and measurements will
be presented in comparison to the omnipresent piston loudspeaker. The advantages in perception and hearing
will be mentioned for further research.
INTRODUCTION
In this paper the author will outline the basic theory of the bending-wave sound transducer as
a resistive controlled driver in comparison to the piston loudspeaker. The fundamental descriptions
has been made by Rice and Kellogg, comparing the elastic, resistance and mass
controlled units for harmonic motion [1]:
elastic control ( ) const.
K
F
F = K ⋅ x t ⇒ X = = (1)
resistive control
f
X
fR
F
R
F
X
dt
dx
F R u t u t
1
~
2
= ⋅ ( ) ∧ ( ) = ⇒ = = ⇒
ω π
(2)
mass control 2 2 2 2 2
2 1
~
4
( ) ( )
f
X
f m
F
m
F
X
dt
d x
F = m⋅ a t ∧ a t = ⇒ = = ⇒
ω π
(3)
The kinds of energy are for the elastic-controlled motion potential energy, for the resistivecontrolled
translation energy and for the mass-controlled kinetic energy. Further research on
mechanics and structure-borne sound about a resistive behaviour let to the realisation of the
resistive-controlled driver [2].
THEORETICAL DESCRIPTIONS
1. The mass-controlled driver
The theoretical description is known from the literature. The sound pressure is proportional to
the acceleration of the piston, shown in the formula [3]:
( ) ( , , ) ~ ( )
4
²
( , , ) 0
c
r
p r z t A t
c
r
A t
z
a
t z r p − ⇒ − 

 

= 
ρ
(4)
p(r,z,t) = sound pressure at position r, z at time t c = speed of sound in air
A(t-r/c)= acceleration at time (t-r/c) ρ0 = density of air
a = radius of circular piston
2. The resistive-controlled driver
A bending-wave transducer is a “resistive-controlled” device by implying that a force will
produce a proportional velocity, which leads to an exact following sound pressure radiation of
the incoming signal. To reach this the mechanical impedance has to be resistive and the
electrical impedance of the voice coil is negligible. Further mechanical requirements in this
case are: a large pliable circular plate with a matched impedance, so that no reflections will
occur at the centre and outer boundaries. The motion of the plate can be described by the
bending wave equation; i.e. membrane tensions (which would lead to non-linearities) must be
absent. The radiation load of the air in front of the diaphragm can be neglected because of the
higher weight of the diaphragm.
The mechanical impedance Zm of an infinite thin plate in vacuum is purely resistive, which is
also true for higher frequencies in air [4]:
Z B h m =8'ρ ⋅ (5)
Zm = mechanical impedance B’ = bending stiffness per unit width
h = thickness ρ = density
The theoretical evaluations on the presented bending wave transducer were completed by
Prof. Dr. Manfred Heckl in 1978 under taking into account the above mentioned requirements.
The aim was to determine the sound radiation of such a configuration, with the time
history of the sound pressure being of particular interest.
Figure 1: a circular plate excited along a ring with the used coordinates and variables for the calculation
The sound pressure radiated by a very large plane plate is given for the radial symmetric case
by the formula [5]:
∫ ∫
∞
−∞
∞
= − −
0
0 ( , ) ( ) .
2
1
( , , )
2 2
ω 0 ω
π
p r z t e ω p k J k r e k dk d r r
j k k z
r r
j t r �� (6)
If the plate is excited by a radial pressure distribution of the form p r t A( , ), which is in the
present case a ring-shaped excitation, we have
( ) ( )
( 2 2
0
0
2 4 4
0 0
4 )
( , )
r B r
r
r
B k k k k
j J k a F
p k
− −
=
ωρ
π
ω ω
ω
��
�� (7)
Because of the assumption that membrane tension is absent, we always have k k r B << in the
far field, i.e. for k k0 r > ; therefore
2
r
2a z
F
p r z t
j
m
F
k k
J k a J k r e e k dk d
r
r r
j k k z j t
r r
( , , ) r
' '
( )
= ( ) ( ) .
−
− −
∞
−∞
∞
∫ ∫ ρ
π
ω
0 ω ω
2
0
0
2 2 0 0
0 4
0
2 2
��
(8)
The integral over kr can be obtained from a comparison with the calculation of the radiation
from a small piston membrane, where we can derive the result of the bending wave transducer:
)
² ²
(
4 ' ' ² ²
( , , ) 0
0
c
r z
F t
m r z
p r z t
− +
⋅ +
=
π
ρ
(9)
This result says that the time history of the sound pressure near the symmetry axis corresponds
exactly to the time history of the force acting on the plate, which is related by
F Z v m = ⋅ 0 with the diaphragm velocity and hence to the time history of the current in the
voice coil, whereby the mass of the voice coil is negligible. Therefore, time histories of currents
with sudden changes, e.g. square wave, are reproduced correctly in the radiated sound
pressure. The time-lag due to sound wave propagation in the air is expressed by the argument
c
r z
t
− 2 + 2 .
p(r,z,t)= sound pressure at position r,z at time t
r = perpendicular distance from the symmetry axis which passes through the centre of the ring
z = distance from the plate
t = time
ω = integration variable (angular frequency)
J0 (..) = Bessel function of order zero
j = −1
kr = integration variable (wave number)
k0 = ω c
c = propagation speed of sound waves in air �� p(..) = wave number spectrum of the pressure
B = bending stiffness of the plate
m' ' = mass per unit area of the plate
kB = 4 ω 2m' '/B = wave number of free bending waves
REALIZATION
Figure 2: Sketch of the Manger sound transducer
The presented bending wave transducer, which is protected as Manger Sound Transducer,
has an electrodynamic motor working with two voice coils on one layer. Mechanical in serial
operation and electrical in parallel it is possible compensating for emf which is generated by
the voice coil movement. The inductivity of the voice coil is 18μH, about 1000 times smaller
than a conventional voice coil inductivity. The total weight of the voice coil is only 0.4 g. By
this specifications the influence of the motor is only resistive in the interesting frequency
range. The diaphragm diameter is 190 mm.
MEASUREMENTS
The dispersion of the bending waves on the diaphragm with the relation λB ~ 1/√f can be
shown with laser Doppler vibrometry. Measurements were made at various frequencies.
Figure 3: Laser Doppler vibrometry measurements at frequencies of 100, 200, 315, 1000, 3150, 10000 Hz
The time behaviour of the Manger sound transducer is shown in step response measurements.
The input signal is an electrical step. The theoretical step response in air is shown in comparison
to the step response of mass-controlled driver constructions.
Figure 4: Electrical input, theoretical ideal step response in air, step response of the Manger sound transducer,
step response of a 3-way-piston loudspeaker measured in 1m
CONCLUSION
The proof for the time precise transduction using a flat, pliable circular plate as a resistivecontrolled
device was made by theoretical and practical means. The improvement of the
aperiodic behaviour which is closed to the ideal transient response in air leads to a new
awareness of sound reproduction in time and frequency. It enables a general improvement of
sound reproduction and offers new ways of research on human perception and hearing.
REFERENCES
[1] Rice. C.W., Kellogg E.W., “Notes on the development of a new type of hornless loud speaker”,
Convention of the A.I.E.E., 1925
[2] Cremer, L, Heckl, M., Ungar, E., Structure-Borne Sound, Berlin, Springer Verlag, 1973, pp.102
[3] Morse, P. M., Vibration and Sound, New York: ASA, ch.VII.26
[4] Cremer, L, Heckl, M., Ungar, E., Structure-Borne Sound, Berlin, Springer Verlag, 1973, p.281
[5] Heckl, M., Acustica 9, p. 371 (1959)

The ear doesn't care one way or another how the sound is produced, only that the vibrations coming in are closely representative of something. If whacking a kitten with a hammer in a certain way could produce the exact same vibrations as a piano, then you would hear it as a real piano. Period. It's like saying that a calculator needs to think the same way we do in order to function properly. The only thing that matters is the result.

It's one thing to have a speaker sound good, as in many ribbons and the Manger that are at 5-10% distortion across the board, but it's another thing to have a speaker that is *transparent*. Fortunately for pseudo-scientists and PT Barnum types, most people seem to look for "good sounding", not "transparent".

The Manger driver is another example of selling the methodology, not the result. Of course, this is the standard by which most "high-end" companies operate, making Derek no different from any other charlatan, but if it walks like a charlatan, talks like a charlatan.........

If whacking a kitten with a hammer in a certain way could produce the exact same vibrations as a piano...

Dude, you are just sick... Sick I tell you! :eek:

Your key must open up the gates of Hell instead of Heaven. :p

Dude, you are just sick... Sick I tell you! :eek:

Your key must open up the gates of Hell instead of Heaven. :p

It is just being his usual self;)

Using a purely hypothetical example is sicker than using complete BS to trick people out of their money? Okay, whatever :rolleyes:

I do understand the basic operating principle of the Manger driver. Anyone who'se ever "snapped"
a bedsheet or tablecloth to spread it out smoothly has seen bending wave behavior and propagation in action.

Your Manger drivers can be though of operating as ring radiators, which is "ripple mode",
which is what the aforementioned guitar amp speakers often do, in addition to multiple
assorted other forms of cone breakup modes.

Classic examples would include Celestion "greenbacks" and most any other guitar speaker
in common service. These speakers operate in quasi-pistonic mode only at LOW volume
levels and at LOW frequency levels.


I return again to the mythology of matching source and sensor response curves to make the point
that it is not necessarily an ideal solution to make the source (the speaker) operate in the same
mode as the sensor (the ear) any more than it is to make the frequency response curve of a
speaker identical to the frequency response curve of the ear.

Quite the contrary, it's better for accuracy's sake to attempt to reproduce the actual
sound of interest so that it measures and sounds exactly the same as the original sound.
The point is to REPRODUCE the sound, not modify it in any way, and you don't achieve
that by attempting to emulate the behavior of a FLAWED listening device, which would
be our ears.

Yes, I say flawed. Our ears are by no means perfected sensors. If you had a speaker that
worked EXACTLY like them, but in reverse, you would have a poor speaker.
We think our ears are so great, but what do we have to compare them to? It's not
like we can try out different ears and see how they compare. A dog would be LESS
than impressed with our hearing. So would an owl. Many animals have hearing which
is better than ours in some respects. And there are many microphones that are
far superior to our ears in their ability to pick up a large dynamic range of sounds over a wide frequency range.


A characteristic of the Manger drivers as I've seen them is the star-shaped diffuser.

Show me a speaker that requires a diffuser and I'll show you a speaker that the designer
obviously thought needed some help for its poor dispersion characteristics. That diffuser
is not an enhancement, it's a band-aid.

The bending wave motion you champion is the same thing that most every other
speaker designer tries to design OUT of his speakers, as that's really nothing less
than mechanical distortion. The necessity of a star-shaped diffuser ALONE lends
considerable support to this viewpoint.

Other issues: To propagate bending wave motion evenly across the entire speaker
surface, over a wide frequency range, you'll have considerable demands to place on
the manufacturing process. The speaker's cone has to have even, uniform flex
response in every direction, which by itself precludes any woven material for use in
the cone, as it has been shown that breakup modes in woven cones tend to be
related to the direction of weave. You'll need polymer cones made to a very precise
standard, and the method of attaching the cone to the frame will have to be very
uniform and repeatable as well. The surround will have to be very uniform as well,
and after all that, you'll still have the phase cancellation issues that MUST accompany
bending wave operation, at any frequency which has a short wavelength in relation
to the cone diameter.

I'm not opposed to someone making a speaker that's GENUINELY superior. Particularly if
it's done at a price range that's affordable to enthusiasts who aren't highly paid doctors
and lawyers, such as myself. (I enjoy my work too much to be well paid for it. :) )
But, I think you're pursuing an inherently flawed concept based on my understanding
of how it works vs. how a conventional speaker works.


I have a suggestion for you: Buy a wide assortment of raw drivers of all sizes and
types from all the usual manufacturers of high end speakers. Vifa, SEAS, ScanSpeak,
Dynaudio, Focal, etc. Mount those drivers in a test cell in an anechoic chamber and
run measurement sweeps on them through the entire audio spectrum and beyond.
Analyze them for frequency response flatness, harmonic behavior, and directional
response. Look at their response curves with an eye toward finding speakers that
don't start performing badly very suddenly when you get out of their optimal frequency
range, and when you're done with that, design the simplest crossover networks
to achieve best performance. Match up the best woofer with the best midrange
and the best tweeter, build inert, properly sized, low diffraction shape enclosures
for the set, provide suitable crossovers that match the driver requirements, and try
them out. I think that you'll have an EXCELLENT speaker from the very start,
equalling or exceeding the performance of the Manger drivers , and with considerably
less development time and money investment.

The fundamental problem with the Manger type driver is that it operates in bending
wave mode. And that IS a problem when dealing with reproduced frequencies that
have a wavelength shorter than 1/2 the diameter of the speaker cone. You're going
to have a situation where part of the cone is moving away from the listener while at the
same time another part of the cone is moving toward him. This is an automatic phase
cancellation problem, and at higher frequencies the problem will become more
pronounced. At very high frequencies you may have several waves propagating across
the surface of the driver at the same time, and nothing good can come of that in terms
of freqency response OR directivity. You'll have phenomenal phase cancellation issues
at high frequencies that will result in abysmal polar response. But you'd be crossing
over to a tweeter at lower frequencies than that, hopefully...and it'll be a tweeter that
doesn't operate in bending wave mode, does it?

As for the quality of pistonic movement, these days, most drivers that genuinely
belong in the high end category tend to do a rather good job at moving in a highly
pistonic fashion, and even at high excursions, even the surround on such speakers
isn't a source of significant harmonic distortion.


Please stop trying to post .pdf files here. It will not work. The board code doesn't allow for that.


CJ

Besides, as I said before, DEQX, by its very nature, makes the most of drivers that are pistonic and can do very little for non-pistonic drivers. So you're using virtually incompatible technologies to achieve a unique blend of expensive mediocrity. But it all sounds good in a marketing brochure.

