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post #91 of 494 Old 03-23-2011, 01:13 PM
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Quote:
Originally Posted by Tom Danley View Post

“Its nice to do it full range but only Danley can offer it. Is there a huge difference?? No one can prove it in a controlled test.”

It is unfortunate you cannot simply hear the difference from your computer.
Actually one reason our sales have grown so well is because as one consultant put it “nobody has anything that sounds or works like your products”.
While that was in reference to much larger scale sound than the home, the reference certainly included all the traditional large companies, in a market where side by side comparisons are common.

Take a squint at the Portfolio where our products are used normally, what business we are in, there will be at least four more large stadiums with our systems running this fall too, then remember, we are 6 years old now.

In order to do something better than the other choices available to a system designer, one has to solve one or more problems he faces.
One of those so far as fidelity is presenting as close as possible to the same sound to as much of the pattern as possible, over as wide a frequency range as possible.

When you have two subwoofers and place them close together, less than about 1/3 wavelength, they combine into one source, radiate equally in all directions and add coherently into one more powerful source. If you were to reverse one of them, they very nearly cancel each other out entirely.
As you increase the spacing they no longer add coherently but produce an interference pattern. For example at a 1/ 2 wavelength spacing, the two sources produce an interference pattern like a figure 8 when the polar pattern is viewed, two lobes and two nulls. AS one increases the spacing the number of lobes and nulls increases and because the addition is not coherent, reversing one source only alters the shape of the interference pattern, no cancellation global happens.

While this condition exists in most multi-way loudspeakers at least at crossover, it is addressed by careful aiming of the lobes and nulls at crossover so that at the listening position there is a minimum perturbation.
In a commercial sound speaker this is undesirable as it means the spectrum changes as a function of position left or right up and down etc. Remember ideally we want all the seats to get the same signal and you cannot do this with an interfering source.. Also ideally we want a constant directivity system with a high forward directivity to minimize room sound.

That means that if you going to have the horn confine the pattern, the sources have to all combine when the dimensions are small enough to allow coherent addition. AS a result, there are no lobes or nulls in the polar’s and because the horns are as large as the enclosures, the pattern loss F is as low as possible.

Now, now of this sounds like it means squat in the living room except for one really big thing.

AS these got better and better, acting more like one single source and not spread out in time, a weird thing happened.
First, one can literally stick your head inside a horn like an SH-50 and the image never wavers from floating somewhere in front of you.
There is no distance required for the sources to “mix”, these radiate like one driver.
Next, if you play one speaker with a voice say, you can easily hear how what direction it is but as they got better, they got HARDER to hear how far away they were in depth. Not radiating that “identity” also meant that the stereo image was very strong, the strongest I have ever heard with speakers in a normal configuration and no trickery.

Now, none of this imaging stuff was art of the goal, in fact I didn’t know what was happening at first. I developed the Synergy and earlier Unity horns while listening to music through them.

My goal was following Dick Heyser’s insight on time arrival, to make one source from many. Part of that allowed a way to eliminate the phase shift normally associated with crossovers as well, truly resulting in one source much closer to occupying one instant in time over a broad frequency range.
As for what a coax driver does, that does depend, the B&C we used in the SH-100, one of our very first products works well but all of the possibilities so far as a driver that I looked at were unusable for one or more of several reasons. Most people are aware of the problems with edge diffraction or that tweeters should not have recesses and edges and such nearby.
They can picture that sound spreads out and that sound can re-radiate from anywhere there is a significant discontinuity.
The horn is a way to much more consciously deal with and control the surfaces of the sounds path as it radiates, to produce a simple part of a sphere.
Once the wave front is large enough relative to the wavelength, it can radiate freely without the horn walls.

The synergy horn then is a way to drive a single large CD horn, over a broad frequency band, without self interference, without the phase shift crossover normally produce. To the great degree it radiates a simple lobe of a single source with a high to back front to back energy ratio. It just turns out that this works very well for stereo imaging.

Obviously people have been plenty happy with “prior art” but coming up with an audibly better mousetrap has proven a good strategy in a market that has many well known giants .
As for a controlled test, well listen to a pair in stereo and you tell me what you hear.
Best
Tom Danley

"Sit down an listen, it's about the sound, it's why you got into audio"


Thanks for posting, awesome stuff as always

no one sits at a computer and figures this stuff out. We buy and do the proper control tests.

