Ask and ye shall receive. Mark has uttered the death knell for the V3 thread which is "stay on topic", so here's a new one.

Lee asked why digital speakers haven't taken over yet. In addition to Frantz' good answer about audiophiles clinging to orthodoxy, I've heard the following -

1. "I can't choose the amps, the cables, the DACs, etc, etc, etc. "
2. "I can't *use* my [tens of $thousands of] current audiophile gear that I have accumulated."
3. "I don't trust digital"
4. "I'd have to convert my albums to digital and back and I don't like that idea, let alone the idea of bypassing the DACs in my $10K CD player
5. Limited selection - Too expensive, too inexpensive, not the right color, not the right form factor, where's the wood finish, I want ribbons, dipole, bipole, ported, sealed...... - kinda like finding the exotic hybrid or electric car that gets you hot and bothered. There's like one of those.
6. Confusing and or not the right sound - "No sir, we don't have DSP speakers in 'Chunky Monkey' or 'Cherry Cheesecake', but we have French Vanilla......"
7. Poor marketing and an intransigent dealer base who finds selling conventional gear more profitable and ongoing. "Sell the problem, then sell 10 solutions down the road". What do I sell the current $6K NHT Xd customer? Nothing. What do my competitors sell after selling a $15K or $20K speakers that doesn't match the show room experience at home? New amps, new preamps, new CD players, new cables, new power cords, new power conditioners...........DSP speakers are also lower profit margin for the dealer and typically requires a lot of trade-ins, so there's little incentive.
8. Stereo focus. Most DSP speakers, especially DEQX ones are totally focused on stereo while even most of the hardcore audiophiles are integrating home theater. I had one customer sell his Xds because he couldn't find a center channel to keep up, but then finally got two new pair and uses one half of one set as his center. Plus it's hard to wire for DSP rears if you don't have 4 or 6 conductor or power/ethernet to the right locations. Meridian does full DSP HT, but it's pricey and it's proprietary (and sounds mighty awesome).
9. Fear factor. I don't think a lot of people feel comfortable being the first on their block to abandon expensive old technology for expensive new technology, same reason why we had trouble selling Tivo and Sonos and Vudu for the first year of each product. People are naturally skeptical of paradigm shifts, but then sales snowball as more and more people report good experiences.

Let us rather focus on the merits of Digital Crossovers rather than Digital ACTIVE speakers... There is certain amount of restriction in Active speakers. They are what they are and you cannot much change what they do.
Active Digital Crossovers on the other hand let us mix and match to our heart content.. It could arguably be advanced that superior results can be obtained through this approach rather than the fixed Active speaker one... One can then use almost ANY passive speaker and use what he/she deems most appropriate for amps and cables...

High end is a hobby. Most people find it more fun to use high end contact fluids then to measure their rooms or speakers. Voodoo still defines high end than anything else. Ask at work colleagues how they define audio......sad, very sad, all prejudiced come true.

Professionals have understood this a long time ago. That is why there is no main reference monitor using passive x-overs, only active or DSP designs.

Also we need more common availability of digital interfaces for multichannel, not only on the most expensive and rediculous priced items. That is either 4x spdif or 4 AES/EBU for 8 channels. I only know a handfull of such products....

Andreas

I find it too easy and too convenient to paint ALL audiophiles with such a thick brush... I have heard my share of Pro Monitors and they did not convince me ... The fact that it is a hobby does not mean that we are not looking for performance.. The Mix and match aspect of what we tend to do is actually related to performance ... Measures tell part of the story not the whole of it... Measures need to correlate with what people prefer... Telling me that this monitor measures flat and thus sound good despite my ears yelling me the contrary is a poor approach IMHO.. I will not repeat is verbatim but your rationale that the reason why people do not like Pro monitors is that they are too revealing does not hold much water.. some of these may measure flat but still sound bad... A question do ALL PRO speakers sound alike? If they were ALL perfect they shoudl ALL sound the same don't you think. As an aside several High End speakers do measure exceedingly well.. This has been repeated countless times wihtout much proof... Most HiGh End speaker do measure quite well and some don't.. the all ecompassing statements need to be refrained for an honest and rational discussion...

Please do stop the audiophile-bashing once and for all. This will make for a more constructive debate... if this thread is simply about bashing us, the Audiophiles , I am not sure it will live long, I for one will simply not post in it...

Please do stop the audiophile-bashing once and for all. This will make for a more constructive debate... if this thread is simply about bashing us, the Audiophiles , I am not sure it will live long, I for one will simply not post in it...

Frantz, you are indeed a saint, though I think there is a point to the fact that it *is* viewed as a hobby and people do it as much for the fun of playing with gear as for the fun of listening to music. But you are right, so on to substance!

If you look at digital crossovers in there most basic form, the Behringer or Meridian or Phase Technology dARTS, for instance, you're simply doing a more precise, less lossy 24dB/octave crossover. There's no heat loss, no heat induced changes, there's no modulation of the crossover frequency from fluctuating driver impedances, no need to pad down a tweeter by 2 or 3dB to match the midrange volume, poorly matched etc, etc.

In theory, you could lose some audible resolution with a digital crossover if you're using a digital volume rather than VCAs on the other end (DEQX and Meridian does analog volume control on the other side), but our ears also lose resolution at softer volumes so this somewhat offset. The key is to adjust the gains so that you are at full resolution at your highest used volume rather than at 6 or 10dB louder than that.

The biggest advantage of DEQX is not that it can do a better, more transparent crossover. That's easy. The Behringer does that. In theory, any speaker that doesn't require driver compensation in the crossover will benefit from a Behringer in predictable, though perhaps subtle ways.

Sorry Frantz, but you are picking on me for the "human truth" that has prevented the breakthrough in consumer mainstream for such a long time, same is still the truth for analogue active systems, they also still make up only a very small fraction of the high end audio market. Ask yourselve why we are where we are. I work in a consumer electronics company, I hear the stories every day why complicated stuff is not selling, although by far superior. Why aren't we all driving electric yet ? One day we will.....

My first 5.1 digital fully active system was roughly 10 or 12 years ago. With the Meridian 565 and 5 Philips DSS930LE digital active 2.5way speakers. That was AC-3 as soon as it was available on LD on a fully digital active system. Philips was and is mainstream, and did not make the break through, Meridian neither in high end, not even today, they are still the colorful birds in high end audio. So where is the progress in the last 10years. There is non. I bet market shares of digital active speakers are still the same, if not worse.

We have landed at the rediculous situation that high end people understood the benefits of digital DSPs in minimum phase systems as standalone processors offer (Dolby) or in their HT processors/pre-amplifiers (Sharc/Motorola), but to bring that into their speakers, no way. Obviously not possible.

In video we all use measuring/test material to determine the quality. In audio, that seems impossible to go by science. Once we see 4 spdif outs on any Sony HT receiver, you know the technology made the breakthrough.

There is one more reason not mentioned that has also prevented so far the break through and annoyed people. The digital evolution in the past 10 years. You put digital technology into each speaker (3 DACs per 3way speaker plus DSP), and then it all changes, you need to up-date each speaker/each way. Meridian clients know the up-grade path to well, that was from 16 Bit or so to 20 to 24, from 44,1 to 96 to 192KHz. Each time, all speakers. Now we have reached a quality where serious high end people struggle to hear any difference anymore in blind A/B tests. Although many will say consumers will have a hard time to hear a difference to anything above 16Bit/44,1, but more is always better in their minds. Marketing is too powerful, that one could simply overcome his human thinking on the numbers.

It is said that speaker design is the art of compromise and this is very much the case. If you look at most drivers, they're good for about 2 octaves. Above that, they start to ring and/or resonate and dispersion narrows. Below that, distortion begins to build up, often rather sharply. There are cheats you can do to extract more - multiple drivers can reduce low frequency distortion, but that causes lobing and acoustic distortion except in the woofer range. If you get a driver that is extremely well behaved in the upper octaves, you tend to give up some resolution for self-damped, good behavior. Even frequency response often goes, requiring some compensation.

Look at the SEAS W15. It's ideal operating range is 2 octaves, from about 500Hz to 2000Hz and its behavior in this range is nearly flawless. At 2K, it's starting to lose dispersion. By 5kHz, it's got all kinds of ringing behavior. By 250Hz, it's starting to compress and distort. The more shallow the crossover, the more distortion and ringing you let through. But use a steeper crossover and you push it closer to its limits without side effects.

If you look at most 1" tweeters, their dispersion is actually quite poor over about 10kHz and they ring like a bell at 20kHz. But push them below about 2500Hz and they start to induce fatigue from added distortion. (Distortion below 1000Hz is usually relatively benign, but distortion over 1000Hz is increasingly bad).

So, every 3-way speaker on the market has compromise, even $100K ones. But if you use steeper DSP crossovers, you can squeeze a bit more out of them, maybe get 7 or 8 of the 10 octaves done well. Even using very steep crossovers and very high quality drivers, Xd still has some compromise in the top octave and in the octave between 125Hz and 250Hz. But this is a major victory compared to getting 5 or 6 octaves right. With steeper digital crossovers, you can do with 3 drivers what it would normally require 4. But if you wanted to build a 'no compromise' full range speaker, it would take at least 5 drivers with current technology. And even then, it is massively tricky to get them to blend and sound coherent.

There is one more reason not mentioned that has also prevented so far the break through and annoyed people. The digital evolution in the past 10 years. Y

Of course, now you can get a high performance 6-channel 24/96 DAC very cheaply, thanks to A/V receivers. In fact, the core technology required to do speakers cheaply and easily rests neatly in a cheap multi-channel receiver. 6 or more amp channels, multi channel DSP, multi-channel volume, sufficient DSP for the crossover/EQ functions. I've been trying to convince NAD to adopt DEQX and convert their T785 (easily done with different card modules) into a stereo DSP speaker system.

I have heard my share of Pro Monitors and they did not convince me

I'm curious as to what particular models you've heard?

The problem is maybe that digtal DSP is not the best solution? Ever think of that? The same with people thinking that a mic and digital room eq can fix the sound as good as real life acoustics treatment.

NIN

Digital is more than CD NIN and Digital Signal Processing is a very mature technology that permeates most aspects of your entertaiment life, be it watching a DVD, listening to music through an iPOd a CD a PC or talking over he phone cell, landline or Skype... The system you sneer at as "a mic and digital room eq" is a little more involved than that. It is by no means a panacea but it can solve problems that Rooms Treatment can't; one of these being the correction of drivers aberration... Digital Room Correction cannot make an acoustically bad room great but in conjunction with Room Treatment Digital Room Correction should provide a level of performance we could not even dream of ... I still use a good old Passive crossover with regular electronics... I will thoroughly audition the behold (their name is indeed with all capital letters) system as I consider it and similar systems the wave of the future.. we will resist all we want but Digital has steadfastly overtaken analog...

If you look at B&W's 800D brochure, it is an excellent presentation of the struggles involved and the compromises taken when trying to do a 3-way passive speaker. For instance, trying to do a *single* midrange that has wide dispersion, yet decent power handling, they went for the FST design that acts like a smaller cone at higher frequencies (a bit of a rationalization, but....). BUT, they also talk about breakup and cone resonance that occurs (that they feel they've sufficiently controlled). That is occurring pretty much throughout the upper midrange. And how do they blend a completely pistonic diamond tweeter with a driver that is not pistonic at all? By using a 4kHz 6dB/octave crossover that allows more driver distortion to come through *but* allows it to blend over several octaves rather than a sharper transition. They also bring up their preference for pistonic aluminum bass drivers, but because the FST driver doesn't play low, they must cross over the bass region too high and that would allow aluminum ringing to get in.

The general beef against steep crossovers is that the drivers don't have time to 'blend' their sonic signatures and the idea being that lower order crossovers allow the flavors and dispersion of the drivers to merge. BUT, if the drivers are accurate, pistonic, low distortion and wide dispersion at the crossover, you can use steep crossovers and get a very seamless blend while shifting distortion/resonance spectra out of the used range. If you had the ability to use much steeper crossovers, you could switch the 800D's midrange and woofers to very pistonic drivers that performed better in the used bandwidth while lowering distortion and keeping the dispersion very high. That's my only real beef with the 800Ds. They're not harsh like the 800N, but they do retain a low level grunge that, while dismissable, really isn't something I'm used to hearing on digital active speakers such as the Xd or other speakers that have rigid drivers. I may hear other artifacts, but not a general wide bandwidth grunge. It is something that you wouldn't notice if you hadn't lived without it for so long, but it is there. Most speaker designers spend all of their energies making this grunge difficult to notice.

The problem is maybe that digtal DSP is not the best solution? Ever think of that? The same with people thinking that a mic and digital room eq can fix the sound as good as real life acoustics treatment.

I set up a system with some old, but expensive Triads and they sounded muddy from the bass through the midrange until I ran Audyssey on them. No amount of room treatment would have fixed that. There were clearly some inaccuracies that needed to be fixed in the speaker.

This is the difference with impulse response correction. You can actually fix the original event at the speaker, not try to mask later room effects which are dramatically more complicated and technically impossible to correct. Audyssey does both speaker impulse and room impulse response correction. The former works pretty well, the latter is a bit more questionable. DEQX does an even better job of speaker correction and skips the room. The problem with room correction is that it's a multi dimensional problem, basically a set of different problems with no one solution. Speakers are more 1-dimensional.

Also, DSP essentially eliminates certain problems and compensates for others. No passive crossover can do this. Once many of the problems are removed or reduced, you find that solving the remaining problems are not only much easier, but you can use more advanced and higher performance solutions.

I set up a system with some old, but expensive Triads and they sounded muddy from the bass through the midrange until I ran Audyssey on them. No amount of room treatment would have fixed that. There were clearly some inaccuracies that needed to be fixed in the speaker.


Well, I should say, buy a new speaker instead. :)

Otherwise, I don't really agree with you.

Otherwise, I don't really agree with you.
What don't you agree with in what he said?

Well, I should say, buy a new speaker instead. :)

We'd thought of that but figured they would still perform well. The cabinets are well done and the drivers we pretty good, but they clearly need some EQ. The Audyssey did that and the system sounds great now without the added expense.

Otherwise, I don't really agree with you.

I'm still taking that one in.......

As I said before, it all depends on the guy/guys that do this. To think digital active speakers is better just because they are digital active speakers are not really a good move, IMO. It all depends on how it is all done.

I have not heard NHT/DEQX stuff so I cannot commant on that.

It all depends on how it is all done.
How insightful.

As I said before, it all depends on the guy/guys that do this. To think digital active speakers is better just because they are digital active speakers are not really a good move, IMO. It all depends on how it is all done.

No one was saying that a digital speaker is automatically better than a passive speaker, but it is a pretty sensible to say that a digital crossover is more transparent than a passive crossover, not to mention a whole lot more flexible and faster to bring to market.

No one was saying that a digital speaker is automatically better than a passive speaker, but it is a pretty sensible to say that a digital crossover is more transparent than a passive crossover, not to mention a whole lot more flexible and faster to bring to market.


In what way would they be more transparent?

In what way would they be more transparent?

Well, there's no capacitors, inductors or resistors in the path, the amps are attached directly to the drivers, there's no modulation of the crossover frequency due to constant impedance changes with the drivers, no compression due to overheating components, no signal loss etc, etc.

Can you show that in any measurements?

If I had some expensive test gear, I'm sure I could. Do you have any measurements to show I'm wrong?

No, but I think you maybe simplify stuff. Some think that Meridian make the best speakers because they way they are doing the crossover (and other stuff), but the is really just opinion, not a fact.

Is it only those old NHT that have that digital crossover?

No, but I think you maybe simplify stuff. Some think that Meridian make the best speakers because they way they are doing the crossover (and other stuff), but the is really just opinion, not a fact.

But that's not what we're saying. I do think their implementation is impressive, though technically a bit simple compared to DEQX and they could use better, more exotic drivers.

Is it only those old NHT that have that digital crossover?

No, there are half a dozen other speakers now using DEQX - the Pulserods, the Graz ribbons, the Legend Acoustics Tikandis, the Acoustic Zen Maestros, the Overkill Audio speakers, etc. The Tikandi has the closest to perfect execution of what I've seen (not heard) so far.

...not to mention a whole lot more flexible and faster to bring to market.
Perhaps that is why digital active speakers are flooding the market daily.

But that's not what we're saying. I do think their implementation is impressive, though technically a bit simple compared to DEQX and they could use better, more exotic drivers.

No, there are half a dozen other speakers now using DEQX - the Pulserods, the Graz ribbons, the Legend Acoustics Tikandis, the Acoustic Zen Maestros, the Overkill Audio speakers, etc. The Tikandi has the closest to perfect execution of what I've seen (not heard) so far.


I will try to see if I can listen to any of these here in Sweden.

Well, there's no capacitors, inductors or resistors in the path, the amps are attached directly to the drivers, there's no modulation of the crossover frequency due to constant impedance changes with the drivers, no compression due to overheating components, no signal loss etc, etc.
Doug Self (the amplifier designer and book author) somewhere wrote that crossover coils may cross-talk. He suggested that the crossover should be removed from the speaker enclosure and spread out over more real estate.

The Tikandi has the closest to perfect execution of what I've seen (not heard) so far.
How would you know that they are the closet to perfect execution if you haven't heard them? What is it specifically about what you have seen that leads you to this conclusion?

How would you know that they are the closet to perfect execution if you haven't heard them? What is it specifically about what you have seen that leads you to this conclusion?

Simple - As a DEQX dealer, I've learned the following -

1. Pistonic [rigid] drivers work best (more precise, more linear, better inband performance)
2. A single midrange works best (no lobing/acoustic distortion)
3. Directional [monopole] speakers work best (fewer reflections to consider)
4. Proportional speaker sizes work best (better hand off from driver to driver)
5. Acoustic suspension works best (no porting to consider)
6. Minimum baffles work best (more driver, less cabinet sound)
7. Low diffraction baffles work best (more consistent off axis response)

The Tikandi nails 1, 2, 3, 4, 5 and 6. They don't do the low diffraction design like the Xd or, say, Thiel, but that's okay, can't have everything, I guess. Graz attempts dipole ribbons which are more problematic for DEQX. Many of the others use flexible drivers (which makes no sense) or drivers that are hyper small (which makes no sense) or use multiple midranges and/or tweeters (which REALLY makes no sense).

Simple - As a DEQX dealer, I've learned the following...
When did you become a DEQX dealer? You might want to contact DEQX and have them update their website to correct its dealer network because you're not listed as one. Or do you consider yourself a DEQX dealer because you carried the NHT Xd back when it was still being manufactured.

I was a DEQX dealer for awhile, but when they asked me to renew, I passed because the market was mostly internet, rather than local and I'd started to sell Xd by then. I got tired of people calling asking for my 'best deal' on a unit. I maintain a good relationship with them and may sign back up again, but with an entirely different goal.

I was a DEQX dealer for awhile, but when they asked me to renew, I passed because the market was mostly internet, rather than local and I'd started to sell Xd by then. I got tired of people calling asking for my 'best deal' on a unit. I maintain a good relationship with them and may sign back up again, but with an entirely different goal.
What products did you carry in your store?

digital processing is a tool. a tool that in the right hands can be tremendously powerful.

It all depends on whether you go with auto setups, or get a little more in depth, or better yet have a person that REALLY understands acoustics and sound. and have them combine placement, with treatments, and then wringing every last bit of performance out of the system by dialing things all the way in.

digital processing gives a level of control that was previously not even dreamed of. and of course this is both the best thing, and the worst thing that could happen.

Personally i think that fully digital speakers (all processing and amps "in" the speakers) where all you run is either a network cables or blanced line level to each speaker along with power, will not ever really take off. precisely for the reasons listed earlier in this thread. there are too many variables in speakers (sound, finish, price point, etc) to make this economically feasible. but driving those babies with first class didgital processing is indeed the way of the future. and more and more speaker companies will find it in their best interest to have a "custom" processor that does what they feel is the best to their speakers. (a la pro bose stuff from a while back. God help you if you did not have the processor for the 802's with you) so you could still buy wilson X2's (or whatever) and get the dave wilson stamp on the (now external) crossovers/processing.

Another upgrade to come OB! :D

My perspective is a bit like the old Miller Lite commercials where Billy Martin was asked if he preferred "less filling" or "more taste" and he tells them "both" ... but in that case he could get both (asserted anyway) with a single beer whereas in the audio world it takes multiple different beers.

I don't believe one technology is "preferable" or "superior" to another, at least at this point in the development cycle.

I've owned LOTS of the leading digital gear and have spent literally thousands of hours tweaking them in my rooms. I've used Meridians MRC, I've got an Audyssey Pro (balanced) box, I've had two channel and multichannel Tact gear, I've got a DEQX, and I've got several Behringer units. Most of these systems I used with several "bespoke" speakers that were purpose built for an active system (Salk MTMs, Selah Accuton/Fountek line arrays, Accuton MTs in sealed cabinets, etc.) I've even gone so far as to have bespoke amps built for some of these.

I've had three different measurement and acoustic "pro's", folks who regularly post on these boards, custom tweak those setups in my rooms.

I've owned quite a few fairly high end "traditional" speakers, including the biggest Dunlavy's, the Krell Lat1's, big Genesis ribbons (350SEs), and have listened to the big Revel, Soundlab, Talon, Maxx and Hanson units (all of which I genuinely enjoyed).

So, a few assertions not supported by any measurement.