Hello CJ,

It's a shame PDF's don't display on the forum as the Celestion Greenback guitar amp bass / mid speaker PDF proves it is exactly the same as all other bog standard PISTONIC cones. There is no such thing as a bending wave guitar amp speaker, it does not exist!
I have visited the Celestion factory on several occasions (they are based a couple of hours away from me in Ipswich) and I can assure you the Greenback driver (or ANY guitar amp speaker) is not a bending wave transducer in any way shape or form, by design or accident. Please read Celestions on WebPages at ; lhttp://professional.celestion.com/guitar/products/classic/detail.asp?ID=6
I can not be more categorical in my answer without resorting to the kind of language that the intellectually challenged often use against me so all I can say is that you are 100% wrong.
Your understanding of guitar amp speakers is fundamentally flawed and until you can grasp the basic difference between pistonic drivers design & operation combined with their associated cone break up modes and a bending wave driver there is no point in me spending any time discussing the subject in any detail with you. I am sorry if I am sounding harsh but it is obvious we are not on the same page when it comes to the mechanical and or electrical operation of loudspeaker drivers!
In your last post all your statements regarding the Manger driver are all based on your lack of understanding about the Manger driver.
For example you state " A characteristic of the Manger drivers as I've seen them is the star-shaped diffuser.
Show me a speaker that requires a diffuser and I'll show you a speaker that the designer
obviously thought needed some help for its poor dispersion characteristics. That diffuser
is not an enhancement, it's a band-aid."

CJ, the Manger driver does not have any "diffuser". There is no sound diffuser (or phase plug) required, the driver as superb naturally room filling dispersion characteristics. The star shaped surround you refer to is an integral part of the diaphragm designed specifically to absorb the transient wave as it reaches the edges of the driver. To go back to the pebble dropped into a pond analogy think of it as the reeds growing around the edge of the pond to absorb the ripples.

Your term "ring radiator" is at best misleading as it congers up images of the cheap little ($150 in small trade volumes) tweeters that ScanSpeak / Vifa etc churn out. They again are bog standard pistonic dome tweeters with the same motor / suspension / voice coil / magnet layout as all the rest. The only USP is the built in phase plug (or diffuser!) to give it the concentric ring appearance. It does not operate in a bending wave or rippled mode as you incorrectly state, It is a bog standard pistonic tweeter. Feel free to email Lars at Skan Speak technical in Denmark he will set you straight!
I have over tested and used over 100 drivers from all the "usual suspects" in the so called high end driver world and I am very well versed in their strengths and weaknesses. Your suggestions (which are perfectly valid) on how to design the ultimate loudspeaker system are how I and just about every speaker designer starts out. The important thing is where your R&D takes you and what you can do with the results.
I am very happy to put my designs up against anything out there at any price and the first of the big UK "shoot outs" will start in the Spring, assuming the competition shows up!
The level of engineering, material science and astonishingly high assembly tolerances that are involved in the construction of each pair of Mangers drivers is so far beyond that of the ridiculously over priced diamond, ceramic, Nomex, carbon, Kevlar etc cones and domes it is hard for me to give you a meaningful comparison . Suffice to say that your concerns raised in your statement : "You'll need polymer cones made to a very precise standard, and the method of attaching the cone to the frame will have to be very uniform and repeatable as well. The surround will have to be very uniform as well,..."
are fully addressed and then some!

I hope the above helps and hopefully you will read more on the subject and maybe we can find some common ground on which to further the discussion based on fact and genuine understanding of all the technologies concerned.

"Time Will Tell"

Derek.

Using a purely hypothetical example is sicker than using complete BS to trick people out of their money? Okay, whatever :rolleyes:

Imagining up the idea of hitting a kitten with a hammer as an example is sick... Whatever the other person is doing is irrelevant to the sickness it takes to come up with such an example.

I side with CJ in this argument.. In no way does the paper Overkill cites proves the superiority of the Manger over pistonic drivers...

Allow me to be very skeptical... Reading from the literature on the web site...I am not convinced...

What an interesting discussion.

--Regards,

Imagining up the idea of hitting a kitten with a hammer as an example is sick... Whatever the other person is doing is irrelevant to the sickness it takes to come up with such an example.

If it makes you feel better to think so.

If it makes you feel better to think so.

As better as it makes you feel to think up such examples...

As better as it makes you feel to think up such examples...

Didn't make me feel better or worse, it was purely picking two words out of the air and inserting in a sentence to exaggerate a point.

One thing I've learned about the difference between arrogance and confidence is that arrogance is founded in insecurity, almost like a bipolar version of confidence. Whereas confident people like to discuss or even argue a point, arrogant people feel the need to personally attack others at every opportunity, so as to put them, in their mind, below them. They climb to their sense of self over the backs of others, rather than it being an innate feeling. The hypothetical example had something to do with the discussion, calling me "sick" does not. Nor does OB's ongoing MST 3K style commentary.

Derek has a unique style of arrogance himself, calling others "100% wrong" or "intellectually challenged" (hmmm who else fits that description? ), when it seems more to me that he is being intellectually dishonest, either to himself or to us, in order to promote his particular idea of he world.

Didn't make me feel better or worse, it was purely picking two words out of the air and inserting in a sentence to exaggerate a point.

One thing I've learned about the difference between arrogance and confidence is that arrogance is founded in insecurity, almost like a bipolar version of confidence. Whereas confident people like to discuss or even argue a point, arrogant people feel the need to personally attack others at every opportunity, so as to put them, in their mind, below them. They climb to their sense of self over the backs of others, rather than it being an innate feeling. The hypothetical example had something to do with the discussion, calling me "sick" does not. Nor does OB's ongoing MST 3K style commentary.

Derek has a unique style of arrogance himself, calling others "100% wrong" or "intellectually challenged" (hmmm who else fits that description? ), when it seems more to me that he is being intellectually dishonest, either to himself or to us, in order to promote his particular idea of he world.

This has to be the most arrogant and self-indulgent post in the thread so far, not to mention hypocritical.

I seen no PRACTICAL difference between a driver that operates in "bending wave mode" by design and a driver that generates outward-moving waves in the cone as a product of distortion break-up. Unless my understanding of the Manger driver is TOTALLY flawed, that's indeed what it's doing, but by design.

It all comes down to this: To create sound, air must be moved. The transducer must displace air by movement. Period.

Which mechanical method does the drive use to displace air?

Conventional drivers do it by pistonic movement. The quality of that pistonic
movement is HIGHLY variable but it's quite good in drivers that are well
designed and well engineered and run within their ideal operating range.

However, when you run a speaker outside of its range in which it behaves
well in the pistonic mode, you will get parts of the cone that do not move
in phase with the rest. This is a mechanism by which harmonic distortion
is generated. Multiple harmonic distortion modes are possible. They can
often be visualized as "petals" on a flower. Two, three, four, five, six...
almost any reasonable number of these modes can appear, singly or in
combination, according to a variety of factors associated with the mechanical
design of the various components of the driver. And, a conventional driver
can operate in the "ripples in a pond" mode in some cases, but usually only
at high frequencies, outside of its designed operating range, and in cases
where the cone has maximal strength in an annular pattern (ring pattern)
and less strength in the radial directions. This mode is likely to occur only
in conjunction with other petal breakup modes, I think.


As I understand it, the Manger type driver propagates a wave across the diameter of the cone, which can be visualized as a spreading ripple.


Am I wrong about that?


What happens with a Manger driver if you drive it at a high enough frequency
that the highest frequency present has a wavelength shorter than half the cone diameter?

You WILL get phase cancellation effects. The effect will be progressively
worse at higher frequencies.

A conventional driver suffers from similar limitations, to be fair about it. This
will happen even if the motion of the cone is perfectly pistonic but the
frequency being produced is too high for the cone diameter.

But...conventional drivers also offer greater efficiency as the entire
cone is employed in air displacement while it's operating in pistonic mode,
while with a Manger type driver of the same size, there's less air
displacement occurring as the active area is always less than the
area of the cone surface, plus the edge is highly damped and produces
virtually no output.

You can not make me believe that the Manger driver is superior in any way
as it has its own unique set of weaknesses, and no advantages that I am
able to see. It's simply a reinvented wheel, and maybe not as good as
a well-engineered wheel of the conventional variety.


CJ

Hi CJ,

Sorry about the delay in getting back to you, the last week has been hectic as everyone wants all things AV installed by Christmas!
The two main points you raise in your last post are valid and often wrongly confused, I will answer them in reverse order if I may.

First your quote;
" You WILL get phase cancellation effects. The effect will be progressively
worse at higher frequencies. "

This is a classic audio myth, it is completely unfounded and is totally wrong.
There is no such thing as "phase cancellation", it has never existed and never will in audio (maybe in Star Trek if you invert the plasma injectors and cross connect the Dylithium crystal generators....!) here is why.
In free air an audio signal (compression or rarefaction of the air molecules) is either in phase or out of phase with the rest of the signal, you can not "cancel phase" you can only invert phase. You can get constructive or destructive interference between two separate audio signals which will then result in peaks and troughs (perceived as loud and quiet) in the combined signal. This is SIGNAL cancellation NOT phase cancellation.
It occurs to some degree or other in all loudspeakers with more than one driver, the most severe cases are two or three way passive crossover systems using "minimum phase" (that's a bad joke in its self) crossovers with huge overlap between small domes / ribbons, medium size midrange or bass midrange drivers and large bass or sub woofer drivers. Large frequency bands are routinely covered by two entirely different drivers with unequal mass to BL ratio, unequal voice coil to Sd ratio's, different suspensions and of course located at different points on the baffle! Now that lot will give huge problems with interference patterns causing a range "phase related" distortions caused by the different cones and domes overshooting at different time intervals as well as each individual driver constantly overshooting and under shooting its stop start position.
In addition while the whole cone come assembly is over and under shooting (the Yo Yo mass on a spring model) the actual cone or dome will also start to break up. This starts occurring long before the XMax or power handling limits are even approached. By the time the XMax limit is reached you are well into the "flower petal" (seen using laser interferometer imaging) cone break-up and this causes yet more distortion due to different parts (petals) of the cone overshooting outwards whilst others are undershooting inwards.

This type of distortion is actually closely related ( sounds equally unnatural) to the ghost echoes (driver overshoot) of cones and domes. What is actually happening at the driver / air interface is as follows.
When a cone is asked to compress the air molecules it must accelerate outwards (+ve signal) using the voice coil and former to shoot forward "dragging" the cone along with it and when the cone is asked to rarefy the air molecules it must shoot inwards (-ve signal) again dragging the cone along for the ride.
Now, for a moment at least, lets assume the problems of aerodynamic imbalance of the cone profile, the spider & suspension non linearity's and the ambient temperature / humidity effects on the mechanical and BL motor functions of the cone / dome driver have all been solved.
This leaves us with the huge problem of a tiny mass (voice coil) trying to accelerate, decelerate and then accelerate in the opposite direction asw fast as it can while it is attached to a huge mass (the relative mass of the cone, spider, suspension and surround are tens or hundreds of times greater than the mass of the voice coil wire) which takes far longer to start, stop and change direction.
I have already listed in other parts of this post and on my web site all the fundamental failings of conventional drivers so I wont repeat them yet again. Suffice to say they cant work, they don't work and their gross errors are further amplified by the use of passive crossovers.

Are you asking about driver / cabinet edge difraction?
If so that is another subject and I am happy to answer any detailed questions on that subject.
Your other (first) point was ;
" I seen no PRACTICAL difference between a driver that operates in "bending wave mode" by design and a driver that generates outward-moving waves in the cone as a product of distortion break-up. Unless my understanding of the Manger driver is TOTALLY flawed, that's indeed what it's doing, but by design.
It all comes down to this: To create sound, air must be moved. The transducer must displace air by movement. Period. "

I hope my explanation above proves that uncontrolled cone break up is indeed a bad way to try and reproduce a natural time coherent (naturally and perfectly in phase throughout the "lifespan" of the sound) sonic event.
Lets now contrast the above "dogs breakfast" of fundamental failings with the only true (non tensioned membrane) bending wave driver.

Go back to the analogy of the pebble being dropped into the middle of a calm pond to demonstrate the ripples of sound energy travelling out from the centre of the Manger driver. A very important point to remember is the total absorbsion of each pressure wave as it hits the edge of the drivers star shaped surround. Think of the reeds around the edge of a pond breaking up and absorbing the ripples. What this means is that each individual pressure wave is cleanly generated and then...... nothing, nothing at all NO Ghost echoes, no Yo Yo mass on the end of a spring, no cone break up and there fore No time domain distortions.
THE NEXT PARAGRAPH IS VITAL!
Please remember that all naturally occurring sounds (musical or otherwise) can only consist of an initial pressure wave (air molecule compression) followed by a decay (pressure stabilisation back to ambient) or a rarefaction followed by an increase in pressure back to ambient. This applies equally to an instantaneous snapping of a twig AND OR a percussive transient piano note with a 20 second decay!

Most people fail to understand that all sounds can only be made up of two simple pressure events i.e. compression or rarefaction (enter the digital one's and Zero's analogy!) followed by air pressure stabilisation back to ambient.
That's all there is folks, it really is binary simple!!

So this is exactly what the Manger driver does, it sends out ripples originating from an almost infinitely variable (well actually 29,700 i.e. the 29,700Hz usable range) size of point of origin and these ripples are created with a rise time of 13 uS (thirteen one millionth's of a second) which is between 20 and 150 times faster than the best of the best cone / dome ribbon and electrostatic drivers. Now the even more important part, there are no ghost echoes or Yo Yo mass on a spring oscillations to cause the insidious time distortions because the patented tension free polymer diaphragm and surround have complete and near instantaneous energy absorbsion properties. Similar to the human ear drum.
Can you now see the fundamental differences between the hundred year old cone / dome mechanical Yo Yo and the true tension free membrane bending wave principal ?
People often ask me why I am so critical about cones and domes, when you start to grasp the size of the divide which separates them, then you will know why!

"Time Will Tell"

Cheers

Derek.

