Loudspeaker directivity by Roy Allison

[genek]

No AR-3a -- I mean none whatsoever -- will perform today like they once would, mainly because no AR-3a tweeter has survived the oxidizing-foam dilemma. The damping foam inside of the tweeter domes has probably crumbled to powder. The foam in the gap deteriorates, as does the foam "pad" that is placed under the paper dome for damping. They are all gone now, so no telling what the response characteristics would be today.

All we have to work with is what we have, Howard. Whatever the response is, it still sounds quite grand.

[Zilch]

They are all gone now, so no telling what the response characteristics would be today.

Hasn't someone here measured them?

I own the best speakers of all time, actually.

Who here would ever have guessed?

And the world's most perfectly manicured driveway, and most pristine workshop as well.

I am a has been, and happy to be that way.

That too, of course.

FACT is, you are a VICTIM of wide-dispersion speakers.

I have long felt that serious buffs should invest in a good RTA....

All but free today, and better, even.

[Try and keep up, wouldya please.... ]

[genek]

I have a pair of 10pi tweeters stashed away for a rainy day along with the necessary bits to update the HF portion of the crossover to AR-11 spec, though they probably also suffer from the same problems you're concerned about. But I'm not enough of a "serious buff" to pull apart speakers that are working well enough for me as-is. I'll update if one of my existing 3a tweeters bites the dust,

[genek]

Hasn't someone here measured them?

I suppose he means mine haven't been measured...

[Zilch]

I suppose he means mine haven't been measured...

No, he means that HE has, and posted the data for Howard to ignore, along with virtually everything else inconsistent with his particular belief system, which holds that Allison is best, and AR but a pale second.

Do we doubt for a moment that Howard's favorites would do better than ARs in similarly contrived LvR demos? Better than live?

[Hell, doubtless even the ones he built himself would.... ]

[speaker dave]

Pink noise is a killer, simultaneous blanket signal that reveals things that simply would not show up with musical or home-theater playback.

So, your pink-noise and ruler test is more rigorous than what typical home-listening playback requires. Yes, diffraction issues may mean a lot if one entertains themselves with pink noise, but while such noise has its uses (I used it aplenty when doing my own speaker reviewing), using it the way you indicate delivers misleading information.

Again, if diffraction was a big deal the Villchur LvR concerts would have been a bust. They wern't.

Howard Ferstler

I suggest pink noise because the effect is immediately obvious. But in my experience, if you hear it on pink noise you soon hear it on music, especially music of a busy nature.

But have you tried it? Why speculate if it is so easy to do? You can try it from 10 feet and then try it from 20 feet. let me know if you hear it or not, I'll take your word for it.

It is easy to poo poo an idea, yet this is so easy to try. Either I am right or I'm wrong, try it and tell me.

[tysontom]

BTW, the LST was tried by AR in the early going of the Grover L v R demo. The LST couldn't do it--not because of any output or power-handling issues, but because its multiple MR and HF drivers betrayed its origin every time. Whether it was driver interference or a too-different radiation pattern from the live source or something else altogether, isn't known.

But they did try the LST and it was no go.

Steve F.

Yes, the AR-LST was tried (briefly with AR-10π tweeters), but I believe the spectral balance of the LST was too diffuse for this fairly close-in LvR demonstration. However, the true reason for not using the AR-LST was that it was not a part of AR's new Advanced Development Division. The AR-10π -- the new flagship -- was the new speaker that would help AR realistically benefit from this demonstration.

The Neil Grover live-vs.-recorded demonstrations received only a fraction of the fanfare of the original AR-3/Fine Arts Quartet. AR did not capitalize on the public-relation's opportunity of this mid-1970s event. Relatively few people knew about it, and I don't think it received a great deal of press coverage. On the other hand, the AR-Fine Arts concerts were conducted all over the country more than 75 times, and there were follow-on concerts done with guitarist Gustavo Lopéz and the well-known 1910 Nickelodeon LvR done at the 1966 High Fidelity Music Show in NYC (and elsewhere). Even the 1955 New York Audio League AR-1/Aeolian-Skinner concerts in Mt. Kisco, New York, drew a larger audience.