(1) The best active crossovers and room correction software can sound very nice. But, it takes a LOT of work to make them work work superbly. You can get to the 80% or 90% level pretty easily, but that last 10% is very hard, takes a lot of time, and requires expertise akin to an advanced engineering degree. It's an order of magnitude easier to get a turntable dialed in than to get these active units dialed in, and it's not easy to get a turntable dialed in!

(2) None of the commercially available units sound truly terrific until they are heavily modded. Most need their analog stages significantly upgraded, and most don't have truly "state of the audiophile art" digital stages either. The end result is that they all, to me anyway, have artifacts that sound "hard" and "tizzy" and dare I say it "overly digital" unless you choose to spend money and void the warranties. The degree of improvement from modding these units is not subtle, akin to the step up from a Sonic Frontiers tube preamp to an Audio Research Reference preamp (a transition I've experienced.)

(3) Even before modding, and certainly after, the sonic improvement of a speaker where you replace the passive with the active is usually pretty amazing: more transparency, more detail, more information, just plain more. It's like the first time you hear a great digital stack with a truly great digital recording: what it does well it does really well and you never forget what's possible after hearing it for the first time.

(4) At the same time, there's generally something "subtractive" going on with all these digital units. You get those genuine improvements at a cost. The speakers tend to be less enjoyable over extended listening, they tend to become "too revealing", and they tend to require more "volume management". In many ways, this experience is the same as what I experience in switching between digital and analog source material. On my Basis/Graham/Koetsu system I hear amazing "liquidity" with no obvious lack of information or detail. But when I play the same recording on a dCS stack I hear things I don't hear on the analog gear. But over time I miss what I'm not getting on the analog gear and then listen to that. But then I miss the dCS stack. Sigh: crossovers are the same.

In my experience I have yet to find both "less filling" and "great taste" in a single approach. The best passive speakers sound amazing in ways that, in my experience, even the best active crossovers don't yet deliver. And, the best active crossovers deliver sonic experiences that the best passive systems don't.

The debate should not, at least in my opinion, be about which is superior to the other and why. Instead, the real question is "if you choose to experiment and play with the active approach, what's required to really get the most out of the experience?"

Sorry for being so long winded. It took me over a decade to switch entirely to digital sources from analog sources, and I still occasionally miss the best analog source experiences. I expect the same long transition to occur, at least for me, with crossover and room correction technology downstream from the source.

Dizz, I agree with you *except* that I think networked speakers, wireless or cabled, is clearly the future.

Bruce, I agree with you *except* that I've *never* heard hardness or a 'too revealing' nature from either DEQX or Meridian. Ever. In fact, it's the exact opposite. I hear more music, less speaker, more refinement, less harshness. Honestly. I've never felt I was 'missing' anything, I was too busy hearing things I'd missed on passive speakers. No speaker I've ever owned plays loud as well as the NHT Xds. Zero fatigue, even after hours and hours at nearly full volume.

I think networked speakers, wireless or cabled, is clearly the future.

I would restate that in my thinking as I think networked speakers, wireless or cabled, SHOULD clearly be the future.

I too hear things with the DEQX I've never heard before, and genuinely enjoy it.

But, over time I miss the "liquidity" and "wholeness" of the best passive crossovers. (Similarly, over time I miss the DEQX with the best passive crossovers. My dilemma is solved via an architecture that keeps two chains in the room, with one set of sources and one set of speakers. Just as, for a decade, I kept both analog and digital sources.)

Almost all of the hardness can be eliminated with modding. The DEQX can become amazing when the innards are approached without regard for cost.

I've heard the Meridian 6000, 7000 and 8000 speakers on multiple occasions. Despite their technical architecture (which in IMO defines the state of the art for how digital should be done) hey don't float my boat.

I would restate that in my thinking as I think networked speakers, wireless or cabled, SHOULD clearly be the future.

Well, once you spend the money involved for DSP and amplification and the intelligence required, assuming it's built in because it is less expensive, it's a short toss to wireless networking. I'm working on a company now to work on this.

I also cannot confirm that digital active speakers usually sound thin and harsh. I think it's not an issue of digital vs. analogue, at least not today anymore, but rather an issue of a linear speaker vs. a sounded high end speakers.

All I can confirm that at trade shows I have listened to alot of them in non optimized rooms giving harsh sounds due to too much hard reverb.

Digital speakers I heard, some I owned :

- Philips DSS930, liked them alot
- Philips DSS940, ok
- Revox Scala, great
- T+A A3D or A4D, ok
- Meridian - various, not my style at all
- Genelec 8240, love them

I heard as well :
- big Chario towers on Audionet DSP unit
- B+W Matrix 800 reference towers on Audionet DSP unit

And one additional remark I would like to make. Never bring your so beloved passive reference high end speaker to an engineer with an anechoic chamber access for DSP correction (personalized compensation curve). You may hear the most hard, truthfull profound facts on your beloved gear, that only tough man can withstand :D

Merdian - various, not my style at all
Aesthetically or sonically?

First of all, I was a Meridian fan, owned a very early used 861 with 20 Bit ballanced card architecture, if I recall correctly, before that a Meridian 565, that was 18 Bit I think. Man, I loved Trifield and I still have an Ambisonic record around. Once I can grap that 565 for the good old times somewhere cheap I pick one up, just to remind myself how much I loved the work and the nice Meridian people I met in Frankfurt (former place of German High End show). The mix mode was the hype in those days, also Peter is raving about that much.

However, that is were my wallet ended. The Meridian speakers seemed overstyled to me (6000/5000 Series back then), the appeal I did not like at all, the 8K series was back then not available, which is probably superior and in a different world. It was the time when I realized that stereo should have the smallest and tightest phantom image between any two speakers to be able to listen to the room in the recording, not to the room your are sitting in. The demos way back then where always to big in sound, I never felt attracted and as said my wallet said also no for 5.1 or 7.1. Later came the race for more bits and sampling rates and I was really glad I did not go that way. I admit looking at money is a big influencer. I do not think is was due to technology (drivers) Meridian used or any FR influences in the sound. The package never felt right. Also a bit later I did fell in love with Geithain (and Genelec) studio monitors. Nothing then mattered anymore.

The Revox was way back impressive due to their slim stylish appearance and sound. The T+A I had the smallest time listening to. All Philips I owned, sometimes 6 of them. Genelec DSPs I own today. All experiences in different rooms, different events. So beware :D

Let's pimp the thread with some pictures :

DSS930

http://www.mfbfreaks.nl/images/digitaal/dss930/dss930.jpg

DSS940

http://www.mfbfreaks.nl/artikel/digital/940/1/thumbnails/tnfoto03.JPG

Both I owned, very good for smaller rooms. DSS930 I loved....

Revox Scala

http://www.uptownaudio.com/revox/Scala_digital.jpg

T+A had A2D, A3D, A4D.....

http://img167.imageshack.us/img167/691/dsc00017hw7.jpg

Meridian was there all the time, no pictures needed....

And today these are my reference for small rooms....

http://www.audioexport.de/live/genelec/genelec_8250_back_503x800.jpg

I have a pair of Genelec 8250A. I find the sound too dull compared to my other digital active speakers (successors of the Revox speakers: Campana).

I find the 8240 just right....

Are you listening near field ?

Which companies have preamp processors that have digital outputs for 7.1? (Not counting Meridian, which I gather uses proprietary connections.)

How about these?

http://www.avsforum.com/avs-vb/showthread.php?t=1063481&highlight=jl+audio+speakers

Lee

In the past Meridian had 4x SPDIF (565) = 8 channels, that was in the "before HDMI times".... :D

The TACT, of which Peter shows pictures of on a regular basis has obviously 4 AES/EBU outs.....but no HD sound chips, right ?

If you only need stereo you can use a pair of dsp speakers, take the SPDIF out of the cd player and run into a professional processor, like a cheap Behringer and convert to AES/EBU.

The JLs look nice, but I have not understood, if their inputs are digital as well as analogue or just either one ? Genelec offers both....

Hi
Sorry to be long winded...

I have no doubt there will be resistance but in the end we will see more of these... I understand that the thread is about Digital ACTIVE speaker. I believe it would have been more encompassing if it were about Digital Crossovers in general. The more one understands the various compromises that a passive crossover represents the more one would weigh toward Active Digital Crossovers. I would like to see more Preamps/DAC with a built-in crossover. I would not mind analog AND digital outputs.. Analog to drive analog amplifiers and Digital well to drive DAC based Power Amplifer of which the behold seems to be one of the trailblazers (Who else does that kind of thing Boz? TacT?). It would provide a less jolting upgrade path to Audiophiles desirous to keep their beloved amps, that it be tubes or SS or their cables...

What one should understand is that a crossover network ( that's how they used to be called) has a lot of work to do , aside from routing frequencies to drivers... They must also equalize the drivers levels and try to correct obvious driver aberrations, soa side from band, high or low pass you would see some notch filters here and there...They arefar from ideal in this regard. In a nutshell a crossover passive or active try to perfrom a mathematical transformation of the signals that go through it... With a Passive crossover the approximation is simply not good... In digital it is posible to to completely perform in real time the mathematical function with virtually no error and to add correction to the function results... Time Alignment for a subwoofer that had to be placed a good distance from the mains to avoid a room node? but now small differences in arrival time? .. No Problem you can delay the signal to yourheart content so as to have the Main and the sub acoustic center appear exactly aligned and with virually NO distortion something TOTALLY impossible with a passive approach. The fact that each band of frequency is handled by a specific amplifier is one of the bonus the active approach, passive or active... SO one can have a brutal SS for serious Bass control and depth, a Tube Triode for luscious midrange and a SS for the treble is you' re so inclined... It will not necessarily cost less but by using the most appropriate amplifers, one shall obtain better results than with a single amplifeir...

Like anything else they are not a panacea... At the end the art of speaker designs remains.. Simply using Digital Crossovers does not guarantee great speakers.. The best pen in the world does not guarantee great poetry either.. IT is simply a tool and need a practitioner of the Arts or the Science to yield greatness... but for a given Practioner the better the tool the better the results and on this Digital Crossovers are theoretically and in practice better than analog...

By the way I was an analog holdout for a very long time until a few months... I can simply say that I have seen the light... My analog gear just like my cables SHALL remain the same for the foreseeable future their hours have passed... I am embracing fully the digital ( BRIGHT) future

Frantz, what crossover / speaker chain have you chosen?

The main audiophile benefit of digital that can't be done with analog (or active analog) is crossovers with zero group delay over a given low frequency cutoff. You can simulate the benefits and drawbacks of group delay with a program called phase arbitrator, by Thuneau. There are two approaches you can take to understand the benefits, you can either see if you can tell the difference with headphones with an allpass filter, or you can see if you can tell the difference with your speakers. A lot of things have to be right with your speaker crossover and room for you to hear an improvement with phase correction.

Other than that, I'm betting home theater will enable more active loudspeaker designs. By ensuring that the speakers only need to have response at 80Hz and above, you can have smaller power supplies (also enabled by more efficient woofers for a more limited bandwidth). Also, I imagine digital will enable more active designs simply because it seems quality IC's get cheaper over time. I don't think the analog components will ever get cheaper; one second order lowpass stage in my active analog crossovers costs on the order of $10, those resistors, capacitors and opamps add up quickly.

From a design perspective, digital makes a lot of sense for prototyping. I started with a digital crossover before I printed an analog circuit board. Once I went back to analog design iterations for this version, it takes a whole lot longer to A/B changes. But that doesn't mean a manufacture would put out a GOOD loudspeaker any sooner, the digital prototype I had before the analog version only took me so far (I'm going to see if I can increase the fidelity of the digital prototyping system to take me further and save me time to take fewer analog revisions in future designs).

The last thing that needs to be addressed is well rounded expertise. I don't think everyone that designs speakers is qualified in all aspects necessary to put together a competent system as a whole. Throwing boutique components in your crossover/amplifier system won't do you any good in solving a good many electrical engineering problems. Of course, I'm sure the engineers at National,Texas Instruments, Analog Devices, will eventually make their systems completely dummy proof, if they haven't already.

Nothing yet... I will move very cautiously.. I hate equipment-hopping. I have kept my current system almost the same for 5 years or more... I feel the urge to change speakers.. but am extremely satisfied with my electronics... I am interested in a hybrid approach... Active Digital Crossover but the rest of the system would be regular analog amplifier and passive speakers sans-crossover.. My current speakers lend themselves very much to active crossovers.. The cost could be substantial, when you use 3 amps of similar qualities my current reference being far from inexpensive... I also need the most tranparent Pream/DAC/Crossover my ears will find and I don't even know where to begin my search, let alone audition.. So it is a project.. but one I am looking forward to.. I forget to add that I am researching Music Servers and DAC capable of the highest resolutions... The behold looks better and better to me .. I must hear it first.. My ears not my eyes (reading a FR and other specs) are my final judges...

My room uses all active speakers. All speakers except the subwoofer are digitally active. My LRC are Dynaudio AIR25's and the rears are AIR6's. All the AIR speakers are using AES digital input from a TacT TCS.

It took me several years to upgrade to the AIR speakers, mainly because I thought there was going to be more processors arriving to output a decoded digital signal. TacT and Goldmund should be at the top of anyones list if they are going to consider digital active speakers. Theta does it, but doesn't allow for volume control and Meridian limits output to 44k.

I'm in the middle of the upgrade, so everything is far from optimium. Give me another month and I'll know if it was a good move...

Meridian limits output to 44k.
Actually Meridian speakers are 96/24.

Actually Meridian speakers are 96/24.Yes but there's no volume control on the digital output unless connected to Meridian speakers. The VC is in the speaker.

It is my understanding that Meridian limits the digital output to 44k when connected to a non Meridian speaker.

I too hear things with the DEQX I've never heard before, and genuinely enjoy it.

But, over time I miss the "liquidity" and "wholeness" of the best passive crossovers. (Similarly, over time I miss the DEQX with the best passive crossovers. My dilemma is solved via an architecture that keeps two chains in the room, with one set of sources and one set of speakers. Just as, for a decade, I kept both analog and digital sources.)

I think it's a case of implementation. It took NHT 5 years to bring Xd to market. It shouldn't have taken that long, but OTOH, there was a lot of tweaking and discovery along the way. I've never heard a lack of 'liquidity' or 'wholeness' from digital active designs relative to passive crossovers. Generally the opposite. Xd was one of the least 'digital sounding' speakers I've heard. Very smooth and the best integrated sub/sat I've heard.

I'm trying to convince NAD to offer digital outputs on future cards for their modular T175 and M15 preamps. The problem is a lack of a digital speaker standard with on/off and volume information encoded in the signal. That means that IP will likely become the de facto standard.

Nothing yet... I will move very cautiously.. I hate equipment-hopping. I have kept my current system almost the same for 5 years or more... I feel the urge to change speakers.. but am extremely satisfied with my electronics... I am interested in a hybrid approach... Active Digital Crossover but the rest of the system would be regular analog amplifier and passive speakers sans-crossover.. My current speakers lend themselves very much to active crossovers.. The cost could be substantial, when you use 3 amps of similar qualities my current reference being far from inexpensive... I also need the most tranparent Pream/DAC/Crossover my ears will find and I don't even know where to begin my search, let alone audition.. So it is a project.. but one I am looking forward to.. I forget to add that I am researching Music Servers and DAC capable of the highest resolutions... The behold looks better and better to me .. I must hear it first.. My ears not my eyes (reading a FR and other specs) are my final judges...

I would suggest that 3 inexpensive amps will outperform 1 expensive amp every day of the week. So i wouldn't worry about getting less than exotic amps in a tri-amp system.

It took NHT 5 years to bring Xd to market. It shouldn't have taken that long, but OTOH, there was a lot of tweaking and discovery along the way.

And John I made this discovery today. I'm not certain of the source but you may want to look into it if it's true and buy up all the NHT parts you need to last you.


The company is still in business, Customer Service, Parts and Repair Services will be ongoing BUT the firm is shutting down regular operations as of March 31, 2009.

They go on to say...

"Now will be your last opportunity to order NHT products. Product will be available on first come, first serve basis - we reserve the right to accept (or reject) any order. No "runs" on any product will be allowed. We are out of iC1's currently. Surely there will not be enough Classic Three's to go around so we recommend you focus on other products."

Two remarks :
===========
This discussion should not be digital vs. passive x-overs. An active x-over is already far superior to the passive one, as it sits before the amps and is free from driver relationships mentioned by others here. I'm not saying you need to like the sound of pro speakers, but pros have understood the tight controll of such a design and you find only analogue active designs in reference main monitors or eventually digital active designs.

On volume controll. Genelec offers via GLM software on XP the possibility to steer all volumes of all involved speakers. It's still a burden for home cinema to use a PC to steer volume of speakers, but at least it is possible, if the processor does not offer it.

However, if the processor doesn't do it and the digital speakers are set to -0dbFS you may end with artifacts at low levels, depending how well dithering is implemented. Here I'm not the expert though, but I had some probs with my 5 Philips and the Meridian 565 back then at low levels.

It is my understanding that Meridian limits the digital output to 44k when connected to a non Meridian speaker.

1x FS (44.1 or 48K) depending on the sampling rate of the input.

I'm trying to convince NAD to offer digital outputs on future cards for their modular T175 and M15 preamps. The problem is a lack of a digital speaker standard with on/off and volume information encoded in the signal. That means that IP will likely become the de facto standard.

Cat5 / Cat5e / Cat6 is an inexpensive, easy to work with and excellent cable for low level signals.

In the past Meridian had 4x SPDIF (565) = 8 channels, that was in the "before HDMI times".... :D

They still do. The newer addition will be "SpeakerLink" which is a Cat5 solution. I don't know how long before it gets added to the processors, but it is in place across almost all of their loudspeaker models now.


The TACT, of which Peter shows pictures of on a regular basis has obviously 4 AES/EBU outs.....but no HD sound chips, right ?

I thought that was coming.

If you only need stereo you can use a pair of dsp speakers, take the SPDIF out of the cd player and run into a professional processor, like a cheap Behringer and convert to AES/EBU.

WHat's going to control volume in that configuration?


The JLs look nice, but I have not understood, if their inputs are digital as well as analogue or just either one ? Genelec offers both....

The JL AUdios are analog active loudspeakers. Actually they're kind of an odd hybrid. Analog input, A/D conversion, DSP processing, D/A conversion followed by amplification.

Assuming there was a standard, it probably wouldn't be too difficult to add in a digital input to the Primacy speakers.

An active x-over is already far superior to the passive one, as it sits before the amps and is free from driver relationships mentioned by others here.

Yes, but the lack of choices on the speaker side and the prepro side (with the Meridian being castrated) might offset this for some people. I wish the top of the line Denon and Anthem units, for instance, had digital outs.

Hi John,
I did not follow much after I sold the first version of the 861, but I thought with hi-res formats and MHR somehting changed on the digital out. Good to hear they are still the same.

Quote:
If you only need stereo you can use a pair of dsp speakers, take the SPDIF out of the cd player and run into a professional processor, like a cheap Behringer and convert to AES/EBU.

WHat's going to control volume in that configuration?

Either processor or the speakers (which can be quite cumbersome, as you may want it by remote). Some active speakers actually came with their own stereo processor for hook up to most often used media, like Revox did. That was smart.

I thought that was coming.
Hope so, although Tact is not my style.

The JL AUdios are analog active loudspeakers. Actually they're kind of an odd hybrid. Analog input, A/D conversion, DSP processing, D/A conversion followed by amplification.
Not odd, but odd indeed not offering direct digital inputs.

Assuming there was a standard, it probably wouldn't be too difficult to add in a digital input to the Primacy speakers.
Well, AES/EBU is one....SPDIF as well....

syswei, I see your remarks more as a question of taste, and that we cannot argue about :D Technically, I do not see the constraints you mention.

And John I made this discovery today. I'm not certain of the source but you may want to look into it if it's true and buy up all the NHT parts you need to last you."

Source is the owners of the company. Pretty sad, though I'll find out if they're willing to sell, I had other buyers lined up before the last sale. Chris Byrne is a great guy, but he just doesn't have the CEO gene, so I was expecting it to happen. When they took over, I gave them an agenda of 20 things they could do to turn around the company. They did none of it and did quite a few things that bordered on suicidal, including pissing off their entire dealer network (again). That's why I just gave up last year, despite OB's assertions that I was 'let go'.

They still do. The newer addition will be "SpeakerLink" which is a Cat5 solution. I don't know how long before it gets added to the processors, but it is in place across almost all of their loudspeaker models now.

I understood that it was just on the 7200s, but I could be wrong, though that is what I was told (or maybe read). I know it's not on the DSP3100s. It's a little more elegant, though not as simple as I'd have liked with the AC11.

WHat's going to control volume in that configuration?

Well, you could use a McCormack 5.1 analog preamp.

The JL AUdios are analog active loudspeakers. Actually they're kind of an odd hybrid. Analog input, A/D conversion, DSP processing, D/A conversion followed by amplification.

Same as NHT Xd. The way Meridian does it is better, but more expensive. It would still qualify as digital active if the crossovers are digital.

Assuming there was a standard, it probably wouldn't be too difficult to add in a digital input to the Primacy speakers.

The general lack of interest has seemingly prevented even the proposal of a standard AFAIK. Well, I though I heard somebody floating something, but not sure what happened.

syswei, I see your remarks more as a question of taste, and that we cannot argue about :D Technically, I do not see the constraints you mention.

