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Reverberant vs Direct field strengths


Howard Ferstler

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Please, Howard, look at Toole Fig. 16.6 b] and c] again, and think about it a bit from the perspective of generating an accurate ipsilateral first reflection.

Geddes suggests, "Forget it; it's the contralateral we want for enhanced ASW...."

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Yeah, I know I promised.

However, I still find it odd that a guy who is tooting his horn as loud as you (thousands of posts, remember, with suggestions that we come over to your other site locations to read what you have to say there) would not want to attach his real name to his work. Of course, one advantage to not using your real name is that later on, down the line, if you are proven to be a fool you do not have to worry about your real-world status. Nobody can laugh at you out there where people actually live if nobody knows your real name.

I post under my real name, because that is my name and I am not afraid to hang my opinions on it. If I were still in the audio journalism business (and it looks like The Sensible Sound is not goint to be revived, and I had no intention of writing for the new magazine, anyway) or trying to sell books (they are all OP, and I no longer get royalties) I could see where me using my real name would look like shameless self promotion - and for money, yet. However, I am retired, so that is not an issue.

What is at issue is personal integrity, and as I noted above I am not afraid to hang my opinions (even if they someday are proved to be in error) on my real name.

Howard Ferstler

A big part of "personal integrity" is doing what you say.

-k

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Here's a pair of Karma Indignias at tweeter height and on acoustic center between them at 42". In this instance, "reverberant" begins with the floor bounce (the first reflection) at 8.42 ms. The quasi-anechoic window is 5.25 ms wide, and latency is 3.17 ms. The sum (Violet) is unwindowed.

Let's you and them fight.

[see my beer bottle there? ;) ]

post-102716-1242198302.jpg

post-102716-1242198447.jpg

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YIKES! Got horns?? I surmize from the photo in post #27 of all the e-wave mods your bias clearly lies with horns. Are these all your 'babies' Zilch? That seems like a lot of hardware for someone who has a 'grille cloth emporioum'.

With each bounce, the intensity is diminished not only by the absorptive and diffusive qualities of the surface or object doing the reflecting, but also the increased path length getting to the listener. Draw the ray diagrams for your listening room to analyze this. Your dominant reverberant field is fiction.

The path of the first reflection from a speaker like AR3a is shown in Toole's Fig. 16.6. Toed-in such that the direct comes from 0° on-axis, and the reflection comes from -73° off-axis outboard. Alternatively, from flat against the front wall, the listener listens from 23° inboard and the reflection comes from 50° outboard. The intensities and spectral content of these off-axis sources are shown in Allison & Berkovitz.

Imagine that if you like, Howard, but it's make believe your talking here. AR3a's directivity is easily calculated from the Allison & Berkovitz data, and flat at Q=2 it's not; far from it, in fact.

You're talking to the guy with 100 CD waveguides, and presume he can't do it better? I can build a LST equivalent in approximately 27 seconds here with true, flat, uncontaminated constant directivity to 180° beamwidth and beyond. Yet you suppose nobody else has done this? It's routine in sound reinforcement, actually, and I have suggested how you might try it yourself at home for peanuts.

I do believe Ken got that; he also suggested why it likely failed.

You've been hyping your Allisons for 20 years now; the reverberant field dog don't hunt anymore....

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YIKES! Got horns?? I surmize from the photo in post #27 of all the e-wave mods your bias clearly lies with horns. Are these all your 'babies' Zilch? That seems like a lot of hardware for someone who has a 'grille cloth emporioum'.

That pic from over three years ago represents the culmination of "Quick and Dirty," a one-year-long pursuit of contemporary waveguide technology in comparison to horns, most all JBL, chronicled in LHF's first mega-thread, which grew so large during that time period it had to be split and indexed to fit in the database. I endured far worse abuse in the course of documenting that early work than has ever been mustered anywhere else, and was invited to leave on multiple occasions before the forum founder and administrator stepped in and added a DIY forum to accommodate such endeavors, which has now grown to the verge of eclipsing the original technical advice forum, formerly the site's primary focus, in popularity.