--Tom Tyson

[Zilch]

In any case, the bottom line is music, and Villchur proved that the diffraction issue (among other things, such as driver positioning on the front baffle) is not as big a deal as many "purists" would care to concede.

Spoken like a diehard subjectivist.

Funny how the obviously manifest diffraction problems with the AR-3 systems employed did not cause various audio notables who attended (and wrote up their positive impressions in audio and newspaper articles) to suddenly say, "ugh," and become repelled by the discrepancies. They should have heard those diffraction artifacts, but shame on them.

The playback occurred in large, reflective rooms with the audience immersed in the Beranek reverberant field, a further contrivance distinguishing LvR from the realities of domestic listening.

"Eddie [Villchur] was a master showman."

[He also understood the variables, and how to manipulate them for maximum promotional benefit.... ]

[speaker dave]

OK, I just tried it using one of my home-built systems in my smaller installation.

First, I got my long-suffering wife to carefully move the vertically oriented, perpendicular aligned ruler (actually, a 12-inch long, one-inch wide paint stick) closer to and further from the tweeters, over about a three-inch span - back and forth and back and forth. (The source was one pink-noise channel of the Delos "Surround Spectacular" test disc engineered by John Eargle and David Ranada.) Then, I had her hold it, again vertically, at one location about two inches out and angle it back and forth from about 45 degrees inward, through 90 degrees, and then 45 degrees outward. Back and forth, back and forth, back and forth.

Howard Ferstler

My wife also helps on those kind of tests. She thinks I'm crazy but she hides it well.

Thanks for trying it.

David

[tysontom]

Yes and no, I think. It certainly didn't materially affect the impact that the introduction of AR's products had on the state of speaker design. But as EV originally wanted to sell his invention to someone rather than run his own company, the invalidation of the patent may have played a role in his continuing to manage and grow the business for another five years. Had the AR patent held up, it could potentially have enabled him to sell off the company and its IP and get out of the building without having to stay there to build the market share up as high as he did.

The patent fight was not well-known to the public; it was arcane and somewhat convoluted, as with most legal cases, and the big thing was that Ed Villchur was always considered the father of the air-suspension loudspeaker and the dome tweeter -- pure and simple. By the time of the patent fight, AR was strongly entrenched in the high-fidelity business. Villchur's top-notch ads (he wrote them all), the unusually stellar product reviews, Consumer Reports magazine top-ratings -- early on -- and the various write-ups in the magazines and newspapers about AR's pursuits that won it such high favor and helped propel the company to high market share.

As you say, Villchur did originally want to simply sell his invention and move on to writing and research. With the lack of success in selling the idea to other hi-fi manufacturers and the influence of his student Henry Kloss, Villchur became convinced to start in business -- especially since Kloss had the loft in Cambridge and some seed money from some friends. Villchur said many times that he wanted to get "out of the rat race," as he always put it, and when Teledyne came along and agreed to his terms and conditions (for one thing, assuring that all top-echelon managers be maintained at their present salary and have an employment contract for at least five years after the sale in 1967), he was all too happy to retire from AR.

--Tom Tyson

[tysontom]

Spoken like a diehard subjectivist.

The playback occurred in large, reflective rooms with the audience immersed in the Beranek reverberant field, a further contrivance distinguishing LvR from the realities of domestic listening.

"Eddie [Villchur] was a master showman."

[He also understood the variables, and how to manipulate them for maximum promotional benefit.... ]

There you go again, Zilch! Criticizing and denigrating AR even though you rarely have your facts straight.

Look at this picture of one of the AR LvR concerts, and tell me (1) that the room was, as you say, "reflective," and (2) that the listeners were "immersed in the Beranek reverberant field -- a further contrivance…." It is obvious that the room is damped and the listeners were quite close to the AR-3s. Why do you make those assumptions, not base in fact?