It's not purely a matter of taste. The current prepros that include digital outs also happen to be a bit behind the times as far as offering features. If those features are useful to me, then going with digital speakers isn't necessarily a superior overall solution. In principle, one could use an analog-out prepro and add a set of AD conversion outboard, but that adds cost and potentially degrades the sonic result.

My room uses all active speakers. All speakers except the subwoofer are digitally active. My LRC are Dynaudio AIR25's and the rears are AIR6's. All the AIR speakers are using AES digital input from a TacT TCS.

It took me several years to upgrade to the AIR speakers, mainly because I thought there was going to be more processors arriving to output a decoded digital signal. TacT and Goldmund should be at the top of anyones list if they are going to consider digital active speakers. Theta does it, but doesn't allow for volume control and Meridian limits output to 44k.

I'm in the middle of the upgrade, so everything is far from optimium. Give me another month and I'll know if it was a good move...

Very interesting, I didn't know anyone on AVS had Dynaudio AIRs. Will be interested to read about your findings once your upgrade is complete.

syswei, to me it's taste. Until we get 4x AES/EBU or 4x SPDIF outs on any processor out there, be it Onkyo or Denon or else, I go the way JL does. I use a HT processor with 8 analog XLR outs and feed DSP active and analogue active speakers.

That way I have one more A/D + D/A conversion in the dsp speakers, but that is nowadays an easy one at 24 Bits. I get rid of much more sound compromising hardware, that is analogue passive x-over. I also get active controll (bi-amping) in all speakers and I get that highly precise dsp x-over with best and steepest slopes. I'd rather stick my head into my room accoustics than to fear another conversion.

One day we have a prefect world and we all share that dream...

Latest iteration of Trinnov processor has fairly advanced digital crossovers, bass management, and PEQ, plus, volume control. However, it lacks any surround processing.

I'm considering using it for four way crossover duties for Left / Right speakers, three way for the Center, and one way for the four surrounds.

I find the 8240 just right....
Are you listening near field ?
Yes. They are actually too powerful and the amplifier noise is too high for sitting so close (3m).
Any recommendations for a pair of another brand? Must have AES-EBU in and very low noise from 2m away.
Intended use side speakers for 7.1 system.

I think the problem right now is that the pro speakers lack the great acoustic design and most high-end speakers lack the digital technology. Even those JLs, using soft cones, makes no sense except for those that like a softer, less resolving presentation. Promising, but another example of there not being sufficient selection to suite everyone's taste. Though I wasn't a fan of the dual domes (purely for high output) and the horizontal layout, these still born NHT Pro Studio DEQX speakers sure had the all metal magnesium and aluminum drivers -

http://aes.harmony-central.com/117AES/Content/NHT/PR/M80Xd.jpg

Yes. They are actually too powerful and the amplifier noise is too high for sitting so close (3m).

MHafern, that is not clear to me. Either you mean "No" instead of "yes", that you are not sitting near field, which is actually ca. 1,5 meters or 5 feet, or the noise is too high to sit closer than 3 Meters, which is far field, then "Yes" makes sence ?

My point was a different one. The other speakers you have appear to be really, really good 3 way monitors, which probably have a better bundling characteristics for listening beyond what Genelec specifies for the 8250 (which is only 2,3 meters and near field). That means the 8250 will get sooner a darker timbre due to reverb kicking in although is has DCW, which is not helping in the lower midrange and upper bass power response. Power response is there mainly decided by the bass/midrange driver size. Hence the 3 way speaker might sound brighter at 3 meters for example, which is a good sign, a sign of more direct sound, as in such high end speakers I would not expect any sounding.

You can try to shelve the 8250 up a bit with GLM. On the noise it is the way it is. I can only advice, if you don't like them feel free to disposal them to my address :D

I do not like the JL Audio approach... I would avoid it.. Aside from Behold, TacT (not sure on that by the way)what other company (ies) have a Pre with Digital Crossovers and Analog outputs?

I don't think it's an approach that needs to be avoided *although* I am surprised to see it on a $20K/pair speaker.

I'd rather have an added 24/96 DAC/ADC than go through passive components.

Which companies have preamp processors that have digital outputs for 7.1? (Not counting Meridian, which I gather uses proprietary connections.)

Here are pics of the DCI enabled Tact TCS MK III handbuilt to our combined Home Theater and DCI specs.

Cleanest sounding preamp with HDMI connections that I have heard. It creams the Denon with a level of transparency that is fascinating. The denon sounds muddy by comparison, the onkyo thin and tinny. Of course this is a BETA UNIT WITH SEVERAL ISSUES BUT AS A 12 CHANNEL SURROUND PROCESSOR THIS IS SOME SERIOUS ENGINE.

http://www.miamibadc.com/Images/FEB-006.jpg

http://www.miamibadc.com/Images/FEB-051.jpg

http://www.miamibadc.com/Images/FEB-071.jpg

http://www.miamibadc.com/Images/FEB-072.jpg

The Tact doesn't appear to have enough analog outs to do active crossovers in a surround environment ....

Assume three ways for the front L/C/R, four surrounds not actively crossed, and two subs. That's 15 analog outputs against the 12 in the picture.

Can you add more analog outs to the Tact? Or, would you have to go digital out to Tact amps with their built in multichannel crossovers?

The Trinnov has enough capacity to do all the crossovers and bass management (and more), but lacks any surround decoding that the Tact has in spades.

Or, would you have to go digital out to Tact amps with their built in multichannel crossovers?

yes.

Cinermax, one thing that's pretty annoying, and, limiting the spread of active crossovers (and similar digital processing): vendors locking us into their proprietary technology stacks. It'd help if there was an agreed set of architectural standards.

I can't actively cross with Tact or Meridian unless I use all their gear, or, construct kludgey work arounds.

I might even give Tact a try, once again, if I wasn't locked into their amps too http://www.avsforum.com/avs-vb/images/smilies/smile.gif

Hi John,
I did not follow much after I sold the first version of the 861, but I thought with hi-res formats and MHR somehting changed on the digital out. Good to hear they are still the same.

It did. It allowed for transfer greater than 1x FS (88.2K and 96K). Hi-res (2x FS) must travel on an encrypted path which MHR provides.

1x FS can travel with or without MHR encryption.

I understood that it was just on the 7200s, but I could be wrong, though that is what I was told (or maybe read). I know it's not on the DSP3100s. It's a little more elegant, though not as simple as I'd have liked with the AC11.

You're wrong. It's been added to the 8000, 5200 as well.

Current line of DSPs are 3100, 5200, 7200 and 8000 so 3 out of 4. My guess is that it will go into the next electronics pack update on the 3100.


Same as NHT Xd. The way Meridian does it is better, but more expensive. It would still qualify as digital active if the crossovers are digital.

I have a problem with the A/D and D/A in the path where it's extraneous.

I have a problem with the A/D and D/A in the path where it's extraneous

I think here we finally come to the very bottom of feelings, when we talk about digital active speakers and available digital interfaces from processors/pre-amplifiers.

Within high end, comming/looking from/at the past with 16Bit/44,1/48KHz A/D-D/A alot of feelings have evolved, we still keep alive.

Today we have AD/DA @ 24Bits up to 96Khz, the later up to 192Khz. I think until one has optimized his room to 0,3sec specs in reverb, it's just fair to say that another AD/DA coversion when done right, it totally harmless, when compared to a bend/sounded FR, and x-over artifacts by a passive x-over.

As said, by going analogue or digital active, you also get another benefit of bi- or tri-amping, tighter driver controll in the speakers.

Here are pics of the DCI enabled Tact TCS MK III handbuilt to our combined Home Theater and DCI specs.

Nice, but where is it? When is it available??

MHafern, that is not clear to me. Either you mean "No" instead of "yes", that you are not sitting near field, which is actually ca. 1,5 meters or 5 feet, or the noise is too high to sit closer than 3 Meters, which is far field, then "Yes" makes sence ?

Sorry, I was not aware of how far exactly near reaches. :) I sit ~2m away.

My point was a different one. The other speakers you have appear to be really, really good 3 way monitors, which probably have a better bundling characteristics for listening beyond what Genelec specifies for the 8250 (which is only 2,3 meters and near field). That means the 8250 will get sooner a darker timbre due to reverb kicking in although is has DCW, which is not helping in the lower midrange and upper bass power response. Power response is there mainly decided by the bass/midrange driver size. Hence the 3 way speaker might sound brighter at 3 meters for example, which is a good sign, a sign of more direct sound, as in such high end speakers I would not expect any sounding.

I have Tact room correction. That should help, no?
If the Genelec are made for sitting so close, what's the point of the available power and basic high system noise (since the amplifier is always fully on)? Hearing damage? You can not sit so close and not lower the volume digitally by 25db or more or you get blasted.
The Klein and Hummel boxes seem to have lower noise. Any experiences with these?

FYI guys, here is an external digital crossover (and more) which I have seen bundled with Dynaudio pro monitors and Chord amps:

http://www.xta.uk.com/products-series4.html
http://www.xta.uk.com/pdfs/XTA_4SERIES_BRO.pdf

I have Tact room correction. That should help, no?
If the Genelec are made for sitting so close, what's the point of the available power and basic high system noise (since the amplifier is always fully on)? Hearing damage? You can not sit so close and not lower the volume digitally by 25db or more or you get blasted.
The Klein and Hummel boxes seem to have lower noise. Any experiences with these?

No, not to bring this disussion of course, but the Tact will not help on power response, that is the bundeling capability of the speakers. That bundeling of sound (aka directivity) is in the treble and upper midrange done by the DCW of the baffle, the so called wave guide, and in the low midrange and upper bass by the 8 inch driver in the 8250. In the very low bass no controlled directivity is possible, except for cardiod speakers, like Geithain. The Tact will either solve the impuls FR or only the perceived mixture of impuls FR plus room reverb to come extent, to a certain overall target sound (as does Audyssey by "Reference" or "Flat" curve). But what it does in your room I cannot tell from here. I can only tell you, that usually bigger speakers/drivers will bundle the appropriate wavelengths better, at least this is my understanding. So the perceived difference can be due to directivity, if both speakers draw impuls FRs like a line.....

As you have the Tact in between, I 'm sure you made the comparison between both of your speaker pairs without it ? In case the 8250 sounds to dull, you can shelve with GLM the treble up. If that does not help, it can be the room or the other speaker were indeed more transparent. Then the only question would be why ?

On noise I fond it Ok, for a speaker with almost linear response to above 20KHz, which logically disloses any noise more dramatic. Did you adapt the input sensitivity on the back ?

As you have the Tact in between, I 'm sure you made the comparison between both of your speaker pairs without it ? In case the 8250 sounds to dull, you can shelve with GLM the treble up. If that does not help, it can be the room or the other speaker were indeed more transparent. Then the only question would be why ?
On noise I fond it Ok, for a speaker with almost linear response to above 20KHz, which logically disloses any noise more dramatic. Did you adapt the input sensitivity on the back ?
I compared only without the Tact so far, actually.
Input sensitivity is nothing but digital volume control if you use the digital in (which is the whole point of the exercise for me). The amplifier is always at full blast and volume change is only possible by digitally reducing source volume at the player or in the speaker with the switches on the back side. The system noise is constant and can not be influenced since the analogue amplification is constant. My older speakers have variable analogue amplification so the problem does not arise.

Input sensitivity is nothing but digital volume control if you use the digital in

Let's take the discussion off-line and discuss this by PM. I found this on "digital in" for 8000 series, I only use analogue so far. Maybe you are right, maybe not, maybe there is no effect of the below at all :

"If the digital source device has a digital level monitor pot or graphical volume fader that controls the digital level, it may be advantageous to lower the level control either on the computer interface or the loudspeaker’s back panel controls, which in turn will force the use of more of the digital [bit] resolution in the volume control."

I have a problem with the A/D and D/A in the path where it's extraneous.

In theory or reality? Bob Stuart would tell you he could do about a dozen 24/96 AD/DACs and you wouldn't be able to hear it. Just sayin'.

In theory or reality? Bob Stuart would tell you he could do about a dozen 24/96 AD/DACs and you wouldn't be able to hear it. Just sayin'.
Do you have a link?

No, jeesus, why does ever thing need a link? He said it at a talk on the audibility of sampling rates and bit depths. But that Meridian uses digital transfer because it makes *sense*, as 'in theory'.

No, jeesus, why does ever thing need a link? He said it at a talk on the audibility of sampling rates and bit depths. But that Meridian uses digital transfer because it makes *sense*, as 'in theory'.
Because you routinely make stuff up and hence have no credibility.

You're wrong. It's been added to the 8000, 5200 as well.

Current line of DSPs are 3100, 5200, 7200 and 8000 so 3 out of 4. My guess is that it will go into the next electronics pack update on the 3100..

Now that I think of it, I believe I was thinking of the apodizing filters.

Because you routinely make stuff up and hence have no credibility.

Do you have an example?

Hi

It is best to avoid both on a theoretical and on viewpoints successive Ad to DA conversions. I would like to know in what context Stuart said it because it is far from the best way and lead to audible non-linearities.
As I am beginning to see from this most interesting thread and despite the fact that I believe that Active Digital Crossovers are the future, the single biggest problem seems o be the lack of standard... I tend to think in two-channel terms. In a surround environment the lack of standard is clearly apparent... I do not know for example how such systems would work with the new HD Surround formats.. nor do I know how they would deal with whatever DRM schemes there would be in the Digital stream... Any answer on that Gals and Guys?

As I recall, Bob was pointing out the efficacy and transparency of current AD/DAC technology, as in the ability for a Meridian piece to transparently digitize the sound of SACD through the 5.1 inputs and in general. I believe he said that they could take a signal and ADC/DAC it a significant number of times before there was a subjective difference. Of course, there would be some small numerical differences in the signal, but that subjectively, it would be transparent. That wasn't possible with earlier, lower bit, lower sampling rate conversions. He also said that 24/96 was overkill (20/66, I believe was his magic number) and 24/192 was a waste of storage space, though he didn't express a serious problem with overkill.

I'd be surprised if John K wasn't at the same talk. I also asked Bob about digital amps and using the amp as the convertor, but he said it wasn't ready for prime time, though they were looking at it. This was about 5 years ago.

I agree. The new 24/96 AD/DAs have become so good, if we leave the jitter talks for a moment under the carpet, where in the past some audio mashines were supposed to be near the quality of a landline telephone, that at least one or two more conversions will not be of real "signifcant" importance in the overall context. And of course this is only easy for those to except that have and admit to have at least failed once in any a/b blind volume matched listening test. No "cable-listners", as we call people dwelling in the land of high end cables will admit it. No chance. For them it simply cannot be, another AD/DA at that high level must have substance, it most be of significance, even though they may listen in untreated rooms, with huge reverb and too far away from their speakers. Another AD/DA must be bad.

And there we are back to my favorite discussion in "high end" audio. What is important, what has real significance. Does "a bit more air in the treble" many preceive when they buy new hardware show real significance, or isn't it a "s-shaped" FR response of a speaker coloring the sound ? Does the exchange of wire really show signifcance, like hey, I think there is "a bit more depths", or isn't it to have a well treated room with a low RT60 ? Are contact fluids the real ear opener, or isn't it rather a well defined directivity of a loud-speaker for non colored off-axis sound.

It's more about freeing you mind than anything else :D

I will say that if you take a digital volume control and run it on a signal, the sound quality gets atrocious *if* you raise the volume where you can pick up how atrocious it's getting. But our ears also lose resolution with volume, so if you have your analog gains set properly, ADC/DACs and digital volume or analog volume ahead of the crossover is a minor issue, possibly a completely inaudible one. If you don't have it set to maximize bit depth, then there will be a sound loss. So any DSP speaker with analog inputs should have a gain control on the back for maximizing performance.

Hi

It is not .. just "freeing" your mind... Let's not make of Digital a perfect process. There are differences between DACs. All 24/192 DAC do not sound alike... which means there are variations and cascading variations leads to more...well variations so that the input shall be quite different and audibly so, from the output... A process that minimizes such AD then DA transitions, IOW taking Digital from input to output yields the best theoretical AND practical advantages... If you want to maintain that as some have put it here on AVS that: Digital is Perfect then we have not much to discuss .. these are opinions that have been elevated to beliefs and as such are not debatable.

I don't think anyone is calling digital 'perfect', nothing is perfect, certainly not analog. The question is whether minor, likely inaudible processes are inconsequential compared to the gains. I suggest they are and the only thing is that there are better and worse ways of doing things. If you compared the NHT Xd which uses an 'unnecessary' DAC/ADC, it still easily outperformed the 3x$ DSP6000 which has the preferred full bit, all digital connection with analog volume, at least at normal listening volumes.

IOW, all of these things are small elements of a big thing. All things equal, sure, but thing aren't equal. Acoustic design and the power of the processing is still more important than whether the signal is pure digital or whether it has an extra process in the middle.

All 24/192 DAC do not sound alike

Hmmm.....how can you tell ? Some have say 112db S/N, some 113dB S/N, some maybe 120+db S/N. You think you hear the difference of 1db S/N ? Isn't it more likely you hear the difference of the analogue part after the DAC, as you actually cannot listen to a DAC alone ?

Let's skip the discussion. If someone feels (and hears) another 24/96 conversion eats his sound quality to death, so be it.

Hmmm.....how can you tell ? Some have say 112db S/N, some 113dB S/N, some maybe 120+db S/N. You think you hear the difference of 1db S/N ? Isn't it more likely you hear the difference of the analogue part after the DAC, as you actually cannot listen to a DAC alone ?

Let's skip the discussion. If someone feels (and hears) another 24/96 conversion eats his sound quality to death, so be it.

Even if all DACs are "indistinguishably perfect and transparent" at the chip level, IME the analog stages in these devices still sound different.

My DEQX has a pretty high quality D/A and A/D built into it. (The stock box was good, and the mods I had done made it quite a bit better.) If I insert that into my normal chain and have it perform only an A/D and then D/A, it's clearly audible. Subtractive/adverse is another issue: while the sound is different it's not obvious on all material that it's worse.

This from an adopter and supporter of active / digital crossovers.

If you compared the NHT Xd which uses an 'unnecessary' DAC/ADC, it still easily outperformed the 3x$ DSP6000 which has the preferred full bit, all digital connection with analog volume, at least at normal listening volumes.
I take it you mean in your ever so humble opinion.

Andreas
If to you same measurements means same sound then more power to you... My point is that if we have reach a point where ALL DAC sound the same then we have hit perfection or at the very least a plateau.. The approach of an to D followed by a Dto A then followed by another is flawed.. It is fact. It may be a usefil or even necessary compromise but not the ideal.. Skipping the discussion is all OK with me.. You have not proven that the approach is valid so we can leave it at that....

I take it you mean in your ever so humble opinion.

It wasn't all that close. However, the DSP7200 is a big step up from what I've heard so far. DSP6000 driver package is pretty long in the tooth. Like 15 years. So, I'm not saying it was an entirely fair fight. Just saying that there are other things that are more important.

Frantz, do you think you could accept that, done properly, the DAC/ADC effect would be minimal, possibly close to inconsequential in the scheme of things? The problem is that we don't have a universal standard, of which I am aware, for controlling the volume of DSP after the effect, so building in a proprietary solution means a proprietary, closed system. The JL Audio, while I wouldn't have chosen those drivers, does have the advantage of working with anything, even in a multi-channel system. And, I suspect it is good enough to have other companies eager to follow.

It wasn't all that close. DSP6000 driver package is pretty long in the tooth. Like 15 years. So, I'm not saying it was an entirely fair fight. Just saying that there are other things that are more important.
I'm not sure I understand what you are saying here. Do you mean for the price the Xd "easily outperformed" the DSP6000s from a value perspective or that, price aside, the Xd "easily outperformed" the DSP6000s?

I'm not sure I understand what you are saying here. Do you mean for the price the Xd "easily outperformed" the DSP6000s from a value perspective or that, price aside, the Xd "easily outperformed" the DSP6000s?

The latter. But this is because the Xd used much more advanced, newer generation drivers and much more advanced processing. DSP7200s are somewhere in the ballpark though, have some pretty kickass dynamics and a are big upgrade from earlier Meridan efforts. Keep in mind I'm a Meridian dealer, just being honest here.

A 'perfect' DSP speaker would have digital inputs, analog volume (or gain adjustable digital volume), the very most advanced drivers, at least a 4-way or 5-way design and serious adjustability to its environment but until we have that, sometimes little things such as am extra DAC/ADC aren't enough to stop a product from being better.


BTW, did you have an example of how I 'make things up' or were you making that up?

Even if all DACs are "indistinguishably perfect and transparent" at the chip level, IME the analog stages in these devices still sound different.

Yes Bruce, that is what I ment towards Frantz.

Thx for the honest words. You're sure the bybass mode will not route the signal through the DSP as well ?

You're sure the bybass mode will not route the signal through the DSP as well ?

Not entirely, but do know that there is zero processing applied; there's no additional time / phase / frequency signal manipulation in the bypass mode.

In theory or reality? Bob Stuart would tell you he could do about a dozen 24/96 AD/DACs and you wouldn't be able to hear it. Just sayin'.

Two points to make here:

1) Not everyone does things as well digitally as Meridian.

2) I said extraneous -- at every domain junction there is the chance to screw it up. So if you only do one domain conversion there's less spots to screw it up. That also means you better get it right.

