Reverberant vs Direct field strengths

[Zilch]

How sad for owners of AR1, AR3, AR3a, AR 10 pi, AR LST, and AR 303 that their low bass and mid bass is compromised. Somehow they don't seem eager to trade up to Gedlee. They must be "uneducated."

I'm not biting, and don't have to; the record is abundantly clear.

So where do I hear a pair of these gems in the NY Metro area or are they only sold as kits? Funny, when I asked the same on another blog site about where I could hear Audio Note speakers he raved about, there were no dealers in the NY Metro area, perhaps the most sophisticated, most affluent, and largest single market in the world. When I finally heard them at a trade show, I knew why there were no dealers. There's always a good reason if there isn't.

Seems to me AR didn't have much in the way of dealers, either. Some argue that once AR started to rely upon them for distribution, that played a significant role in the demise.

Trade show is always the optimum environment for critical listening, yah.

We're talking principles here, and it doesn't have to be the Geddes product used to explore them.

Follow RoyC's lead; he's well ahead of you in understanding these, now.

Edit: OOPS, here's the UPS guy with another kit. This one's for a video you won't watch, either....

[soundminded]

I'm not biting, and don't have to; the record is abundantly clear.

Seems to me AR didn't have much in the way of dealers, either. Some argue that once AR started to rely upon them for distribution, that played a significant role in the demise.

Trade show is always the optimum environment for critical listening, yah.

We're talking principles here, and it doesn't have to be the Geddes product used to explore them.

Follow RoyC's lead; he's well ahead of you in understanding these, now.

Edit: OOPS, here's the UPS guy with another kit. This one's for a video you won't watch, either....

" the record is abundantly clear."

I'll say. Owners of AR 12" woofer systems don't need to buy subwoofers because after over 50 years....it's still about the best subwoofer you can get. What does that say about the competition?

"Seems to me AR didn't have much in the way of dealers, either. Some argue that once AR started to rely upon them for distribution, that played a significant role in the demise."

Amazing that without a dealer network, AR managed to garner the highest share of the speaker market ever. I think at one point it was something like 28%. Now how do you suppose that happened? Must have been word of mouth advertising. People heard them in someone's home and had to get a pair for themselves. That must be it.

"Trade show is always the optimum environment for critical listening, yah."

Doesn't seem to be one coming up in my area. Gedlee wasn't at the last one. When I heard the Audio Note speakers there, all Peter Qvortrop wanted to play was his blaring rock and he complained about the room's acoustics time and again. When he played one of my discs, Marian McPartland at Maybeck Hall, it sounded terrible. Her magnificent Baldwin SD-10 sounded like a toy piano.

Seems everywhere I go, there's Bose speakers on sale. BJ's. Best Buy. their own stores in the malls. They must be doing something right even though I wouldn't buy one. It wouldn't surprise me to see their little set-ups appear in the supermarkets one day. People like them even at what seem like rediculous prices. Build a better mousetrap and the world will beat a path to your door. It may not be high fidelity in any sense that audiophiles value but Joe sixpack loves them...if he can't afford them.

[genek]

Amazing that without a dealer network, AR managed to garner the highest share of the speaker market ever. I think at one point it was something like 28%.

According to Villchur's Stereophile interview, Stereo Review had it at 32% for 1966 (the last year that Villchur ran the company).

[Zilch]

I'll say. Owners of AR 12" woofer systems don't need to buy subwoofers because after over 50 years....it's still about the best subwoofer you can get. What does that say about the competition?

You are obviously determined to get me kicked out of CSP.

In any case, subwoofing is not the issue, rather, midbass capabilities. Also, there's no way to coax the AR 12" into playing up to 1 kHz worth a whit and with the requisite dispersion to match a waveguide for use in a 2-way.

That was also a major challenge in the vintage East Coast design days: devising a tweeter that would play low enough to work with a low Fs, high Q acoustic suspension woofer and also provide reasonable HF extension and dispersion, hence the many alternative hybrid designs with their inherent compromises, none of which proved up to the task.