I have one of the original tapes that was made by AR of Fine Arts Quartet, and in this particular tape (this was an early tape recording of the musicians, AR-3s and the audience's reaction during an actual concert), Leonard Sorkin, First Violin, stopped the music about half-way into the concert. He said, "…by the way, could we have a show of hands on how many people could detect the switchovers from our live playing to the reproduced music through the speakers?" There was a rather large showing of hands. He said, "…well, I'm sorry to tell you this, but except for the first two bars, the entire part was playing through the AR-3s."

Image One: AR Live-vs.-Recorded concert

[soundminded]

OK, I just tried it using one of my home-built systems in my smaller installation.

First, I got my long-suffering wife to carefully move the vertically oriented, perpendicular aligned ruler (actually, a 12-inch long, one-inch wide paint stick) closer to and further from the tweeters, over about a three-inch span - back and forth and back and forth. (The source was one pink-noise channel of the Delos "Surround Spectacular" test disc engineered by John Eargle and David Ranada.) Then, I had her hold it, again vertically, at one location about two inches out and angle it back and forth from about 45 degrees inward, through 90 degrees, and then 45 degrees outward. Back and forth, back and forth, back and forth.

I sat about 10 feet from the speaker (my normal seating location), about 20 degrees off axis.

Result: no change in spectral balance at all with either procedure. I also tried it at arm's length (about two feet), and then I could hear a slight difference, and I mean slight. Frankly, I was surprised, because I actually thought the differences would be seriously audible. The differences between so-called identical speakers when compared this way were audible, and yet this test of yours was not even close to that kind of contrast.

Now, my systems (picture attached) have two tweeters, vertically mounted (midrange drivers are mounted above and below them, resulting in a vertical MTTM array), and they are those ultra-wide dispersing Allison convex dome jobs that radiate about as strong 90 degrees off axis as they do on axis out to beyond 10 kHz, although the vertical orientation obviously reduces dispersion in the vertical plane. (They look too large to radiate widely in the photo, but the small domes are protected by screen covers that give the impression that the diaphragms are larger than they actually are.) The midrange drivers are 4-inch Tang Band jobs with a phase plug to improve their dispersion. The crossover frequency between the midrange drivers and the tweeters is about 4 kHz.

I decided to go the first procedure one better and got out a 3-foot yard stick so that the midrange drivers would be included in the program. Again, I had my wife do the moving while I listened from 10 feet away, and again I could hear no difference. Well, maybe a very, very slight difference, but as with the first operation, the difference I hear between so-called identical speakers using pink noise was way, way more emphatic.

My guess is that with super-wide dispersing drivers that present a dominant reverberant field even well into the top octave the diffraction issue becomes even less emphatic than with conventionally radiating drivers.

So, good try, but I was not impressed. Yeah, I sure did learn something: I was correct the first time.

Howard Ferstler

Howard;

"Funny how the obviously manifest diffraction problems with the AR-3 systems employed did not cause various audio notables who attended (and wrote up their positive impressions in audio and newspaper articles) to suddenly say, "ugh," and become repelled by the discrepancies. They should have heard those diffraction artifacts, but shame on them."

They did. The sound from the musical instruments was diffracting off the speaker boxes. That is how real music works. The musicians don't sit in isolation chambers. The more musicians there are present, the more diffraction the sound bouncing off each others musical instruments and music stands there is. Ever consider that it is the lack of diffraction that is the distortion?

"Result: no change in spectral balance at all with either procedure. I also tried it at arm's length (about two feet), and then I could hear a slight difference, and I mean slight. Frankly, I was surprised, because I actually thought the differences would be seriously audible. The differences between so-called identical speakers when compared this way were audible, and yet this test of yours was not even close to that kind of contrast."

That is because you are deaf. I'll bet you can't even hear the difference between one wire and another let alone putting speaker wires on tees. How could your insensitive hearing possibly reveal anything more than the slightest change on a test so telling as pink noise. How many recordings of pink noise have you reviewed? How many do you even own? When you become an expert on pink noise, then repeat the test. Then you'll begin to understand what high end audio is all about By the way, how pink was your pink noise anyway?