The good, the bad, the ugly, and the beautiful of what I did is available for perusal and reference, and despite moving elsewhere to pursue other endeavors, I remain the site's #2 most prolific (and to some, it's most infamous) contributor. The roots of E'Wave are clearly apparent in that pic and the thread itself. I am proud of what I did there, which has aged respectably over the intervening years, and freely share what I learned during the course of my tenure in LHF loudspeaker design boot camp with any who care to appreciate it. The quest for knowledge continues full tilt to this day, and I have many new friends worldwide to show for the effort.... ;)

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YIKES! Got horns?? I surmize from the photo in post #27 of all the e-wave mods your bias clearly lies with horns. Are these all your 'babies' Zilch? That seems like a lot of hardware for someone who has a 'grille cloth emporioum'.

Look in the back of it and you will see its tail. But be very careful not to turn around and lean over it its presence. If you do, you might wind up with a pitchfork in your rear channels. ;)

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Those more conventional jobs certainly had wide-enough dispersion, and of course they also did not have any of the horizontal interference effects that happened with the two-panel versions. They imaged better. However, the super-wide-radiating jobs, with their outputs being powerful to 135 degrees off axis, managed to bounce a huge amount of wide-bandwidth sound off of the front wall in a very immediate manner (remember, the two-panel jobs, as well as some of the single-panel jobs were designed to be located right up against the front wall to keep the woofer close enough to get away from mid-bass cancellation artifacts) and this tended to make them extremely spacious, as those reflections were subsequently bounced off of the side walls after the more direct signals were also bounced. Wide and spacious sounding as the more conventional systems were, the two-panel jobs were spacious in the extreme. Even Julian Hirsch admitted that he liked the effect, as did (and do) a number of the Allison fan club and other members of the wide-dispersion group. Those speakers have a kind of unique sound that few conventional speakers can duplicate.

Howard Ferstler

One thing to think about in this whole discussion of "what radiation pattern", "how wide a dispersion" is that, in the end, we are only marginally shifting the ratio of direct to reflected energy at a given point in the room. I know from experience that the waveguides that Zilch is a proponent of would have a d.i. of about 10dB (that is typical d.i. number of a 90 by 90 degree horn). If a front firing speaker has perfect omnidirectional radiation then it would have a d.i. of 3dB. A system with drivers on more than one face can have a lower d.i. and in fact a configuration such as a Bose 901 has effectively a negative d.i. Still, the difference of 7 dB for the two conventional systems would be similar to moving out to a little more than twice the listening distance from the more directional system. That is, the strength of the direct field relative to the reverberent could be set to any desired value by choosing your listening distance from either type of system. If you want a direct field dominated, very focused sound then sit closer. If you want the speakers to disappear and have a diffuse sound field, then back away from the system.

We know that this is the case, that leaning in towards our speakers gives a more detailed sound, sitting farther away a more diffuse sound. Based on this, how can anyone argue that a given dispersion pattern is right in absolute terms, anymore than it is right to prefer a seat in the balcony over a seat towards the front of the concert hall? That Dick Small and Neville Thiele seemed to favor a more direct sound field over a diffuse one is again a matter of taste rather than absolutes. Toole in his book talks of a number of "professional listeners" (studio workers) who, when comparing some diffuse speakers to some with more directional radiation, claimed that they would need the more directional systems to do their work, but might enjoy listening to the diffuse systems at home.

The argument regarding what exact frequency response the room reflections need to have (that it needs to be as flat as the direct sound) is an old but unproven one. I know that Daniel Queen was a big proponent of that but I don't think he offered any proof beyond "it ought to be a good thing". Certainly the notion that power response needs to be flat has been discredited by numerous experiments. The best test, as I quoted in another thread, was when Lipshitz and Vanderkooy experimented with independently manipulating the direct field and reverberent field from a speaker system. They strongly concluded that flat power response achieved by distorting the direct field was wrong (as you acknowledged, Howard) and that even achieving flat power response without distorting the direct field led to a system that was too bright.