[We've got that knocked, now.... ]

[soundminded]

"In any case, subwoofing is not the issue, rather, midbass capabilities. Also, there's no way to coax the AR 12" into playing up to 1 kHz worth a whit and with the requisite dispersion to match a waveguide for use in a 2-way."

If what you say about getting the 12" woofer to play up to 1Khz worth a whit wasn't possible, then the LVR demos with AR3 would not have been possible either. There would have been obvious major discrepencies between the sound the musicians produced and what the speaker produced. No 12" AR speaker I'm aware of was ever a 2 way speaker. I see no reason why a speaker system has to be confined to only two ranges of drivers.

"That was also a major challenge in the vintage East Coast design days: devising a tweeter that would play low enough to work with a low Fs, high Q acoustic suspension woofer and also provide reasonable HF extension and dispersion, hence the many alternative hybrid designs with their inherent compromises, none of which proved up to the task."

It still is for many manufacturers. Their woofers don't go low enough, the dispersion of their tweeters is poor. To fudge this limitation in their engineering, they tell you to buy a subwoofer and insist "imaging" whatever that means is the only thing that matters and that narrow dispersion tweeters is the way to achieve it. They try to make lemonade out of lemons but they are still too sour for my taste. Most current deisgns strike me as mediocre and easily reverse engineered but why anyone would care to is beyond me.

"You are obviously determined to get me kicked out of CSP."

The only one who can do that is you.

[genek]

No 12" AR speaker I'm aware of was ever a 2 way speaker.

AR-1, the one with the now ridiculously-overvalued 8" fullrange as its tweeter.

[genek]

In any case, subwoofing is not the issue, rather, midbass capabilities. Also, there's no way to coax the AR 12" into playing up to 1 kHz worth a whit and with the requisite dispersion to match a waveguide for use in a 2-way.

We know from history that the 11/12" AR woofer matched up well enough at 1Khz with an 8" cone and a 1.5" dome for AR to be able to sell quite a few of both, but since AR never tried to match it with a waveguide, perhaps you can explain to us how its woofer dispersion needs differ from those...?

[Zilch]

If what you say about getting the 12" woofer to play up to 1Khz worth a whit wasn't possible, then the LVR demos with AR3 would not have been possible either. There would have been obvious major discrepencies between the sound the musicians produced and what the speaker produced.

The prosecution again rests. In addition to providing dispersion beyond 30° in the higher frequencies, AR lowered the woof/mid crossover from 1 kHz to 575 Hz, allegedly because the woofer was "beaming" at 1 kHz in AR3. The LVR demos were no big whoop, and are evidence of nothing of substance in these respects.

No 12" AR speaker I'm aware of was ever a 2 way speaker. I see no reason why a speaker system has to be confined to only two ranges of drivers.

Other factors being equal, 2-way is superior to multi-way, but it's only recently that advancing technology has moved those "other" factors closer to equality.

AR-1, the one with the now ridiculously-overvalued 8" fullrange as its tweeter.

755A was never a tweeter, and AR ultimately augmented it with one.

We know from history that the 11/12" AR woofer matched up well enough at 1Khz with an 8" cone and a 1.5" dome for AR to be able to sell quite a few of both, but since AR never tried to match it with a waveguide, perhaps you can explain to us how its woofer dispersion needs differ from those...?

AR was trying to achieve hemispherical dispersion across the full bandwidth. Now recognizing that this is not only unnecessary, but also, detrimental in some respects, contemporary designers seek a smooth transition in dispersion between drivers consistent with controlled directivity in the mids and highs.

To a large degree, the directivity of cone transducers is defined by their size and geometry, and the parameters are well known and understood; they all "beam" above some frequency, and one need only look at the polars to determine an appropriate operating region for any particular one.

http://www.classicspeakerpages.net/IP.Boar...ost&id=4564

http://www.jblpro.com/pub/obsolete/2123.pdf

100° is a "push" for most 15" drivers at 1 kHz, whereas many 12" drivers get there easily, and can be crossed to a 90° waveguide somewhat higher.