No, jeesus, why does ever thing need a link? He said it at a talk on the audibility of sampling rates and bit depths. But that Meridian uses digital transfer because it makes *sense*, as 'in theory'.

It's not theory. Digital is a much more robust transmission format.

if we want to be very quibbly... i think we should say that digital is not a transmission format. it is a signal format. Virtually all signals, follow analog wave transmission rules.

It's not theory. Digital is a much more robust transmission format.

Robust, sure, but that doesn't mean you can't go back to analog for a few feet and back to digital and still have a great result. Analog still works quite well. DAC and ADC still works quite well. We're talking about the difference between 'ideal' and 'practical'. I haven't seen too many speakers that even approach what I would call 'ideal', so an ADC/DAC isn't that big of a deal, bigger fish to fry.

This discussion is now drawn to AD/DA, as we said we miss interfaces for digital active speakers, and like the JL audio does not even have a digital input. In reality, we have SPDIF (IEC958/75ohm) and AES/EBU(110ohm) for digital transmission. But isn't it the chicken and egg principle, which was there first ? Are we missing digital interfaces or are we missing digital active speakers ?

For DACs comparison it would be cool, if someone would make a small unit with 4 different DACs in the same box one could switch through via remote, for double blind level matched a/b testing. Say, throw in a Wolfson, a BB, a selected BB and a Crystal DAC and whatever high end DAC, but same analogue out. If you hear then a clear difference, then the discussion is worthy. of course AD/DA needs to be done right, at least for the money we spend, but at 24/96 chances are very good you won't hear another conversion significantly. And if you do, what is worse as asked ? Another conversion, or to have a passive x-over/speaker and no bi- or tri-amping....we are circling here.

Andreas:

Maybe it's just me, but if we don't talk about the ideal solution and then work towards it we end up with the status quo.

I would love for the digital active speaker market to grow by leaps and bounds, but it isn't exactly taking off.

BTW, Tannoy has some digital active speakers with digital and analog inputs, the Eyris iDP line.

I think it's important to look at the final arbiter - the measured and subjective performance, not tiny little details. Of all the things that could go into a DSP speaker, the two things that would matter least is 1) an extra 24/96 ADC/DAC and 2) the speaker cable used.

I would love for the digital active speaker market to grow by leaps and bounds, but it isn't exactly taking off.

The demand for wireless speakers will change that. Fast. If companies aren't ready for it, they will be left behind. The foundation for this is currently being built. As I understand it, one of the reasons NHT is liquidating is so they can come out with some sort of wireless digital speaker thing. Well, that's the rumor.

Well John, we cannot force people to understand. As said one day we all drive electric, because after we did it, and it became mainstream, as usual we will scratch our heads why we didn't do it earlier.

I think the "ideal" solution is clear and already here, it only fails due to taste and a little bit cumbersome handling. The ideal solution is a fully digital chain.

A bit off topic, but does anyone have experience with active analog crossovers?

Several guys I know and trust have heard modded Marchand units and say the sonics are amazing.

I suspect a large fraction of the improvement we hear with active digital crossovers is getting the crossover in front of the amp, rather than digital vs. analog per se.

If an analog crossover is well done, it should work as well as a digital crossover +/-. The true advantage of the digital crossover is its ability to keep the signal digital as long as possible, to do time/phase adjustment, to do FR adjustment, etc, etc. Those are huge factors in the quality of a DSP speaker.

One of the things that is interesting about the NHT Xd is that it sounds so radically different from conventional passive speakers that hardcore audiophiles often either react negatively to the new sound or just don't know what to make of it. The more they listen, however, the more they like it IF you can get them to listen more (and usually they won't). But plain old music lovers had no such negative reaction. They fell in love with the sound within seconds. I believe that, in 20 years, people will look back at it and say 'wow, they really got that right and why the heck didn't it take off"

John

Keep in mind YOUR thread is NOT about the Xd.. Dang it John! It is a good speaker but it was lacking; the argument it is so good that people reacted negatively is flimsy at best.. On the crossover side I agre in part with you . It is not the ability to perform corrections that is the only advantage of Digital crosovers it is the fact that they can perform the needed mathematical function almost perfectly.. I keep on repeating it a crossover is a filter or several filters.. A filter is a device that at the core performs a mathematical functions (or at the very least should perform it). Analog Filters are a crude approximation of these functions.. very, very crude... A digital filter can actually perform the exact needed function with virtually no errors... That in itself should make them sound better in theory in practice there are implementation problems and they account for the widely different results...

Keep in mind YOUR thread is NOT about the Xd.. Dang it John! It is a good speaker but it was lacking; the argument it is so good that people reacted negatively is flimsy at best..

It doesn't matter, Xd is gone! Well, almost gone. As is NHT. But what you see as 'lacking' is PRECISELY what I don't want to hear from a speaker - the sound of the speaker! All you had to do was drop these in the same room as a $20K speaker, almost ANY $20K speaker (including/especially Magnepans) and they would tell you exactly what is wrong with the other speaker, how it is coloring the sound, where the resonances were, the peaks, the dips. The Xd is NOT the best DSP speaker that can be built, but it remains better in many to most ways than many if not all passive speakers. I will not retract this, no matter how many times you push me to do so. Point source is just plain more natural than a large baffle of drivers. Buy a set of Xds, keep them in your house and I guarantee they will increasingly draw you to them and away from the Maggies.

Besides, I'm just pointing out that an ADC/DAC is simply not crippling, even though it is not 'ideal'.

On the crossover side I agre in part with you . It is not the ability to perform corrections that is the only advantage of Digital crosovers it is the fact that they can perform the needed mathematical function almost perfectly.. I keep on repeating it a crossover is a filter or several filters.. A filter is a device that at the core performs a mathematical functions (or at the very least should perform it). Analog Filters are a crude approximation of these functions.. very, very crude... A digital filter can actually perform the exact needed function with virtually no errors... That in itself should make them sound better in theory in practice there are implementation problems and they account for the widely different results...

Well, you still get ringing with any crossover. Meridian says that it has made what they call 'apodizing' filters, which, if I understand their press material (which remains press material), they are able to emulate a 'perfect' filter with little or no ringing. Or that's what they seem to imply.

Some digital speakers -

http://www.carltonaudiovisual.com.au/images/legend/tikandi.jpg

Legend Acoustics Tikandi w/DEQX

http://www.stereotimes.com/images/Acoustic%20Zen%20pic%202.jpg

Acoustic Zen Maesto w/DEQX

http://blog.stereophile.com/ces2006/wasatch.jpg

Wasatch w/DEQX

http://cms.whathifi.com/Images/125930879bli.jpg

B&O

http://www.cryo-parts.com/images/ces_2009_pulserod_right-2.jpg

SonicWeld PulseRod w/DEQX

http://www.cepro.com/images/slideshow/Meridian-front-right.jpg

Meridian DSP7200s

http://www.instablogsimages.com/images/2008/09/26/arvus_prerenaissance_osLhA_52.jpg

Arvus w/DEQX

http://www.salksound.com/gallery/HT3-bubinga-t.jpg

Salk HT3 w/DEQX

http://home.jlaudio.com/graphics/HomeSection/NP08/PX3-FLT.jpg

JL Audios

http://forum.ecoustics.com/bbs/messages/47077/299297.jpg

NHT Xd w/DEQX

http://hiddenwires.co.uk/resourcesarticles2008/articlespic20081201-02-02.jpg

Phase Technology dARTS w/Audyssey

Why no pictures of Meridian speakers in your cavalcade of digital active speakers?

Why no pictures of Meridian speakers in your cavalcade of digital active speakers?

Still looking for pictures, but was going from the new, more obscure ones first.

Still looking for pictures, but was going from the new, more obscure ones first.
Meridian currently makes five digital active speakers: the DSP8000, DSP7200, DSP5500, DSP5200 and DSP3100. All but the DSP8000 also come in horizontal center versions. In addition, they make two digital active subwoofers: the SW5500 and the SW1600. The digital active subwoofers have both a digital and analog inputs. Pictures are available on their website.

http://www.meridian.co.uk/product-model/loudspeaker-systems/dsp8000-digital-active-loudspeaker.aspx

Meridian currently makes five digital active speakers: the DSP8000, DSP7200, DSP5500, DSP5200 and DSP3100. All but the DSP8000 also come in horizontal center versions. In addition, they make two digital active subwoofers: the SW5500 and the SW1600. The digital active subwoofers have both a digital and analog inputs. Pictures are available on their website.

http://www.meridian.co.uk/product-model/loudspeaker-systems/dsp8000-digital-active-loudspeaker.aspx

Yes, I know all this, being a Meridian dealer and all (and having just set up a 7200/3100 HT system a week or so ago). When you think digital speakers, the first thing that comes to mind is Meridian. I was looking for more obscure DSP speakers and was working backwards. I guess I don't talk about Meridian as much because it is the 8000 lb elephant in the room.

John

Keep in mind YOUR thread is NOT about the Xd.. Dang it John! It is a good speaker but it was lacking; the argument it is so good that people reacted negatively is flimsy at best.. .
Frantz,

Additionally, John keeps attempting to make one of the FAULTS of the Xd crossover into
a virture - the high order, steep slope crossover. The steep crossover made the designer's
job easier by essentially "decoupling" the passbands.

Unfortunately for the end user; the steep crossover comes with a SEVERE price that is
dictated by the mathematics - the steep crossovers have "pre-echo" which is acausal
and smears the sound. John Atkinson actually MEASURED the pre-ring; so don't let
John do his usual fabrication that it was magically cancelled by the other out of passband
driver. It would have been a better speaker with smoother crossover transitions and an
improved radiation pattern if they had "blended" the drivers at the crossovers instead of
the discontinuous cut-off that was implemented.

Mother Nature is "continuous" and any product wishinig to emulate Mother Nature should
be free of artificial discontinuities.

The Xd is good - but it is definitely NOT "great"; as we have discussed many times
here before. For the low price; it's pretty good - although my colleague "smokester"
believes one can do better for the same price.

........

What can also be seen from fig.11 is that each drive-unit's step is preceded by some low-frequency ringing. But because the tweeter's and woofer's acoustic outputs appear to have opposite polarities, this pre-ringing should to a large extent cancel, at least on the tweeter axis. That this does in fact happen is shown by the XdS's overall step response (fig.12), the tweeter's positive-going step smoothly handing over to the woofer's negative-going step, this in turn correlating with the superb frequency-domain integration between the two drive-units seen in fig.7.

The 'ringing' caused by two drivers not in perfect synch off vertical axis is far more audible, measurable and dramatic, especially with D'Appolito speakers. The Xd is absolutely 'great', as has been said in every review. "Class A" for instance.

Yes, I know all this, being a Meridian dealer and all ...
You need to get in touch with Meridian to update their website. You are not listed as an authorized dealer.

........



The 'ringing' caused by two drivers not in perfect synch off vertical axis is far more audible, measurable and dramatic, especially with D'Appolito speakers. The Xd is absolutely 'great', as has been said in every review. "Class A" for instance.

John,

The "ringing" that John Atkinsons refers to here is NOT due to drivers being "out of sync"

It is the ringing can be a part of high order crossovers. John will probably ignore this
reference as he always does - but for those interested - the "pre-ringing" is described
by Keith Howard in his Stereophile article: "Ringing False":

http://www.stereophile.com/reference/106ringing/

Specifically look at the graphs of impulse respons [ first column ] for minimal phase
filter and compare to all the others. The minimal phase filter is the only filter in the
group that doesn't "pre-ring". The Xd filters were NOT minimal phase.

http://www.stereophile.com/reference/106ringing/index1.html

The Xd had an acausal, unphysical "pre-ring" that can not be acoustically cancelled
exactly because the two drivers have different passbands. The "pre-ring" is mitigated
to a degree on the speaker axis, as John Atkinson points out - but who is seated
simultaneously on the axis of both speakers?

The "pre-ring" is audible - and that's what counts.

You need to get in touch with Meridian to update their website. You are not listed as an authorized dealer.

They'll get to it. We just signed back up after letting things lapse for a year or two.

The "ringing" that John Atkinsons refers to here is NOT due to drivers being "out of sync"

I'm talking about the 'ringing' that would occur in, say, a Wilson X2 in the upper bands off axis. Not exactly the same thing, but the poor vertical dispersion is much more problematic. With DEQX, you can choose any filter you want, from 6dB to 300dB/octave. You simply choose the slope that results in the best sound. Period. NHT and others have found that the steeper crossovers fix more subjective and objective problems than they create.

Ringing is a tiny problem because it is self canceling at tweeter axis. However, steep crossovers lower motor distortion, cone resonance, improves horizontal dispersion, dramatically improves vertical dispersion, increase SPL, etc. Adding one smaller problem substantially improves 4 or 5 other areas of performance. Great tradeoff.

The "pre-ring" is mitigated
to a degree on the speaker axis, as John Atkinson points out - but who is seated
simultaneously on the axis of both speakers?

Everybody if you're seated. It's a *horizontal* axis. Therefore, at anywhere approximately 32" off the ground (typical head height when seated), the pre-ringing cancels.

The "pre-ring" is audible - and that's what counts.

So is lobing. So is motor disortion. So are cone resonances. So are +/-8dB frequency response errors. It's like saying Halle Berry isn't hot because she has a mole on her butt or something.

What are the drivers in the Acoustic Zen Maestro and the Wasatch? (Particularly the mids and the ribbons.)

How do the Maestro's use DEQX in a four way? (Where is the passive located, or is there a non DEQX in the chain somewhere?)

What are the drivers in the Acoustic Zen Maestro and the Wasatch? (Particularly the mids and the ribbons.)

Not sure. I wasn't thrilled with the sound of the treble on the Wasatch speakers. I think they applied too much correction or something, but the mids and bass sounded great.

How do the Maestro's use DEQX in a four way? (Where is the passive located, or is there a non DEQX in the chain somewhere?)

I think they are operating it as a 3-way with the bass/midbass running parallel. That's a guess, but it's either that or they're adding another crossover for the bass only, either active or passive.

Ringing is not a matter of DRIVER John it is a function of the CROSSOVER.. VERY steep Croosover slopes DO produce ringing... It is measurable... IT WAS MEASURED.. I know you will come with some twist of language to show that it is not.. Steep crossovers are NOT a panacea they create too many problems of their own... If it were so easy to "just choose" the best slope PERIOD then everybody given a DEQX would produce infinitely great speakers.. Wait! Sorry I think that is your point... Sorry...

I will just leave you with the opportunity to derail and/or destroy your own thread by a quasi compulsive tendency to inject ANY discussion with a mention of the absolute superiority of he Xd over anything else...

And that is what is so maddening about hyperbolic statements.. At the current price of the Xd ($3000) they are the proverbial steal... You get a pair of speakers, amp and a sub.. Very good simple system.. I might just grab a pair of X-2 for a FL apartment..

Good they are! Perfect they aren't.. Wilson X-2 Territory? Not on this planet!

Ringing is not a matter of DRIVER John it is a function of the CROSSOVER.. VERY steep Croosover slopes DO produce ringing... It is measurable... IT WAS MEASURED.. I know you will come with some twist of language to show that it is not.. Steep crossovers are NOT a panacea they create too many problems of their own... If it were so easy to "just choose" the best slope PERIOD then everybody given a DEQX would produce infinitely great speakers.. Wait! Sorry I think that is your point... Sorry...

Frantz, where are you getting this? And please behave more like the Frantz I know. Yes, there is ringing. Pretty much all crossovers ring. What I am saying is a) this largely cancels on horizontal axis (as John Atkinson says) and b) by allowing a little more ringing in the system, you are able to improve 4 or 5 other parameters simultaneously, parameters that are extremely difficult to improve without the steep crossovers.

I will just leave you with the opportunity to derail and/or destroy your own thread by a quasi compulsive tendency to inject ANY discussion with a mention of the absolute superiority of he Xd over anything else...

Again, I didn't say that Xd has ''absolute superiority over anything else". I said that it does many things better than virtually any passive speaker I have ever seen measured. This is factual, not hyperbole. That does not make it 'better' subjectively or objectively as it doesn't do *everything* better. However, it points out the flaws in current passive speaker design very nicely. I expect these kinds of asymmetrical arguments from others, but not you.

Good they are! Perfect they aren't.. Wilson X-2 Territory? Not on this planet!

Again, I never said they were perfect. Nor have I ever said that anybody would absolutely prefer them over X2s, though i imagine somebody might, including probably me. But they will absolutely do some things better than X2s. Vertical dispersion, for instance. Horizontal dispersion. Measured FR accuracy. X2s will likely play louder with lower motor distortion. That is not hyperbole, it is factual and predictable.

Even if the X2 sounds subjectively better to most people, does it, in fact, make sense to spend 20 times as much for a speaker that is measurable inferior in many ways? In this day and age, I think we would both say it does not. Not when we can see what $3300 in processing and amplification does for $2700 worth of speakers.

I NHT and others have found that the steeper crossovers fix more subjective and objective problems than they create.
John,

NHT may have concluded that - but that is NOT the conclusion of Keith Howard and
Leo Spiegel, the chief designer for the original Apogee speakers:

http://www.apogeespeakers.com/leo_spiegel_interview.htm

Leo Spiegel states that they tried steep crossovers when designing the Apogee Stage;
and found that the drivers in this two-way unit didn't integrate. He stated that when
steep crossovers were employed, one could hear the two drivers distinctly instead of
the desired effect of having a seemless whole.

Leo Spiegel used a lower order, more gradual crossover to "blend" the output of the
drivers over the crossover range.

Theoretically, one would expect a more seamless transition in such an approach. If
you suddenly switch from a large driver to a smaller driver - which is what a steep
crossover does - for nearly the same frequency; you shift from one size "antenna"
[driver] to another. You have a sudden shift in radiation pattern - the larger driver
has a narrower dispersion since it is closer to the beaming limit, where as the small
driver is more isotropic.

The only problem the steep crossover really solves is the designer's problem of doing
what Leo Spiegel does and blend the driver output in the crossover regime. The steep
crossover decouples the crossover problem and makes the DESIGNER's job easier
by not having to blend together the output of two drivers as does Spiegel.

However, the price of making the designer's life easier is paid by the end user in a
poorer quality listening experience.

Adoes it, in fact, make sense to spend 20 times as much for a speaker that is measurable inferior in many ways?
If the speakers which are "measurably inferior"in the few aspects of speakers that are actually measured sound better, yes. Measurements do not tell the entire story.

John,

NHT may have concluded that - but that is NOT the conclusion of Keith Howard and
Leo Spiegel, the chief designer for the original Apogee speakers:

http://www.apogeespeakers.com/leo_spiegel_interview.htm

Leo Spiegel states that they tried steep crossovers when designing the Apogee Stage;
and found that the drivers in this two-way unit didn't integrate. He stated that when
steep crossovers were employed, one could hear the two drivers distinctly instead of
the desired effect of having a seemless whole.

Leo Spiegel used a lower order, more gradual crossover to "blend" the output of the
drivers over the crossover range.

Theoretically, one would expect a more seamless transition in such an approach. If
you suddenly switch from a large driver to a smaller driver - which is what a steep
crossover does - for nearly the same frequency; you shift from one size "antenna"
[driver] to another. You have a sudden shift in radiation pattern - the larger driver
has a narrower dispersion since it is closer to the beaming limit, where as the small
driver is more isotropic.

The only problem the steep crossover really solves is the designer's problem of doing
what Leo Spiegel does and blend the driver output in the crossover regime. The steep
crossover decouples the crossover problem and makes the DESIGNER's job easier
by not having to blend together the output of two drivers as does Spiegel.

However, the price of making the designer's life easier is paid by the end user in a
poorer quality listening experience.

Exactly. Because Apogee doesn't use pistonic drivers. They have distinct coloration that MUST be blended in order to prevent the drivers from being audible as distinct entities. But if you use drivers operating pistonically in the used range, then you can pass from one to another steeply without audible seams. Apogees and other ribbons sound nice in a euphonic way but are increasingly irrelevant. I have not liked the sound of ribbons in conjunction with DEQX ever time I have heard it. But pistonic drivers are an entirely different story.

If the speakers which are "measurably inferior"in the few aspects of speakers that are actually measured sound better, yes. Measurements do not tell the entire story.

No, but it does allow you to immediately see what even $100K+ passive speakers do not do well.

No, but it does allow you to immediately see what even $100K+ passive speakers do not do well.I don't think I would buy speakers blind based on measurements, and I don't think I would buy one speaker over another if it didn't sound as good even if it measured better. Perhaps you, like DougWinsor who also worships at the alter of measurements, would.