If you look at Toole's early paper on rank ordering a group of 16 speakers, you will see that 3 of the top 4 systems in his blind listening test have significant holes in their total radiated power, Several lesser ranked speakers have both flatter and smoother total radiated power. The only conclusion to be drawn from this is that smooth and flat axial response is more important than smooth or flat power response.

David

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Look in the back of it and you will see its tail. But be very careful not to turn around and lean over it its presence. If you do, you might wind up with a pitchfork in your rear channels. :rolleyes:

The spit has already been adeptly administered.

[The rotisserie is next.... :P ]

*******

I'm not finding where you asked for the data I posted at #42, but does the reverberant field CSD tell us anything about the nature of ZilchLab, the room?

Clearly, from the frequency responses, it is not significantly altering the spectral balance above the transition frequency....

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What is more interesting is the name of the speaker. Where do the people who design and market such items come up with those kinds of names, and what kind of individual would feel comfortable telling his friends that he owns a pair of Karma Indignias?

About 40 DIYers thus far, and Indignias are now receiving wider exposure elsewhere.

If you had read the thread, you'd know that the name derives from a serendipitous slip of the Zilchster's middle finger, AKA, "the bird."

Another open source design collaborative, there's no need to go madly clicking that one too, now, Howard; it's doing quite well presently, with its mere 946 posts and 42,461 views.... :rolleyes:

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1. It seems logical to me that one would want the broad-bandwidth radiating angle of any speaker system to be close to the same from top to bottom.

It's fundamental: bass is different, y'know -- wavelength, standing waves, room modes, nulls, transition frequency, all that stuff.... :rolleyes:

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I see the picture. What it lacks is additional arrows showing multiple reflections.

Speaker Dave has explained this to you, if I may paraphrase, "We don't listen with 22 ears."

Tell us again how important the medial front-wall reflection from ultra-wide dispersion speakers is, please, the ones you have damped with the drape there.

If you weren't running 7.1, I'd be suggesting you look up the absorptivity of wood paneling.... :blink:

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Speaker Dave has explained this to you, if I may paraphrase, "We don't listen with 22 ears."

Tell us again how important the medial front-wall reflection from ultra-wide dispersion speakers is, please, the ones you have damped with the drape there.

If you weren't running 7.1, I'd be suggesting you look up the absorptivity of wood paneling.... :blink:

Zilch, it must have occurred to even you that the only difference between listening to speakers in one room as opposed to another, or from being located in one position in the same room as opposed to another, or from an anechoic chamber for that matter is the reverberant field created by the room boundaries. Since it is common experience that the same speakers sound different from room to room, spot to spot, you don't need a mountain of data to come to the conclusion that the reverberant sound field is an overwhelming factor in practically any room and its specific nature bears heavily on what you will hear. It should also lead you to the conclusion that unless sound systems are engineered to compensate for these differences, no two sound systems will sound alike or for that matter even the same sound system rearranged in the same room will sound different. Yet knowing this, people who design these systems pay lip service at best to this inescapable fact. This leads to the inevitable conclusion that all of the words written about them notwithstanding and however successful their marketing was or how people like them, as an engineering effort to achieve a specific result they are all failures because the people who engineer them are clueless. Good engineers do not go into this field, it simply isn't important enough or challenging enough to warrant wasting an engineering career on. It's the reason I didn't.

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Zilch, it must have occurred to even you that the only difference between listening to speakers in one room as opposed to another, or from being located in one position in the same room as opposed to another, or from an anechoic chamber for that matter is the reverberant field created by the room boundaries.

There is no reverberant field of the nature found in large spaces such as concert halls as posited by Allison using the Beranek model and full-tilt embraced by Howard.

You're quick to assert that audio engineering has failed because the models are wrong, yet you rush to the front line to defend this outmoded one, long since repudiated?

Read the book.