[soundminded]

I have reviewed a number of large and small outboard subwoofers for magazine reviews, and own three good ones right now: Velodyne F1800RII servo, Hsu VTF-3 MK3, and SVS 16-46 that I modified to go even deeper. All three can break to 20 Hz "flat" with no sweat. The big Velodyne can hit 110 dB in my main room at 20 Hz, measuring 17 feet from the sub's location

But, yes, with MOST music the AR-3a woofer and its kind can pretty much do the job. I had dual 10-inch woofers in each of my Allison Model Ones years ago and compared to the AR-3a systems I also had at that time the bass reach was pretty much a draw. Solid to 40 Hz, with a rolloff that resulted in the output being maybe 12 dB down at 20 Hz. Good, but not great, but also easily able to deal with typical program sources, even stuff with plenty of bass. My current IC-20 Allison models are about 9 dB down at 20 Hz. Still a bit better, but also not in the same class as the subs.

While, as I noted, most music can be handled by those regular woofers OK, if you are a pipe-organ or wild synthesizer music fan the subs will clearly make a difference. (I am no goofy bass nut, but if you want to check out the bass performance of any system hunt up a demo disc entitled "Bass Mekanik, released as 8848 by Pandisc records; make sure you strap on your seat belt first.) In addition, the subs can not only go lower, but can also go much louder down low, which can be important with home-theater action-movie materials that can be pretty "whumpy" at times.

Still, you own AR-9 systems and those have two 12-inchers each, and so I would imagine that you are going to be getting close to good subwoofer performance from those four drivers. But even those woofers are not going to be flat to 20 Hz. (Actually, the modified SVS unit I mentioned above is flat to 17 Hz.) So, subs do have a place in good audio installations. For one thing, as Allison has pointed out, most full-range speaker systems have their bass drivers located in such a way (with the system pulled out from the walls some distance) that a bass cancellation suckout will occur. By using an outboard subwoofer, a crossover point can be chosen that puts the bass suckout notch below the crossover controlled operating range of the satellites, and with the sub properly located as well, the notch will be above its operating range. Suckout notch problem solved, thanks to the use of a subwoofer.

Ironically, there is also the issue of room gain, which because of boundary reinforcement can result in the low-bass ramping upward in most rooms below 30-35 Hz, or so, and that will sometimes make good conventional woofers be functionally flat down to 20-25 Hz. Under those conditions the best subs will actually be UP some amount down at 20 Hz, which with a lot of recordings works better than simple flat response to 20 Hz.

Well, subs are interesting items, and I have had plenty of experience reviewing quite a few good, OK, and, um, not so OK ones over the years for magazine reviews. Plus, they are fun to play with.

Howard Ferstler

The servo based sub-woofer systems are probably not nearly flat to 20 hz either without the servo system. AR9 has its resonance point tuned to 28 hz, AR3 types to 42 hz. Resonance is at critical damping of .707. After considerable consideration, I realized that the performance of woofers was most easily understood (by me) by studying Newton's second law of motion as applied to forced oscillation. (I thought I'd made a real discovery but then after reading Sam's handbook, I realized that Theil and Small had based their parameters on the same analysis.) This is the same equation used for many phenonema, such as tuning the suspension of an automobile. It's also ironically the same equation used for analyzing LCR circuits. It's called a second order ordinary differential equation. It's explanation regarding mechanical systems and approximate solution can be found in any college physics textbook or book on mechanics dynamics. I look at woofer design as the superposition of its electrical resonance (easily solved with a filter network) and its mechanical resonance which can be optimized for a particular driver size and enclosure size and then further improved by more electrical filtering. The same equation also can be used to understand other designs like ported designs and why their concept is probably fatally flawed.