Some digital speakers - http://www.salksound.com/gallery/HT3-bubinga-t.jpg

Salk HT3 w/DEQX

Since you listed the DEQXed Salk HT3A, this might be a good point to also repost what their designer, Dennis Murphy, had to say about DEQX:

Again, I don't really disagree with you about the superior flexibility possible with DEQX-type machines. But I do know that if you start with high quality drivers that don't have weird peaks that can't be deat with using a simple trap circuit, it's possible to match the sound of the DEQX, or at least come close enough that most listeners could not pass a blind test. Actually, that's wrong--the DEQX can fix room bass peaks (and so can much cheaper devices). Aside from room effects, Jim and I strained to hear a difference between the HT3 and the HT3A. We finally decided that there was a bit more presence in the DEQX in the upper midbass. I switched the bass-mid cross to second order acoustic, and that fixed that (this was a long time ago). We could hear no advantage to whatever phase correction DEQX was implementing, and this has been my experience in other demonstrations. There is a theoretical advantage, but the real world advantage just hasn't been substantiated yet. Still--if the price were much lower, and I thought people would put up with the added complexity, I would recommend that Jim switch out of passive Dennis to Active DEQX.
http://www.avsforum.com/avs-vb/showthread.php?p=15520811#post15520811

BTW. here's the new Apogee "Definitive" speaker using DEQX. Not how I would do it, but one thing we know - the original Apogee designers may have tried a 24dB/octave passive crossover, but they never had the opportunity to try DEQX -

http://www.apogeeacoustics.com/images/definitive-pairside-bw-mlr.jpg

Apogee Definitive w/DEQX - $105K (Au, I believe)

I don't think I would buy speakers blind based on measurements, and I don't think I would buy one speaker over another if it didn't sound as good even if it measured better. Perhaps you, like DougWinsor who also worships at the alter of measurements, would.

I wouldn't expect anyone to buy based on good measurements. However, I might avoid a speaker based on bad measurements.

NHT may have concluded that - but that is NOT the conclusion of Keith Howard and
Leo Spiegel, the chief designer for the original Apogee speakers:

http://www.apogeespeakers.com/leo_spiegel_interview.htm


First, Keith Howard was not talking about crossover filters, and JA and Kal both had a hard time identifying the ringing filters on his blind test. I think it would reasonable to think that ringing artifacts are fairly subtle at best after reading that article.

Second, the Apogee comparison is not appropriate given that they were using analog crossovers, which have lots of artifacts as you increase steepness, and they were trying to combine two very different radiators: a dipolar ribbon and an omni woofer. The NHT design blends two similar drivers.

Also, is your argument about acausality or steep filters? The Stage was done with analog filters, and therefore cannot have acausal filters.

Third, it is not clear at all that the aspect of the sound of the NHTs you dislike is due to the ringing.

--Andre

Since you listed the DEQXed Salk HT3A, this might be a good point to also repost what their designer, Dennis Murphy, had to say about DEQX:

Again, I don't really disagree with you about the superior flexibility possible with DEQX-type machines. But I do know that if you start with high quality drivers that don't have weird peaks that can't be deat with using a simple trap circuit, it's possible to match the sound of the DEQX, or at least come close enough that most listeners could not pass a blind test. Actually, that's wrong--the DEQX can fix room bass peaks (and so can much cheaper devices). Aside from room effects, Jim and I strained to hear a difference between the HT3 and the HT3A. We finally decided that there was a bit more presence in the DEQX in the upper midbass. I switched the bass-mid cross to second order acoustic, and that fixed that (this was a long time ago). We could hear no advantage to whatever phase correction DEQX was implementing, and this has been my experience in other demonstrations. There is a theoretical advantage, but the real world advantage just hasn't been substantiated yet. Still--if the price were much lower, and I thought people would put up with the added complexity, I would recommend that Jim switch out of passive Dennis to Active DEQX.
http://www.avsforum.com/avs-vb/showthread.php?p=15520811#post15520811

Interesting that Dennis Murphy posted those comments just a month ago in response to Alimentall's gushing over DEQX as the next coming.

I wouldn't expect anyone to buy based on good measurements. However, I might avoid a speaker based on bad measurements.
Duh.

Interesting that Dennis Murphy posted those comments just a month ago in response to Alimentall's gushing over DEQX as the next coming.

Also interesting that a guy who's job it is to build passive crossovers not only has respect for DEQX, but also admits to being endangered by it.

Also interesting that a guy who's job it is to build passive crossovers not only has reverence for DEQX, but also admits to being endangered by it.

Reverence?

Just more Alimentall-twisted interpretations. I think Dennis' words speak for themselves. No one here needs your twisting, John.

Also interesting that a guy who's job it is to build passive crossovers not only has reverence for DEQX, but also admits to being endangered by it.
It is interesting that he said:

"There is a theoretical advantage, but the real world advantage just hasn't been substantiated yet." And this is from someone you say has reverence for it.

Reverence?

Just more Alimentall-twisted interpretations. I think Dennis' words speak for themselves. No one here needs your twisting, John.

I am taking this from other comments from Dennis. Actually, I meant to use the word "respect". He has said that the job he does will eventually be obsolete.

It is interesting that he said:

"There is a theoretical advantage, but the real world advantage just hasn't been substantiated yet." And this is from someone you say has reverence for it.

I do believe he has also said in other posts that it is much easier to get a given result with DEQX, whereas passive crossover design is a time intensive labor of love.

Cost is the primary thing keeping DSP from taking over. Once the total cost added per unit is equal to or less than the cost of passive crossover development, it will take over *even if* it isn't better (which it is) because mass market companies will adopt it en masse and give real headaches to flat earth high-end companies. Wi-fi speakers also require internal amplfication, so it is a *cheap* addition to move to DSP crossovers at that point. And wi-fi speakers are coming. En masse. Meridian's next gen speakers will be IP and probably even wi-fi.

Hyperbole, oversimplification will destroy any serious discussions. I have posted my point of view and sincerely believe that the Digital Route to crossovers and music reproduction in general is the future... I refuse the point of view that any design using a Digital implementation is Automatically superior to ANY product utilizing more traditional approaches. I also refuse the weak argument that if it measured better and even it sounds crappy then it remains superior and that those who did find it lacking do not have good hearing... Very similar to those derided "Audiophile" arguments. I welcome balanced and constructive arguments not hyperbole and simplistic rationalization ... I am however beginning to see the contrary here...We shall see where that leads...

P.S. It is very easy to say the Xd measured better but better than WHAT? Can anyone point me to measurements of very large speakers such as the Wilson X-2? I have not seen any. I have heard the X-2 and my ears tells me very few speakers are in its league.. Very few.. Those who have heard it can attest to that..

Cost is the primary thing keeping DSP from taking over. Once the total cost added per unit is equal to or less than the cost of passive crossover development, it will take over *even if* it isn't better (which it is) because mass market companies will adopt it en masse and give real headaches to flat earth high-end companies.
When is the cost of an analog to digital converter and DSP crossovers going to be cheaper than the cost of analog crossover components. Don't forget, even if you use external amplification, you are still going to need a power cord going to the speaker to power the ADC and DSP making installation more difficult. I certainty think digital active speakers are terrific - I own three of them myself - but it it is never going to succeed on a cost basis when a handful of analog parts cost so little.

When is the cost of an analog to digital converter and DSP crossovers going to be cheaper than the cost of analog crossover components. Don't forget, even if you use external amplification, you are still going to need a power cord going to the speaker to power the ADC and DSP making installation more difficult. I certainty think digital active speakers are terrific - I own three of them myself - but it it is never going to succeed on a cost basis when a handful of analog parts cost so little.

Pretty soon if you consider the amount of design time it takes to design a passive crossover that approaches the sound of a digital crossover. Inductors are pretty pricey. Or if you consider the increasing demand for wireless speakers with onboard active electronics.

Hyperbole, oversimplification will destroy any serious discussions.

I agree. So will taking someone's specific statement and *inferring* hyperbole and then oversimplifying it into a blanket statement. IE putting words in someone's mouth.

I have posted my point of view and sincerely believe that the Digital Route to crossovers and music reproduction in general is the future... I refuse the point of view that any design using a Digital implementation is Automatically superior to ANY product utilizing more traditional approaches.

Again, I've never said this.

I also refuse the weak argument that if it measured better and even it sounds crappy then it remains superior and that those who did find it lacking do not have good hearing... Very similar to those derided "Audiophile" arguments. I welcome balanced and constructive arguments not hyperbole and simplistic rationalization ... I am however beginning to see the contrary here...We shall see where that leads...

I am only going by my experience on this, with *hundreds* of demos with audiophiles, music lovers and just plain normal people. YMMV. You have one anecdote, but I have hundreds with Xd and with Meridian DSP speakers, as well as with DEQX driving various speakers.

P.S. It is very easy to say the Xd measured better but better than WHAT? Can anyone point me to measurements of very large speakers such as the Wilson X-2? I have not seen any. I have heard the X-2 and my ears tells me very few speakers are in its league.. Very few.. Those who have heard it can attest to that..

Well, we can use the Maxx2 where it gets easily outperformed in the dispersion and FR accuracy range while the Xd hangs in there in other areas reasonably well. In fact, the Xd is more accurate at any point within ~30 degrees up, down or to the sides than the Maxx2 on axis. Partially DSP, partially just good design. But I can all but guarantee a similar result with most any monopole DEQX implementation because of the massive crossover flexibility and impulse response correction. That's the beauty of digital, being able to do what is difficult to do in the passive domain. The ability to 'have your cake and eat it too'. That's why we both say that DSP is the crossover technology of the future.

Well, we can use the Maxx2 where it gets easily outperformed in the dispersion and FR accuracy range while the Xd hangs in there in other areas reasonably well. In fact, the Xd is more accurate at any point within ~30 degrees up, down or to the sides than the Maxx2 on axis. Partially DSP, partially just good design.
Have you ever actually listened to the NHT Xd and the Wilson Maxx2 in the same room at the same time. If not, then you can to continue to jump up and down and say measurements, measurements, measurements, but you are in no position to say the Xd is a better sounding speaker than the Maxx2.

BTW. here's the new Apogee "Definitive" speaker using DEQX. Not how I would do it, but one thing we know - the original Apogee designers may have tried a 24dB/octave passive crossover, but they never had the opportunity to try DEQX
John,

That's why I said the "original" Apogee in my previous post.

There's a guy named "Graz" in Australia who has been making replacement ribbons
for Apogee speakers that has acquired the rights to the Apogee name a couple years
ago. The "Definitive" and the "Synergy" are his speakers.

Neither the "Definitive" nor the "Synergy" is a product of the design efforts of original
Apogee founders Jason Bloom and Leo Spiegel. The original Apogee company
was acquired by a Canadian company in the '90s; and they essentially let the company
die:

http://www.apogeespeakers.com/company_history.htm

Jason Bloom unfortunately died after falling off a ladder several years ago.

Have you ever actually listened to the NHT Xd and the Wilson Maxx2 in the same room at the same time. If not, then you can to continue to jump up and down and say measurements, measurements, measurements, but you are in no position to say the Xd is a better sounding speaker than the Maxx2.

I have never said the Xd is 'better sounding', that is a personal assessment, unless you can show that, in level matched blind tests, most people prefer one product over another. I keep my arguments to objective performance, and simply pointing out particular areas where the Xd measures better, partly to mostly because of DSP.

John,

That's why I said the "original" Apogee in my previous post.

There's a guy named "Graz" in Australia who has been making replacement ribbons
for Apogee speakers that has acquired the rights to the Apogee name a couple years
ago. The "Definitive" and the "Synergy" are his speakers.

Neither the "Definitive" nor the "Synergy" is a product of the design efforts of original
Apogee founders Jason Bloom and Leo Spiegel. The original Apogee company
was acquired by a Canadian company in the '90s; and they essentially let the company
die:

http://www.apogeespeakers.com/company_history.htm

Jason Bloom unfortunately died after falling off a ladder several years ago.


I achieved very good results with the full-range Apogee ribbons using the active crossover and 4 Krell monoblock amplifiers. There were some problems in the lower bass with that model (the Apogee Grand, the $80K flagship that followed, incorporated a dynamic subwoofer with the 3-way ribbon design) and ribbon excursion, however.

I'm sad about Jason, as we were good acquaintances.

Lee

That's why I said the "original" Apogee in my previous post.

I understand, but you can't take ribbons which don't behave pistonically, and translate that to all types of drivers. Pistonic drivers have precious little 'sound' blend with other pistonic drivers when used within their best operating range.

Well done DSP crossovers and impulse response correction can be of benefit with essentially any speakers if used properly. BUT the greatest benefit will be with proportionally sized pistonic drivers sealed within an acoustically benign cabinet. The Revel Studio2 is a near perfect example, less the ported woofer design, of the type of speaker that would benefit most from DEQX. The primary 'color' of the drivers is shifted into a range beyond the crossover point, and then filtered out so that there is no energy going to the cone where it might excite resonances. Obviously a perfectly rigid cone would be best, but it doesn't exist, so all we can do is pick a cone that behaves *better* within the used bandwidth, then cut out sharply the areas where it behaves worse.

First, Keith Howard was not talking about crossover filters, and JA and Kal both had a hard time identifying the ringing filters on his blind test. I think it would reasonable to think that ringing artifacts are fairly subtle at best after reading that article.

Second, the Apogee comparison is not appropriate given that they were using analog crossovers, which have lots of artifacts as you increase steepness, and they were trying to combine two very different radiators: a dipolar ribbon and an omni woofer.

Andre,

NO - Leo Spiegel was NOT attempting to combine a dipole and an omni. This interview
was on the design of the Apogee Stage - which is a ribbon tweeter and ribbon woofer.
[Later on Apogee mated the two-way Stage with a omni woofer and called it the
"MiniGrand". But the speaker in question in the interview is the Stage which has
two dipole ribbon drivers.]

My argument is twofold. One is with steep filters in general because of the discontinuity
in radiation pattern. The filter in that case can be either analog or digital.

The other is the pre- and post-ringing that one can get with a digital filter.
The ringing of the Xd is something that I heard when we demoed the Xd at OB's house.

In comparison to the resident Lamm-driven Wilson X-2s; transients - in particular the
crash of cymbals was "smeared" and "overhung" on the Xd in direct comparison to a
very crisp "cymbal-like" sound from the resident Wilsons.

The Wilsons with OB's fine front-end electronics gave a very convincing illusion of a
"you are there" sound; while the Xd's seemed to call attention to the fact that they were
a reproduction.

I understand, but you can't take ribbons which don't behave pistonically, and translate that to all types of drivers. Pistonic drivers have precious little 'sound' blend with other pistonic drivers when used within their best operating range.
John,

It doesn't matter whether the drivers are "pistonic" - besides that is only an approximation
anyway - true drivers are really not pistonic.

The relevant physics here is "antenna' theory - and loudspeaker drivers are "antennas".

Suppose we have a speaker like the Xd satellite - with a 5" cone and a 1" dome - or
whatever the Xd has. Suppose "fc" is the crossover frequency and the crossover is
very steep - so the range in which the two drivers overlap is very narrow, if not zero.

A frequencies just below fc; the 5" cone is doing the radiating - and the radiation pattern
is that of whatever wavelength corresponds to frequency fc being radiated with a 5"
antenna. The size of the antenna vis-a-vis the size of the wavelength determines the
radiation pattern.

Now we increase the frequency slightly to get us above fc into the tweeter passband.
The frequency is not only slightly above fc - so the frequency hasn't changed much -
but it is enough to put us into the tweeter's passband.

Now we have a 1" antenna radiating a wavelenght that is only marginally different from
the one the woofer was radiating. However, the size of the antenna has changed
suddenly from 5" to 1"; and hence the radiation pattern suddenly became more
isotropic with a slight increase in frequency.

Real musical instruments don't do that - they don't change their radiation pattern in the
frequency span of just a few Hertz. It would have been better to blend the output of
the drivers so that the transition from the 5" radiation pattern to the more isotropic
pattern of the 1" driver took place over a greater span of frequencies so that it was
less noticeable.

A sharp crossover between two different sized drivers is going to give a sharp transition
in the radiation pattern as a function of frequency at the crossover. Real instruments
don't have sharp transitions in radiation pattern. The artificiality of this transition calls
attention to the fact that the reproduction is an artificial one.

Again - Mother Nature doesn't have these sharp transitions in radiation patterns - why
would one try to emulate Nature with a characteristic that Nature doesn't have?

My argument is twofold. One is with steep filters in general because of the discontinuity
in radiation pattern. The filter in that case can be either analog or digital.

Actually, this is ameliorated with DEQX. You can see this with the Xd measurements, both horizontally and vertically. The tweeter is crossed down low at 2kHz where the midrange is just beginning to lose its dispersion. Therefore, steep crossovers, used properly, give you *less* discontinuity in dispersion. But, of course, DSP doesn't *force* you to use steep crossovers, it simply gives you the *option* of using them.

The other is the pre- and post-ringing that one can get with a digital filter.
The ringing of the Xd is something that I heard when we demoed the Xd at OB's house.

Like Andre, I'm not sure that's what you were hearing. I think that's what you think you were hearing. It's okay not to like them if it makes you feel better.

In comparison to the resident Lamm-driven Wilson X-2s; transients - in particular the
crash of cymbals was "smeared" and "overhung" on the Xd in direct comparison to a
very crisp "cymbal-like" sound from the resident Wilsons.

Well, 'crisp' is certainly a staple of Wilson tweeters, though others just say 'bright' or 'aggressive'. In any case, in response to quibbles from reviewers, the NHT's treble filter attributes were altered to make the treble more flat and less rolled off. I believe that they felt that leaving the tweeter operate with a slight rolloff would make for a more forgiving, better all around speaker, but many audiophiles felt the were too rolled off and so they simply made the correction, much to the delight of those that heard the before and after. As a drummer, I can say I haven't heard a treble that I like better than Xd, though I thought the B&W Diamond was better in some ways, not quite as good in others.

The Wilsons with OB's fine front-end electronics gave a very convincing illusion of a
"you are there" sound; while the Xd's seemed to call attention to the fact that they were
a reproduction.

I can tell you with an extremely high degree of certainty that DEQXed X2s would sound better than passive ones. Maybe better even with just a Behringer.

Well done DSP crossovers and impulse response correction can be of benefit with essentially any speakers if used properly.
John,

I agree with that - with the proviso that the phrase "used properly" means that steep
crosssovers are to be avoided.

I can tell you with an extremely high degree of certainty that DEQXed X2s would sound better than passive ones. Maybe better even with just a Behringer.
John,

Unless you have actually done the experiment and put a DEQX on the X-2;
your assurances are meaningless.

If you want to make that claim to a scientist - you have to do the experiment.

Reverence?

Just more Alimentall-twisted interpretations. I think Dennis' words speak for themselves. No one here needs your twisting, John.

Digital filtering is a powerful technique and you can do a lot with it.

However, like any technology it can be mis-used.

Steep crossovers are not a virtue in and of themselves. The ideal speaker is not one
in which one has a cadre of independent, decoupled drivers; each handling a given
passband with zero regard to what its neighbor is doing.

Ideally, the response of the system should be continuous in both frequency and in
radiation pattern. Sharp transitions are an anathema to the continuity and smoothness
of the response.

John,

Unless you have actually done the experiment and put a DEQX on the X-2;
your assurances are meaningless.

If you want to make that claim to a scientist - you have to do the experiment.

I'd love to, but I don't think OB will let me touch them. If I had $150K, I'd buy a speaker company. It is very easy to predict a more coherent sound with better off axis performance and a much tighter FR. The Maxx2 was measured in Stereophile as /-8dB. I'm sure adding a decimal point to that would help it sound subjectively better.

Here is the off axis dispersion of the NHT Xd, out to 90 degrees in each direction. The only speaker with smoother and broader off axis dispersion that I've seen measured is the omnidirectional MBL -

http://www.stereophile.com/images/archivesart/Nxttdfig08.jpg

Like Andre, I'm not sure that's what you were hearing. I think that's what you think you were hearing. It's okay not to like them if it makes you feel better.
John,

I had no preconceived notion. I listened to the X-2 and I listened to the Xds.

There was just "something" about the Xds that sounded "un-natural" There was something
about what I was hearing from the Xds that said "You are listening to a reproduction."

The Wilson X-2s were saying "You are listening to the real thing"; and although I knew
I wasn't listening to the real thing - the Wilsons were VERY convincing.

So I listened very critically!! I wanted to know what about the sound from the Xds
was subconsciously tipping me off that they were artificial.

One of the things that I identified was the sound of cymbals. The Wilson X-2 produced
the correct transient sounds that a cymbal makes. You hear the initial "click" of the
drumsticks hitting the metal. You hear a "ringing" as the sound waves in the cymbal
propagate outward from the hit site; but have not yet "discovered the boundary of the
cymbal" You hear the "shimmering" as the multiple reflections from the edge of the
cymbal are all interacting. The Wilson gives you a cymbal that really sounds like
a cymbal.

The Xds just sort of went "shhh" - and totally missed all this microdynamics that made
the cymbal sound so life-like. The DEQX digital processor in the XdA unit is doing the
temporal integration demanded by the digital approximation of the filter by summing
together the output of the various "taps" along the unit's delay chain.

That summation and averaging is what smears the transients that I heard so crisply
on the Wilsons. I could hear the "smeariing" and also understand WHY the digital
processing was giving me the smearing.

The frequency and temporal responses of a filter are not independent. [ They are
Fourier Transforms of each other ] If you are not judicious in your use of the DSP
in the frequency domain [ like demanding steepness in the filter ], you can very well
screw up the temporal response.

Here is the off axis dispersion of the NHT Xd, out to 90 degrees in each direction. The only speaker with smoother and broader off axis dispersion that I've seen measured is the omnidirectional MBL -

John,

The problem is that you can mess up the temporal response when you over-constrain
the frequency response.

As an analogy; you can build a car that has great gas mileage - if you build it out of
balsa wood - so that it has terrible crash survivability.

You can also build a tank that is great in crashes - but gets horrible gas mileage.

Good engineering design is that art of compromise - and the optimal design rarely, if
ever lies at the limits.

You are showing me the mileage figures over and over again for the balsa wood car;
and totally MISSING the point that my objection is to the poor crash performance.