[This is a diversionary tactic, obviously. You WANT everyone else to remain clueless to the very core.... :blink: ]

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There is no reverberant field of the nature found in large spaces such as concert halls as posited by Allison using the Beranek model and full-tilt embraced by Howard.

You're quick to assert that audio engineering has failed because the models are wrong, yet you rush to the front line to defend this outmoded one, long since repudiated?

Read the book.

[This is a diversionary tactic, obviously. You WANT everyone else to remain clueless to the very core.... :blink: ]

First of all, I am the first to agree that the revereberant sound fields in a home listening room have nothing in common with the reverberant fields of concert halls. Nothing. the implied assertion by Dr. Bose that somehow his direct reflecting 901 can reproduce concert hall acoustics is ludicrous.

But it is you who have consistently dismissed the importance of reverberant fields in listening rooms in the subjective performance of loudspeakers. That is clearly not the case as I have demonstrated by pointing out the reality that the same loudspeakers never sound the same in different rooms or in different locations in the same room.

I stick with my assertion that the engineering effort that has gone into studying loudspeaker performance and achieving a consistent goal within the restrictions of what such as device is capable of given the limitations of recordings is a miserable and failed engineering effort which in no way justifies the cost of most loudspeaker systems on the market today. And I re-assert my contention that the career possibilities open to anyone with an engineering education today given the many exciting avenues available to it would make it foolish to waste it on this unimportant and unchallenging area. It does make a fine hobby though.

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First of all, I am the first to agree that the revereberant sound fields in a home listening room have nothing in common with the reverberant fields of concert halls. Nothing. the implied assertion by Dr. Bose that somehow his direct reflecting 901 can reproduce concert hall acoustics is ludicrous.

And neither can wide dispersion. Villchur, Allison and Bose merely sing different renditions of the same '70s "Live Performance" song.

But it is you who have consistently dismissed the importance of reverberant fields in listening rooms in the subjective performance of loudspeakers. That is clearly not the case as I have demonstrated by pointing out the reality that the same loudspeakers never sound the same in different rooms or in different locations in the same room.

It's not coming from an imaginary isotropic integrating reverberant field, and assuming it is leads to erroneous conclusions which are unproductive, at best, but more commonly, detrimental to sonic quality.

What does Ken mean when he says "get beyond the fusion/coloration time" here:

http://www.classicspeakerpages.net/IP.Boar...amp;#entry80050

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"And neither can wide dispersion."

Whatever others have said, I never did. Resynthisizing that kind of sound field elsewhere is a monumental undertaking that is well beyond the current state of the art. It is not on the recording. I also made that clear and I re-assert that it is not on binaural recordings in a manner that is analogous to the way it is heard live either.

"It's not coming from an imaginary isotropic integrating reverberant field, and assuming it is leads to erroneous conclusions which are unproductive, at best, and more commonly, detrimental to sonic quality."

The isotropic field in a concert hall is entirely different from the one in a home listening room. The best that can be hoped for from a conventional sound reproduction system is to render the sound of musical instruments as they would be heard if they were in your room but even that is beyond the skill of today's engineers. AR demonstrated 50 years ago that they could do it on several occasions with specially made recordings and that is as close as anyone has gotten before or since.

"What does Ken mean when he says "beyond the coloration?""

I don't know. He'll have to answer that himself or someone else who speaks his language will have to answer for him.

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AR demonstrated 50 years ago that they could do it on several occasions with specially made recordings and that is as close as anyone has gotten before or since.

And we now know, from Allison himself, that many quality loudspeakers can/could do it as well or better. I suspect, properly configured, today's Bose Wave Radio might even succeed.... :blink:

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And we now know, from Allison himself, that many quality loudspeakers can/could do it as well or better. I suspect, properly configured, today's Bose Wave Radio might even succeed.... :blink:

Alison is entitled to his opinion but he hasn't proven it in public.

I will tell you again what I said once before that you apparently forgot. I am not Howard Ferstler. I agree with him on some things, I disagree with him on others. Don't ascribe his views to me.

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Alison is entitled to his opinion but he hasn't proven it in public.