Maybe 60 day trial? I will pay for shipping
btw, I didnt know its only 6 years....very cool and congrats!!!!

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post #92 of 494 Old 03-23-2011, 01:32 PM
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Loving my DTS-10 kit and would have a tough time saying no to this speaker kit, particularly if it could hit 80hz and was reasonably priced. Thankfully, Danley is a fair man. If this becomes a reality, sign me up for 3!
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post #93 of 494 Old 03-23-2011, 05:10 PM
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Quote:
Originally Posted by penngray View Post
I will state that phase coherence is 1000 times more important the the subtle HOM differences from top end drivers.
Have you determined that by measurements?

One thing is for sure, eliminating the archetypical horn sound of yore is far more important than phase coherence.

Do we know what eliminated it from the current "good" horns?

Was it just measurable lower distortion?

Do we know that it's not HOM's?

Noah
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post #94 of 494 Old 03-23-2011, 05:22 PM
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Originally Posted by noah katz View Post
Have you determined that by measurements?
From so many discussions that it makes my head hurt. There is a reason the Large horns measure the best over on DIYAudio (see wavelet analysis stuff) and there is a reason larger JBL designs sound pretty damn good.

I have the larger horn on order so I will figure it out first hand.

Quote:
One thing is for sure, eliminating the archetypical horn sound of yore is far more important than phase coherence.

Do we know what eliminated it from the current "good" horns?

Was it just measurable lower distortion?

Do we know that it's not HOM's?
If we are going to discuss HOMs then we should pick a side, Geddes and Danley do not actually agree on the topic

Sharp Angles in horns causes diffraction, which is one of the symptoms behind HOMs. Geddes waveguides, SEOS-15 or IWATA waveguides have no sharp corners. Danley horns have sharp corners interior and the baffle is not a nice round over.

You see its a big debate that has gone on for years and years and it will not be solved here. So far Im siding with Geddes on the HOM issue, the amount of data and academic research he has is unmatched on the topic.

This has no bearing on how good either speaker design is though since both design do other things very, very well and those choices can minimize any inherent flaw in either design.

Conclusion, HOM in this discussion is not important and so far I still have the same conclusion that a large horn with a 2" CD has the same idea behind it as Danley synergy horns when we are only running 400Hz to 15KHz on each.

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post #95 of 494 Old 03-23-2011, 07:59 PM - Thread Starter
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Did anyone define "HOM"?

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post #96 of 494 Old 03-23-2011, 08:57 PM
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Not really

It is not "open-minded" to reject knowledge - Bob Lee
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post #97 of 494 Old 03-24-2011, 12:11 PM - Thread Starter
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Originally Posted by penngray View Post

Not really

I guess we may never know.

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post #98 of 494 Old 03-24-2011, 03:52 PM
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I cannot wait to see if people build these or not. I find them(and anything from tom) to be fascinating.

Does anyone know if Disneyland uses Danley Sound Lab stuff? I thought that they looked similar to the synergy horns but I wasnt sure and did not get a chance to look at them when I was there.

Trying to enjoy the simple things in life.

 

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post #99 of 494 Old 03-24-2011, 04:07 PM - Thread Starter
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Quote:
Originally Posted by Kimeran View Post
I cannot wait to see if people build these or not. I find them(and anything from tom) to be fascinating.

Does anyone know if Disneyland uses Danley Sound Lab stuff? I thought that they looked similar to the synergy horns but I wasnt sure and did not get a chance to look at them when I was there.
There was a discussion regarding Disney in another thread. I am not sure what the conclusion was there.

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post #100 of 494 Old 03-24-2011, 04:55 PM
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interesting read. edgar paper on mid horns. big file.

http://www.volvotreter.de/downloads/...range-Horn.pdf


LL

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post #101 of 494 Old 03-25-2011, 09:38 AM
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Quote:
Originally Posted by penngray View Post

I understand the trade offs but HOM discussion is a read herring, Im not convinced that Danley has solved the Coax mystery more then BMS, B&C, etc. So much that other phase coherent designs are so inferior.

Actually, upon going through this thread again, I think Danley might be onto something truly unique. Something Tannoy Dual Concentric replacement-worthy.