I think (to simplify) that what he is saying is that in nature, full range sound is generated from a single point source. COnventional 2 or 3 or 4 way systems have 2 or 3 or 4 point sources to reproduce those same sounds. so since this is a different method of reproduction, and this has inherent flaws (combing and wave interactions) it sucks and should be abolished by all (i am paraphrasing) :D

Since the manger creates both the mid and highs via more of a single point source, it is better, is not affected by wave interactions and thus far superior. As such its glories should be trumpeted from the highest hilltops.

This is typical of companies that talk about the unique advantages of their product without ever mentioning or acknowledging the unique downsides. Only *they* can take the unique high distortion Manger driver and make it sound right.

The problem with non pistonic drivers is that they all seem to be very high distortion because they aren't producing the actual signal properly. They sort of do that, then they add a whole bunch of other things because you have vibrations rippling back and forth on the driver. It's why B&Ws don't sound right to me.

Besides, DEQX is designed specifically to take a collection of multiple drivers and make them behave more like a perfect point source with little interference between drivers. So, using it with the Manger design is just silly. A 4th order L-R crossover would have worked about as well and would have been a whole lot cheaper. Then everyone could afford the wonders of an Overkill Audio system. Oh, but wait, the idea here is to only fool the richest of the gullible.

Take a specific frozen moment in time in the life of a Manger driver. That moment in time is when a given high frequency signal is rippling its way out from the center of the cone to the edge. At this moment, there's a forward-moving ring in the cone, and a backward-moving ring in the cone. Take a slice through the middle of the speaker and you'll see two active areas at once. They're doing the same thing at the same time but
in two different locations.

What do you have when you have two high frequency radiators operating in tandem?

You have phase issues...plenty of them. IF you're operating above the critical frequency of that radiator. Your overall frequency response will look like a comb filter.

But you DON'T have two effective radiators with a Manger driver...you have many, or
more specifically, its behavior is that of a ring radiator in which the ring is of variable
size AND variable output. Phase anomaly nightmare, here we come!

As the active moving area of the cone of a Manger driver means that the ripple locations
are dynamic, suddenly you're looking at a VARIABLE comb filter. The dynamic behavior
of such a system would have interesting and complex effects on the overall frequency
response, in every location around the speaker. You'll even get ON-AXIS phase problems with a SINGLE driver, a problem that is virtually unheard of with conventional
speakers.

And let's address another issue: Output.

In any conventional driver, the full active area of the driver is capable of reaching the
full designed excursion of that driver. This makes it relatively easy to achieve high
(realistic concert level) SPLs, needing just a reasonable amount of power and efficiency
in order to achieve that objective.

The Manger driver, being a non-tensioned membrane which is fully edge damped,
has, for any comparable driver size range, very little excursion capacity, or so I'd imagine. This will limit acoustic efficiency and CERTAINLY limit total driver SPL capacity.

I think a Manger driver used for bass would simply be a stupid idea. It might be passable
for a midrange and quite usable for a tweeter, though.


I have already listed in other parts of this post and on my web site all the fundamental failings of conventional drivers so I wont repeat them yet again. Suffice to say they cant work, they don't work

That right there is really an amazing bit of hyperbole. CLEARLY, it's UTTERLY obvious
that conventional drivers CAN work, and DO work, and quite a few of them do a really
excellent job of it.

At the very least, try toning down the overstatements. It's a given that I'm not going to be buying any Manger drivers any time soon, and in part due to the exaggerated and
sometimes inaccurate claims made about them and conventional drivers.

I'm not a big fan of people who stretch the truth or break it entirely.


CJ

Hello CJ,

Just to keep things interesting I will respond to your points in order of appearance!
Your first quote is:
" Take a specific frozen moment in time in the life of a Manger driver. That moment in time is when a given high frequency signal is rippling its way out from the center of the cone to the edge. At this moment, there's a forward-moving ring in the cone, and a backward-moving ring in the cone. Take a slice through the middle of the speaker and you'll see two active areas at once. They're doing the same thing at the same time but
in two different locations. "

Your description and obviously your understanding (despite my clear explanations!) of how the Manger driver operates is in serious error.
There is no forward or backward motion at all in the Manger diaphragm at any point.
The only motion is a circular wave radiating outwards from the centre of the diaphragm, like the pebble in dropped in the centre of a pond.
There are no phase issues at all, just like the human ear drum when the sound is channelled down to the centre of the ear drum and the sound ripples out in a circular pattern. There is no backward or forward motion only a singular energy pulse (the wave) which represents the sound transient peak. Each and every other individual sound is represented by its own energy pulse (or wave) and all these separate waves have the same lightening fast response time (rise time and settling time) with no ghost echo. Once again like the human ear drum.

Your second point ;
"What do you have when you have two high frequency radiators operating in tandem?"

This is a flawed and non valid question as there simply are not two high frequency radiators operating in tandem.
You have completely failed to grasp how the Manger driver works.
Your third point;
" You have phase issues...plenty of them. IF you're operating above the critical frequency of that radiator. Your overall frequency response will look like a comb filter."

This is simply incoherent rubbish and once again you are using terminology that does not exist.
i.e. " critical frequency"
What is this???!!! There is no such thing as a "critical frequency"
There is driver resonant frequency in free air, box resonance, driver and box combined resonance and a few other frequency related parameters but no such thing as "critical frequency". Where did you read this term?! Audiogon and the DIY forums are not valid reference sources!
Your third point :
" But you DON'T have two effective radiators with a Manger driver...you have many, or
more specifically, its behavior is that of a ring radiator in which the ring is of variable
size AND variable output. Phase anomaly nightmare, here we come!"

Again your complete lack of understanding is resulting in worthless ramblings.
One of the key advantages of the Manger driver is that IT IS an infinitely variable pure point source!
This is a highly desirable feature that top international designers from Tannoy, Beyma,KEF, LINN, Thiel, Quad and every dual concentric driver manufacturer has been striving to achieve.
As for your criticism of "variable output" that's just a joke, do you want a driver with fixed output?! Frequency response is nothing to do with output.

Your fourth point ;
"As the active moving area of the cone of a Manger driver means that the ripple locations
are dynamic, suddenly you're looking at a VARIABLE comb filter. The dynamic behavior
of such a system would have interesting and complex effects on the overall frequency
response, in every location around the speaker. You'll even get ON-AXIS phase problems with a SINGLE driver, a problem that is virtually unheard of with conventional
speakers."

Again this is just plain wrong. For the same reasons as I have listed above and in previous posts which you have failed to understand (or read)

Proceeding to your next point ;

"And let's address another issue: Output.
In any conventional driver, the full active area of the driver is capable of reaching the
full designed excursion of that driver. This makes it relatively easy to achieve high
(realistic concert level) SPLs, needing just a reasonable amount of power and efficiency
in order to achieve that objective.

Here you now demonstrate that you also have no understanding of conventional drivers operating principals or their capabilities & limitations.
In no particular order... So you believe that a typical high end (Scan Speak, Focal, Accuton, Eton etc) can achieve realistic concert levels...
Do you know what typical concert SPL'S are? Peaks of 120dB to 130dB are common with a full size orchestra. That's why musicians and conductors have special earplugs to protect their ears. Orchestral peaks can easily exceed even big Rock concert PA systems.

It is impossible for ANY high end driver (even state of the art PA drivers and compression drivers need to be massively paralleled in huge arrays and assisted by huge horns to approach classical orchestra SPL peaks) to reach "realistic concert levels".
110dB to about 117dB or maybe 118dB is the current realistic max SPL with low distortion and this is only possible with a fully active DSP crossover. All passive crossovers fail to make the cut.

In addition your concept or "power and efficiency" is obviously flawed.
The Manger driver is a genuine 91dB sensitive for 1 watt at one meter, across its entire 300Hz to 30KHz operating range. This is over 4dB higher than the average speaker driver as tested and measured by John Atkinson from Stereophile magazine during the last 15 years!
I have used a TWENTY FIVE WATT VALVE AMP at the last two Hi Fi News shows in London to prove this very point. The very large rooms were over 30 feet long by 20 feet wide with high ceilings and people were amazed at the massive 114db peaks of CLEAN LOW DISTORTION music we were making. We have won three best in shows and Robert Harley was also very impressed by our baby system back in CES 2005.

Your closing comment ;

"I think a Manger driver used for bass would simply be a stupid idea. It might be passable
for a midrange and quite usable for a tweeter, though. "

I have never used the Manger for bass, I only use it from 300Hz upwards. But thank you for your well informed and knowledgeable opinion.

If cones and domes are so fantastic and work so well how come the ultimate $ Million Hi Fi systems fail so completely in convincing us we are listening to an orchestra?
Cones and domes my satisfy you, they appear to satisfy most of the people most of the time, but they dont satisfy me and they dont satisfy the very fortunate 0.001% 0f the population who make up my potential customers.
So I have no issue or problem with the 99.999% of people who are happy with what they know, I am simply here to give some good news to fortunate few, there is now a better way...

Time Will Tell

Derek.

Point being (though I'm probably on ignore since Derek can't handle reality), if you start the ripple, there will be a trough as well as a peak. The wave will move some air forward as it undulates, but half a wavelength behind, it will be pulling air back. So, a 4000Hz note would have ~4" wavelength. So, 2" away from a "push", there will be a "pull" at the very same time. Pistonic drivers don't do that. I suspect that's why the Manger has such high measured distortion which everyone seems to be able to measure except for Derek. It's useless to argue about it as he's brainwashed himself into being a true believer. Apparently, the Manger does no wrong.

Of course, if he sends them to Soundstage and they measure anywhere close to a $5000/pr PSB T6, I'll eat those words.

My God, will this thread never stop!

"The horror... the horror..."

(unsubscribed)

What an interesting discussion.

AGREED...I would like to jump into these shark infested waters, but for my own personal safety I will just tread close to the shore!!

I've decided to go knee deep....I will leave the tech stuff to the techs lets say they do sound great (better than real lIfe):rolleyes: why would you only have one style (look), that for me is not very attractive. These are not good looking speakers IMO and why do they weigh so much. What do put in them...lead?

You are also coming to this forum and marketing your product so why not send a set to a highly regarded member for them to review? I am sorry but calculating shipping crates is something you should of thought of long before you started making these things.

You intially seemed quite polite in the beginning of this thread, but be aware that you are slowly starting to break. I can understand your excitement, but this is AVS over $20K forum filled with sharks, piranahas and even killer whales.

Joey

Joey

Hi Joey,

Yes you are right and I apologise to CJ for my "starting to crack" having compared the tone of my last post to my earlier postings I can see a steady decline in my own (usually high!) standard. Even although I stand by 100% all my technical points I was wrong to be so blunt (but never rude or abusive as several members are towards me) and again I apologise to CJ.
I get very frustrated repeating the same 5 or 6 points time after time but even assuming I am correct the golden rule applies :
"he who loses his temper loses the argument".
So deep breath and good Kharma to all, regardless of their opinions and understanding, as the Fun Loving Criminals would say ;
"we all bleed red even bending wave dis-believers"!!!
I am in discussion with two well known UK forum members (one of them is also a respected on-line reviewer) and they will be carrying out a series of listening tests and comparisons in a couple of months time.
In addition I am arranging a full series of independent tests and measurements in a state of the art laboratory (with anechoic chamber and laser interferometer equipment) carried out by a leading international driver designer who has worked for a series of ultra high end manufacturers. He also holds many patents on both pistonic and flat panel driver systems. His reports will be definitive and comprehensive.
They will once and for all prove or disprove the science behind the driver and the test results will provide a solid platform on which to build a serious marketing campaign. I have some heavyweight VC investors waiting on these results so its not just for the benefit of forum members!!
The marketing plan obviously will start in the UK, then Europe and we aim to secure a USA showroom by the summer 2008.
From a marketing stance here is an interesting statistic, 95% 0f our potential client base (which as previously stated is approx 0.001% of the developed worlds population) have no Hi Fi or AV media interest or activity.i.e. They do not read the AV / Hi Fi magazines, do not join forums or read on line reviews and never attend shows. They do attend car, boat, fashion, and niche luxury goods shows, they do read exclusive luxury goods magazines and surf for the "best of the best" goods and services. But when it comes to AV and or Hi Fi they almost always delegate the purchase to their interior designer, or architect.
On the looks of the speakers they are a combination of how it has to look and how we want it to look. "Form and Function" they look very different, they use totally different technology and of course they sound very different
from all conventional cone/dome boxes.
Within the tiny niche we are operating the speakers looks are already being described as gorgeous, contemporary and even iconic!
We cant please all of the people all of the time.....!

As always, "Time Will Tell"

Cheers

Derek.

So, your target audience are people who buy products from the magazines they stuff in airplanes?

the argument about why we are not convinced we are hearing the actual orchestra comes from two speakers (lets call it two point sources) trying to duplicate an orchestra. lets call that 30 point sources all playing at the same time.

So the issues are not what a driver can reproduce. THey are related to both what can be captured with... a point source, and the phisiology involved in then ramming it out of two speakers. (no matter what the drivers)

Now if we were talking about a true LCR recording... then maybe closer.

OK, explain this to me in a BRIEF description: If the Manger driver doesn't operate in the manner of a spreading ripple, and it doesn't operate as a conventional pistonic cone,
how DOES it operate?

How EXACTLY does it displace air, without which no sound can be produced?


CJ

Well, what he's saying is that it does do the "spreading ripple" thing, but that it is absorbed by the outer surround. That just means that it is likely a little less distorted than if it weren't absorbed well. The problem is that when do the ripple thing, the panel or whatever it is has to either be infinitely flexible or it will cause other resonances because the material can't flex enough to support the concentric ripple. This shows up clearly on the B&W FST driver with whopping big peaks and dips at different points in the cone (that are designed to somewhat cancel but........).

In any case, using a perpendicular "ripple" to create sound, is inherently problematic, no matter how much effort you put into improving it.