Allison has apparently narrowed his "reverberant" window to 30 ms of late.

That's one or two bounces, max, outside Howard's closet and bathroom.

[There's harmonic convergence happening here.... :blink: ]

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Another point that I think needs to be understood is the importance of CD, Constant Directivity. We must consider that without CD we cannot have a flat power response and a flat axial response. Most reserchers agree that the power response is very important for tone coloration while the direct response tends to be the major factor in imaging. The industry is all too focused on getting a flat "axial" response, but to me this is probably the least important measurement.

In a polar diagram, the axial response represents a very small portion of the radiated sound field, its a small disk at the center, but the off axis points represent every greater areas - annuluses of increasing area. The axial point is therefore the least significant point for the power response - it has almost no effect on the power response. Further, there are very good reasons for one to not be directly on-axis of the loudspeaker (another topic), and the classic "sweet-spot" approach to sound design is kind of hedonistic. In a home theater there can be six or eight people listening - a sweet spot is simply not viable in that venue, and lets face that’s the venue of the future.

For these reasons the power response and the polar responses must be smooth and flat even if the axial response is not. In my designs I pretty much ignore the axial response seeking to get the best 22.5 degree response with smooth and flat polar/power response. Typically the axial response is not ideal in this scenario.

Now in a small room the situation is even more constrained. That’s because the sound system in a small room needs to avoid the very close-by room boundaries to as great an extent as possible. The very early reflections and the lack of a [temporal] gap between the direct sound and the reverberant field will create confusion in the image and a poor timbre of the sound. This means that in addition to needing CD, we need CD with a very narrow coverage angle - not a trivial task.

In my years of research I have only ever found one way to get CD and narrow directivity at the same time and that is with a horn. But classic horns sounded, if not terrible, certainly colored, distorted, not good! I spent nearly 20 years on this problem since I could see that horns were the solution to the CD and narrow coverage problem, but only if we could solve the sound quality issues.

The solution, that I have found, is a waveguide, with a foam plug. This device has the sound quality of the very best direct radiators, but a much better pattern control - true CD. Then lest we not forget about signal power and power compression. A compression driver will have a fraction of the power compression of a small tweeter and loads more headroom. What’s not to like!!

Our imaging and timbre perceptions are nearly dominated by the sound above 1 kHz. The musical content, the rhythm, etc. are carried by those frequencies below 1 kHz, but our "perception" is inordinately weighted by the response above 1 kHz. There is a very good reason for this psycho-acoustically, and it has to do with the way the neurons fire in the ear (an interesting topic in and of itself, but the important point to note is that we process sound differently above and below about 1 kHz).

So getting the 1 kHz. and up right is paramount to a good perception of coloration and imaging. I feel that far too little attention is paid to this critical region in the marketplace because it is here that we see all kinds of problems and yet it is here that we should be the most concerned.

I view sound system design in three major frequency ranges - low frequencies, where modal effects and the room dominates, there is no imaging or psychoacoustics to worry about, its simply a matter of adequate output and smooth spatial and frequency response (more on this in another thread); 200 Hz - 1000 Hz, probably the most forgiving of the three regions, our auditory system is only just beginning to be capable of resolving spatial aspects (localization) and it is not yet very good at resolution of time delays, reflections and frequency response. If you are going to compromise something do it here as it will have the least noticeable effect.

Above 1 kHz is where we live as far as music is concerned. This region is ultra sensitive to time delays, reflections, frequency response, diffraction, all the things that tend to mess up coloration and imaging. Mess up this frequency region and you won't be able to recover the sound quality. Here is not where you want to make compromises for sound quality....

http://www.diyaudio.com/forums/showthread....threadid=103872

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The various Kitchen items like Reverberant vs. Direct Field, Allison on Soundfields , etc. have all been very interesting. The spirited exchanges from both anecdotal and rigorous engineering viewpoints have made for good reading. Keep ‘em coming.