Acoustic suspension speakers are equalizable with their relatively modest falloff of 12db per octave within their power handling limits. Bose 901 tuned to over 180 hz can be equalized flat to around 26hz. I was curious to know why AS woofers have lower harmonic distortion than other woofers of comparable manufacture and I have a theory. The restoring force on an AS driver cone is applied uniformly over the entire surface of the cone mostly by air pressure. This minimizes the shearing force transverse to it. For other types, the restoring force is applied at the circumference at the outside and at the center. Any mechanical imbalance from one part of the circumference to another will tend to cause the cone to twist. An imbalance between the outside and inside will cause it to shear. These are exhibited as harmonic distortion if the cone deforms. This is not visible to the naked eye, happening too quickly and over too small a distance to detect. Stronger plastic and aluminum cones are less prone to this problem but usually do not damp out their own internal resonances as well as paper fibers. BTW, a single AR 12 inch driver can withstand impulse inputs of over 1 kw according to Julian Hirsch's measurements. Therefore used in sufficient multiples and with adequate power, AR 12" woofers can probably equal and may even surpass all other single woofer designs for both loudness and low harmonic distortion at any frequency.

[soundminded]

Other factors being equal, 2-way is superior to multi-way, but it's only recently that advancing technology has moved those "other" factors closer to equality.

I don't see why a two way is better. It takes a major effort to overcome the fact that to cover 10 audible octaves with what appears to be a non resonant transducer, each driver would have to cover 5 octaves without significant resonance. But dynamic loudspeaker drivers are inherently resonant devices and are usually good for only 2, 2 1/2 or 3 octaves at best. When you add a subwoofer, you no longer have a two way system, you have a three way system. Without one, 2 way speaker systems are invariably deficient somewhere. Gedlee's like most others today clearly in its deep bass region (two octaves missing.) KLH model 6 in its midrange and lowest octave. Dynaco A25 in its deep bass. Even as a 3 way system, AR3a had a problem matching a small dome to a 12" woofer. The solution was the 4 way AR9 and AR90.

[Zilch]

It takes a major effort to overcome the fact that to cover 10 audible octaves with what appears to be a non resonant transducer, each driver would have to cover 5 octaves without significant resonance. But dynamic loudspeaker drivers are inherently resonant devices and are usually good for only 2, 2 1/2 or 3 octaves at best.

Many modern compression horns can cover 5 octaves; smaller waveguides do 4.5 octaves with ease, as I have demonstrated above. You need only prove it to yourself at this point.

Call Geddes systems 3-Way if you like; he considers them "augmented" 2-ways, for which there is considerable justification, being that the subs are multiples, and not in the same cabinets with the mains....

[soundminded]

Many modern compression horns can cover 5 octaves; smaller waveguides do 4.5 octaves with ease, as I have demonstrated above. You need only prove it to yourself at this point.

Call Geddes systems 3-Way if you like; he considers them "augmented" 2-ways, for which there is considerable justification, being that the subs are multiples, and not in the same cabinets with the mains....

What a bunch of hooey. AR9's woofers are in a separate enclosure from the rest of the drivers. It's still a 4 way system. Who does Geddes think he's kidding? I think he's had one augmented fifth too many.

[Zilch]

What a bunch of hooey. AR9's woofers are in a separate enclosure from the rest of the drivers. It's still a 4 way system. Who does Geddes think he's kidding? I think he's had one augmented fifth too many.

Separate chamber within the same enclosure is not the same as separate subs.

The key distinction is being able to move them anywhere in the room, which is essential for normalizing the LF modes. Again, read the book.

[break out the SawZall, and we'll let you call yours 3-ways.... ]

[soundminded]

Yep. The Velodyne servo subs, mainly because the enclosures are really small compared to the requirements for driver size, have to be equalized considerably. Actually, Allison did that later on with his electronic subwoofer (ESW) add-on device that allowed one to equalize several of his models for flat response to 20 Hz. The device also contained both high and low-pass filters at the extremes to keep speakers out of distress with inaudible overload inputs. It did not have a servo-feedback function, but the standard Allison woofers were low enough in distortion for that to not really be needed. Most ported subs also need to be equalized to some extent; the Hsu Research TN and VTF models, for instance, but the EQ will be built in to the supplied amps.