[Zilch]

There you go again, Zilch! Criticizing and denigrating AR even though you rarely have your facts straight.

I'm not criticizing or denigrating anything here other than participants' reliance upon these contrivances as support for a belief system. Toole gave them the full measure of their merit.

Oh, YAH, that's my living room with at least the 30 people in six rows of seating shown, and the fully draped front wall that Howard just told us would ruin NRC's listening room for evaluation of wide-dispersion speakers....

Look, if all we have left as proof of anything substantive is these subjective LvR demos, it's NOT science by any stretch, and we'd be best served by figuring out the factual basis for what is likable about ARs as opposed to making stuff up regarding what we imagine that to be.

Amateurs focus on techniques and technology, pros focus on results.

I'm about to post the "SpitWad" over on Tech Talk forum; y'all can build it and figure out who's zoomin' who here....

http://techtalk.parts-express.com/showthre...899#post1647899

[soundminded]

There you go again, Zilch! Criticizing and denigrating AR even though you rarely have your facts straight.

Look at this picture of one of the AR LvR concerts, and tell me (1) that the room was, as you say, "reflective," and (2) that the listeners were "immersed in the Beranek reverberant field -- a further contrivance…." It is obvious that the room is damped and the listeners were quite close to the AR-3s. Why do you make those assumptions, not base in fact?

I have one of the original tapes that was made by AR of Fine Arts Quartet, and in this particular tape (this was an early tape recording of the musicians, AR-3s and the audience's reaction during an actual concert), Leonard Sorkin, First Violin, stopped the music about half-way into the concert. He said, "…by the way, could we have a show of hands on how many people could detect the switchovers from our live playing to the reproduced music through the speakers?" There was a rather large showing of hands. He said, "…well, I'm sorry to tell you this, but except for the first two bars, the entire part was playing through the AR-3s."

Image One: AR Live-vs.-Recorded concert

The wide dispersion of the AR3 (and AR3a) tweeters allowed the spectral balance of the reproduced sound to be relatively constant over much of the audience including for those sitting more than 45 degrees off axis. No modern speaker would stand a prayer of duplicating such results. If the FR were flat for those sitting near the axis of the speakers, it would exhibit severe HF rolloff for those more than even a few degrees off axis while if it were equalized to have the correct tonal balance for those even moderately off axis, it would be unbearably shrill on axis. In either case, the difference between the live and recorded sound should be immediatly obvious to anyone with normal hearing except those in a narrowly defined sweet spot where the balance is correct. In fact the falloff of response of modern tweeters with increasing frequency and angle is so pronounced and constant it may be impossible to produce enough high frequencies appreciably off axis to sound flat to anyone no matter how much HF boost is applied. While AR3 and AR3a like all other speakers having a single forward firing tweeter cannot have both flat on axis response and flat power radiation at the same time they come far closer than other speakers (except for Allison's of course most of whose models have more than one tweeter.) The difference here is telling. So is the uniformity of high frequency dispersion of my restored AR2ax speakers which have the same spectral balance in my listening room 45 degrees off axis as on axis, the largest angle possible the way they are arranged toed in catty corner and placed in the corners of my room at the moment.

The inability of most modern speakers to accurately reproduce the deepest bass would make it impossible to duplicate the sound of the cello, especially on its lowest string. If there were a double bass as well such as in the Schubert Trout Quintet, you could kiss all comparisons with any but the most expensive speakers with the deepest undistorted bass good-bye. They just couldn't cut it. In this regard, when properly equalized both AR9 and original Bose 901 are up to it. In my listening rooms, both require considerable bass boost to do it though. In the case of 901 the boost can only be called enormous exceeding 30 db (including the 18 db boost of the Bose equalizer.) AR9 requires about 15db including the contribution of the crossover level switches. Exact amounts depend on the particular recording. AR9 and Bose 901 can also reproduce the timbre of the Steinway piano in my room but unless you are at least 10 feet away from the AR9s the piano sounds like a point source. The real Steinway piano doesn't sound even remotely like a point soruce at any distance, in fact exactly the opposite is true. In this regard, the direct firing speaker even with the vertically and laterally augmented high frequency propagation is at a severe disadvantage. While timbre is correct, spatial imaging is all wrong.