Hi,
What a difficult thread to read, due to those individuals who just HAVE to make their points, over, and over and over... Derek, I'd like to see if you can expand on your choice of the DEQX as your active crossover manager, simce I happen to agree with you that this is one of the futures of audio. I'm in the process of researching the different sysems available and to see if they might be aplicable to my situation, MBL 101'e, which do have a separate woofer unit. Also, I read the review on 6moon, but I wasn't clear on how your mods actaully helped the sound. I ask since there is a fairly well-known man, Steve Nugent (at least in audio circles), who does modfy the DEQX units, often for more than the original cost of the unit itself.

Thanks,
David

Well, what he's saying is that it does do the "spreading ripple" thing, but that it is absorbed by the outer surround. That just means that it is likely a little less distorted than if it weren't absorbed well. The problem is that when do the ripple thing, the panel or whatever it is has to either be infinitely flexible or it will cause other resonances because the material can't flex enough to support the concentric ripple. This shows up clearly on the B&W FST driver with whopping big peaks and dips at different points in the cone (that are designed to somewhat cancel but........).

In any case, using a perpendicular "ripple" to create sound, is inherently problematic, no matter how much effort you put into improving it.

If you're right, then my mental visualization of how this thing operates is 100 percent accurate.


And you know...it's still a fundamentally flawed concept.


It's ALWAYS wrong to attempt to make a source that responds in the same manner as a receptor unless the receptor is "perfect".


And our ears are FAR from perfect. They're quite limited, being definitely inferior the hearing systems of many other animals. Non-flat
frequency response, non-linear response over varying sound pressure levels, harmonic distortion...our ears are tubes, man, not solid state!


You don't model a speaker after how the ear works, you model a speaker to give the most accurate reproduction of a reference signal!

Never use flawed systems as the basis for your new designs!


If you had an essentially perfect microphone, with a flat, linear response over the entire range of hearing, and used it to record an acoustic
instrument's sound, and the recording chain was also essentially perfect, and then you played back the recording through an essentially
perfect amplification system, through an essentially perfect speaker, and then recorded ITS output on the SAME recording chain, you'd
have an essentially perfect copy of the original recording.

This would be ideal. Anything that doesn't result in two substantially identical recordings is flawed. The greater the deviation, the greater
the flaws.

Yeah, there's more to it than just measuring a speaker by means of a single placement of a microphone, but you get the picture.


CJ

You got it ^

In theory, a perfect piston is the way to go, we just have to keep getting pistons closer to perfect, not go off on a course that can't ever be close to perfect because of inherent flaws.

This thread has gotten absolutely silly with all of the personal attacks and the arguments from people who understand just a little bit of physics (and that is not to say that I understand all of the principles at work perfectly).

I am an engineer. I work for a company in a field where proper acoustic reproduction of a source is of primary importance. I am also a DIY audio hobbiest. I have played with lots of first rate drivers from Accuton, Raven, Focal and Dynaudio. I've built various designs of cabinets. I've built all sorts of different crossover networks both series and parallel. I've invested in good measurement microphones and software. I've had varying degrees of success with my projects but they have always been fun.

I'm a junkie. I've always sold off my last project and worked on the next until recently. Two years ago I built a Manger zerobox using a pair of Lambda SB 10's in each cabinet and thought it was first rate. Still I thought I could do better with the crossover as the Manger just didn't mate up perfectly to the Lambdas even as good as they are. So I started to screw around with a Behringer active crossover just to see what I would find pleasing vs. buying a bunch of parts and building a batch of crossovers. Once I thought I had a good grasp on what I would like I bought some Mundorf parts and went back to a passive crossover.

Later I had an opportunity to purchase a used DEQX preamp and so I did. I took the Mundorf crossover out of the system and started playing with the DEQX software to correct for the bumps in my room response and selected a very steep FIR filter (something I couldn't do with the Behringer). The system was radically improved. The Lambda's and the Manger's mated up much more coherently. Now I'm not going to claim that this couldn't all have been done by someone who is an excellent crossover designer for a system in an ideal room but that just isn't the reality of what most of us have.

I've gone on to play with the DEQX with some of my other projects that haven't had much of a listen in some time and the DEQX does improve everything I've ever built. I can't claim that everything sounds perfect. I can say that my better projects with the DEQX best anything that I've ever heard that is commercially available. I can also say without hesitation that my Manger Zerobox project with the DEQX is far superior to any of my other projects.

My other audiophile friends also give this project heady praise. One friend offered to trade his Eidolons to me. Rather I've agreed to build a set of speakers for him, unfortunately the Lambdas are no longer available.

In any case, I wanted the rest of the forum to know of my experience in experimenting with these drivers and the DEQX. In my experience I've not heard anything that compares and that isn't to say that something isn't out there. But considering that it cost me roughly $4.5k to build my toys, I'm pretty certain that nothing I can afford would. Is there room for improvement? Yes. Do I stay awake at night worrying about it? No. I've finally got something that finally just reproduces music and lets me forget about the rest. This hobby is supposed to be fun. My system is that.

Well, I'll put a little bit of physics up against pseudo science any day.

Building a good sounding speaker isn't that difficult, especially with DEQX. Having one that actually measures well and is a real step forward is different.

I'd put my support behind that concept.

Now try it WITHOUT the DEQX. And better yet, evaluate the Manger driver ALONE with no crossover in direct side-by-side comparison with a comparable top rated driver operating under the same conditions.


Any VALID statement of superiority will survive a dispassionate, objective, level playing field test.


At the end of the day, I want my stereo system to deliver the intensity, enthusiasm, and glory of an inspired bunch of musicians putting their souls into their work....if that's indeed what they are doing. If the band is "off" that day, I expect to hear that, too.

I want accuracy. The burden of making it beautiful to hear is left to the musicians and recording engineers
and mastering engineers. Make a beautiful sound, record it with precision, reproduce it
with precision, and you get a beautiful sound.


I stand by and repeat my previous statement that the correct way to make a "perfect"
driver is NOT to make it work like a VERY imperfect eardrum. To attempt to do so is
simply, to borrow John's word, "pseudo science" at or near its very worst.

If you wanted to make a perfect robot, you would be a fool to give it a humanoid skeletal system. Our skeleton design is successful but has many problems, limitations,
and issues relating to our long and incomplete process of evolution and adaptation.


CJ

Hi Audiopath,

What a relief to hear from someone who is actually qualified to talk about the Manger driver.
As you can tell I have to repeat myself 10 times in order to make one simple point and if they don't like or understand the point they say :
"well exactly.... the Manger cant work cause no one else says it can work...."

They ask for science and white papers, I give them the science and white papers and they cant understand it!
Anyway that's all part of the forum fun and games and it sure makes me appreciate dealing with the open minded guys who enquire about my products.
Thanks for your input and sharing your experience with both high end pistonic drivers with passive crossovers and the Manger driver with the DEQX crossover.
I started out in the 1980's with ATC, Focal (JM Lab) ScanSpeak, Eton, & Raven, drivers and all the "Holy Grail " silver foil, air cored oil and angel dust passive crossovers. After about 10 years (I am a slow learner!) I progressed to active analogue crossovers with fully active bi or tri-amped systems.
This was a huge upgrade as in got rid of the dynamic sponges (or passive crossovers as some people call them!) which ruin time and phase coherence.
It was only in 2000 that I discovered the Manger driver at the High End show at the Kempinski hotel in Munich, Germany.
Wow! I thought if they can make it sound good (almost very good) in a cheap MDF box with a shallow sloped passive crossover and a wimpy ScanSpeak bass driver (I had moved on to Pro bass drivers by then) who knows what it will sound like with a proper cabinet, active crossover with steep slopes and a serious bass system!
And so it began... You know how it goes from there.

I have spent 1000's of R&D hours experimenting with both DSP and analogue crossovers blending the Manger with a range of bass and or low midrange / bass systems and I am happy to share a few (but not all!!!) golden discoveries with you.

(1) The DEQX is a ground breaking product and is very good value.
The Linear phase crossovers are superb. I have found that 66dB per octave up to 96dB per octave at 300 Hz gives really astonishing results.
Avoid going too steep as the minimum time delay will creep up towards audibility and be careful when crossing over to a sub at 100Hz or lower. Sometimes L R at 80Hz or 100Hz combined with Linear phase at 300Hz gives better overall results. The DEQX is still limited on computing power, (I am currently looking at an alternative DSP platform with 6 times the number crunching power of the DEQX) so try not to run it at its Max.
The room correction is superb and is actually able to perform as a full bandwidth driver EQ as well as room EQ. Some DSP platforms are only effective below 300HZ (i.e. Meridian)

(2) The DEQX speaker correction function is at best a waste of time & computing power and at worst it will seriously degrade the sound WHEN APPLIED TO THE MANGER DRIVER. It works beautifully with all conventional two or three way "pistonic" driver speaker systems. As the Manger is already a pure point source with naturally occurring perfect time and phase coherence the very best the DEQX could do, in theory, is to match this performance.
In reality its the accuracy of the speaker measurement that actually dictates the performance of the DEQX speaker correction and it is impossible to achieve the perfect individual driver measurements in any domestic environment. An anechoic chamber and pro equipment are essential to achieve the required perfect measurement results.

(3) The Switch Mode Power supply in the DEQX is a sonic compromise that I can not live with. The RCA & XLR connectors are also compromised in both electrical grounding and crosstalk performance. The A to D converter is very average and the casework and overall build quality (or lack of it!) gives rise to serious resonance problems. The digital volume control is very bad (massive loss of resolution) and the analogue volume control is not much better!

(4) Due to the short comings listed in (3) I have had to abandon all modifications and upgrades to the DEQX and I now simply buy in the raw DSP and mother board from DEQX and build my own unique design from the ground up. Its taken us over three years or trail and error (lots or errors!) and has proved to be very expensive ($15K).
The finished product is far too expensive to be on the shopping list of most domestic AV buyers but actually it is still good value at an average of $3,000 per function i.e.

(1) a six channel DAC,
(2) a two channel A to D converter,
(3) a full function remote controlled pre amp,
(4) full room correction with real time full bandwidth EQ,
(5) a superb USB to digital converter to facilitate state of the art computer audio playback.

So I hope some of the above helps with some of your DIY projects and please feel free to share some more stories as its a pleasure to reply to you!

Regarding the other recent postings by cmjohson and his supporters I wont bother responding to the repetition and rehashing of their flawed arguments and obvoious lack of understanding or experience. I think your last post will more than satisfy the silent majority of the other (approx 4,500 viewings on this thread!) forum members!
One QUALIFIED independant experience speaks more powerfully than all (4 or 5 of them!) the UN-QUALIFIED individuals with ZERO experience of the Manger / DEQX combination.
It really proves that you really should know what you are talking about before you say you disagree!

As always "Time Will Tell"

All the best

Derek.

Hi David,

Sorry about the delay in getting back to you, I have not been paying much attention to this thread recently as it has become boring and repetative (and therefore so have my replies to the repitition...!) but I just noticed your question.
I think I partially answer your question re the DEQX in my reply to Audiopath but here is some more advice on how best to upgrade your MBL 101 speakers.

(1) The MBL speakers will greatly benefit from going fully (3 way) active with the DEQX.
Find a genuinly experienced DEQX installer who can provide you with at least 3 or 4 very happy customers with similar big high end rigs. The DEQX is USLESS without the proper installation, in fact it will be a DOWNGRADE if it is not carefully set up and calibrated with the Earthworks reference mic, not the standard Behringer mic!
(2) Try to use three identical power amps as mixing and matching different power amps will result in phase errors occurring AFTER the DEQX has done its thing. Different power amps have different phase characteristics and its almost impossible to correct these in a domestic situation. Three identical "average" performance power amps will sound much better than one really superb power amp with two average power amps. Strange but true!
(3) Try to stretch the budget to buying the digital out option with the DEQX, THIS IS REALLY IMPORTANT. You can then (when funds permit) add on a 6 channel DAC or say three stereo DACS such as the Benchmark DAC 1 or some good second hand DACS as they are all crashing in price.
Using external DACS is a big upgrade as computing and DAC technology improves so quickly (every 18 months you get big advances) this will "future proof your "system as the core DEQX DSP functions are really superb you can always keep up to date with external DAC upgrades at low cost.
(4) Avoid all stranded cable everywhere, especially speaker cables and interconnects. The sonic reasons for this will become obvious when you start to approach time coherent audio performance. Locate your power amps as close to the speakers as possible and use short speaker cables and longer interconnects.
(5) Ensure your mains is as clean as possible, the ultimate is a series of giant 24volt SLA battery packs with DC to AC invertors to power your electroniocs.

I hope this helps and good luck with the project!

Cheers

Derek.

You could always buy the DEQX box with the digital output feature for about $4K, then add three excellent DACs for about $2000 and a 5.1 capable analog preamp for $2000 and have that level of performance for half the price.

I agree, this is getting silly, but obviously we have someone here who's got a product to push and, just like Bose, can come up with all sorts of "creative" reasons why his device is "perfect" and everything else is flawed. Yet, if it was such a great idea, with SO many
people out there trying to come up with the next better thing, why is there just one
company pursuing this one?


And I restate my earlier question, which went unanswered:

OK, explain this to me in a BRIEF description: If the Manger driver doesn't operate in the manner of a spreading ripple, and it doesn't operate as a conventional pistonic cone,
how DOES it operate?

How EXACTLY does it displace air, without which no sound can be produced?


Would you be so kind as to answer those questions, Derek? Perhaps your answers
may cause me to see the light as you see it.

But fail to answer those questions, and you'll take a hit on credibility in my eyes,
and MAYBE others will think the same thing.

I give you an opportunity to EXPLAIN rather than just resort to veiled personal attacks
and question my knowledge and qualifications, of which you actually know nothing.

But I'll give you a hint: I've been involved in various aspects of the electronics industry
for 32 years now.