The Xd graphs just show that it was designed to get good frequency response - but
the Xd is a "one trick pony". It does one thing well - but not the pantheon of multiple
characteristics that I expect in a great speaker.

The Xd is like the amps and receivers of the '70s that had tons of negative feedback
so that they would measure well on a THD benchmark when fed a 1 kHz sinewave.
Yes - those amps really "locked in" on that 1 kHz sinewave and got great THD metrics.

But music is not a 1 kHz sinewave - and those amps were terrible on music.

You can show me the THD metrics of those amps all day - but that is not going to
convince me that they were good amps. It just showed that the engineers designed
the product to the test; so they would measure well, and thus make good ad copy.

The Xd evidently was designed with the same philosophy in mind.

I have never said the Xd is 'better sounding', that is a personal assessment, unless you can show that, in level matched blind tests, most people prefer one product over another. I keep my arguments to objective performance, and simply pointing out particular areas where the Xd measures better, partly to mostly because of DSP.
Then you need to be perfectly clear that when you say things like "easily outperforms" you really just mean measures better if you actually measured them or would theoretically measure better if you did not measure them. As you admitted, while you might eliminate a speaker on the basis of poor measurements, you would not buy a speaker based on measurements alone. Therefore all the pie in the sky about DEQX doesn't mean much unless you are actually comparing two speakers in a listening room. You may say one "performs better" but unless it sounds better, all the measurements in the world won't do you a bit of good. If you say that you are keeping your arguments about objective performance, then limit them to instances when actual measurements exist and are readily available. Otherwise, they are not objective arguments, they are merely theoretical arguments or opinion.

John,

I agree with that - with the proviso that the phrase "used properly" means that steep
crosssovers are to be avoided.

Well, I think it just depends on the subjective and objective results. If steeper crossovers work better, maximizing multiple parameters while only being worse in one, so be it.

The Maxx2 was measured in Stereophile as /-8dB.
Over what frequency range. Without specifying a frequency range, the +/- db range tells you nothing.

Well, I think it just depends on the subjective and objective results. If steeper crossovers work better, maximizing multiple parameters while only being worse in one, so be it.
Unless of course the one parameter that is worse makes the speaker sound bad.

The Xd graphs just show that it was designed to get good frequency response - but
the Xd is a "one trick pony". It does one thing well - but not the pantheon of multiple
characteristics that I expect in a great speaker.

That's not true, it does many things extremely well, that's the whole point! It has exceptional, even SOTA FR. It has exceptional, even SOTA horizontal dispersion. It has exceptional, even SOTA vertical dispersion. It plays extremely loud without audible distortion or fatigue. I would say the same as you substituting $100K speakers. They are usually the 'one-trick pony'. they play loud with low distortion and big bombastic bass. But little else. If you stand between two Xds, it will sound coherent and natural. If you stand between a 'high-end' passive speaker, it will sound like a disorganized, out of phase mess. I think a speaker should sound good most anywhere in your listening room, not be optimized for a ~3'x3'x1' area where you can put your head.

The Xd is like the amps and receivers of the '70s that had tons of negative feedback
so that they would measure well on a THD benchmark when fed a 1 kHz sinewave.
Yes - those amps really "locked in" on that 1 kHz sinewave and got great THD metrics.

Not really, because DEQX optimizes *multiple* parameters simultaneously. Not just one. That's the beauty of it. Leaving the engineer with fewer problems to solve. What's that term you use? Fewer areas of constraint or something to that effect?

Over what frequency range. Without specifying a frequency range, the +/- db range tells you nothing.

http://www.stereophile.com/images/archivesart/wilmaxx2fig3.jpg

Unless of course the one parameter that is worse makes the speaker sound bad.

I think that's what I just said.

I have heard the X-2 and my ears tells me very few speakers are in its league.. Very few.. Those who have heard it can attest to that..


May I ask what speakers are in the same league as the X2, according to you?

I think that's what I just said.
Actually what you said was:
If steeper crossovers work better, maximizing multiple parameters while only being worse in one, so be it.

Actually what you said was:

Semantics. I'm saying you do whatever improves the *overall* performance, however you define that as an engineer or designer.

Do you have anything to add to this thread besides 'devil's advocacy'?

I listened to the X-2 and I listened to the Xds.

There was just "something" about the Xds that sounded "un-natural" There was something
about what I was hearing from the Xds that said "You are listening to a reproduction."

The Wilson X-2s were saying "You are listening to the real thing"; and although I knew
I wasn't listening to the real thing - the Wilsons were VERY convincing.

I think that while it is useful to know that the people who heard the two apparently universally preferred the Wilson/Lamm over the Xd/DEQX, there are too many variables here to draw any conclusion re the merits of active digital crossovers. For instance, my understanding (and I don't own one) is that tube amps actually add to their output the type of harmonics present in live music, while SS doesn't. And obviously, the speaker drivers and cabinet sizes differed vastly.

A more appropriate experiment, as you pointed out, would be to compare the exact same speakers using the same amps, with only the crossover different. The comment from Dennis Murphy I think is useful in suggesting that digital active, comparing an HT3A to an HT3, has some promise, but makes only a subtle difference in itself, and to many, might not be worth the cost.

A more appropriate experiment, as you pointed out, would be to compare the exact same speakers using the same amps, with only the crossover different.


I agree :)

It plays extremely loud without audible distortion or fatigue.

In the Soundstage measurements it exhibited power compression in the 120-700Hz range at 90dB, and this became very dramatic (like -5dB) at 95dB. And as I've pointed out, distortion is worse than the PSB Synchrony One that your store carries.

It has exceptional, even SOTA vertical dispersion.

KEF Reference series is better in that department.

NO - Leo Spiegel was NOT attempting to combine a dipole and an omni. This interview
was on the design of the Apogee Stage - which is a ribbon tweeter and ribbon woofer.


You are right --- that was my mistake. However, this introduces new problems. Ribbon drivers are a large fraction (and often larger) than the wavelength of the top of their passband, compared to the relatively small drivers on the Xd. At 600 Hz (as cited in the article), we're talking 2-foot wavelengths, and the woofer ribbon's size is in that ballpark. Also, its behavior, like most ribbons at the top of their passband, is certainly far from pistonic, as resonances in the ribbon's physical structure are proportional to the wavelength of that frequency, too. I am not surprised that they would have integration problems with steeper crossovers.

The only reasonable conclusion one can draw from the Apogee story is that perhaps steep, analog, passive filters may not be appropriate for full-range ribbon speakers. Steep, analog, and passive are also three filter characteristics that do not play well together. I would suggest that Apogee's experience has little bearing on a modern, high-powered DSP system that's optimized for thousands of FIR taps applied to drivers that are far better behaved and placed in a much more forgiving context.


The other is the pre- and post-ringing that one can get with a digital filter.
The ringing of the Xd is something that I heard when we demoed the Xd at OB's house.


To be precise, you would get pre-ringing with FIR filters. Post-ringing can happen with any kind of filter. Have you tried Keith Howard's ringing test? If so, how was your performance on it?

The Wilsons with OB's fine front-end electronics gave a very convincing illusion of a
"you are there" sound; while the Xd's seemed to call attention to the fact that they were
a reproduction.

You can only determine this if you were present at the original recording session. For example, the Xds may have been more truthful to the actual recording, and the X2s may have been euphonic.

--Andre

You can only determine this if you were present at the original recording session. For example, the Xds may have been more truthful to the actual recording, and the X2s may have been euphonic.So if you were there at the original recording session, only it didn't sound like you were there but it sounded like you were listening to speakers which made it sound like you weren't there, then the Wilson X2s would be euphonic if they made it sound like you actually were there.

John

That this where we don't agree.. It is simply not possible to infer that a speaker sounds better than another by simply looking at a FR graph... Indeed the FR measurements of the XD with the DeQX are remarkable. It continue to beg the question that such results can be achieved with most speakers using Digital Room Correction.. whether they are active, passive, analog, Digital or whatever... This by the way does not in any way diminish the solid value and the good performance of the XD on that most everyone agrees... My problem is the way you portray the XD as the speaker by which any other should be judged NOT verbatim but in essence that is your position: The XDs are not. That the Xd system represented an excellent value , yes! That they represent the ultimate in speaker design NO! Emphatically. This I am stating whether you implied it or not call it pre-emptive strike...

Wide dispersion is not always desirable, it could even be said it is best to avoid it in the high frequency where it leads to a tilted "light" sounding balance.. The speakers start sounding thin.. so limiting the horizontal dispersion in the treble can be and often IS a design CHOICE! Steep Crossovers present many problems and these are audible. Where we converge is that Room Correction applied to most any speaker is likely to lead to better sound...People who have used such do not go back. The technology is not mature as we (I included) would like to think. Given a Tact or other most people are likely to do more harm than good, I am reminiscent of a session that I had with an Audiophile friend in NYC who had the TaCT/Boz system... It was clear from his FR reading that their was in the FR a clear bump around 6~7 KHz and he corrected it, resulting in a the disappearance of that 2dB bump. Fine; but now, horns and brass no longer had that "plhtlaaaat" throaty characteristic sound, they sounded too much the same no difference between a hautbois (don't remember the name in English ) and a trombone or a flugelhorn .. so we left the bump alone and the brass came golden and fine.. that is an anecdote indeed but the audiophile in question could attest to that.... The issue of better frequency response does however point to the use of DSP to ameliorate in Room response of speakers after , of course room treatment.. I must also say I am not defending expensive .. There are too many Audio Products on the Market whose sole attribute is their expensiveness not their performance. I don't think the High End Audio has delivered performance commensurate with some of the price tags ( $30,000 speaker cable being my favorite huh, nonsense) and this , to me needs to be reversed and I sincerely think it shall be..

Not really, because DEQX optimizes *multiple* parameters simultaneously. Not just one. That's the beauty of it. Leaving the engineer with fewer problems to solve. What's that term you use? Fewer areas of constraint or something to that effect?
John,

You don't always want fewer constraints.

You can have too few constraints - in which case your system is "under-determined".

You can have too many constraints - in which case your system is "over-determined"

The key is to have the number of constraints match the "degrees of freedom"
[ Do you remember that term? ]

If you have a linear system of "n" equations in "m" unknowns; then
n > m is overdetermined
n < m is underdetermined

if n = m; only then can you have a unique solution.

You are right --- that was my mistake. However, this introduces new problems. Ribbon drivers are a large fraction (and often larger) than the wavelength of the top of their passband, compared to the relatively small drivers on the Xd. At 600 Hz (as cited in the article), we're talking 2-foot wavelengths, and the woofer ribbon's size is in that ballpark.
Andre,

Since the ribbon is a dipole - it's not the length that matters - it's the width.

The ribbon dipole acts like it is infinitely long with a limited horizontal dispersion. The
horizontal dispersion is the characterisitic "figure-8" radiation pattern of a dipole when
viewed from above.

You can only determine this if you were present at the original recording session. For example, the Xds may have been more truthful to the actual recording, and the X2s may have been euphonic.
Andre,

I think it is valid to hone in on the sound of something like a cymbal. I know what a
real cymbal sounds like - and there really isn't that much variation in the sound of
cymbals.

Additionally, I know well from the PHYSICS of how a piece of metal like a cymbal
is going to sound. I know I am going to hear the strike of the drumstick, at which time
the rest of the cymbal is silent because it doesn't know it has been hit yet. The rest
of the cymbal finds that out as the pressure wave propagates out from the hit site.

I know that the cymbal is going to ring before the waves reflect from the edges of the
cymbal. I know after the waves reach the edge and reflect and criss-cross the cymbal;
it has the distinctive "shimmer" sound.

Listen to a real cymbal; and you will hear the dynamics of the cymbal crash.

The Wilson X-2s presented all this information to me in a a life like way - just as one
would expect from a real cymbal. The Xd just flat out didn't do that. It didn't present
the detail - it just "mushed" it all together into a "shhh" sound.

I don't need to be at the recording session to know that the Wilson is not being euphonic.
John tried that argument the first time I posted this. He suggested that what was on the
recording was the mushed "ssshhh" sound - and that the Wilson created all these
transients and microdynamics because it was being inaccurate.

BALONEY. The Wilson speakers are not "smart enough" to take a mushed "sshhh"
and deconvolve from that the microdynamics that one expects from a cymbal.

No - the simple analog crossovers and drivers in the Wilson can't do that. Those
microdynamics HAD to be on the recording.

The DEQX in the XdA is really "smarter" than what is in the Wilson - it's a computer
after all. However, the computer is using its "smarts" in processing the sound in a
way that makes it worse.

The problem, as Keith Howard's article and the graphs of the various filters show; there
is a "conjugate" relationship between temporal and frequency response. If you attempt
to go for maximally flat frequency response - you mess up the temporal response.

Look at the three "all pass" filters - numbers 5, 6, and 7 in Howard's article at:

http://www.stereophile.com/reference/106ringing/index1.html

These 3 filters have the best frequency response of any of the filters - ruler flat as
seen in the third column. However, they also have the rattiest temporal
response of any of the filters.

That's what happens - when you optimize for the best frequency response; you get
inferior temporal response. Conversely, if you optimize for the best temporal response;
you don't get the best frequency response.

The best solution is to seek a compromise. The "best" solution won't be perfect in
either the frequency domain nor the temporal domain.

When someone shows you a curve that shows "perfect" response in one of these
two domains - it just means that they NEGLECTED the other one.

if the NHT's were so Awesome John... i would think there would be more people on your side.

When i see these discussions i am reminded of dennis...

Dennis: You're foolin' yourself. We're livin' in a dictatorship! A self-perpetuating autocracy in which the working classes...

Woman: (interrupting) Oh there you go, bringing class into it again...

Dennis: That's what it's all about! If only people would...

Arthur: Please, please, good people, I am in haste. Who lives in that castle?

Woman: No one lives there.

Arthur: Then who is your lord?

Woman: We don't have a lord.

Arthur: What?

Dennis: I told you. We're an anarcho-syndicalist commune. We take it in turns to sort of act as a sort of executive officer for the week.

Arthur: Yes.

Dennis: But all the decisions of that officer have to be ratified at a special bi-weekly meeting...

Arthur: Yes I see.

Dennis: ...by a simple majority in the case of purely internal affairs...

Arthur: Be quiet!

Dennis: But by a two-thirds majority in the case of more major...

Arthur: Be quiet! I order you to be quiet!

Woman: Order, eh? Who does he think he is?

Arthur: I am your king!

Woman: Well I didn't vote for you!

Arthur: You don't vote for kings.

Woman: Well how'd you become king then?

[Angelic music plays...]

Arthur: The Lady of the Lake, her arm clad in the purest shimmering samite held aloft Excalibur from the bosom of the water, signifying by divine providence that I, Arthur, was to carry Excalibur. THAT is why I am your king!

Dennis: (interrupting) Listen, strange women lyin' in ponds distributin' swords is no basis for a system of government! Supreme executive power derives from a
mandate from the masses, not from some farcicial aquatic ceremony!

Arthur: Be quiet!

Dennis: Oh but you can't expect to wield supreme executive power just because some watery tart threw a sword at you!

Arthur: SHUT UP!

Dennis: Oh but if I went 'round sayin' I was Emperor, just because some moistened bink lobbed a scimitar at me, they'd put me away!

Arthur: SHUT UP! WILL YOU SHUT UP! [Grabs Dennis]

Dennis: Ah! Now we see the violence inherent in the system!

Arthur: SHUT UP!

Dennis: Oh, come and see the violence inherent in the system! Help! Help! I'm being repressed!

Arthur: (muttering) Bloody peasant!

Dennis: Oh, what a giveaway! Did you hear that? Did you hear that, eh? That's what I'm on about! Did you see him repressin' me? You saw it, didn't you?

I suspect it's not entirely the digital crossover math / slopes causing the sonic issues some hear with the NHTs.

The DEQX is terrific, but the analog stages (and clock and power supplies) are far from truly amazing, at least with the older model most have heard. IME there is a significant "artificial" imprint that largely goes away with modding. (That's with the older units. I have no experience with the latest iteration which is supposed to have better analog stages, power supplies, clock, etc.)

On a related note, I'd be surprised if Dennis wouldn't hear a large improvement in the HT3s with an upgraded DEQX. Even so, he's an incredibly talented crossover designer, and I've really enjoyed owning some of his work; the passive HT3s are incredibly transparent and musical.

I've never heard the NHTs and have no ax to grind either way.

In the Soundstage measurements it exhibited power compression in the 120-700Hz range at 90dB, and this became very dramatic (like -5dB) at 95dB. And as I've pointed out, distortion is worse than the PSB Synchrony One that your store carries.

Power compression in the low midrange won't give you fatigue. You start to get a sense that the midrange can't keep up quite as well, but it still plays very loud without fatigue. The SynchronyOne also plays very loud without strain, but doesn't have the resolution or imaging of the Xd. But it is a great speaker also, especially for the money, especially for being passive.

KEF Reference series is better in that department.

True. Coincident design has some advantages. NHT actually considered a coincident design (I asked Jack about this), but found that they could get better subjective performance with closely stacked drivers and high slope crossovers.

John

That this where we don't agree.. It is simply not possible to infer that a speaker sounds better than another by simply looking at a FR graph...

I didn't say you could. You can infer that one speaker is more tonally accurate than another by simply looking at a FR graph (measurement procedure being equal).

My problem is the way you portray the XD as the speaker by which any other should be judged NOT verbatim but in essence that is your position: The XDs are not. That the Xd system represented an excellent value , yes! That they represent the ultimate in speaker design NO! Emphatically. This I am stating whether you implied it or not call it pre-emptive strike...

I did not state this. Why do you keep arguing this way? I would say, however, that Xd is a speaker that should be used as *a* reference, especially for certain traits that passive speakers struggle and often fail to achieve.

Wide dispersion is not always desirable, it could even be said it is best to avoid it in the high frequency where it leads to a tilted "light" sounding balance.. The speakers start sounding thin.. so limiting the horizontal dispersion in the treble can be and often IS a design CHOICE!

True, though it *is* desirable in a well treated room or else you will end up with a dull sound.

Steep Crossovers present many problems and these are audible.

Yes, but as I keep repeating, drivers that are singing the same tune present even more problems that are even more audible.

Where we converge is that Room Correction applied to most any speaker is likely to lead to better sound...People who have used such do not go back. The technology is not mature as we (I included) would like to think. Given a Tact or other most people are likely to do more harm than good, I am reminiscent of a session that I had with an Audiophile friend in NYC who had the TaCT/Boz system... It was clear from his FR reading that their was in the FR a clear bump around 6~7 KHz and he corrected it, resulting in a the disappearance of that 2dB bump. Fine; but now, horns and brass no longer had that "plhtlaaaat" throaty characteristic sound, they sounded too much the same no difference between a hautbois (don't remember the name in English ) and a trombone or a flugelhorn .. so we left the bump alone and the brass came golden and fine.. that is an anecdote indeed but the audiophile in question could attest to that.... The issue of better frequency response does however point to the use of DSP to ameliorate in Room response of speakers after , of course room treatment.. I must also say I am not defending expensive .. There are too many Audio Products on the Market whose sole attribute is their expensiveness not their performance. I don't think the High End Audio has delivered performance commensurate with some of the price tags ( $30,000 speaker cable being my favorite huh, nonsense) and this , to me needs to be reversed and I sincerely think it shall be..

I agree. Speaker response correction is one thing. Room response correction over 300Hz is mostly a magic trick that fakes most people out. UNLESS, the speaker is set up improperly. We find that Audyssey can make a mediocre system sound quite decent. But struggles to make a good system sound any better or even as good.

John,

You don't always want fewer constraints.

if n = m; only then can you have a unique solution.

If you have fewer constraints, you can have more than one right answer to the remaining problems. That is a good thing. One unique solution is not the desire goal. The goal is to remove as many design constraints as possible so you can find the *best* of multiple solutions.

if the NHT's were so Awesome John... i would think there would be more people on your side.

Well, I think most any Xd owner would be mostly to completely on my side, but there are less than 200 nationwide. About half of those have 2 or 3 sets. Only about 5 or 10 on AVS and only one or two in this forum.

So if you were there at the original recording session, only it didn't sound like you were there but it sounded like you were listening to speakers which made it sound like you weren't there, then the Wilson X2s would be euphonic if they made it sound like you actually were there.

That's tautological. If you weren't at the original event, how can you say that a speaker transported you to the original event? At best, you can say that the speaker's reproduction reminds you of an event that you've previously attended.


Since the ribbon is a dipole - it's not the length that matters - it's the width.

The ribbon dipole acts like it is infinitely long with a limited horizontal dispersion. The
horizontal dispersion is the characterisitic "figure-8" radiation pattern of a dipole when
viewed from above.

Measurements of ribbons say otherwise. The response, especially near the top of the passband, is ragged, not at all smooth, and hardly a figure-8 since they do not have enough horizontal dispersion for the front and back wavefronts to meet appreciably. Again, look at the wavelengths involved, and the dimensions of the ribbon (horizontally).

Vertically things matter since ribbons exhibit vertical standing waves that break up their pistonic motion among many other things. This is trivially observable as kinks in the speaker's input impedance at the frequencies of the resonances.

And ribbons would only be infinitely tall if they go from floor to ceiling, and both floor and ceiling are perfect reflectors.


I think it is valid to hone in on the sound of something like a cymbal. I know what a
real cymbal sounds like - and there really isn't that much variation in the sound of
cymbals.