While I don't think I'm the first to do so (see AudioJosh, supra at post 67) I just noticed something really, really cool about the SM60F (I assume F-model, because it does not have visible taps down the horn for woofers) from notnyt's picture, infra:

Quote:
Originally Posted by notnyt View Post


Look closely at the throat. I was expecting something like their SH100; a visible coaxial driver. But that's not what Danley is doing. Look at the throat! From that picture, it looks like he's in fact divided the drive-unit into two parts:

the coincident compression driver fires straight through the horn,
but the woofer fires through the four taps slightly down the horn's mouth.

That (bandpass midbass loading + bandpass gain due to the mid's limited bandwidth) might be why the system is so much more sensitive than the raw drive-unit. Also, with that loading he's probably able to get the same output (or close to it) out of the single driver as he did out of the four midranges on the ur-Unity, assuming at least that the Misco (?) closed-back drivers used previously had ~1mm of throw.
(I'm assuming that the SM60x uses a variant of the 5" BMS coax; I think Mssrs. Danley and/or Beaver wrote something to that effect once. I'm also assuming that, as is usually the case, the 5" BMS's compression driver is far more efficient than the 5" woofer around it, so the woofer was the limiting factor previously. EDIT - looked at the graph, not an assumption that the CD is more efficient, but measured fact.)

IOW, he's totally taken the potential "Doppler distortion" issue totally out of the equation. Also, because both drivers are loaded discretely, there's much less room for the highs to bounce around than there would be with a 1" HF driver firing through a 2" throat horn.

I wonder if the horn molding butts against the driver, or if it actually replaces whatever waveguide/phase plug structure is in the polepiece. (Or if it's a bespoke driver for Danley with threads for the Synergy horn.)
Regardless, it's a fascinating piece of design/engineering. Much more so than I originally expected. I'm really looking forward to seeing what they come out with for us. Even more so than I was before I noticed what was up in that pic.

Quote:
Originally Posted by noah katz View Post

But I have to say, unless Tom comes up with something completely different, the only way I can see to make these a lot cheaper than the finished product is charity, given that the most expensive parts is likely the molded horn.

I'm not a production engineer, but my understanding is that with molded plastic parts the primary cost is in the tooling. Once that is done, the marginal cost of each part is relatively low. SO, if DSL is making a new product, the business justification for a DIY kit could be to more quickly amortize the up-front tooling costs without cutting into their real markets.
I could be way off, of course. That's just idle speculation.

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post #102 of 494 Old 03-25-2011, 09:38 AM
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Originally Posted by penngray View Post

You see its a big debate that has gone on for years and years and it will not be solved here. So far Im siding with Geddes on the HOM issue, the amount of data and academic research he has is unmatched on the topic.

Dr. Geddes has also admitted that the foam plays a much bigger role than the profile. I think it was in a diyaudio discussion with "Patrick Bateman" about the impact of foam plugs on very suboptimally-shaped car-fi waveguides.

So, Synergy kit (modded post facto) with Geddes foam plug, anyone? Let's call it a Danlee horn.


Quote:
Originally Posted by LTD02 View Post

one idea to differentiate the horn kit would be to make it ~90 x ~45.

william cowan has experimented with these.

left side, click "unity, the finale" for diy unite horns with input from t.d.

http://www.cowanaudio.com/

Due respect to PaulW's amazing "Octagon," but that is the coolest home audio system I've ever seen. Look at those measurements, and how not at all it intrudes upon the room!

I note also that he's using Peerless XLS "subs" directly under the Unity. That is to say, up to about 400Hz. And getting measurements that clean (with EQ, but that's what anyone with a system that sophisticated is going to do anyway). Hmm, someone I know has a quad of 830500's not currently in use...

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post #103 of 494 Old 03-25-2011, 11:35 AM
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Originally Posted by DS-21 View Post

Dr. Geddes has also admitted that the foam plays a much bigger role than the profile. I think it was in a diyaudio discussion with "Patrick Bateman" about the impact of foam plugs on very suboptimally-shaped car-fi waveguides.

FWIW, I found that discussion, here.

Quote:
Originally Posted by Patrick Bateman, 9/29/2009 View Post

*** The thing that's enlightening about my experiments is that the three things mentioned in the previous post [foam, roundover, bracing of waveguide] seem to be as important (if not more than) the shape of the horn itself.