There’s one thing I’d like to toss in at this point. There has been some discussion as to whether or not it was AR’s intent to re-create the so-called “concert hall experience” by way of their wide-dispersion approach with the 3a and 5. (This is different and quite apart from whether AR intentionally employed a HF rolloff to simulate the concert hall tonal balance, popularly referred to as “concert hall slope.” That’s another discussion, somewhat tangentially-related to the dispersion/immersion issue, but it’s not the same discussion. I'm not addressing that here.)

I do not believe that AR was trying to recreate the concert hall experience by virtue of their wide-dispersion dome MR and HF drivers. AR’s goal with their dome drivers was wide-angle sound coverage of the listening area, so that listeners did not have to be seated directly on axis of the speaker in order to enjoy its reproduction.

AR’s own 1971 literature (the very height of the 3a, 5 and “new” ¾” tweeter-equipped 2ax) states this quite clearly:

“Because of their small size and hemispherical shape, these units give even sound coverage at all audible frequencies in all directions, not only side-to-side, but vertically as well. AR speaker systems sound the same, standing on an end or on a side, whether heard directly in front or at an appreciable angle off-axis.”

I submit that Allison’s paper on Soundfields was not the direct, immediate marketing reason for their use of wide-dispersion dome MR and HF drivers; rather the marketing hook of ‘you can enjoy stereo from anywhere, regardless of where you’re seated relative to the speakers’ was the advertised benefit of the wide dispersion.

AR’s own literature never talks about the 3a recreating an immersive concert hall experience because of its wide dispersion, but AR’s literature DOES tout the benefits in listener/seating flexibility and listening area coverage afforded by their unique (at the time) use of wide-dispersion dome MR and HF drivers.

Whether the 3a actually was a wide-dispersion speaker (due to its intrusive cabinet molding, etc), whether the reverberant field is meaningful and influential, and to what degree, in a home listening situation, whether Allison/Berkovitz used assumptions now proven or since discredited, etc. these are all interesting discussions.

But AR—as stated very clearly in their own literature—presented their wide-dispersion dome drivers as chiefly having the benefit of better listening area coverage and more flexibility in listener seating. Nothing more. They never said in their lit or advertising that the 3a’s dispersion would absolutely recreate a concert hall-like experience.

Steve F.

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Steve:

I'm not biased one way or the other regarding AR speakers. However, I looked back at Tom Tyson's original post on AR advertising which is thankfully still in the AR discussion area and the 3rd attachment on his list and decided to make this post before Zilch jumps on it with more distasteful remarks:

http://www.classicspeakerpages.net/IP.Boar...ost&id=4839

It says the BSO was accompanied by AR-3a 'systems' reproducing the composer's tape. "The requirement was authenticity of reproduction without distortion of the acoustical setting provided by BS Hall" and shows a picture of six 3a's sitting on a bare BS Hall stage. I'm not sure what to conclude from this, but my interpretation of the ad is AR was indeed trying to promote (besides low distortion) AR-3a's concert hall realism - if not at least implicitly.

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The published FR curves for the GedLee Speaker are IMO horrible. It seems to me that this is no constant directivity speaker by any stretch of the imagination. Arbitrarily trying to break the FR into three regions that are subjectively somehow of different importance as Gedlee does seems to me to be a way to fudge a theory to fit the hardware. My experience is that for reproducing the timbre of musical instruments accruately, ALL of the audible frequency range is important, there are no unimportant regions.

the Gedlee speaker has no deep bass to speak of you need to buy an outboard subwoofer if the speaker cannot be equalized for deep bass. At around 100 hz, the speaker is virtually omnidirectional as would be expected. As you go up from 100 hz, things get progressively worse. On axis the speaker is essentially flat except for a peculiar dip starting at about 4.5 khz, reaching a minimum of around 5db at around 6.25 khz and then crossing its 2 khz point at around 9khz. It reaches a maximum of +1 db at 10 khz and then falls steadily until about 12-15 khz where it falls off a cliff. Output at other angles do not exihibit the on axis dip and peak. Instead, they show a progressively increasing fall starting in the 500 - 800 hz range. flatten to about 7 khz, then start falling again to about 12-14 or 15 khz where they start a steep decline. At 45 degrees off axis, the 1 khz output is down about 4-5 db from the 200 hz output level and 10 db down at 10 khz. Starting at about 45-52 degrees off axis, a progressively worse fall between 1 and 2 khz occurs. By 60 degrees it's around a 5 db fallof in this narrow range. Were the speaker equalized for flat total power output, its on-axis and near on-axis frequency response would show a monumental peak, probably at least 10 db at 10 khz.