Sorry, but I'm not buying this. There are many, many problems with this line of argument. For example, the room where the cymbal is played greatly affects its sound, as does the miking technique, mic response, mastering, and mixing. If it's also played by a drummer whom you've never heard live, then the musician's technique is another uncontrolled variable. How can you tell any of these effects apart from what you think the speaker's doing to the signal, and whether the speaker's doing the right thing or not?

And you keep bringing up the Keith Howard article without addressing the fact that experienced audio listeners had a very hard time hearing the effects of his filters. Please explain how that jives with what you've said about ringing.

--Andre

and there really isn't that much variation in the sound of
cymbals.

Hah! Try telling that to any drummer!

Besides, the NHT treble is +/-1.5dB. The Maxx2 tweeter is +/-5dB, more than 3 times as inaccurate. Not sure how you can accurately produce a cymbal when it is objectively that inaccurate. I do believe they are the same tweeter, no?

I didn't say you could. You can infer that one speaker is more tonally accurate than another by simply looking at a FR graph (measurement procedure being equal).

I would say that is not nearly as simple as that statement.

It's true however, IF one listen to ONE speaker in anechoic chamber on axis (no stereo effect involved). If listening is done in a real room, one can not just look at a FR-graph and say A is more tone accurate then B. At least that's not my belief.

/Chuck

just a quick question on the ringing of steep filters (I won't go into audibilty etc).

re the deqx, it can go up to 300 db etc, but afaik even deqx does not recommend (usually) that steep a slope.

How steep is too steep? (with digital x-over slope I mean) I guess morbius would say 300 is too steep, but is 48 db too steep? 100?

This I guess relates back to the 'uncertainty principle' in audio? the more we tighten the FR the more we screw the time, and reverse. Is it all down to the individual case, where for a given set of drivers what works best is not the same as another set?

I think that some of the problem here is that units like the deqx are NOT plug and play (perhaps historically we have become used to simply plugging something in and that is that), it can take a lot of time to get a handle on using it a system before we get the optimum results.

Do we reckon Dave Wilson got his desired results in an afternoon?

Similarly, to get the optimum result with a unit like this could very well take longer than an afternoon!!

Frantz (?), I can relate to your anecdote about fixing the midrange measurement with the tact. I have only a little direct experience with it, but that experience is consistent with yours. The trouble ( I suspect) is that the added eq was trying to fix a room problem. It is perfectly valid to fix rooms problems in the bass with eq, but fraught with danger perhaps at the higher frequencies.

That is my own personal 'objection' with the full range corrections from the LP...too much room in it. I'm sure there are a lot of successful results gotten (as the supporters can attest to), my own view is that the correction should only apply to the speaker, make it as accurate as it can be (by whatever measure is best for you), then (ignoring the bass room interaction) 'whatever you get in the room is what you have in the room'.

(Then fix the bass that you get in the room)

Well, you still get ringing with any crossover. Meridian says that it has made what they call 'apodizing' filters, which, if I understand their press material (which remains press material), they are able to emulate a 'perfect' filter with little or no ringing. Or that's what they seem to imply.

I'm responding in reverse order.

An apodizing filter has absolutely nothing to do with crossovers. It's used to remove artifacts of the initial process -- which causes pre and post echo in the impulse response. Removing the pre-echo results in a much more natural sound.

Removing the post-echo is handled by the human interface, i.e. our brain throws it away as it is masked by the louder sound of the impulse.


As far as digital crossovers, M uses a 48dB per octave crossover, and the only artifacts are 130+ dB below the main level signal. That's literally inaudible.

Greg:

Any filter is capable of introducing pre and post-echo it is not specifically limited to crossovers.

The actual process of A/D at 1x FS itself creates pre and post-echo in the impulse response. As FS goes up, the amount of pre- and post-echo diminishes.



Best,

And ribbons would only be infinitely tall if they go from floor to ceiling, and both floor and ceiling are perfect reflectors.

In fairness to Greg, he did say "acts" infinitely tall, not that they were in fact infinitely tall.

An apodizing filter has absolutely nothing to do with crossovers. It's used to remove artifacts of the initial process -- which causes pre and post echo in the impulse response. Removing the pre-echo results in a much more natural sound.

I was just wondering out loud if it could be applicable in the future.

As far as digital crossovers, M uses a 48dB per octave crossover, and the only artifacts are 130+ dB below the main level signal. That's literally inaudible.

Didnt realize they'd switched. I remember the older ones to be at 24dB/octave. I wonder if that is why the DSP7200s sounded notably cleaner and more precise to me.

I would say that is not nearly as simple as that statement.

It's true however, IF one listen to ONE speaker in anechoic chamber on axis (no stereo effect involved). If listening is done in a real room, one can not just look at a FR-graph and say A is more tone accurate then B. At least that's not my belief.

Well, the speaker's job is to be accurate. You do not want a perfectly flat response at the listening position or it will sound thin and aggressive.

Power compression in the low midrange won't give you fatigue.

Probably so. After all, if the volume at a certain frequency range is 5dB of more below where it should be, that part of the frequency range isn't likely to be fatiguing. You call that an advantage?

You never cease to amaze me. You sing the praises of the Xd's FR, but then practically ignore its power compression. Anyone with half a brain will realize that significant power compression means that the FR is far from flat when the system is played loud. And it is far from flat on the louder passages / transients when the system is played at more moderate levels. I understand that with music, short-term peaks of 15-17dB above the average level of a recording are pretty common. So even if one is listening at an average level of 90dB, the music is calling for peaks of 105dB. At 90dB, the Xd already exhibits compression. At 95dB, it is much worse. One wonders how bad it gets at 100dB and 105dB.

Difference @ 95dB, 50Hz - 20kHz (measured @ 2m)
http://www.soundstagemagazine.com/measurements/speakers/nht_xd/linearity_95db.gif
Curve: difference from 70dB at 95dB

So, if the Xd were perfectly flat at 70dB, the curve shows the FR at 95dB. Again, one can only imagine how bad it gets at 100dB or 105dB. Pretty sad above 100Hz, I'd say, and unusually bad in that frequency range for a speaker in the price range of the Xd (even the new, inventory-liquidation price). Oh, and if the listening distance is more than 2m? Even worse power compression.

This post isn't really about the merits of an active crossover approach. But since many of your posts are really about how great the Xd is, please, John, stop making the Xd out to be a giant-slayer. People on AVS are mostly smarter than that.

Probably so. After all, if the volume at a certain frequency range is 5dB of more below where it should be, that part of the frequency range isn't likely to be fatiguing. You call that an advantage?

No need to be sarcastic. Subjectively, it is an error of omission, rather than the additive errors on most speakers so it is extremely benign. Yes, you can hear it, but it's relatively subtle. It is also improved with the updated crossover. If it were up to me, I would have used a tower format with multiple 8" woofers and a 300Hz or so crossover. Problem solved. Still, when you look at the overall picture, it still does many things better than very expensive speakers.

I don't know why people insist on putting the words "giant killer" or "giant slayer" in my mouth. It shows poor reasoning and logic skills to do so, aside from the fact that this was not my claim.

I don't know why people insist on putting the words "giant killer" or "giant slayer" in my mouth

hmmm...

the Xds pretty well trounced anything I've compared it to in the $15K-$25K range

If you ever wanted the sound that $20K+ speakers aspire to have for next to nothing, a used set of Xds is the best speaker bargain on the planet, bar none.

NHT's Xd is still my favorite all around speaker. I've heard nothing at any price I'd rather have.

I don't sell Xd anymore, but they're still one of the best speakers you can get at any price.

I can tell you that Xds are, IMO and measurably, better than Thiel CS6s, Genesis 5.1s, B&W 800D/801D/802D, Meridian DSP5500s/6000s, Vandersteen 5As, Focal Electra Bes and Linn Espek actively triamped speakers off the top of my head. Maybe that isn't big leagues to you, but I would say it is.

I don't consider B&Ws or Thiels or any of the speakers that they handily beat (measurably, subjectively) to be 'giants'. The industry may. I consider them to be flawed, overpriced, even 'mass-market' speakers. But it is what people think of as 'the big leagues', at least in reputation. The Rockport Arrakis probably qualifies as a 'giant'. Xd won't kill them, though it will still do a few things better. In order to be a 'giant' killer, first you have to find a true giant, not a Napoleon, then you have to match it or beat it in every important way. Xd can't do that to the best speakers. HOWEVER, it does do many things better and the areas where they get beat aren't that important to me. It still *IS* my personal favorite speaker and I *do* think it is one of the best speakers available at any price, though I do think they could easily be improved upon with another DEQXed design and I think I would likely replace them with the Tikandi at some point if nothing cooler comes out.

The Rockport Arrakis probably qualifies as a 'giant'. Xd won't kill them, though it will still do a few things better.
If you haven't measured the Rockport Arrakis, how can you say the Xds will do a few things better? Perhaps you mean the Xds theoretically might measure better in a few respects. Who cares what a discontinued speaker theoretically might do.

If you haven't measured the Rockport Arrakis, how can you say the Xds will do a few things better? Perhaps you mean the Xds theoretically might measure better in a few respects. Who cares what a discontinued speaker theoretically might do.

A lot of people seem to care and even seem aggravated about it. As in "how DARE they measure better in *any* way!". One look at the design and you know they won't do vertical dispersion well. Does it matter? Maybe not, especially for their intended 'giant room' audience. But *subjectively* haven't heard a D'Appolito design that I like, so I will always seek a single midrange or 4-way design with a separate midbass and and an upper midrange, especially for midfield listening.

A lot of people seem to care and even seem aggravated about it. As in "how DARE they measure better in *any* way!".
There isn't a single member of AVS that cares about it or is aggravated. You're tilting at windmills.

Then how come I always seem to be the windmill? I refuse to change my opinions based on years of experience, just to 'play nice' with people who are intolerant of the opinions of others. Besides, it has little to do with the Xd itself. It is a proof of the DSP concept, what it can do, even with a low budget solution, and a window on the future. "A harbinger of things to come", I think is what Stereophile repeatedly called it.

Then how come I always seem to be the windmill?
You'd have to ask your therapist.

You'd have to ask your therapist.

At least I have knowledge to contribute.

Speaking of which, as Syswei pointed out with the compression issue, even with steep crossovers and impulse response correction, you really have to stretch things to get the best performance. Every driver has limits. The best ones have an octave, maybe two where they behave in a nearly ideal fashion, with wide, smooth dispersion, low distortion and low cone resonance.

If you look at the SEAS W15, it is flat and smooth as can be, textbook so, from about 125Hz to 500Hz. Two octaves. But you have to cross it over higher if you want to remove distortion and/or compression. 250Hz, really (NHT pushes it to 110Hz-150Hz depending on filter, I believe the Tikandi crosses it a bit higher, like 180Hz if I remember correctly). Fortunately, distortion and compression are somewhat benign, so engineers often choose that over other factors like cone resonance. So, looking up in the range, from about 500Hz to 4000Hz, it is a bit inaccurate with an ~5dB bell curve thing happening around 2kHz. This, fortunately, is easily fixed by the impulse response correction in DEQX, so it's not a notable issue. However, once you get to 2kHz, dispersion narrows. This is common in most speakers near the tweeter crossover because a low pass crossover doesn't stop high frequencies, it just progressively lowers them. So a 12dB/octave 2000Hz crossover has tons of treble (and associated resonances/narrowing of dispersion) coming from the midrange . But if you cut off the signal steeply enough, you can push the crossover to 2kHz and retain very wide dispersion.

So, that leaves us with really 2 octaves of excellence from this driver. NHT pushes it for another octave and a half, for better or worse, out of necessity for this design and for the limits of a 3 band speaker. Legend moves both crossovers higher because it is a tower configuration and they know where the woofers are. The treble crossover is 2.6kHz. So, again, about 3.5, almost 4 octaves. Either way, because of some pretty horrific driver behavior starting at about 5kHz and peaking an 8kHz, you want to cut this off sharply so that *no* energy gets to the speaker at these frequencies. Both Legend and NHT do this, the secondary result being virtually no acoustic interference between the drivers. In both cases, the tweeter has to handle 3-3.5 octaves, which means they will both begin to narrow in dispersion by 10kHz. Of course, this is just accepted with most any design, even exotic ones. A smaller tweeter would do better, but would have to be crossed even higher. Legend is says that it gets better overall performance at a higher crossover point, allowing some narrowing of the dispersion, assumedly for better tweeter performance.

In addition, the woofers are flat above 50Hz, but need to be EQed below that to remain flat. Most speakers just peak and then rolloff, but unless you have a big cabinet and big drivers, you can't do this that easily without some EQ.

So Xd has some small compromises in the first octave, the third/fourth octaves and the very top octave, but is nearly ideal everywhere else. Imagine how hard this is to do with a 3-way speaker without steep crossovers. This is why most companies give up a little and use larger drivers and/or multiple drivers for low distortion, but poorer off axis quality and greater cone resonance. IOW, most speakers have compromises throughout nearly every octave, not just in a few places. 4-way and 5-way design can help eliminate these, BUT, passive crossovers aren't terribly transparent and speaker designers often try to minimize the number of crossover points.

Well, the speaker's job is to be accurate. You do not want a perfectly flat response at the listening position or it will sound thin and aggressive.

Yes, but "accurate" is a bit more complicated then a measured FR-curve on axis in a anechoic chamber. If you use the speakers for stereo reproduction (aka fantom projected sound) the response is not going to be accurate, even if the speakers FR is dead flat.

I know that a flat response at the listening position is not going to be psychoacoustic flat.

/Chuck

The strange thing about a flat FR is that in the Frequency domain it is the ideal situation... It adds or subtracts nothing.. So why does too often a flat FR at the listening position translates into too bright, tinny, fizzy , thin and a lot more negative epithet? Why does a tilted curve that attenuates smoothly the treble often appears to "sound" better? It has begun to dawn on me that we must consider the temporal response of a speaker as well. I don't know if there are any paper or study on the subject but it seems that ONLY trying for Flat FR at the listening position may screw some parameters that our perceptive system deems important... there again the capacity to manipulate the signal that Digital Crossovers afford the designer can be put to good use. It should also be noted that expediency is not in itself an advantage of Digital Crossovers.. They do not allow you to do things necessarily quicker from the Designer point of view actually as Morbius has remarked if indirectly they may create too many choices and that in itself require more knowledge to deal with properly.. So the first iteration of a product will have the designer latching on one particular parameters, in the case of the XD it is clear that Flat.. exceptionally flat FR was the goal and it was achieved but it might have been at the expense of some other characteristics that for the listeners approximate more the reality of an acoustic event... I sincerely believe we are far from measuring all that matters... yet it looks like DSP with all that it can provide the speaker designer is a very powerful weapon to have in their arsenal. It can only further the quality of Music reproduction in our home ... I am off talking about the Xd the thread is about Digital Crossovers...

Yes, but "accurate" is a bit more complicated then a measured FR-curve on axis in a anechoic chamber. If you use the speakers for stereo reproduction (aka fantom projected sound) the response is not going to be accurate, even if the speakers FR is dead flat.

Well, yes, there is an accuracy disadvantage to stereo that makes the sound a bit thinner than what is normal. Multi-channel helps this considerable, which is why Meridian and Lexicon are proponents of converting stereo to multi-channel.

I know that a flat response at the listening position is not going to be psychoacoustic flat.

We are accustomed to distance from the sound source, which means a little more rolled off upper mids/treble and room gain in the bass that makes the sound a bit richer and warmer than perfectly flat. Perfectly flat is like sitting outside with the speaker 3' from you.

The strange thing about a flat FR is that in the Frequency domain it is the ideal situation... It adds or subtracts nothing.. So why does too often a flat FR at the listening position translates into too bright, tinny, fizzy , thin and a lot more negative epithet? Why does a tilted curve that attenuates smoothly the treble often appears to "sound" better? It has begun to dawn on me that we must consider the temporal response of a speaker as well. I don't know if there are any paper or study on the subject but it seems that ONLY trying for Flat FR at the listening position may screw some parameters that our perceptive system deems important... there again the capacity to manipulate the signal that Digital Crossovers afford the designer can be put to good use.

You seem to be talking, not about 'temporal' problems and more about room EQ/listening position target curves.

It should also be noted that expediency is not in itself an advantage of Digital Crossovers.. They do not allow you to do things necessarily quicker from the Designer point of view actually as Morbius has remarked if indirectly they may create too many choices and that in itself require more knowledge to deal with properly..

Depends. You can always take an unlimited time massaging anything. OTOH, I could take a speaker into an anechoic chamber, get a 90% of maximum result within a day and get the product to market. Then offer a download 6 months later with further tweaking. Of course, when you're building your *first* DSP speaker, you have a lot more options going towards your ideal acoustic design. You have more options, but most all of them are better than could be achieved with passive design and could be brought to market more quickly. Now that NHT has done their first digital speaker, they could much more easily and quickly build a second. Well, you know, if they were to stay in business.

If you have fewer constraints, you can have more than one right answer to the remaining problems. That is a good thing. One unique solution is not the desire goal. The goal is to remove as many design constraints as possible so you can find the *best* of multiple solutions.
John,

Unfortunately, when you have too few constraints you oft get grossly INFERIOR
results because you get spurious solutions.

For example, we do a lot of hydrodynamics simulation. One of the problems you can get
in hydrodynamics is "hour-glassing". Consider three zones - one atop the other. The
equations may constrain the sum of the volumes of the three - but not the distribution.

What will happen is the middle zone can shrink in volume while the top and bottom
zones grow in volume. The three zones take on the shape of an "hourglass" or a
woman's figure - wide at top and bottom and slender in the middle.

That's what one often gets when one "under-constrains" the solution - you get the
opportunity for the system to behave VERY BADLY

You want to have the system properly constrained - not over-constrained and most
certainly not under-constrained.

... and hardly a figure-8 since they do not have enough horizontal dispersion for the front and back wavefronts to meet appreciably. Again, look at the wavelengths involved, and the dimensions of the ribbon (horizontally).
Andre,

The ribbon dipole HAS to have a "figure-8 like" dispersion due to the physical symmetry.
The dipole looks the same front and back except that the two side radiate with opposite
phase. If the direct radiation doesn't have a null at the side - then which side wins?
If the radiator is a true dipole - you CAN'T have one side winning - because then the
radiator wouldn't be a dipole because it wouldn't be symmetryic.

And ribbons would only be infinitely tall if they go from floor to ceiling, and both floor and ceiling are perfect reflectors.
They approach looking infinitely long at much lesser lengths. You need to a get a good
book on wave theory which includes expansions in spherical harmonics.

http://www.kettering.edu/~drussell/Demos/rad2/mdq.html

Sorry, but I'm not buying this. There are many, many problems with this line of argument. For example, the room where the cymbal is played greatly affects its sound, as does the miking technique, mic response, mastering, and mixing. If it's also played by a drummer whom you've never heard live, then the musician's technique is another uncontrolled variable. How can you tell any of these effects apart from what you think the speaker's doing to the signal, and whether the speaker's doing the right thing or not?

The room response is separated in time. I'm talking about how the cymbal sounds when
it is first struck. The room response doesn't enter into that - because the sound waves
haven't had a chance to hit the room boundaries.

The drummer isn't going to be able to appreciably affect the dynamics of the response
of the cymbal. The drummer hits the cymbal - and the rest is dictated by the physic
of the cymbal. The drummer can't alter the speed of sound in the cymbal metal no
matter what he/she does; nor the geometry - and THAT'S what gives rise to the effects
that I am noting.

And you keep bringing up the Keith Howard article without addressing the fact that experienced audio listeners had a very hard time hearing the effects of his filters. Please explain how that jives with what you've said about ringing.

I don't know about the others - but I sure can hear the difference. I think it has to do
with knowing what to listen for. If you understand the mathematics, and know what the
effects of the artifacts are - you can train yourself to listen for them.

just a quick question on the ringing of steep filters (I won't go into audibilty etc).

re the deqx, it can go up to 300 db etc, but afaik even deqx does not recommend (usually) that steep a slope.

How steep is too steep? (with digital x-over slope I mean) I guess morbius would say 300 is too steep, but is 48 db too steep? 100?

This I guess relates back to the 'uncertainty principle' in audio? the more we tighten the FR the more we screw the time, and reverse. Is it all down to the individual case, where for a given set of drivers what works best is not the same as another set?
Terry,

Verry good!!! There IS an "uncertainty principle" here. It is closely related to the
Heisenberg Uncertainty Principle in Physics - and the mathematics that dictates the
existence of these principles is the same. You can't know the position and momentum
of a particle simultaneously to arbitrary accuracy. The position of the particle is analogous
to the temporal response. The momentum of the particle is analogous to the frequency
response. If you attempt to determine the momentum to "perfect" accuracy - you
destroy the information on the position of the particle.

Likewise, just as terry states; if you attempt to be "perfect" in the frequency domain;
you are being inaccurate in the temporal domain.


Do we reckon Dave Wilson got his desired results in an afternoon?

If all Dave Wilson and company were doing is tweaking their crossovers in SPICE or
some other circuit modelling program; then they could get a result in an afternoon.

But that is NOT what they do. Dave Wilson and his engineers LISTEN to their product
and they make tradeoffs. They may allow a degree of non-flatness in the frequency
response curve in order to get a better temporal response. Dave and his staff are being
good engineers. They know FR is not some "Holy Grail" of audio quality that has to be
optimized at all costs. They are doing what all good engineers do in designing a product;
they are making tradeoffs.