Everyone seems to obsess about the shape of the horn, when those three things seem to matter a great deal also. ***

and reply

Quote:
Originally Posted by Dr. Earl Geddes View Post

hate to admit it but this is entirely correct. I have kept kind of mum about this realization (which I made quite awhile ago - it doesn't play well into my position) but its absolutely correct. More correct than I think that you would even guess. Its not good for business to give away all ones secrets, but there is more to all this than meets the eye. By hook or crook you are catching up to what I've found over the last six years of development. There are still some things that are hidden in the cracks, but you'll probably figure those out.

I mean "cut-off frequency" and "loading" -- who cares!!

That comment combined with stuff Danley's written (and people have heard) makes me seriously wonder if the ideal home audio mains aren't Synergy horns in larged-roundover cabinets with foam plugs. (Presumably, the latter two things would be post-kit mods, though if the kits come with a low-diffraction cabinet, assuming there's a cabinet at all, that would be ideal.) Maybe some of us will be able to find out soon.

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post #104 of 494 Old 03-25-2011, 12:58 PM
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Hi DS-21
I am not sure I did mention that specifically. I was able to use the coax driver in an SH100 because the final radiation angle was the same as the cone's and the transition error at the hf exit was smallest of the possible choices.

The SM- series does use a coax driver but in a different way as you noticed. The cone is a compression driver as you suspect.
This configuration was one I wanted to get to eventually but it took a while to be able to get into molding horns like this. You can get the jist of how it works from the patent application which shows a cutaway view , examine Fig7 here;

http://www.google.com/patents?id=exX...page&q&f=false

As one can see in the general description, the small volume between the cone and throat acts like an acoustic low pass filter. By sizing these for the frequency involved, one can place the low pass corner just above the highest operating point for which ever range driver that is.
By low passing the mid (and low ranges in this case) before driving the horn, one has greatly reduced the inevitable harmonics the drivers produce, some to many fall above the low pass corner, this harmonic distortion is reduced. In that case the horn increases the radiation efficiency of each driver by increasing the acoustic load on it which reduces it's motion required at a given SPL.

I had meant to reply to Penngray about the HOM question and such but have been working on something. I will try now.

I wouldn't say I disagree with Earl but we do look at things from a different perspective. Earl is one of the very sharpest people I have ever met and I envy Earls ability to look, think, talk and imagine the math. In my head is a large cavity where the math co-processor and math ability would have gone and actually, I have had some of my largest leaps while working with people like Earl on hard technical problems.

If you want HOM's, take a very wide angle horn and drive it with a cheap 2 inch driver, actually I am saying the normal whatnot to do here.

I will explain how I see it, this is based largely on observation while trying to develop acoustic levitation transducers. These operated at 22KHz usually and required to make 160+dB for the levitation.

Also I will speak in practical terms by that I mean a distortion count may never reach zero but once below X is irrelevant or how theory requires bandwidth from DC to infinity to reproduce a square wave but to make one that looks perfect on an oscilloscope only requires about 10 X to 1 / 10 the center F.
Sound as in hifi is sort of like a set of Russian Dolls where the largest one (called 20Hz)is 1000 times bigger than the smallest one (they call her the dangerous one 20KHz). A given event at one frequency is the same at another accounting for scale if you follow.

We are aware of the first transition when we place two or more sources of sound like subwoofers close together. It is the closest thing to a free lunch in audio, when you double the number of sources; you have increased the power by four. This is because you have doubled the drive power with two and you have doubled the radiating area by two and this doubles the radiation efficiency, 2+2 =4, or 6dB.

As long as the sources all remain less than about 1 / 4 wavelength edge to edge, they combine coherently into one new source. If you measured the total sound power (going around the surface of an invisible sphere with a sound level meter) and then you reverse one of the two subs, you would find that because of coherent addition, you have near total cancellation (the principal of active sound cancellation).

AS one increases the spacing acoustically (by leaving the location the same but raising the frequency) one finds that once the two sources are say 1/ 2 wavelength apart, one is into a new form a behavior called an interference pattern. These are made of local regions of addition and cancellations and when viewed as a polar plot, have lobes and nulls.
In this interference region, if one measured the total radiated power and then reverse one source, the total energy may not be effected at all, only the interference pattern changes. Think of it this way, if you reverse one of your hifi speakers, they don't cancel each other because they are so far apart (acoustically) they don't add coherently and (hopefully) what you hear is a funny empty feeling in the middle and no bass (where the wavelengths are larger).