As luck would have it, we have live string groups playing here usually on a weekly basis, usually about 7 or 8 players at a time including 2 cellos. Violin, viola and piano music is played here nearly every day. Accurate reproduction of a violin, especially a very fine one is extremely difficult. Even small errors in FR eliminate its combination of sweetness, clarity, brilliance, and lack of shrillness. The very best of them such as the Guanari del Gesu formerly ex Kochanski now ex Rosand I was once so familiar with also not only combines these qualities in great measure but has enormous power to an astonishing degree for a violin. This is one reason why it sold for ten million dollars at auction last fall.

IMO, were the comparisons made in a smaller room where the early reflections of the muisical instruments from the ceiling and walls to the sides and behind them a considerable contribution to the overall sound field, AR3/3a would not have fared nearly so well as they did in the demos that were conducted for the public. Unfortunately I don't think we will ever find that out. Perhaps one day I'll make an outdoor recording and give it a try...if I can get a certain person to cooperate I'll have to wait until she owes me a big favor. She has no patience for or interest in audio equipment.

[Steve F]

Yes, the AR-LST was tried (briefly with AR-10π tweeters), but I believe the spectral balance of the LST was too diffuse for this fairly close-in LvR demonstration. However, the true reason for not using the AR-LST was that it was not a part of AR's new Advanced Development Division. The AR-10π -- the new flagship -- was the new speaker that would help AR realistically benefit from this demonstration.

The Neil Grover live-vs.-recorded demonstrations received only a fraction of the fanfare of the original AR-3/Fine Arts Quartet. AR did not capitalize on the public-relation's opportunity of this mid-1970s event. Relatively few people knew about it, and I don't think it received a great deal of press coverage. On the other hand, the AR-Fine Arts concerts were conducted all over the country more than 75 times, and there were follow-on concerts done with guitarist Gustavo Lopéz and the well-known 1910 Nickelodeon LvR done at the 1966 High Fidelity Music Show in NYC (and elsewhere). Even the 1955 New York Audio League AR-1/Aeolian-Skinner concerts in Mt. Kisco, New York, drew a larger audience.

--Tom Tyson

I'm quite sure this is absolutely correct--the real reason for using the 10 Pi's and not the LST was to confer credibility and acclaim onto their current TOTL speaker, the 10 Pi.

It's a shame that the Grover LvR's didn't get more publicity. IMO, this demo was several orders of magnitude more difficult than emulating a string quartet, and the achievement of the 10 Pi in emulating the power, impact, and frequency range of a live drum set far surpassed the AR-3's achievement in reproducing a string quartet. Yes, a string quartet has all kinds of subtle nuances and very high frequencies, and a cello can reach down fairly low in frequency--but the dynamic demands on the system don't begin to approach what Grover's drum set demanded. It was also a very difficult demo for Grover, the performer, much more so than for the members of the FAQ.

There was also the time period to consider--in 1962, "stereo" was relatively new, solid-state was just coming on the scene, and the AR-3's were pretty unique as speakers. By 1976, stereo was old hat, high-power amps/receivers were commonplace, and the audience/market for 'gear' was mostly younger people, not middle-aged suburbanite homeowners like in 1962. Culturally/socially, the impact in 1976 couldn't match that of the L v R demos of the '60's.

On to another subject:

Zilch said, "and we'd be best served by figuring out the factual basis for what is likable about ARs."

I posed the very same question myself (after good-naturedly chiding Speaker Dave for not tackling the question himself), and I posted my impression.

I haven't heard from anyone else, but since Zilch has posed the same question, I'd love to hear his and others' responses, in very specific terms, as I tried to do in Post #49 in this thread.