Actually, the servo feature in the Velodyne models is overkill. The feedback function sure does get the distortion low, but I have done A/B comparisons between several F and HGS series models and much cheaper competing (and ported) models from Hsu Research and SVS, and even with test tones it is hard to hear differences at moderately high levels down to really low frequencies. At really high outputs the Velodynes do excel with test tones, but with music or movie-program sources the differences are functionally nil. Still, for those who want theoretical advantages it is probably satisfying to own a Velodyne. Paradigm also had a servo model for a while (the Servo 15, which may or may not still be available) and when I reviewed it I marvelled at the fact that, its smaller driver size notwithstanding, it could hold its own right up to very high levels with the 18-inch Velodyne F1800RII. Later HGS series Velodynes seem to have a more robust (and possibly more durable over the long haul) rubber surround, but overall their clean-bass capabilities seem to not be greater than the earlier F series units. A later HGS-15 I reviewed could not play as loud at 20 Hz as my own F1800RII, in spite of having double the amp power. They now have a DD series that include built-in parametric equalization (with accompanying microphone for setting up), and that is probably not a bad idea. They are outrageously expensive, however, and I have never reviewed a DD model.

I agree about the AR 12-inch woofers. Add enough of them and they will vibrate the planet.

Howard Ferstler

Servo systems work on the indentical principle as negative feedback and are analyzed with the same equations. For me this was some of the toughest math I ever encountered. Often negative feedback in audio amplifiers fails because the designer does not fully understand or appreciate the principles and how to apply them. The motion sensor for a servo subwoofer is usually a velocimeter or accelorometer, at least the ones I'd seen in the 1960s. They were mounted on the cone or dustcap. I'd always thought an extra voice coil would make a better sensor. Is that what Velodyne uses? The sensor compares the linear motion of the cone or voice coil with the driving voltage from the amplifier. Differentials of the driving signal or integrals of the servo sensor signal may be necessary depending on what type of sensor is used. A velocimeter would be a better choice than an accelorometer IMO because only one such circuit would be required, for an accelerometer two would need to be cascaded with additional error. The driver is driven by a difference signal which constantly compares the input signal and the sensor output and corrects its motion. Unlike a negative feedback system which cancels harmonic and intermodulation distortion in an audio amplifier, this type of servo system cannot correct for distortion due to cone breakup or flexing and resulting harmonic modes. In a well designed system, the feedback loop is frequency limited so that the loop gain never exceeds unity when the phase response is 180 degrees or the system will go into spontaneous oscillation. The system should be well damped by control of the FR of the loop gain. Should the loop ever open up due to component failure in any element, the result would be havoc.

[soundminded]

Velodyne uses an accelerometer under the dust dome, but I am not sure regarding the details of its design. I know that when you turn on a normal system and tap the woofer cone the "thump" will sound different (stiffer) from when the system was not turned on, due to negative feedback. The servo network takes this still further, and when you tap the cone of a servo sub it is like tapping a plaster wall over concrete. No resonance at all.

For the latest details on the design from the company you would probably have to go to their web site, but of course usually what you get at such locations is advertising hype, although there may be some workable info about the feedback network and sensor. In any case, their servo subs work very well, but I do think they are more expensive than what the serious subwoofer enthusiast needs to spend for equal subjective performance. I got a great deal on my F1800RII, because I was reviewing it and got an "accommodation price." I rather doubt I would have sprung for it at list, however, since my wife would have put her foot down.

Howard Ferstler

The availability of low cost high quality high powered amplifiers from companies like Crown and QSC (and many plate amplifiers), high quality woofers like Dayton RSS315-HF, and electronic equalizers and crossovers should make building a reasonably priced high performance subwoofer relatively easy for most DIYers interested in speakerbuilding. I've got a couple of empty JBL cabinets for 15" woofers in my basement I may seal up and turn into AS subwoofers myself.