Sound can bend around corners just fine within some boundaries.
Sound can bend around a low frequency horn just fine, I have passed 22KHz sound through 3 feet of copper hypodermic tubing, wrapped around a coffee cup, with no problem. This bending can be done when the inner and outer acoustic paths in the bend are less than about ¼ wavelength different start to finish.

Here is an example of a device I developed called a Paraline used as an acoustic lens. We use it in a couple of our products but the illustration is better here in a design built by some friends under license. In this case used to convert a point source into a uni-phase plane wave (for use in a line array in live sound). Note how the sound path bends and converges with all paths being equal.

http://www.vtcproaudio.com/paraline02.html

We all know that say a 30 Hz horn requires a wall sized mouth to be ideal and this is true for one flow by helicopter. Theory requires, either by boundary reflection or actual that the mouth circumference should be about one wavelength at that low corner frequency.
The reason for that size is the radiation resistance curve, the curve goes from sloped to flat in this region and so continuing horn past here has no significant effect on efficiency.

Thus, an octave higher, one finds the end of the region of impedance transformation has moved up the horn towards the throat the point where it is now about 1wl in circumference and so on.

Octaves above the low cutoff, the active region well back in the horn but the unused part now serves to confine the radiation angle. In Don Keele's paper what's so sacred about exponential horns we have first steps into designing the horns directivity. (if you reading this so far, Google up his paper later). In it he also comes up with a thumb rule which defines the frequency where a horn mouth looses pattern control based on it's dimension and angle.

His interest can be seen when you consider that the exponential horn and others similar in shape have the above behavior and because of the shape of the horn, as the frequency climbs, the pattern width narrows according the portion of the horn governing the pattern at that frequency.

Again, I don't visualize math like Earl but to me his horn does this; It recognizes especially that as the waterfront becomes acoustically larger, that there is a maximum rate of change one can undertake based on avoiding a secondary radiation (something like edge diffraction). One can get a feel for how this could be when you consider that at 20KHz, the wavelength is only 5/8 inch!

That means all the impedance transformation has taken place well within the driver and even a one inch exit is large enough to have directivity, to confine the radiation angle to 60-90 degrees (depending on the driver internal geometry). You want HOM's put a big old driver on a big old 90 degree horn. Picture how well a source several wavelengths across fills the horn with luscious horn soundeewwww don't do that, it's like finding your cat left you something special in your shoe except for your ears..

Frankly, I don't know what to call what I hear with the Synergy horns now. As they got better and better in the measurements, more like one source, they sounded different too. It was not what I expected or would have guessed, nothing like that, the sound got simpler. Also, if I played a voice through a single speaker, it was a snap to hear what direction it was BUT it became much harder to hear how far away it was with your eyes closed. I have been calling it source identity for lack of a better term.

I have had a TEF machine for about 30 years now and have taken a zillion loudspeaker measurements as well as on all kinds of goofy stuff. I never saw anything that would explain what happened and this has was technically troubling while lead to a frequent topic to ponder. Eventually it gradually dawned on me what an explanation was.

Understand, this is how I see it right now.
We measure with a microphone which is one place in space.
WE hear from two points in space BUT we have learned that all the ripples and comb filtering ones ears CAUSE as a function of position are how we can hear height, front to back and such, domains seemingly inaccessible with only two reference points. We can't hear any of those huge deviations because they are the only thing we know, we don't hear a source grossly distorted because of what our ears do to it with changing position. In many ways, we do not hear like we measure.

If a speaker presents essentially the same signal to both ears, there is little or nothing for your ears to identify as a source location. However, if the source radiates differences that your ear can localize, then the physical location in depth is easy to identify with your ears closed.
On the other hand, take the grill off of an SH-50 and listen to it with a voice etc and you can literally walk up and put your head into it and it always sounds like it's somewhere floating in front of you.