CJ

Okay. I'm going to make this as quick as I am able. The reason I began work on designing a speaker with the Manger was because of its great measurements. This is also why I selected the Lambdas for the bass drivers. In any of my projects I've never tried to select some middle-of-the-road driver just to see if I could make it sound good and mate it up to some other drivers lying around my little lab. I've never aspired to go to market with a loudspeaker line so I've never had to make that compromise. I'm not trying to design to meet a retail price point. In every project, aside from my first few kits when I was a university student, I have attempted typically not to do something completely revolutionary but instead to build the best possible loudspeaker that I could afford to build. Typically my projects were inspired by my hearing some commercial offering that is far beyond my means. I began investigating and built a very nice pair of loudspeakers using the Accuton drivers after hearing Avalon and Kharma. That is also how I began playing with series crossovers. I take a lot of time and do a lot of measuring when building my speakers. I play with different box shapes and materials. I have invested in good measurement software and microphones. When I measure a loudspeaker I take it out to a football pitch behind my home so I'm not measuring in an enclosed space (sorry no budget for an anechoic chamber. Maybe if we have one more telecom boom). I also take the time to listen. I also draft my well-heeled audiophile friends to come listen and they can be brutal which necessitates my plying them with a few pints.

I have measured the Manger as well as my other drivers in free space and in enclosures and the Manger is superb. The Ravens were also quite nice. You'd be surprised how bad the Dynaudios and Accutons were in comparison. In measuring both the Mangers and the Ravens I put a simple high pass filter in the chain to protect both drivers from low frequency information that could cause damage. This is a common and accepted practice.

One of the great things about the Manger is that it is incredibly linear and that it can operate over so much of the frequency range. Since I was building a two way in a traditional tweeter on top design, I didn't have the worries of comb filtering and lobing when building with a passive crossover. I had one crossover point and the Manger sounded great with the Lambdas. Again I still thought that I could hear the difference between the drivers and measurement did support what I thought I heard. My design incorporated a series crossover and I considered building a steeper sloped parallel design but the phase coherence issues inherent in those designs is what gave me pause. That is when I picked up the Behringer to experiment. Yes, I know they tend to be a bit noisy and they are not "audiophile" quality but they are still a useful tool when looking for flexibility in design and voicing. I later built another passive crossover using what I had learned with the Behringer and I used Mundorf parts. I thought the Manger with the Lambdas were so good that it was only fair to use the best components that I could manage. I'm not aware of any commercial design that uses such high quality components throughout.

Then came the DEQX. No one seems to be debating how good and revolutionary this product is so I won't go on about it. My crossover point is also at 300hz as I didn't want to affect the range of the human voice so much. I love that the Manger remains completely coherent through this range and the little bit of information added by the Lambdas also ain't bad. The Lambdas can be crossed over much higher and still be very clean but coherency of the instrumental and vocal presentation was my primary concern. Using any other mid/high-mid driver would have forced me to adjust my design decision. I agree with Derek that the A/D section of the DEQX is sub par. I don't find myself listening to my treasured vinyl so much now. I'll fix that at a later date. I also think that the D/A section is also not so great and I run two identical DACs from the DEQX and then into my amps. Yep, it sounds pricey but Audiogon is my friend. It would not surprise me that Derek and his electronics designers have been able to drastically improve the performance of the DEQX. That would seem to be a worthwhile investment if designing a state of the art assault on the high end. I'd like to hear it. Maybe Derek can indulge me in my next trip to the UK even though I could not be considered a candidate for purchase. If only the guys at Lotus could be so equally enthused and indulgent.

Incorporating two of the Lambda SB10s in the cabinet means that I have a big cabinet. They move a lot of air. They do what the Manger cannot. With the DEQX the entire system disappears and low frequency extension is also improved. I have two criticisms of the Manger, one is that it does beam at high frequencies. Moving out of the fairly wide sweet spot does roll off those high frequency harmonics that add life to the music. It does not affect the primary tones of the instruments. The second criticism is that it can be so revealing that a lot of my favorite music is revealed to be recorded poorly or overly processed or whatever. You take my meaning. I also imagine that it is revealing enough to really show the different qualities of the equipment chain. I'm not a tweak of the week guy so my equipment chain has not been changed in the past couple of years outside of the purchase of the DACs. But back to the problems with recordings, a lot of my favorite rock just sounds lifeless as it has been compressed to death in post production. I'm talking to you, Tool. Take a lesson from Porcupine Tree.

And lest the naysayers think that too much Twisted Sister in my youth has affected my hearing, I'm offering up the proverbial Pepsi challenge. If anyone is in Charlotte for business or lives nearby, I would love for you to stop by and enjoy a bottle of wine and some music. I think once you hear what these drivers are capable of doing (I also still have the passive crossovers and could put them back in for comparison's sake) particulary with the DEQX smoothing out the room some of the skeptics can be satisfied. From there we can move on to debates much more deserving of such rancor, religion, politics, and one's right to appreciate a sheep wearing lipstick.

I agree, this is getting silly, but obviously we have someone here who's got a product to push and, just like Bose, can come up with all sorts of "creative" reasons why his device is "perfect" and everything else is flawed.

It's the "everything else is flawed" part that is most annoying. There's nothing at all flawed about a perfect [the theoretical one] piston and the closer we get, the more transparent the sound gets. Sure, there are cool things about a single point source for mid/treble, just like there are cool things about 1st order design or dipoles or ribbons or whatever but all of these things are also flawed and none are inherently superior.

The second criticism is that it can be so revealing that a lot of my favorite music is revealed to be recorded poorly or overly processed or whatever. Y

Keep in mind that we hear the exact same comments from owners of speakers that are also high in midrange distortion. Having not heard the Manger, I can't say *however*, people I trust say it's very high in distortion and that is its Achilles heel. When we put some of this "poorly recorded" CDs on speaker we know to be of low measured distortion, many, if not most of these CDs turn out to be very good sounding after all. Typically, a truly poorly recorded CD is fairly obvious on most speakers, not just a few elite ones.

John, yes you are correct. I am trying to get past the hype and just hope that the Manger is not being unduly dismissed. I have built and I have heard commercial designs that will also reveal the differences in sources and equipment choices. I have not changed equipment feeding my latest speakers so I cannot comment as if I empirically know that it would do the same but I trust that it would. I can say that it does reveal more about my recordings than anything else I have heard before. The ones that are bad are always bad, the ones that I thought were good are usually not as good as I had thought, the recording that are indeed great remain so. On a good recording it is amazing how much more you actually seem to hear. It's not quite like listening to truly live music but it is much closer than it has ever been.

As for your friends' measurements of distortion, I cannot comment. I can say that my own measurements do not show the Manger to be that way. The Manger is typically lower in distortion than anything else I have measured. I can also say that when listening to music in my system I don't ever feel like it is overly harsh. Only the biggest recordings ever seem to sound like there is some congestion in the system. And this really is picking nits, most anyone else would probably not notice but the point is that these are not exactly like being there. I don't know of anything that is. It's also why I try to take in as many good live performances as I can. I love music. I want music in my home to bring me as close to that live performance as it can. I was never able to see Miles Davis, or Led Zepplin but I want to close my eyes and listen as if they were there. Every one of my projects seems to get me a little closer. Without the Mangers and the DEQX I wouldn't be as close as I am today. I hope that you can hear these one day. I think you will be quite pleased even if they aren't perfect.

Well, you know, in this case it wasn't the driver, it was the messenger ;)

Oh and everything is flawed, including the Manger as you have noted but I suggest that we can all forgive a man for his enthusiasm and pride in having built an unusual system that is there to help us all celebrate music. Derek is not some nut or charlatan. If I had the same resources I would try to refine my own system and I would continue to try to improve the system using the Manger versus some other type of driver. It's not like Derek is promoting multi-thousand dollar cables, subatomic cable filters, electron aligning paint, or some chi and chakra tuning devices. He's not claiming that he can help you find the G-spot. I can only hope that everyone here is as vociferous in challenging the next batch of candidates seeking election.

Hi Audiopath,

I can really relate to your no compromise "best of the best" attitude and one day in the spring or summer I would love to come over and hear your Deqx / Manger system.
I hope some of the more open minded forum members are able to make the trip before then and let us know what they think.

Musical enjoyment comes down to personal taste at the end of the day but even those long in the tooth "32 years in the business" (or his first year repeated 31 times!!!:) ) hooked on conventional is best "cause my daddy did it that way and his daddy before him...!" will be able to recognise the natural and life like beauty of the Manger driver.

By the way we just fitted out a beautiful home cinema with in wall Mangers and shallow profile bass drivers with two Predator subs and two DEQX crossovers.... Holy moley! Imagine the 3D soundstaging of a two channel Manger rig and then scale it up with a high end DVD front end (Denon AV1 & Lexicon) and the realism really is scary!
Interesting side bar: the standard definition Denon AV1 sounded way better than the latest Toshiba High Def player and also had superior picture quality on all standard definition DVD's.
Your point about poor recordings is also a good one. The low grade recording quality you talk about is a huge problem in both music and video.
Remember that the most common studio monitors are Genelec (or any one of twenty or thirty Genelec clones) and these thin sounding shrill active boom boxes are what the recording "engineer" uses to monitor and master the sound.
I have long been an advocate of an international audio standard for recording and mixing engineers (we already have one for picture quality and THX for replay of sound ) recording equipment and monitors.
Here is a quote from one of my earlier posts in this thread.

" By targeting or voicing an audio system 100% on natural (unamplified) vocals and instruments we can be sure that it is starting from a correct and neutral position.
Just as we have the internationally accepted pantone colours and colour charts for calibrating video screens.
What works for international picture calibration would and should work for audio.
This would enable us (or any other company that uses the Conductor or a high end DSP) to then add more bass more top, more whatever at the end user stage to fine tune the system according to room acoustics and the sonic preferences of the customer (end user). Again when you buy your high end plasma or screen it is individually calibrated to suit your room and your taste.
In an ideal scenario all recordings and studio mastering of movie sound tracks would be created and monitored using an identical and internationally accepted "reference" system.
Maybe one day."

It is illogical to have international standards for REPLAY of music and movie sound tracks (as well as video picture quality standards)and no standards at all for the recording process!
The present state of affairs is that all the AV hardware industry must meet strict standards for replay and we are asked to "trust our investment to chance" when it comes to the recording process! Things must change in order to redress the balance and provide some protection for the customers investment (often substantial investment) in audio equipment.

Thanks again for your input to this thread.

There I will get off my soap box now and finish with a note to cmjohnson.

Mr Johnson, the answer to your last question is no!
I have already clearly detailed (several times !) in this thread all the mechanical principals of the Manger driver, please read through my postings on this thread.
There is no short and simple answer or explanation but there are several detailed and easy to understand (by most other peoples standards) although quite lengthy explanations on the Manger driver mechanical and electrical operation. They are all on the Manger web site with graphs and there is more background and general information on my web site.
I cant respond to any of your quotes from alimental as he is blocked from my screens I don't have to waste time reading his posts.

All the best and a very Happy Christmas to all forum members!

Derek.

It is illogical to have international standards for REPLAY of music and movie sound tracks (as well as video picture quality standards)and no standards at all for the recording process!

A standard for playback *is* a standard for recording by its very nature.

I cant respond to any of your quotes from alimental as he is blocked from my screens I don't have to waste time reading his posts.

Or dealing with questions that you can't answer!

Away, in a Manger...

Mr Johnson, the answer to your last question is no!

It looks to me like the answer is "yes". http://www.manger-msw.de/en/produkte/index.html

The ripple goes out, but it doesn't stop until it gets to the edge (and likely not totally then either). You can see how a 10kHz tone has about 12 peaks and twelve dips, but each successive one would be delayed in time and reduced in volume. As the frequencies go lower, they would behave better as the diaphragm becomes optimal for one frequency, then ceases to work properly. The felt star patter looks like an attempt to make it work over a broad range and dampen down the upper range ripples that shouldn't really exist. IMO, the scans show what is wrong with the concept. Now, maybe after all of the waves are summed, what is left is a decent sound, I don't know. But it's far from perfect, further, on paper, at least, than a pistonic transducer. I don't know what the problem is with a piston, other than the fact that it makes too much sense and Overkill isn't the only one using it.

I have gone back to the Manger site and re-read the .pdf that includes the description of the operating mode of the Manger driver, as well as ALL of your posts in this topic, Derek.

You are what I call a compulsive double-talker. You never want to get down to business
and answer a straight and simple question with a straight and simple answer. Your "explanations" of how the driver work do not merit the term "explanation" but are nothing
but so much obscuration and doubletalk. Your explanations answer no questions in any
relevant or meaningful way.

I learned a LONG time ago that the best engineers give the simplest answers when asked
simple questions. It's the engineers that suffer from shortcomings that will load you
down with a ten-page answer that answers nothing, in response to a simple question
that takes just one sentence to ask.

In fact, PER THE .PDF at the Manger site, the driver has a voice coil and a magnet
assembly and the driving impulse itself is the same as that of a conventional pistonic
driver, though the transducer element itself (the cone or face) is designed to operate
in a different manner.

Different manner or not, the end answer is that the "cone" still displaces air by means
of forward and backward movement of the active section of the cone, which really
means that it's not a fundamentally different driver at all.

What IS different about it is that it's DESIGNED to operate in what some call bending
wave mode but I choose to describe it as a spreading ripple mode, which I believe is
an extremely accurate way of looking at it.

I believe that this is not an optimal way to design a speaker. While it DOES eliminate the
distortion-causing effects of the edges and surround structure of a conventional speaker, it still has its own problems, chief of which is that the entire concept of
operation is fundamentally and seriously flawed.

Yes. Fundamentally and seriously flawed.

Let me explain:

You would argue that in the "real" world, sound comes from point sources, and though
this is USUALLY not true at all, I'll buy that for the purpose of education. So you
argue that sound generated radiates from a point source in a ripple, so to speak,
and so does that generated by a Manger driver.

WRONG. Sound radiated in the real world radiates in a spherical wavefront, or at least
in a spherical section if free radiation isn't possible in all directions due to obstructions.

This is a three-dimensional phenomenon. Think of it as a rapidly spreading bubble of
denser air, followed by one of less dense air as air pressure equalizes behind it.

The Manger driver expresses the signal as a spreading ripple, which is NOT a faithful
representation of the spherical wavefront, but only a two-dimensional shadow of it.
A visible slice of time during the operation of the Manger driver would show a radiating
ring pressure wave, at least near the driver. Ideally, the radiated sound should be
a spherical front. But the Manger driver doesn't generate a spherical wavefront,
it generates a ring shaped wavefront which will propagate both outward away from the
center of the generating location AND inward as well, causing varying amounts of
both constructive and destructive interference, depending on frequency.