http://www.ai-audio.com/products_esp10.html

This is in sharp contrast to AR3a which shows a fairly steady output up to 60 degrees off axis. Nevertheless, because AR3a like all other speakers is nearly omnidirectional at low frequencies, it's on axis response if it were equalized for flat power output would still show a significant peak. Howard Ferstler's Alisons, less so. Even LST would show a peak because while its power output could be made much flatter in the lateral plane without the same on axis peak AR3a would exhibit, in the vertical plane it is no better than AR3a.

That being said, I am not a subscriber to the theory that flat power output even when combined with flat on axis output would create an ideal speaker system even in the limited context I've spoken about elsewhere. This is because like flat on axis frequency response alone, it ignores the change to the spectral balance the room's acoustics cause, that is the frequency selectivity of the reflections. This and not flat power output is what I consider important for accurate timbre because the goal is to get the acoustic field that reaches your ears flat, not the speaker output flat. There are no commercially available speakers I'm aware of that are engineered to take this part of the problem into consideration and deal with it. If there were, then all you'd have to worry about was the enormous variations in the recordings themselves. Once you've solved that problem too, you should hear the instruments with the same timbre as if they were in your room. IMO that's about as good as it can get with a conventional stereo sound system. Concert hall acoustics from two speaker systems is out of the question.

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It says the BSO was accompanied by AR-3a 'systems' reproducing the composer's tape. "The requirement was authenticity of reproduction without distortion of the acoustical setting provided by BS Hall" and shows a picture of six 3a's sitting on a bare BS Hall stage. I'm not sure what to conclude from this, but my interpretation of the ad is AR was indeed trying to promote (besides low distortion) AR-3a's concert hall realism - if not at least implicitly.

The application described was the use of AR-3a's for a performance in the hall, not a reproduction of the hall. The material being played on the speaker was an actual part of the performance, and the statement you quote is intended to express that the use of AR-3a's reproduced the electronic portion of the program (which were modified recordings of various acoustic sounds) in an undistorted fashion and did not create a "PA system in an acoustical hall" sound. Concert source realism rather than concert hall realism.

http://www.classicalarchives.com/work/154019.html

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Steve:

I'm not biased one way or the other regarding AR speakers. However, I looked back at Tom Tyson's original post on AR advertising which is thankfully still in the AR discussion area and the 3rd attachment on his list and decided to make this post before Zilch jumps on it with more distasteful remarks:

http://www.classicspeakerpages.net/IP.Boar...ost&id=4839

It says the BSO was accompanied by AR-3a 'systems' reproducing the composer's tape. "The requirement was authenticity of reproduction without distortion of the acoustical setting provided by BS Hall" and shows a picture of six 3a's sitting on a bare BS Hall stage. I'm not sure what to conclude from this, but my interpretation of the ad is AR was indeed trying to promote (besides low distortion) AR-3a's concert hall realism - if not at least implicitly.

Carl, I think what Genek is trying to say is that the sound that came out of the AR3as was similar to the sound that came out of the BSO....and then the acoustics of Boston Symphony hall worked its magic on it if you were sitting in the audience seats. If those speakers playing those recordings were in your home, the acoustics of your listening room would work its own magic on it instead. It would be like having the BSO come to visit your house...but shrunk down in size to squeeze through the door and into your room :rolleyes: I know you'd like to think you could get all of Boston Symphony Hall in there too with them but sorry no cigar. Maybe one day in some entirely different way ...but not today. Not like that :(

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