It seems to me one thing that fans of ported designs could do to improve their product is to use the woofers in multiples tuned to different frequencies to reduce system Q. Two tuned half an octave apart or three tuned a third octave apart should make a considerable difference. Ported system Q is so great that response falls off at 24 db per octave and therefore, the system resonance is for all practical intents and purposes the lowest usable limit of the subwoofer. From what I can tell, most of the best designs quietly use AS woofer schemes at outrageous prices. A few years ago, I heard a Von Schweikert system VR-1 with a 10" subwoofer that looked like a Peerless. $1800 for the subwoofer alone I think.

[Zilch]

I've got a couple of empty JBL cabinets for 15" woofers in my basement I may seal up and turn into AS subwoofers myself.

These might mate very nicely with a GedLee (or other) constant directivity waveguide system....

[Zilch]

http://seanolive.blogspot.com/2008/12/are-...oudspeaker.html

http://seanolive.blogspot.com/2008/12/part...oudspeaker.html

[soundminded]

http://seanolive.blogspot.com/2008/12/are-...oudspeaker.html

http://seanolive.blogspot.com/2008/12/part...oudspeaker.html

Floyd Toole's successor with the same purely mercenary approach. Not what is accurate and sounds like live unamplified music but what people like and will sell best to make the most profits for Sidney Harman. One more piece of evidence that the problem has beaten the industry to a pulp, it hasn't made a dent at solving it in about the last 40 years, and now is left to survive by conducting popularity polls. BTW, Olive's method even as merely a marketing research tool is badly flawed in serveral important respects.

[Zilch]

BTW, Olive's method even as merely a marketing research tool is badly flawed in serveral important respects.

Clearly, there is value in knowing what won't sell, as well.

I'm confident you will make all of this clear in your upcoming AES convention presentation....

[soundminded]

Clearly, there is value in knowing what won't sell, as well.

I'm confident you will make all of this clear in your upcoming AES convention presentation....

Why wait, I'll give you the punch line here and now. The blunders in Olive's paper should be obvious. First of all, let's not mistake this for a paper which hopes to advance the state of knowledge about acoustics, it clearly has nothing to do with that. This is about marketing. (Cheevers published a master's degree thesis on vacuum tube amplifiers John Curl describes as required reading for all amplifier designers that is just as flawed. These types of people don't impress me.)

Olive's first mistake is that his test speakers are all tested in the same acoustic environment in the same spot to eliminate that variable. But we know that actual results are highly dependent on the acoustics of the room speakers are installed in and where and how they are installed. Preference for one speaker in one environment does not translate necessarily into preference for the same speaker in other environments. One thing we do know is that it is likely none of the speakers have engineered mechanisms to effectively compensate for variables of the environment they are installed in. Few if any commercially available models do and an equalizer or tweeter and midrange control which is rare in itself these days is not sufficient.

Another blunder is the lack of control over the variables of the recordings used in the tests. Recordings vary widely in many areas such as spectral balance, recorded reverberation, microphone selection and proximity to the performers and a whole host of other variables that substantially affects the perceived results. None of these were taken into consideration in the tests. No effort to compensate for any of their differences were made as far as I could tell.

Any valid comparison in a real scientific test, even in market research controls one variable at a time. By switching speaker systems, Olive changes many variables simultaneously and we don't know if the ones he has focused on are responsible for the results or aren't negated by other variables.

We don't know anything about the panelists. We don't know for example if they all or mostly come from an audiophile culture where a particular type of coloration or distortion is preferred and regarded as accurate. Products emulating that coloration would naturally fare better. I didn't see part 2 about the panelitsts themselves. Was their hearing accuity tested to pre-qualify them? Both FR sensitivity and ability to resolve difference in loudness and pitch are critical factors. We don't even know if they aren't half deaf.