A good pistonic driver comes much closer to generating a spherical wavefront over its
operating range.


CJ

Well, I guess this argument isn't going to die over the holidays! (Unless I suppose the thread is closed...)

If only we had a bright scientist type to act as a judge on this.........

Yeah, where's Morbius when you need him! (Of course I guess he'd probably take whatever side you're not on, so what's the use! :D)

Just a glance at the technical notes about the driver look very interesting but I just haven't had the interest to drill down and really figure it out.

If only we had a bright scientist type to act as a judge on this.........

If only there were a speaker to listen to.

......that didn't cost stupid amounts of money.

I was never able to see Miles Davis, or Led Zepplin but I want to close my eyes and listen as if they were there.

I was lucky enough to have seen Zeppelin twice, and it would have been at least three times if Bonzo Bonham would not have basically drank himself to death.
As I had a "inside" line on getting tickets to see them at the old Chicago Stadium for that tour.

But, all may not be lost for you, or me.... As there are still rumors of a limited World and US tour by them in 2008.

Until that is confirmed, there is always the youtube videos, of their recent UK tribute concert.

http://www.youtube.com/watch?v=k7vO3sORuCo&eurl=http://www.youchoose.net/campaign/led_zeppelin_world_tour

Trust me, from have seeing them live in the past, after watching the Kashmir video, I say these guys still have it!
They may look a lot older, but they have not lost much, and they can still put a lot of the other newer popular bands that are out now to shame.

Just watched the You Tube link. Wow. Goose bumps. If this ever comes out on DVD I'll have to break down and hook up a TV to the stereo system. If they ever tour I'll have to break down and forgive Jimmy Page for whoring himself out to Puff Daddy and his constant remix and rerelease of the Zep catalog.

Funny. That You Tube video is the worst quality video and audio of anything that I've seen in the past month but also probably the single most exciting thing I've seen.

Hello cmjohnson,

Thank you for taking the time to read the Manger information and re-read my posts (they are too long but I am not a great editor!) and here I will try to give bullet point answers which should focus us on the (9) specific points you make.
First it is worth noting, (to your credit!) that you have now picked up the correct terminology for three of the phenomena we are discussing. Unfortunately you have still failed to understand the mechanics of the phenomena and more importantly completely misunderstood the context of how they apply to the Manger driver. (See points 3,7,8, and 9)

(1) Your quote ;
" You are what I call a compulsive double-talker. You never want to get down to business
and answer a straight and simple question with a straight and simple answer...."

I disagree (of course!) I have given very detailed and accurate answers using a comprehensive mixture of science, maths and plain old English, i.e. the pebble in a pond and ripples heading out from the centre is a description I have used for years as well as in my recent posts here. Most people including yourself can easily visualise the effect.
The more complex maths and physics that I have to use to give an accurate description is not easily understood by the majority of people but please don't make the mistake of dismissing the Manger driver out of hand just because you cant understand the complexity of its operation.
Many people dismiss "String Theory" just because it is not easily understood and more importantly its not easy to describe in a 90 second summary to impress your peers (some scientists have huge ego's!) over a glass of red!

All I am saying is that there is a technically superior method of converting electrical energy into Kinetic energy (sound waves) and if you care to visit Audiopath you can hear the truth for yourself.
If you make $100 an hour why not work an extra 5 hours instead of spending the next 5 hours of "forum ping pong" ( although its good fun!)
and spend the money on a day trip to Charlotte Carolina and visit Audiopath!
Then even if you love the sound of his system you can always lie and come on the forum and really do some damage to me...!

(2)Your second point, :
"I learned a LONG time ago that the best engineers give the simplest answers when asked
simple questions. It's the engineers that suffer from shortcomings that will load you
down with a ten-page answer that answers nothing, in response to a simple question
that takes just one sentence to ask. "

Is that true Mr Johnson? Well here is my simple one sentence question....

Explain String Theory, thanks.
Or how about...
Explain the oceanic conveyor belts relationship with natural climate change?
Or would you prefer to tackle...
Cold Fusion versus nuclear fission....

Please refrain from your ludicrous sweeping statements and I will refrain from exposing them! Thanks.

(3)Your point ;
"In fact, PER THE .PDF at the Manger site, the driver has a voice coil and a magnet
assembly and the driving impulse itself is the same as that of a conventional pistonic
driver, though the transducer element itself (the cone or face) is designed to operate
in a different manner.
Different manner or not, the end answer is that the "cone" still displaces air by means
of forward and backward movement of the active section of the cone, which really
means that it's not a fundamentally different driver at all. "

Wrong again !

The patented electrical and mechanical operation of the twin (70mm!) voice coils (total Mms 0.04g!!) DO NOT GENERATE ANY FRONT TO BACK DIAGHPHRAM DISPLACEMENT AT ALL.
IT IS NOT PISTONIC!

Mr Johnson please understand this:
A world war 1 propeller driven aircraft and a 2007 Euro Fighter jet both use hydrocarbon fuel to generate thrust BUT THEY OPERATE IN A VERY DIFFERENT MANOR!
There is, I am sure you will agree, a vast difference between the two engines operation despite the common use of hydrocarbon fuel..
Now just because two loudspeaker drivers both use copper & neodymium this does not automatically dictate that they must share any other features or functions.
Do you understand this analogy?

(4) Your next point:
" What IS different about it is that it's DESIGNED to operate in what some call bending
wave mode but I choose to describe it as a spreading ripple mode, which I believe is
an extremely accurate way of looking at it."

I agree with you!

(5) Your next point:

"I believe that this is not an optimal way to design a speaker."

I disagree with you!


(6) Your next point;

"While it DOES eliminate the distortion-causing effects of the edges and surround structure of a conventional speaker, it still has its own problems,"

Yes I agree with you!

(7) Your next point:

"chief of which is that the entire concept of operation is fundamentally and seriously flawed.
Yes. Fundamentally and seriously flawed."
I disagree with you!
Please don't take this personally but you are in way over your head, you simply do not know what you are saying and are clearly not qualified to pass any meaningful judgement.
You and I and every individual are all entitled to voice our opinions but I believe your opinion has no credibility and is based on a total lack of knowledge of the subject matter. The next point underlines this situation clearly.

(8) Your next point :
" Let me explain:
You would argue that in the "real" world, sound comes from point sources, and though
this is USUALLY not true at all, I'll buy that for the purpose of education. So you
argue that sound generated radiates from a point source in a ripple, so to speak,
and so does that generated by a Manger driver. "

Now please let ME explain!
All sounds do come from a point source.
A point souce as defined as "having an acoustic centre or point of origin in three dimensional space"
A snapping twig, a grand piano, a clap or thunder, a triangle, or finger snap, every sound has a point of origin.
Regardless of the scale of the acoustic event every single sound starts as a point source.

NOW LETS BE CLEAR, I HAVE NEVER "argued" THAT SOUND "RADIATES FROM A POINT SOURCE IN A RIPPLE"
These are your words not mine.
It is one matter when you fail to understand an answer, it is another matter altogether when you start claiming that I am making basic errors!

As every basic text book on acoustics explains with lots of easy to understand diagrams sound expands equally in all directions in 3 dimensional space. A point source with a continuous expanding bubble is a correct description.

As I have previously stated.... yawn yawn.. what the Manger driver does is RE-CREATE the initial pressure wave of the POINT SOURCE event with astonishing accuracy and PERFECT TIME AND PHASE COHERENCE!
The sound then CONTINUOUS TO EXPAND OUTWARDS IN A SPHERICAL PATTERN!

All live sounds follow the point source origin with following spherical expansion pattern.
Now all acoustic drivers re-creating the original sounds ATTEMPT to do exactly the same.
If you stand behind or beside or in front of a speaker the only two reasons the volume will vary are interference and cabinet artefacts.
There is absolutely nothing inherently different about how ANY raw driver radiates (NOTE RADIATE NOT ORIGINATE!!!) sound into 3D space from an actual live event i.e. A piano will radiate equally into 3D space, so would ANY driver if it was not for the cabinet and interference patterns caused by inherent cone / dome / ribbon / diaghphram characteristics and properties.

(9) Your last point beautifully encapsulates your INCORRECT understanding of the Manger driver.

"The Manger driver expresses the signal as a spreading ripple, which is NOT a faithful
representation of the spherical wavefront, but only a two-dimensional shadow of it.
A visible slice of time during the operation of the Manger driver would show a radiating
ring pressure wave, at least near the driver. Ideally, the radiated sound should be
a spherical front. But the Manger driver doesn't generate a spherical wavefront,
it generates a ring shaped wavefront which will propagate both outward away from the
center of the generating location AND inward as well, causing varying amounts of
both constructive and destructive interference, depending on frequency."

Again as I have described above and previously this is not how the Manger works.
For the last time... and using the fewest words I can!...
The Manger Generates the initial compression or transient impulse by generating a circular wave (ripple in the centre of the pond) which is completely absorbed by the star shaped acoustic dampener (not a conventional surround) around the outer edge of the driver (think reeds around the edge of the pond).
This pure point source transient then expands outwards into the room in exactly the same way as any other driver!
The "MAGIC" of the Mangert is in the quality of the re-created point source transient i.e. its total freedom from ghost echoes (the YO YO oscillation of a mass on a spring effect that ALL cones domes ribbons and panels are afflicted with) and complete linearity over a the 300Hz to 30KHz bandwidth AND its complete lack of any crossover above 300 Hz.

I could again elaborate on the vital importance of the SPEED of both rise time AND settling time of the Manger when it creates the initial transient pressure wave, or the crucially important flat resistive load with ZERO capacitive or inductive properties and the associated freedom
from unwanted energy storage, or the vital importance of the beautiful tear drop shaped cabinet and SDC material ....but as you are not able to cope with the basics I doubt the more advanced features will appeal!!

"Time Will Tell"

All the best
Derek

PS
I disagree with your last sentence as well!



:)

OK , let's cut it all the way down to the simplest possible question:


If the Manger driver "DOES NOT GENERATE ANY FRONT TO BACK DIAGHPHRAM DISPLACEMENT AT ALL. IT IS NOT PISTONIC!" then how does it generate pressure
waves in air?

If it works as a spreading ripple, and ripples are three dimensional phenomena in a
solid material, then it seems to me that it MUST create some front to back displacement
otherwise it can't generate pressure variations in the air.


I've read and re-read the description but can't get the answer I want out of it.

Maybe it could be visualized using Matlab?


No displacement of air mass means no sound generation. It MUST displace air...so if
it doesn't do it with the aid of any front to back displacement, how DOES it do it?


CJ

The Manger does behave as a piston at the lowest frequencies. The way the Manger works is by using two voice coils that work in a push pull fashion against a diaphragm of with varying surface tension. If you could take a picture of the Manger with a high speed camera and then slow it down one would see that the impulse fed to the Manger generates on the surface a small hemispherical point that spreads as a ripple across the diaphragm's surface. One would be correct to surmise that the off-axis behaviour is different from traditional cone and dome drivers just as it is different from a ribbon. I would not argue that the Manger is superior in off-axis measurements to all others. There is a pretty good description of its behaviour found here: http://www.freepatentsonline.com/3686446.html.

To describe the Manger as radiating in a two dimensional space would be an error. There is a ripple on the surface of a two dimensional plane thus three dimensions. Since the Manger also is a large diaphragm generating a wide range of audible frequencies the Manger is not perfectly uniform in its radiation pattern for all frequencies. But neither are cones and domes, hence the various sizes applied for the different frequencies to be generated (outside of the considerations of the driver's mass). The Manger is large enough to serve as its own baffle at higher frequencies.

The diaphragm's material and the star shaped damper on the surface plus the damper that is of a differing material and density on the underside of the diaphragm are what contribute to absorbing reflected energy and standing waves on the surface of the diaphragm. This is by design.

The motion of the voice coils is indeed pistonic but the diaphragm behaves differently. The diaphragm is not designed to be the surface of a perfectly rigid and uniform piston. Also why the Manger doesn't have a resonant frequency in the same manner as cones and domes, which has to be accounted for with clever crossovers. Obviously good loudspeaker manufacturers also choose differing materials in drivers for different applications to make neutral sounding and efficient n-way loudspeakers. They try to crossover the drivers to minimize exciting the various driver's resonances. This is not a concern when building a loudspeaker using the Manger. Another thing to keep in mind is that the Manger does not have the same excursion as a traditional driver. It moves air very quickly but without huge amounts of force.

I am not touting it as perfect. A careful designer does have different concerns when starting a design with the Manger. I do agree with Derek that the DEQX's speaker correction function is unecessary to apply to the Manger and can actually hurt the performance.

If anyone wants to see a really cool DIY Manger project check out: http://users.skynet.be/accupulse/

This is a beautiful job. I wish I had the ability to make such a nice cabinet, although I'd probably still want to make an egg shaped head unit for better dispersion (similar to Derek's design).

I realized that I forgot to include this in the description of the diaphragm's properties: http://www.freepatentsonline.com/3937905.html

Hi Audiopath,

Thanks for your excellent and un-biased description and explanation which actually reads better (with fewer words as well!) than my efforts to date.

All the best

Derek.

Audiopath, we do understand it, we just don't have the rose colored glasses about it that Derek does.

For instance, if all the panel did was one ripple per frequency, that would be pretty close to an ideal thing, but it doesn't. As the frequencies get smaller, you would have more ripples, more *time* distortion (smear), higher distortion and poorer dispersion. You can't make the thing behave ideally at all frequencies. A pistonic driver will behave pretty close to ideally below a certain frequency, so that's why you cut it off before it gets to that. DEQX is *ideal* for working with pistonic driver. Further, you can't say that there are *no* reflections. Of course there are. Just as a pistonic driver will have some overshoot. The Manger driver just has a different type of overshoot. You can see this in the laser scans of the driver's behavior. There should only be one ripple per frequency, but that's not the case.