Now, ironically that was sort of a side effect of trying to make the all the drivers combine coherently into one source letting the horn produce the radiation pattern. All of the problem one faces providing the best quality sound possible in a large space are so much larger than in the home and why commercial sound has never been as good as in the home.
There, it was clear that the larger the pa system, the worse it sounded generally.
Most of that was from the same self inference from sources too far apart to add coherently yet there was no solution to making one more powerful coherent source. Anyway, it's taken 12 years to get these horns where they are now, feels like I've been writing about that long so I'm going to get back to work now, hope this helps.
Best,
Tom
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post #105 of 494 Old 03-25-2011, 02:58 PM - Thread Starter
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Great post Tom!

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post #106 of 494 Old 03-25-2011, 04:07 PM
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DS-21, amazing quote from Earl, thanks.

But I wonder if it's possibly a bit out of context here, i.e. maybe the radiusing and foam are more important than the horn shape when the latter is some HOM-generating monstrosity cooked up to fit in a dashboard.

Tom, thanks for the awesome illuminating post.

Quote:
Originally Posted by Tom Danley View Post

... the exponential horn and others similar in shape have the above behavior and because of the shape of the horn, as the frequency climbs, the pattern width narrows according the portion of the horn governing the pattern at that frequency.

Is this a fair interpretation of the above:

As freq increases, the wavefront becomes "unstuck" from the horn closer to the throat, with directivity being determined by that narrowing wall angle.

Re HOM's, might you hazard an definition?

From what you wrote above, it sounds like any deviations from the intended well controlled wavefront, with resultant oblique sound paths.

These would be at wavelengths too short (higher freq) for the intended behavior, this the H for "higher".

But I still don't get the "mode".

In Earl's forum at whatsbest before the plug got pulled, he said that all sound energy is carried by modes and that attempts to eliminate them are misguided.

One of those math things, I guess, but he really lost me on that one.

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post #107 of 494 Old 03-25-2011, 04:11 PM - Thread Starter
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Re HOM's, might you hazard an definition?

Still waiting on that.

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post #108 of 494 Old 03-25-2011, 04:54 PM
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Dr. Geddes has also admitted that the foam plays a much bigger role than the profile. I think it was in a diyaudio discussion with "Patrick Bateman" about the impact of foam plugs on very suboptimally-shaped car-fi waveguides.

I personally find it very dubious that HOMs are considered so awful, yet someone of Geddes experience can't find a way to measure something "apparently" so audibly destructive

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Due respect to PaulW's amazing "Octagon," but that is the coolest home audio system I've ever seen. Look at those measurements, and how not at all it intrudes upon the room!

I agree, an awesome system, but it is built into the room, not something possible for most people.

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I note also that he's using Peerless XLS "subs" directly under the Unity. That is to say, up to about 400Hz. And getting measurements that clean (with EQ, but that's what anyone with a system that sophisticated is going to do anyway). Hmm, someone I know has a quad of 830500's not currently in use...

I've heard William's system and it is extremely good: the Peerless drivers run up to 300Hz.
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post #109 of 494 Old 03-25-2011, 05:22 PM
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HOM = high(er?) order mode

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post #110 of 494 Old 03-25-2011, 05:39 PM - Thread Starter
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HOM = high(er?) order mode

Thanks! Sheesh!
I thought we would never get an answer.

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ah, you just wanted to know what the acronym stands for

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ah, you just wanted to know what the acronym stands for

Ya, can't keep track of all these designs and acronyms, etc.

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thanks td! i hope that you are writing your notes in a separate application and then cut/pasting them into the post box. losing a note like that would be a killer.

is there a region where the coherency is most important based on empirical observation? e.g., critical to get it down to 600hz, good to get it down to 300hz, not much to be gained below 150hz, or something like that?

also, have you experimented with binaural recordings using an anotomical accurate manican head with the microphones inside where our eardrums are located? that seems like it would provide an additional layer of insight into what is going on.

interestingly, we do tend to turn our heads to the side when trying to judge distance to a sound source. it is amazing what is going on between our ears.

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Ya, can't keep track of all these designs and acronyms, etc.

Aren't TLAs great?
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But I wonder if it's possibly a bit out of context here, i.e. maybe the radiusing and foam are more important than the horn shape when the latter is some HOM-generating monstrosity cooked up to fit in a dashboard.

If you read that thread, John does several types of horns, and yes, the improvements caused by the foam are greatest on the crappy car horns. But others show improvement, too.