Even honest people make honest mistakes. At a trade show, the chief engineer for Maxell demonstrated for me how his audio tape was superior to TDK's product. He had a then state of the art Nakamichi Dragon tape recorder. When I pointed out that the test comparison was invalid because he'd have to optimize the bias and equalization settings for each tape and then compare the results he....offered me a job. Therefore, if each speaker is not demonstrated in its most favorable light, how can any comparison be valid. Suppose a bi-polar panel speaker like a Magneplanar or Electrostatic speaker were compared in an anechoic chamber with a direct radiating speaker, how would it fare when the very acoustic interaction with a real room it depends on for its unique attributes is absent? How would a Klipschorn fare in an anechoic chamber in regard to its bass relative to a much more modest speaker that doesn't depend on being installed in the corner of a room for its performance?

Nor could sales volume tell us what people like because the decision to buy a particular product may have more to do with the effectiveness of an advertising campaign, favorable reviews by hobbyist magazines, recommendations of golden eared audiophiles especially on the internet, cost, appearance, point of sales pressure from dealer incentives, and other factors not related to actual performance.

This test told us only that those panelists in that particular test preferred those speakers in the order shown and nothing more. I contend it is therefore worthless even as a marketing research tool.

BTW, Cheevers made many of the same mistakes with his thesis on amplifiers. Were I on the judging panel, he would not have obtained a masters degree in Electrical Engineering on the strength of his paper. Nor would John Curl for lauding it.

[Zilch]

Why wait, I'll give you the punch line here and now. The blunders in Olive's paper should be obvious.

You didn't read the paper, obviously.

But, not to worry, we WILL read yours.

[When's it publishing, now...? ]

[soundminded]

You didn't read the paper, obviously.

But, not to worry, we WILL read yours.

[When's it publishing, now...? ]

I read the two articles you linked to, Olive's internet blogs, parts 1 and 3. I did not read the backup pdf files that were a couple of dozen pages each. Also there was no link to part 2 regarding the listening panel and after a short effort of not finding it, I gave up. If there is some illumination in these pages that makes a point worth reading, why don't you tell us what it is and where to find it and if it sounds more interesting than one more re-hash of Floyd Toole's usual jibberish, I might just look at it. Otherwise, I'm not going to waste the time of day.

I'm not sure my own theories will ever see the light of day at AES. They are the underpinnings of my inventions including the one I patented and claim was infringed on. Since this is right now a hobby, and avocation and not my day job, publish or perish does not apply to me. I see no benefit to revealing my own intellectual property in any way that would be beneficial to others but make no money for me so don't hold your breath waiting for it.

[Zilch]

If there is some illumination in these pages that makes a point worth reading, why don't you tell us what it is and where to find it and if it sounds more interesting than one more re-hash of Floyd Toole's usual jibberish, I might just look at it. Otherwise, I'm not going to waste the time of day.

Those tests are typically done with a variety of different music genres, and they've also studied and documented the differences between results obtained with trained vs. untrained listeners, which are summarized in Toole's book. Musicians are terrible listeners, as I recall.

There is no reasonably workable approach to doing A/B testing of different speakers in different rooms, and thus, the "room" is standardized, based upon typical. Anyone who wants to spend the rest of their lives searching for synergy between speakers and their own listening spaces, and tweaking both to optimize the combination, is welcome to engage in such pursuits, but the rational approach to this problem is to design speakers in such a manner that the room interaction is definite and controllable.

Similarly, if someone wants to invest endless hours subjectively determining the optimum EQ for each cut on every recording in their listening libraries in pursuit of realism, which you yourself acknowledge is unachievable given the limitations of recording technology and the incompetence of everyone involved in each step of the process, well, have at that, too.

My point is that you make a virtual career of ridiculing the work of everyone in audio, while yourself effectively contributing zero to advancement of the art, in which context, you occupy conspicuously more space than you rent, but I'm sure there is a vast audience eagerly anticipating the exposition of the results of your considerable and superior efforts dorking with Bose 901s for the past 30 years....