Derek why are you wasting so much time and energy with CMJohnson? No Offense CM Johnson. He obviosly is not a potential customer and is very content on not letting you promote your speaker. Maybe he feels he is doing us all a great favor, so we don't get bamboozled into ordering your expensive speakers without ever hearing them...or maybe he's drinking to much RED BULL;)

THE BOTTOM LINE IS IF THE SPEAKERS DO SOUND FANATASTIC THEN THE WORD WILL GET OUT AND THE SALES WILL COME BASED ON PERFORMANCE IE: SOUND LAB

but if they do not sound good then you will have to use clever marketing tactics and pay reviewers to get the word out. Wasting what I assume is your valuable time on this forum does neither.

I for one, wish you the best of luck in your endeavor...

Now if only they could invent a small teapot that doesn't spill..:(


Joey

John, you are not correct in assuming the appearance of a single ripple. One would notice a single ripple for a single cycle of a given frequency. A continuous signal will display multiple ripples of a certain frequency. One should notice proper and symetrical width for the given frequency, which is what is on display.

Hi Joey,

Thanks for your advice and I know its good advice but one of my (many!) failings is that it pains me to think that I have failed to explain something so important (to me anyway) and that the "rumour mill" will start fouling the USA waters before my products can get there! Agghh I see big halls and empty chairs...!

Joking aside, I suppose I should stop replying to some posts but apart from the two members I have blocked from my screen, I do feel that all the other guys are actually interested in the truth.
I don't mind spending time chatting or posting with any members at all even those who would never consider spending $50K on a speaker system.
I am fully aware that only a tiny percentage of the AV buyers are in the market for my products but it is still good to share ideas and brainstorm different ways of building and designing new products.
I know I come across as a real cocky know it all when I get on my audio soap box but when I am calm (like now) I admit the truth, that I have a lot to learn in life as well as audio. Every single AVS member can teach me "something about something" and I actually never forget that.
Also I am basically not sleeping at the moment as Petra and I have twin sons (12 weeks old) so I am sitting here half asleep with Ryan in one arm and keyboard in the other!

Thanks again for the reality check and have a great Christmas.

Derek.

That's what I'm saying ^ There is no single ripple. That's the issue.

In any case, this reminds me of the Wankel rotary engine. I'm sure it was going to take over the world as well!

Hey, John. We're not connecting on this last one. Is what you think you are seeing a single pulse of a specific frequency and resulting distortions? I'm not sure what you think is being represented. What is being displayed is a continuous sine wave of a given frequency. That is why you see more than one ripple emanating from the center towards the edge of the driver. Notice that the center demonstrates the most energy as it is the current pulse and as a ripple moves out you will notice that it is less intense as it decays. You can see that it is a continuous sine wave that is applied and not a complex wave as the peak to peak distances are consistent. It is not a single pulse or cycle of a specific frequency on display. I also note in looking at this a lack of returned energy from the edge to the center. This could be because the absorbtion and isolation at the edge is just soooo good or it could be that this "snapshot" was taken very carefully at the beginning of the cycle. I'd like to see this done on video as that would answer a lot of questions for all of us. But in any case the Mangers do sound great.

Addressing something completely different, someone at the beginning of this debate had asked why no one else was really using the Mangers for commercial designs. I would guess that it is due to the expense of these drivers. My god, they are expensive. Manger also has pretty limited production capabilities and pretty limited marketing budgets. Plus they always want to sell you three units for the one that you really need. In the years that I have known about Manger and since I bought my first pair to play with, the Manger website has not been changed. No new articles, no new marketing fluff, etc. In the US they had a distributor, then lost that, and now have a new one that I don't think does a lot either. They have had a bit of a cult following in DIY circles and have made some headway in some pretty elite recording studios.

John, I think you're in the home theater business. If you are going to CES you might take some time and look up the US Manger distributor and listen to the Zeroboxes and come back and let us know your impressions.

I should rephrase my sentence in that last post to: I'm not sure that I understand what you think is being represented.

The rotary engine never really took off, did it? Still I'd have been happy at one time with a pretty nifty sports car that used it.

Now I lust for a Lotus.

Actually, those darn Porsches and VWs were pretty popular with their air cooled engines. That wasn't the norm either and there was a pretty good argument for their superiority in certain applications at that time. But I take your meaning. They are all water cooled now.

The poor Manger may indeed be doomed due to the financial consideration of applying it versus using a less expensive set of drivers that can be corrected with a cheap DSP. As DSP horsepower continues to increase the argument for many high end drivers made from rare unobtainium may make less and less sense. Sorry for all of the multiple posts.

Interesting, and the clarification has been helpful. But I see some interesting technical
challenges, which you may or may not choose to describe as design shortcomings.

If one voice coil is pushing on the "cone" (though it's actually a disk) while the other is
pulling on it, this will introduce flexure and start the radiating ripple effect, BUT...for any
given frequency to be produced, there's an optimal spacing between the two voice coils
in order for the unit to operate efficiently. Obviously spacing between the two voice
coils can't be physically changed, so you would have to simulate it by introducing timing
delays into the system for one voice coil. The delay time would be determined by the
frequency being reproduced at that moment. The lower the frequency, the greater the
delay. Ideally, the two voice coils will operate 180 degrees out of phase at any given
frequency.

But there's yet ANOTHER issue to contend with: Complex signals. When a driver is
asked to produce several frequencies at once, there's no one RIGHT delay setting.
You'd prioritize the delay setting to track on the strongest component of the signal,
but that's still a compromise.

Another question to be asked is, is the speed at which the "ripple" propagates across
the cone equal to or near that of the speed of sound in air? Ideally it'd be the same
speed and I can imagine that there would be problems if it wasn't a close match.

And, yes, there IS front to back displacement of the transducer disc, which is
an absolute requirement for it to produce sound. Whether you think of this front
to back movement as cause or as effect, the truth is that without it, there can be no sound.



I'm not against the Manger driver, I'm against the ludicrous statement that all conventional pistonic speakers "can't work and don't work" which is a load.

Hey, John. We're not connecting on this last one. Is what you think you are seeing a single pulse of a specific frequency and resulting distortions? I'm not sure what you think is being represented. What is being displayed is a continuous sine wave of a given frequency.


Well, if it doing it's job precisely, a constant sine wave would cause a single ring around the center and nothing more. There would be a rise, a fall, then absorption. That would cause the air next to the ripple to move forward, then backward, then repeat (as it's a sine wave). But what is happening instead is that the air near the center is moved, then the air next to it, then the air next to that, in succession, so that means that the air that began to move near the center will cause sound to reach your ear before the air that is moved near the edge of the driver. That's probably what causes at least some of the measured distortion and the beaming. To work as well as Derek wants to think this driver works, you'd have to have driver be about 1/2 wavelength long (or maybe it's one wavelength). To be honest, I'm not sure how the driver would function well below about 4000Hz without lots of distortion, not much over about 8000Hz without lots of beaming. That's why I'd love to see comprehensive *independent* dispersion and distortion measurements.

Addressing something completely different, someone at the beginning of this debate had asked why no one else was really using the Mangers for commercial designs. I would guess that it is due to the expense of these drivers. My god, they are expensive. Manger also has pretty limited production capabilities and pretty limited marketing budgets. Plus they always want to sell you three units for the one that you really need. In the years that I have known about Manger and since I bought my first pair to play with, the Manger website has not been changed. No new articles, no new marketing fluff, etc. In the US they had a distributor, then lost that, and now have a new one that I don't think does a lot either. They have had a bit of a cult following in DIY circles and have made some headway in some pretty elite recording studios.

Well, like the rotary engine, they may be simply a different and competent way of doing what a more common technology does. It *is* innovative and unique, I'm only saying that this doesn't automatically translate to good, let alone a good value or world beating. I suspect that if it didn't at least sound good, no one would use it. Of course, people absolutely love a lot of things that I think are very much lacking, like horns, single drivers, etc.

John, I think you're in the home theater business. If you are going to CES you might take some time and look up the US Manger distributor and listen to the Zeroboxes and come back and let us know your impressions.

I am. I won't be at CES, but maybe if I run into them at CEDIA or something. I'm far more curious about the Manger driver than I am about Derek's stuff, which would be ridiculously overpriced even if it was as good as he thinks it is. If I were big into DIY, heck, sure I'd probably get a couple of drivers just for the fun of it!

The rotary engine never really took off, did it? Still I'd have been happy at one time with a pretty nifty sports car that used it.

Now I lust for a Lotus.


Hey, that RX-8 is still out there!

Well, if it's DIY you want, it does look like there is a somewhat slow thread on the Manger driver over at the DIYaudio web site.

http://www.diyaudio.com/forums/showthread.php?threadid=5803

Started in 2002, its most recent post is from last month, after only 4 pages.

Oh, yeah baby, we're kicking their asses with this thread :)

Funny. That You Tube video is the worst quality video and audio of anything that I've seen in the past month but also probably the single most exciting thing I've seen.

Yeah the quality of the video and audio was not at all that great on that song even though it is one of the better ones, but it was also more than enough to see that the actual performance by them sure was and that they still have what it takes. I viewed a few of the others, there might be one or two that are slightly better on the A/V quality than that one, but there is a whole bunch of them where the quality is a lot worse. There is also a clip from a UK TV news station that looked really good, but it also shows only a small fraction of a song.

If you noticed most of the people that were making the recordings, were only using camera/video equipped cell phones and also normal small hand held video recorders. Of all the videos I watched, I only seen one instance in the crowd that looked like they might have had some sort of "pro" A/V gear setup, it was pole mounted video camera of maybe about two to three times larger than the size of most normal low to mid range consumer video recorders, it was very close to being right at about center stage and I'd guess somewhere in the range of maybe 10-20 rows back, and it was also going back and forth at a height of about two feet over the standing crowd like it may have been mounted on a mechanical powered dolly of some sort. If it was any sort of "authorized" pro setup, then I'm guessing a DVD would maybe be something that might be in the near future.

One thing is for sure, they either fully allowed people to take pictures and videos of that concert with no restrictions at all, and if not, then they did the absolute worst job in the world of trying to police and prevent it.

:)Hi CJ,

This is very interesting indeed, but to be honest I am not sure I fully understand what you are saying / asking but if I am correct is the following of any help?

(1) There is no time delay at all between the two voice coils.
One of the main design goals of the Manger was to eliminate all energy storage, both electrical (capacitive or inductive) and mechanical (surround, spider, or cone materials)

(2) In order to generate the transient wave the diaphragm must be "poked" or "hit" with a precise amount of energy for the shortest possible time in order to generate the cleanest ripple of the correct size i.e. how loud the sound needs to be.
Now if I may venture into the world of martial arts to give a useful (I hope!) analogy ....

Imagine Bruce Lee hitting one of the bad guys in the chest. Bruce will concentrate all his energy into one lightening fast blow connecting with the top of the knuckle on his right forefinger, approx 1 square centimetre.
Now Bruce only weighed 80Kg (approx 176 lbs) but it was the speed of his fist on impact, combined with the speed of re-coil, (which in turn launched and added force to the second blow but that's another story) PLUS the controlled minimum surface area of contact that generated such huge destructive force.
Now lets say he could generate 200lbs of foot torque with this single blow. Contrast this with " Fat Al " the 160Kg (352lbs including 100lbs of beer gut and body fat!) bar room brawler who can only take his lumbering un-coordinated swings at half the speed of Bruce.
Now fat Al can also generate 200lbs of foot torque but he does it in a very different way! When fat Al's fist hits the target the 200lbs of foot torque is spread out over the whole surface area of his huge, sweaty, tattooed (a bit of artistic licence if you please!) fist, approx 50 square centimetres. So the destructive force i.e. bone shattering, (David Coulter, my Karate sensei from the 80's had his sternum split with a single blow in a competition!) is only 2% (one fiftieth) as great as Bruce.
Now the last part, imagine how much greater the destructive force would be in both cases if the "target" bad guy was pushed towards Bruce (or fat Al) with an additional 200lbs of foot torque, The destructive force would double.

Back to the push / pull voice coils in the Manger.
The push / pull equal and opposite force design enables the Manger to generate very high energy pulses almost instaneously (rise time of 25uS is 25 ONE Millionth's OF A SECOND!!) using twin ultra light, ultra fast voice coils which are precision aligned to Formula 1 engineering tolerances.

Now your point about phase cancellation created by two (or more) different parts of the diaphragm moving in different directions.

The flat diaphragm is astonishingly clever, please read some of the patent application notes that Audiopath posted the link to and remember that was the old 1976(!) driver, the new 1997 patent is on an even more complex and advanced polymer compound.
What it does is to introduce a combination of variable but controlled rigidity and flexure in order to facilitate the effect of a large surface area broad based energy pulling on to a point, COMBINED with the simultaneous pushing force of a small surface area.
This results in one clean circular ridge (the rings visible in the laser interferometer images) being generated.

Here is another useful take on the energy pulse creation of the Manger. Prof Manfred Hekel believes that the Manger driver (MSW) will only function as designed above 300Hz.
My ears and measurements agree. As soon as it starts to go pistonic below 300Hz it all falls apart and distortion increases at all frequencies when playing music with bass I.e. 100Hz to 200Hz.
Real bass below 100Hz will blow the driver apart at any realistic volume.

Take a look at the photographs of the ridges and also imagine higher and lower peaks i.e. louder and quieter sounds at all frequencies.

Now think about the ratio of the various surface area's of the side walls (two per ridge or ring ) to the peaks (one per ridge or ring) i.e. the surface area of the membrane which is energised and travelling outwards (the side walls of the wave) is approx 6 to 10 times (depending on frequency and amplitude / volume) greater than the surface area of the peak (the top of the ridge) which does move vertically up and away (i.e. pistonic) from the membrane.

Now in addition to the above surface area calculation there is the time / energy calculation i.e. the pistonic ridge "pops up" only once per impulse and only lasts for a fraction of the length of time (one third to one eighth dependant on frequency) that the wave takes to transverse the membrane. So as far as the TOTAL AMOUNT OF ENERGY USED TO ENERGISE THE AIR I calculate that over 92% is used in a transverse wave and less than 8% is pistonic.
So you are correct after all ( all be it only 8% correct!) there is indeed some pistonic motion generated as part of the bending wave transient impulse. So we all agree, and its Christmas Eve AND the twins are asleep!!!