Also, I would expect higher-than-typical HOM's for a Synergy, compared to a waveguide of that size and shape. Why? Diffraction from the midrange bandpass ports along the horn walls.

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I personally find it very dubious that HOMs are considered so awful, yet someone of Geddes experience can't find a way to measure something "apparently" so audibly destructive

You doubt they're a real phenomenon? We're not talking about some technogibberish found in some wire marketer's propaganda here. We're talking about actual science. And they have been (indirectly) measured, by Geddes and others.

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I agree, an awesome system, but it is built into the room, not something possible for most people.

I don't know about that. Most renters, surely no. If one owns a home, why not? His system seems to take much less usable space, and is much less an eyesore, than the typical "plop gear all around the room" approach.

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post #116 of 494 Old 03-26-2011, 09:41 AM
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I personally find it very dubious that HOMs are considered so awful, yet someone of Geddes experience can't find a way to measure something "apparently" so audibly destructive

Here's an approach I came up with.
http://www.diyaudio.com/forums/multi...ml#post2425274
Not sure whether it is showing HOM or something else, but I think it is in the right direction for revealing these.

I wouldn't be too upset about not being able to put a number or even decent graph on such a phenomenon. After all, we can't do much meaningful quantifying of other kinds of distortion either (except perhaps with Geddes' own nonlinear distortion factor calculation). The usual "Harmonic Distortion", and "Intermodulation Distortion" have almost no proven audible meanings. The idea that soundwaves have several different paths to emit from or alternately bounce their ways down between horn walls isn't something very hard to visualize and accept. Separating these effect from other things that look similar (resonances, reflections, driver effects) in response graphs is where the problem comes in.

DIY Synergy horn spreadsheet
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"BMS builds quality CDs and I suspect the BMS Coax is a great CD too."

penn, you may enjoy this one if you haven't already seen it. bms 4590 build. about 2/3 of the way down the page are measurements. the phase response appears to be...um...coherent.

http://forums.klipsch.com/forums/p/64694/633172.aspx

qsc is also using the 4590 in their digital cinema line, though i think they are wasting its potential by crossing it at 1700hz. they even have a little movie about phase coherence. but then they go and mess it all up with their midrange.
http://www.qscaudio.com/products/spe.../dcs_4-way.php

measured phase of 4590.


cutaway of the 4590.


lastly, these guys cross the 4592nd at a surprisingly low 270hz. that looks a little low to me, but 400hz in a home environment seems reasonable.
http://www.bd-design.nl/contents/en-us/d33.html

click on "products" then "loudspeakers" then "orphean mkii". they employ the 4592nd.
LL
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post #118 of 494 Old 03-26-2011, 03:09 PM
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After following this thread for the last few days, I've realized that for the most part, I don't know squat about horns and have no idea what the heck people are talking about.

But one thing I DO know is that I want 3 of them

Blasting brown notes for 10 years and counting!

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post #119 of 494 Old 03-26-2011, 03:26 PM
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"BMS builds quality CDs and I suspect the BMS Coax is a great CD too."

penn, you may enjoy this one if you haven't already seen it. bms 4590 build. about 2/3 of the way down the page are measurements. the phase response appears to be...um...coherent.

http://forums.klipsch.com/forums/p/64694/633172.aspx

I am very dubious about those measurements on that flare (PH4525). It's very close to a JBL 2380 clone (PAudio used to sell a 2380 clone, numbered that way which was identical to the original) and when I first started experimenting with the 4590 (mid 2001) it would drop like a stone below 500Hz and the distortion would raise dramatically before that (on the 2380). On the much larger Arai A290 600 was a minimum, but 700-750 would have been a much better compromise. They went to 400Hz on the Fc 270hz trax I had made, but HF dispersion was extremely narrow and a 500Hz a la Edgar was what I should have had made, especially as I made a midbass trax (EVM12L) to do 200Hz up from the Khorn bass bin a little while later.

PS: the 4590 is a very nice driver. I wish I had an application for mine ATM.
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post #120 of 494 Old 03-26-2011, 04:07 PM
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After following this thread for the last few days, I've realized that for the most part, I don't know squat about horns and have no idea what the heck people are talking about.

But one thing I DO know is that I want 3 of them

I feel the same way, most of what Mr. Danley talks about goes over my head, but I like to think eventually some of it will start to make sense if I read enough of it.
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