[soundminded]

"Those tests are typically done with a variety of different music genres, and they've also studied and documented the differences between results obtained with trained vs. untrained listeners, which are summarized in Toole's book. Musicians are terrible listeners, as I recall."

My observation is that most musicians listen "through" the equipment to the music and are therefore not necessarily good listeners for evaluating audio equipment. I'd say regular concert goers would make a better pool of candidates. This in no way answers my criticisms above. Two recordings not only of the same genre but of the same piece of music even the same instruments made at different times by the same engineer can sound very different. I've got three recordings Ed Thompson made of Earl Wild playing his Baldwin SD-10, two on Chesky and one on Sony and all three sound different from each other.

"There is no reasonably workable approach to doing A/B testing of different speakers in different rooms, and thus, the "room" is standardized, based upon typical. Anyone who wants to spend the rest of their lives searching for synergy between speakers and their own listening spaces, and tweaking both to optimize the combination, is welcome to engage in such pursuits, but the rational approach to this problem is to design speakers in such a manner that the room interaction is definite and controllable."

The only valid comparisons are between live unamplified music and the reproduced facsimile. Testing speaker A against speaker B is utter futility. There is no rational criteria for any judgement. That Olive found a correlation in his test tells us nothing of value even for market research. Some people might prefer a juke box to any of them. Beyond that as I have stated, the engineering of virtually all commercially manufactured speakers is flawed due to the fact that their ultimate performance is radically influenced by the rooms they are installed in yet they provide little or no control to compensate for that variable. The general guidelines that is the current state of the art in suggesting how a room will affect speaker performance is inadequate. The engineers have not done their job.

"Similarly, if someone wants to invest endless hours subjectively determining the optimum EQ for each cut on every recording in their listening libraries in pursuit of realism, which you yourself acknowledge is unachievable given the limitations of recording technology and the incompetence of everyone involved in each step of the process, well, have at that, too."

It is very time consuming but worth the effort. True lovers of the sound of the world's greatest music performed by the world's greatest artists on the world's best musical instruments know that there is no substitute that is nearly as satisfying. It's the distortions of even the best equipment that keeps live performers and owners of concert halls in business.

"My point is that you make a virtual career of ridiculing the work of everyone in audio"

That is all the quality of their work product warrants. Given the lavish money they've had for research not to mention decades of time, remarkable progress in other far more challenging technologies in the same period, and the prices they ask for their best efforts, what else can anyone say and still be fair to them?

"while yourself effectively contributing zero to advancement of the art"

Not exactly true. You are forgetting my patent. In fact in reading what people experimenting with what is called ambiphonic sound have done, it is clear that they use the benefits of the algorithms I invented that appear in the processors they use although not in any way comparable to what I had in mind and surely to far less benefit. If nothing else, their efforts are notable for their ardent try even if their theories are seriously flawed. I haven't heard their work product yet but I have a hunch I would not be particularly surprised by it, having read "the book."

"I'm sure there is a vast audience eagerly anticipating the exposition of the results of your considerable and superior efforts dorking with Bose 901s for the past 30 years"

Actually that effort took about 3 years. Not good considering I knew exactly what I had to do but great results come slowly for me. If you give my claims any credibility at all, I don't see how you can ridicule someone who improved upon the best efforts of a PHD who teaches electrical engineering at MIT, an effort that launched possibly the single most successful privately owned consumer electronics businesses in history. I've yet to hear your $165 wonders.

[Zilch]

If you give my claims any credibility at all, I don't see how you can ridicule someone who improved upon the best efforts of a PHD who teaches electrical engineering at MIT, an effort that launched possibly the single most successful privately owned consumer electronics businesses in history.

Geez, too bad you missed the boat.

I've yet to hear your $165 wonders.

Better hurry, 'cause it's $208 now, including ZilchLab PC boards, plus whatever woofers/cabs you can find curbside on bulk recycling pickup day....