I think I will go and fall asleep to some relaxing piano music...

Merry Christmas everybody!

Derek.

PS I know you can still get some great sounds out of good cones and domes (especially with a DEQX or Conductor) and they are great value for money (especially when you DIY) so my new years resolution will be not to make any (OK as many!) "ludicrous statements!
Peace to all men?!

Now we're getting somewhere. :)

It would seem to me that the two voice coils SHOULD have a variable electrical
delay between them, with that delay being frequency dependent. This is easy to implement when dealing with pure single tones, but can become devilishly
complex when dealing with a complex signal.

I say this because you're using two fixed points (rings, actually, the voice
coil rings to be precise, but decimate the analogy and look at only a radial
cross section through one side of the transducer for simplicity's sake) as actuation points to induce a torsional force. The center point between the
two voice coils can be thought of as the pivot point.

Now, apply complementary impulses to the two drive points and you induce
flexure in the transducer surface, which will propagate in both directions,
inward and outward, but presumably the inward signal is damped at the
center of the transducer. That may not be necessary, but I think that
having to contend with just one signal would greatly simplify matters.
I would venture to guess that the Manger driver does have a mechanism
for damping any inward-radiating impulses.

How do you account for varying frequencies in terms of launching an
efficiently shaped impulse wave through the transducer disc? The two
drive points are close together, much closer than even the quarter
wavelength of the highest frequencies the driver will be called on to
radiate, so it seems to me that it will be difficult at best to achieve an
efficient driving signal, as an efficient drive signal will generate a positive
going and a negative going wave in the disc at the same time, each
in its "correct" spatial location on the disc.

You have to have a rarefaction wave AND a compression wave, both,
or so I would imagine. You have a mechanism to produce both, but the
close and fixed location of the two voice coils would demand that for
efficient operation over a broad frequency range, the two coils would
have to be electronically phased as required by the signal. This would
demand some form of DSP, I think. (Analyze signal for strongest frequency
component, synthesize delayed signal for second voice coil, at 1/f /2 delay
time, and apply first signal to voice coil 1)


I think this driver design actually would lend itself to pulse mode operation
much in the manner of a single bit delta-sigma DAC. The two closely spaced
complementary voice coils are an optimal design for creating fast pulses, but
it seems to me that it's not so good for lower frequency information.
Reapplying them in a delta-sigma system could yield considerable performance
gains, I think.


I'm having fun now. I see how it works and think about how it might work even better. :)



CJ

Hi CJ,

Well here is a first, I am going to have to go away and think about this one!
Very, very interesting concept of how to improve on something that already blows me away!
There is (to the best of my knowledge) no delay at all built in to the MSW and I have meticulously dissected a driver and even reverse engineered a pair of "one off" clones with the chassis machined from solid with brass, so I am sure there is no delay built in at the moment.

Anyway I will mull this over for a couple of days I think!

All the best

Derek.

:)Hi CJ,

I have spent a good a few hours thinking time today and here are my initial thoughts and comments on your suggestions for introducing frequency dependant time delay into the twin voice coils of the Manger.

(1) As you point out this would be " devilishly complex" when dealing with real music. Writing the algorithms would require a small team of people to work full time for 12 months to do this properly. As example the software code for DEQX took Kim Ryrie and 5 members of staff two years to write and another two years to de-bug (beta test with the first 50 sales!). The DEQX crossover is on the face of it more complex as it has multiple functions, but programming for infinitely variable musical signals is actually even more challenging.
I think this alone could be a show stopper as any "halfway house" solutions will compromise the already superb performance.

(2) The Manger does have a central damping point where the diaghphram is connected and mechanically "earthed".
The idea of dealing with one point of contact instead of two is appealing at first glance, but in order to keep the efficiency high (the Manger is a genuine 91dB for 1 watt across its 300Hz to 30KHz bandwidth) you would need to hit the single point of contact with twice the force that the two separate points are currently hit with. This is a problem as it negates all the benefits I outlined two posts ago in my "Bruce Lee Vs Fat Al" analogy.
(3) Your question about ;
"How do you account for varying frequencies in terms of launching an
efficiently shaped impulse wave through the transducer disc? The two
drive points are close together, much closer than even the quarter
wavelength of the highest frequencies the driver will be called on to
radiate, so it seems to me that it will be difficult at best to achieve an
efficient driving signal, as an efficient drive signal will generate a positive
going and a negative going wave in the disc at the same time, each
in its "correct" spatial location on the disc. "
This is I believe already successfully resolved. The 14 (!) neodymium magnets generate an exceptionally powerful magnetic field which in turn have twin 70mm voice coils to saturate in the symmetrical field they generate. The genuine 91dB sensitivity is linear and covers a huge bandwidth. Proof of the real world sensitivity translating into real world dynamics is my use of a 25 watt valve amp at the London HiFi news show to power a pair of my Prey head units. People out in the corridor were saying "wow, that's loud!"
(4) Your point ;
"(Analyze signal for strongest frequency
component, synthesize delayed signal for second voice coil, at 1/f /2 delay
time, and apply first signal to voice coil 1"

I think this falls down at the "Analyze signal for strongest frequency component". Simply put this is the mission impossible I described in point (1) above.

(5) Your last point ;
"The two closely spaced
complementary voice coils are an optimal design for creating fast pulses, but
it seems to me that it's not so good for lower frequency information.

I totally agree. I never use the Manger below 300Hz.
There is indeed great potential for use in a true digital system i.e. not just the loudspeakers.
I have on the drawing board a digital source to Manger driver system with no DAC's and no conventional power amps and still full DSP crossovers and room correction. Its obviously not DEQX based...watch this space!!

Thanks again for your original thinking and genuinely "out of the box" approach, its this kind of brainstorming that leads to breakthrough and advancement of our art.

Cheers

Derek.

DEQX already does frequency dependent time delay, just so everyone knows.

To a certain extent, since it does impulse response correction, it should also help correct for the "ripple overhang" that the Manger seems to have, so crossing it over at 300Hz is only a part of what helps, it's the fact that DEQX is basically attempting to correct many of the inherent flaws in the driver, just as it would do with any driver.

Hi Audiopath,

What are your views on CMJohnsons idea for DSP based delay to control the twin voice coils?

Happy New Year!

Cheers

Derek.

CMJ,

I'm also curious what your delay concept would do that DEQX doesn't do automatically. I'm not quite getting what you're thinking. The DEQX measures all phase/time aspects of the system from the output of the speaker and corrects for it, so, as I understand it, all that would already have been done, unless you're thinking of something else.

I agree, John, I don't understand where CMJ is trying to go here. If the distortions are linear in nature, including magnitude/phase/delay issues, then time-domain correction can handle it. If the distortions are nonlinear but memoryless, then special-purpose calibrations can fix them. Other than that, I don't see what can readily be done for any driver.

I agree, John, I don't understand where CMJ is trying to go here. If the distortions are linear in nature, including magnitude/phase/delay issues, then time-domain correction can handle it. If the distortions are nonlinear but memoryless, then special-purpose calibrations can fix them. Other than that, I don't see what can readily be done for any driver.

What confuses me is wondering what Derek thinks it can do that DEQX can't :eek:

I'm just speculating that the design of the voice coil system on the Manger driver is pretty well optimized for use as an electro-mechanical delta-sigma transducer. It might lend itself well to being operated in a purely digital fashion, just as does a delta-sigma single bit DAC.

Now, is that going to lead to even better performance?

I really don't know the answer to that. But the design itself raised questions and
aroused my curiosity and made me think about additional methods by which it could be operated....non-conventional methods. Using the driver itself as a single bit DAC is
certainly a bit of unconventional thinking.

Hey, if there's any money to be made off that concept, remember where it came from,
OK? I could use an extra source of gas money. :)

Now, as for the idea of delaying the signals to the two voice coils, you have to realize that you've got two lever points on the
transducer disc, at least when viewed in profile, and the spacing between them and the speed of propagation of the wave
will determine the frequency that the system is intrinsically most efficient at. In order to produce a lower frequency impulse
than that, ideally some delay would be added so that the two drive points are phased 180 degrees to each other at that particular
frequency.

The driver will be most efficient when one drive point is 180 degrees out of phase with the other at the specific frequency of interest.

You have a two point wave generator. Those points are close together. Without delay or phasing, the non-equalized frequency response
should be far from flat. With adaptive delay or phasing, the response should be extended, and flatness of response improved, with
no other changes.

Visualize it. It's a bit hard to explain. Wave generation by two points in space in relative motion to each other, moving in what we will
arbitrarily call the vertical plane, resulting in a wave motion propagating in a lateral direction. Move those two drive points to different
spacings and play with their electrical phasing and you'll soon see that this can improve on the frequency response characteristics of the
transducer.

CJ

Hi Michael,

As I said in my last post I think CJ's general idea of using DSP to operate the Manger in a " true" all digital system is interesting but as yet beyond our reach.
CJ is not suggesting a simple post speaker signal "correction" a la DEQX, he is thinking about a far more ambitious and challenging concept altogether.

I would like to clarify your point about the DEQX and its capability in the correction of time and phase errors.
First point is to note that the Manger has inherently perfect time and phase as it is pure point source.
All the DEQX is designed to do (and can do) is to correct the time and phase errors caused by different drivers having large distances (relative to the wavelength of the frequencies they are reproducing) between there acoustic centres in both the vertical and lateral (front to back) planes.
This correction is of course limited by the accuracy & quality of the speaker measurement, the microphone and the DEQX software.
Because the Manger has no lateral or vertical "offsets" there is nothing to correct or improve upon.
As I have already detailed in this thread the use of the DEQX speaker correction can only DEGRADE the already perfect time and phase performance of the Manger.
Kim Ryrie ( the founder and chief designer of DEQX) himself tried and failed to "improve" the Manger in this way at CES 2004 when he carried out his own measurements and "corrections" in one of our CES rooms.

The separate issue of pistonic drivers "ghost echoes" (gross overshoot) is also beyond the DEQX as it uses a swept Sine wave tone (10Hz to 25Khz) to test and measure the speaker drivers. This Sine wave does not even begin to represent the complexities and challenges that a complex and dynamic music signal presents to loudspeakers. For example the perfectly level volume of the sine wave at all frequencies verses the reality of reproducing a delicate low level violin and backing vocal SIMULTANEOUSLY with a heavy tympani and brass section.
A good analogy would be straight line performance of race track only drag car to cover the quarter mile in a straight line with no brakes (they use a parachute to stop!) verses a Formula 1 race car covering 70miles round Monte Carlo!!

I hope this helps put the limitations of the DEQX time and phase corrections into perspective.
The linear phase crossover and room correction / EQ functions of the DEQX are another matter... they are GREAT!!

All the best

Derek.

CMJ, are you talking about running the driver as an unfiltered DAC?

Also, aren't the driver units tied together to function as one system driving the center of the unit? If so, I'm not sure how driving different signals to the different voice coils will do anything electrically or mechanically different from using the same signal (unless they have gross nonlinearities to try to fix). Sending to signals 180 degrees our of phase would just cancel.

Now, if the driver were more of a ribbon, with driver units at each end, it's possible that you could send a ripple at one end, and a cancellation signal from the other, almost like an active room mode cancellation system, well, that might do something cool.

As for Derek's ongoing assertion about pistonic drivers having "gross overshoot" or "ghost echoes", that is only a real issue below 300Hz where the Manger can't even function properly at all (and even then, the woofer doing what it's supposed to in order to create a long wavelength). The Manger functions like maybe a 4" or 5" driver. If you take any quality tower, cut off anything below 300Hz and look at it's transient response, it will not exhibit the problems that Derek states. Only a big lumbering 10" or 12" like Derek uses in his designs will do that and he conveniently pretends it isn't an issue, as though the Manger's presence alone fixes that. Of course the Manger has a very quick settling rate. So does a tweeter. It can't reproduce larger wavelengths, so therefore, it will have a very sharp, quick impulse response.

Yes, you could say that's the general idea. If you know how a single bit delta-sigma DAC operates, think of the driver being operated in much the same mode. But the driver would have to have a voice coil and magnetic circuit that's optimized for operation in what's essentially a pulse width modulation mode with a very high intrinsic pulse frequency.

While on a standard Manger driver the voice coils are tied together, it should be possible
to separate them. If separated and each connected to a separate output channel,
the phasing could be controlled by suitable phase processing.

The signals, if 180 degrees out of phase, WOULD cancel IF they were occuring at the
same drive point. But with the two drive points being physically separated, you now
have two "leverage points" on the driver rather than one, and proper phasing would
allow them to create a wave in the cone with, I think, a considerable increase in efficiency. Proper frequency-dependent phasing would allow this efficiency increase to
be extended over a considerable frequency range.

But, the problem remains that music is not a single frequency at a time. Optimized use
of this principle would require processing of the signal to determine the dominant spectral
component at any given moment and use THAT frequency to set the delay.

Imagine implementing that in hardware! Fortunately, with DSP, it's easy.

CJ

Well, you lost me on the advantages of that kind of operation (especially since I think you'd have to totally redesign the driver), but maybe Michael can wrap his head around it.

Alright, maybe I'm seeing this. Are you saying you'd start a ripple, then have another drive unit start in, oscillating the wave in time (either pulling or pushing) as the ripple crossed it? Sort of like a chorus jumping in a part of a wavelength behind? And either acting to reinforce the wave or stop it? If so, maybe, but I don't think it would work with the Manger, it would have to be a long panel device with multiple drive points singing in perfect sych and even if you did that, I'm not sure there's be any *sonic* advantage to it just a high cool factor.

I'm not sure, either. But it's good to speculate and come up with ideas.

You know, once upon a time, some crazy guys actually thought that man might be able to FLY. What a whacked out idea! What were they smoking, and where can I get some? :)


But the idea was later proven to be quite workable.



CJ