Good audio engineers do that. They don't just "go by the numbers". They know what
the metrics like FR mean - and know the limitations of those metrics. In his review of
the dCS Scarlatti in the July / August 2008 issue of The Absolute Sound, issue #183;
review Jonathan Valin makes the same comment about the engineers at dCS. He
states they know the mathematics behind the workings of their processors; but that
they also LISTEN to them.

If an electrical engineer comes to me with an amp design that has vanishingly small
THD; it propably means he / she loaded the amp with tons of negative feedback as
was done back in the '70s. The engineer has designed the amp to measure well on a
THD test - but that's about all it will do well. The negative feedback doesn't allow the
amp to respond quickly to changes in the signal; and that's what the music demands.

We have an engineer that optimized on a SINGLE metric - and created a LOUSY audio
amp in the process.

Engineers can't be slavish to the metrics. There is no metric that measures absolute
audio quality. There a number that serve as guides to audio quality. However, if one
picks a single metric or a couple and optimizes on those; then that is NOT good
engineering.

Unfortunately, when you have too few constraints you oft get grossly INFERIOR
results because you get spurious solutions.

You want to have the system properly constrained - not over-constrained and most
certainly not under-constrained.

C'mon! That's utterly ridiculous and completely without merit. Paging Dr Grant! Weird science alert! Dr Grant, please come to the thread!


It's this simple - a speaker design attempts to solve a dozen (if you group them) or more different and difficult variables simultaneously. If some of the variables are 'pre-solved' by DSP and others are addressed more easily, then that leaves only a few difficult ones to deal with. It's ridiculous to assert that solving a dozen difficult problems with one solution is "INFERIOR" to solving maybe 4 of those same problems with one solution. This isn't a simple math equation. Yes, you have more possible solutions, but all of them are equal to or, more likely, *better* than the ones that work when attempting to solve more and more difficult problems.

The drummer isn't going to be able to appreciably affect the dynamics of the response
of the cymbal. The drummer hits the cymbal - and the rest is dictated by the physic
of the cymbal. The drummer can't alter the speed of sound in the cymbal metal no
matter what he/she does; nor the geometry - and THAT'S what gives rise to the effects
that I am noting.

I think you should stop trying to discuss drumming technique or the sound cymbals make while you're only several miles away from the truth.

Verry good!!! There IS an "uncertainty principle" here. It is closely related to the
Heisenberg Uncertainty Principle in Physics

Not really.

How steep is too steep? (with digital x-over slope I mean) I guess morbius would say 300 is too steep, but is 48 db too steep? 100?

This I guess relates back to the 'uncertainty principle' in audio? the more we tighten the FR the more we screw the time, and reverse. Is it all down to the individual case, where for a given set of drivers what works best is not the same as another set?


It just comes down to experimentation. Nice thing about DEQX is that you can load three different crossover slopes and then switch between them and see what sounds best. You can expect that, as the slope steepens, cone resonances are lowered, lobing/acoustic interference is lowered, dispersion is increased in both vertical and horizontal domains (unless you already have the horizontal optimized), motor distortion goes down, dynamic range goes up. So you have to listen to what the improvements are in these areas versus added ringing in the crossovers and YMMV.

KEEP IN MIND that the ringing is essentially equal and opposite! If you have a 'positive' ring coming from the tweeter, you will have a 'negative' ring coming from the midrange and they will largely cancel at the listening position and any place to the sides in that horizontal axis. I have not heard any ringing as an obvious artifact. Atkinson thought he was getting an echo once. I have heard this effect once or twice on power up and it was a software issue where the algorithm didn't load properly and the problem went away as soon as the box was restarted. This is an obvious "what happened to my sound?" thing, not a subtle artifact that may or may not be audible. Any ringing is well below the signal and the self canceling attribute only lowers that further. What I do know for sure is that the improvement in off axis response is SO tremendous that I've hear NO passive speaker, except maybe the MBLs that can compete when you're outside the typical sweetspot. The ability to move anywhere in the room, including directly between the speakers or even above them just points to the magnificent job DEQX does and how solving 4 or 5 major audible problems by allowing a small amount of another problem is still a gigantic leap forward in performance, both objectively and subjectively.

As for the Heisenberg Uncertainty Principle, no, Greg's got it wrong there. That's an entirely different concept and obviously not what you meant. Digital crossovers are basic algorithms with predictable results.

The ability to play with alternative crossover slopes and parameters is a nice feature on the DEQX

While I fully understand the math of shallower vs. steeper slopes, I was surprised by how little the sonic differences were between various settings that get argued to death. In my case, the sonic differences between 24db and 96db/octave were very minor for the tweeter to midrange, 24db vs. 200+db was modestly detrimental, moving the crossover point from 1850hz to 2250hz was highly audible, and minor changes to PEQ settings were even more audible.

I've easily spent as many hours tweaking my curves as I would have spent designing a passive crossover (and that was true in the past with my Tact gear.)

It's similar to dialing in a great fully analog two channel setup: it takes many many hours to get positioning, toe ins, stands, etc. "just right". Similarly, it takes many many hours to dial in a digital crossover.

For inveterate tweakers that's a blessing and a curse.

While I fully understand the math of shallower vs. steeper slopes, I was surprised by how little the sonic differences were between various settings that get argued to death.

Agree, some most minor topics are really discussed to death from the theoretical side. Obviously we are in desperate need of more blind and level matched A/B comparsions. I would dare to say some people currently fighting about real triffles to theoretical death would become best friends and fall into each others arms. No wonder I love the pro world :D

Not really.
John,

There sure is an Uncertainty Principle just as Terrry states. It is also very much related
to the Heisenberg Uncertainty Principle - because the SAME mathematics gives you both.

In the Physics world, position and momentum are conjugate variables. Their operators
don't commute. Likewise, with energy and time; those operators don't commute either.

Many times the Heisenberg Uncertaintly Principle is taught saying it has to do with our
abilities to measure. Actually, Mother Nature herself doesn't know the answer any better.

In quantum mechanics, the momentum is related to the wavelength. If you have a
particle whose momentum you know to arbitrary precision; then the wavefunction will
be a single frequency / single wavelength wave for that particle. However, that wave
is unbounded in space - it goes to infinity in both both directions - so you have absolutely
no idea where the particle is.

The only way you know where the particle is would be to build up a wave "packet" - you
add waves of many frequencies together so that the wave function "peaks" in one place.
Now, you have a pretty good idea where that particle is - it is somewhere in the range of
that peak. However, to get that peak - you had to add together waves of many different
frequencies, hence wavelengths, and therefore momenta. So now you, nor Mother
Nature has a precise knowledge of what the momentum is.

The mathematics of digital filters does the same thing. I know you "think" that you can
specify the flatness of the frequency response to arbitrary precsion, while simultaneously
dictating a perfect temporal response. However, you just plain can't do that.

The frequency response and temporal response are related. Just as Keith Howard shows
in his article; Terry is correct that when you constrain the frequency response to be
flat to arbitrary order - you mess up the temporal response and visa versa.

It's basically the same mathematics as the Heisenberg. If you constrain the precision of
momentum to arbitrary order - i.e. a single wave - then by necessity you've messed up
any precision you may have had as to the position.

If you say "Not really"; then I would really like to see your "proof" of "not really". Please
be mathematically rigorous in your proof and include all the requisite Fourier Transforms.

As for the Heisenberg Uncertainty Principle, no, Greg's got it wrong there. That's an entirely different concept and obviously not what you meant. Digital crossovers are basic algorithms with predictable results.
John,

I didn't mean that there was any "uncertainty" in the response of the digital filters.

Frequency response and temporal response are related just like momentum and position
are. When you tighten down on the specification of momentum; you LOSE precision in
the knowledge of the position. That is what the Uncertainty Principle is about - you
can't specify the two non-commuting variables to arbitrary accuracy simultaneously.
Tightening down on one; screws up the other.

That's what happens with frequency response and temporal response; and for the same
reason - the same mathematics.

I never said that there was anything "uncertain" about the behavior of the filter.

C'mon! That's utterly ridiculous and completely without merit. Paging Dr Grant! Weird science alert! Dr Grant, please come to the thread!


It's this simple - a speaker design attempts to solve a dozen (if you group them) or more different and difficult variables simultaneously. If some of the variables are 'pre-solved' by DSP and others are addressed more easily, then that leaves only a few difficult ones to deal with. It's ridiculous to assert that solving a dozen difficult problems with one solution is "INFERIOR" to solving maybe 4 of those same problems with one solution. This isn't a simple math equation. Yes, you have more possible solutions, but all of them are equal to or, more likely, *better* than the ones that work when attempting to solve more and more difficult problems.
John,

Actually this IS a math equation - albeit not a "simple" one depending on your definition
of "simple". Compared to the simulations that I work on - the audio speaker design
problem really is simple.

At the end of the day; in your design you had better have constrained all the degrees
of freedom that the problem has. If you don't constrain a degree of freedom; then
Mother Nature is free to do with that degree of freedom as she wills; and you probably
won't like the result.

Matching contraints and degrees of freedom is well known in the computational physics
and numerical modelling world. We know we get spurious solutions if we don't tack
down all the degrees of freedom that the system has.

The mathematics of digital filters does the same thing. I know you "think" that you can
specify the flatness of the frequency response to arbitrary precsion, while simultaneously
dictating a perfect temporal response. However, you just plain can't do that.

I never said that you could. The goal isn't to have a 'perfect' FR or temporal response, the goal is to have an *improved* FR and temporal response (at least at this point in the development). There is a verification procedure so that you can test the result versus the theoretical result. In the future, I am sure that systems will allow multiple testing procedures that build increasingly precise algorithms, even ones that are adaptive to the content or volume. The result, however, will still be 'certain', as in predictable, plus or minus a reasonable factor of error and beyond what is achievable with passive crossover design. If crossover design was perfect, in the digital or passive domain, the former wouldn't need a verification procedure and speaker designers would have a computer spit out the perfect crossover for any given speaker within seconds.

I mean, I see your point and apologize for misreading it, but this does not take away from DEQX's capability as you can set the parameters for correcting time and FR and focus on one, the other or both, not to mention with a lot of flexibility. NHT spent 5 years developing Xd and another year or two improving the existing filter set in response to consumer and reviewer feedback, for instance. Tis a shame few outside of actual owners have ever heard the improved firmware/filter set.

John,

Actually this IS a math equation - albeit not a "simple" one depending on your definition
of "simple". Compared to the simulations that I work on - the audio speaker design
problem really is simple.

At the end of the day; in your design you had better have constrained all the degrees
of freedom that the problem has. If you don't constrain a degree of freedom; then
Mother Nature is free to do with that degree of freedom as she wills; and you probably
won't like the result.

Matching contraints and degrees of freedom is well known in the computational physics
and numerical modelling world. We know we get spurious solutions if we don't tack
down all the degrees of freedom that the system has.

This remains just BS in the real world.

One thing that I've found in common with digital active speakers is that the 'black' levels in the sound, the deepest details that are relatively low in volume, are much more audible and the system has more dynamic range, not so much by increasing SPL, though that is another benefit, but by decreasing 'noise', compression and/or distortion that appears to be generated by passive crossovers. Meridians do this. With passive speakers, there just plain sounds like something is in the way of the music. And there is. There's nothing like it when your drivers are directly attached to the amps running them, rather than the sonic equivalent of a 3-speed automatic transmission.

One thing that I've found in common with digital active speakers is that the 'black' levels in the sound, the deepest details that are relatively low in volume, are much more audible and the system has more dynamic range, not so much by increasing SPL, though that is another benefit, but by decreasing 'noise', compression and/or distortion that appears to be generated by passive crossovers. Meridians do this. With passive speakers, there just plain sounds like something is in the way of the music. And there is. There's nothing like it when your drivers are directly attached to the amps running them, rather than the sonic equivalent of a 3-speed automatic transmission

Although in the overall picture you are right, I'm not sure, if freeing distortion is the correct explaination. The deepest details are hardly influenced by distortions in an audible sence. That is more something where the ear is really sensible....the midrange.

I would dare to say the main influencer here is the second part what you described John, the driver being directly driven by the amps, nothing better out there and well proven by most good subwoofers. That is why I said before, I would always choose at least an active speaker, analogue active clearly outperforms passive designs, not necessarily by x-over accuracy (although I think it does looking at the low level parts used for an active x-over), but by the amps controlling directly the drivers and freeing the x-over. No main studio monitor (that is most often 3-way) will be a passive x-over speaker.

What the digital x-over will offer though is on top group delay compensation, a better impuls response, at least that is my understanding. This is interesting for bass, especially for bass ported speakers, where usually the bass reflex design will introduce a group delay of several milliseconds depending on the design and that can be corrected. Also most often digital active speakers are sealed designs, which in itself is the better basis for impuls, looking at group delay.

Where I also do not full agree is whether a linear speaker, linear at the listening point, is harsh and thin sounding. Here my practical knowlegde is limited to hearing alot of digital active speakers in non treated rooms in the past. I think in a well treated room the picture changes around. We said a linear FR is absolutley necessary with a smooth power response at the same time !!! Only then the violine has a chance at all to sound like a violine. I would dare to say most bad experiences with linear speakers, linear at the listening spot, are derived from placings in non suitable/non treated listening environments. The room is most often still the weakest part in the chain.

Terry,

Verry good!!! There IS an "uncertainty principle" here.

Likewise, just as terry states; if you attempt to be "perfect" in the frequency domain;
you are being inaccurate in the temporal domain.

well thanks for the very good:), but I only got the idea from your description, I'm sure that was what you had in the back of your mind anyways. So I feel it is inaccurate to say it's 'terry's' idea, nahh I'm a dummy.


They may allow a degree of non-flatness in the frequency
response curve in order to get a better temporal response. Dave and his staff are being
good engineers.



I must say I feel that is stretching it just a tad...I simply can't imagine Dave saying to his crossover guys 'we need a few more db inaccuracy around 2k cause the temporal is going'. (I imagine the voice of scotty from startrek.."capn, we canna go any flatter, the temporal is overheating":D)

In any case, when discussing 'accuracy in one domain leading to inaccuracy in another', were we not talking digital filters? Do you mean it can occur with 48 db (for example) passive networks?

I doubt it??:confused:

Whenever you bring this up (and I'm not doubting the fact of ringing with too steep a digital slope, it has been reported in many places) you seem to use it as a criticism of the deqx. As the deqx can do as small as 6db slopes (and they themselves caution against steep slopes), I'm a little confused about the absolute importance of the point.

I also ask as I use a deqx, and so naturally would like to learn more about it.

Would not the Tact also use digital x-overs? If so, what is it about the Tact approach that makes it immune from this criticism? (or any of the computer based solutions for example, dolby lake and whoever else makes units like these)

It just comes down to experimentation.

the point I tried to make earlier with dave wilson. I bet he does some experimentation too.

Re this ringing everyone talks about, I mean if I ask 'what is this digital ringing', does that mean I am not getting it? Not sure how to phrase it, but is it so obvious that 'you will know it when you have it' type thing?

But I will admit to the feeling that so much of this (well, most things in audio really!:eek:) is so much 'angels dancing on the head of a pin'.

We just did a little blind test on the w/end, whereby we had a twenty thousand dollar front end combo (cdp, 'good' interconnects and cables, class A mono blocks etc) vs a twenty year old denon cdp and amp, house electrical wiring for speaker cables and those crappy little interconnects for hooking it up.

We did it blind (hung a blanket to hide the view) and level matched.

the difference?? To me, totally inconsequential. (to be true, most picked the better as being preferrable, but all agreed that they were surprised at how close it was)

Is worrying about ringing also falling into the negligible category? (esp if we 'ignore' the good digital x-overs and dsp can bring)

There's nothing like it when your drivers are directly attached to the amps running them, rather than the sonic equivalent of a 3-speed automatic transmission.

That's fine, but it is also why active crossovers, whether analog or digital, are imo likely to remain a niche market. By requiring multiple channels of amplification per speaker, you are increasing total system cost. If you take a person who might have bought a 500wpc amp for a pair of 3-way passive speakers and instead use active crossovers, he might then instead go with 3 amps, perhaps 400wpc, 250wpc, and 100wpc...the total cost will still be much greater than the single 500wpc amp of equivalent quality. If total cost is greater, quantities sold of active speakers can't rise to the point where the crossover costs come down sufficiently...so both the active crossover and the amplification ends up costing the user more....and active crossovers will remain a niche market imo.

What the digital x-over will offer though is on top group delay compensation, a better impuls response, at least that is my understanding. This is interesting for bass, especially for bass ported speakers, where usually the bass reflex design will introduce a group delay of several milliseconds depending on the design and that can be corrected. Also most often digital active speakers are sealed designs, which in itself is the better basis for impuls, looking at group delay.

The key to a good DSP speaker is to remove things that create the dreaded 'uncertainty', the less linear aspects of the design. Dipoles are really tricky because you have untended consequences. Same with ports. To be honest, I'm not sure what happens if you try to remove group delay from a ported woofer. But if the system is sealed, it gets a lot easier because the behavior and the end result is more predictable.

Where I also do not full agree is whether a linear speaker, linear at the listening point, is harsh and thin sounding. Here my practical knowlegde is limited to hearing alot of digital active speakers in non treated rooms in the past. I think in a well treated room the picture changes around. We said a linear FR is absolutley necessary with a smooth power response at the same time !!! Only then the violine has a chance at all to sound like a violine. I would dare to say most bad experiences with linear speakers, linear at the listening spot, are derived from placings in non suitable/non treated listening environments. The room is most often still the weakest part in the chain.

Yes, but do you listen to a violin with it 2' from your face or is it at least 10' away? You don't want to digitally remove a distance and room acoustic effect that we are used to hearing and generally like.

That's fine, but it is also why active crossovers, whether analog or digital, are imo likely to remain a niche market. By requiring multiple channels of amplification per speaker, you are increasing total system cost. If you take a person who might have bought a 500wpc amp for a pair of 3-way passive speakers and instead use active crossovers, he might then instead go with 3 amps, perhaps 400wpc, 250wpc, and 100wpc...the total cost will still be much greater than the single 500wpc amp of equivalent quality. If total cost is greater, quantities sold of active speakers can't rise to the point where the crossover costs come down sufficiently...so both the active crossover and the amplification ends up costing the user more....and active crossovers will remain a niche market imo.

The cost of an amplifier channel these days isn't that much more than a good crossover. I mean sure, a cheap crossover costs like $2. And that is great for a $200/pr loudspeaker where every penny counts, but once you get over a few $thousand, there's no reason for skimping on what could be a $50-$100 amp/crossover module (at cost). A 3-way DSP crossover with 3 amps on board shouldn't add more than $300-$500/pr to the cost of a loudspeaker. If the demand were there, it would be on everything over about $1000 or $1500/pr BECAUSE adding $500 to the retail of a speaker by making it a digital active speaker will add much more performance than $500 worth of other improvements. Good drivers are now surprisingly cheap and effective. The only thing holding us back is the chicken/egg demand curve. Kinda like when we first started selling Tivos and Sonos. But then once people realize what they do, they catch on quickly.

One thing that I've found in common with digital active speakers is that the 'black' levels in the sound, the deepest details that are relatively low in volume, are much more audible and the system has more dynamic range, not so much by increasing SPL, though that is another benefit, but by decreasing 'noise', compression and/or distortion that appears to be generated by passive crossovers. Meridians do this. With passive speakers, there just plain sounds like something is in the way of the music. And there is. There's nothing like it when your drivers are directly attached to the amps running them, rather than the sonic equivalent of a 3-speed automatic transmission.


Again, don't believe this have anything to do with passive vs digital active crossover filter.

This remains just BS in the real world.

That is one of the most maddening aspects of your attitude.. That puerile refusal to concede .. regardless of the argument's value . Where is the BS? His statement is factual not an opinion.. Yours however is a trivialization.. . What is wrong with conceding, learn and move on? His points do help understand why correcting at all costs toward obtaining a flat FR is NOT the right path.. it does not mean however that all systems with flat FR presents temporal problems. It points toward something most of us understand intuitively: The less correction needed, the better the results.. IOW if you start with a good speaker in a well-treated room the less correction you need to apply and better your results shall be.
Just throwing digital DSP or anything at less than optimal drivers or cabinets or designs is not going to make a great speaker, Digital Active Crossovers are NOT a sufficient condition for a great speaker... Digital Crossovers are not a panacea.. To use your terms there is no silver bullet in real life.

Would not the Tact also use digital x-overs? If so, what is it about the Tact approach that makes it immune from this criticism? (or any of the computer based solutions for example, dolby lake and whoever else makes units like these)
Terry,

Nobody is "immune" to the problems I spoke of. I'm not against digital crossovers and
digital processing. In fact, I use a TacT RCS 2.2 XP in my own system.

Digital processing and digital crossovers are TOOLS. They can be used for good; but can
also be abused. If you tell the TacT to make the FR ruler flat across the entire audio
spectrum with steep crossover slopes; then it will obediently do what you say and you
won't like the results.

The whole point is that digital processing is a powerful tool - but you have to use that
tool judiciously, and with intelligent understanding of what the tool is doing at your
behest.

If you just crank the "FR flatness" knob up to "11" and think you are doing the best
processing and getting the best sound - then that is just indicative of audio naivete.

How does the quote go; "Moderation in all things, and everything in moderation?"