Steve F.

[genek]

On to another subject:

Zilch said, "and we'd be best served by figuring out the factual basis for what is likable about ARs."

I posed the very same question myself (after good-naturedly chiding Speaker Dave for not tackling the question himself), and I posted my impression.

I haven't heard from anyone else, but since Zilch has posed the same question, I'd love to hear his and others' responses, in very specific terms, as I tried to do in Post #49 in this thread.

I gave up asking that one a while ago, because everybody who might have the technical chops to address it seems more intent on defending their own pet theories about what is and isn't "ideal" in speaker design rather than approaching the speakers as existing phenomenon to be characterized. And even those who are trying to characterize seem unable to do so without editorial comments about the validity or lack thereof of the goals behind the design, as if that really matters for something that was built more than 40 years ago and now sits physically before us as a fait accompli. And let's not get into certain peoples' inability to discuss any of this without taking personal potshots at other posters.

Until someone makes a presentation of "why it sounds the way it does," rather than "why it doesn't sound the way it should, the way it was intended to or the way most people like a speaker to sound today" and then demonstrates the accuracy of their characterization by building another speaker that duplicates it in measurement and listening experience, we'll continue to be treated to dueling opinions that constantly hover on the edge of closing down threads.

[tysontom]

I'm quite sure this is absolutely correct--the real reason for using the 10 Pi's and not the LST was to confer credibility and acclaim onto their current TOTL speaker, the 10 Pi.

It's a shame that the Grover LvR's didn't get more publicity. IMO, this demo was several orders of magnitude more difficult than emulating a string quartet, and the achievement of the 10 Pi in emulating the power, impact, and frequency range of a live drum set far surpassed the AR-3's achievement in reproducing a string quartet. Yes, a string quartet has all kinds of subtle nuances and very high frequencies, and a cello can reach down fairly low in frequency--but the dynamic demands on the system don't begin to approach what Grover's drum set demanded. It was also a very difficult demo for Grover, the performer, much more so than for the members of the FAQ.

There was also the time period to consider--in 1962, "stereo" was relatively new, solid-state was just coming on the scene, and the AR-3's were pretty unique as speakers. By 1976, stereo was old hat, high-power amps/receivers were commonplace, and the audience/market for 'gear' was mostly younger people, not middle-aged suburbanite homeowners like in 1962. Culturally/socially, the impact in 1976 couldn't match that of the L v R demos of the '60's.

Steve F.

I agree with Steve about the intensity and impact of the Neil Grover demonstration, and the fact that it was more difficult on that basis than the AR-3 LvR concerts (which actually began in late 1959 and ran into the early 1960s). However, in terms of faithfully recreating the live sound, the softer ensemble tone nuances of string instruments was arguably more difficult to match -- and changes would have been immediately noticeable -- than the higher-intensity, more frenetic Neil Grover drum demonstration. This is conjecture on my part. Whatever the case, Acoustic Research squandered a public-relations opportunity with the Neil Grover demonstration. By contrast, Villchur parlayed the Fine Arts Quartet concerts into a great AR public-relations windfall, with advertisements and fanfare that went on for years (even today we are talking about it).

There is no doubt whatsoever that the Neil Grover demonstration was far more difficult with regard to power required. The AR-10s consistently required 800+ watt peaks (vs. 120-watt peaks on the AR-3 LvR) to reproduce the drum sound -- mainly rim shots and cymbals according to Victor Campos; in fact, Campos had difficulty in finding an amplifier that could reliably perform on this basis for the AR-10s. Even the highly regarded Dunlap-Clark Dreadnaught 1000 could not sustain the high power into low impedances for very long, and eventually other amps were used. The subtle ensemble reproduction and plucked strings from violins and guitars were reproduced clearly and faithfully by the AR-3, and even the drum and percussion sound of the 1910 Seaburg Nickelodeon were reproduced without a hitch by the AR-3, but there was never the impact and power that came with the Neil Grover live-drum sound.

--Tom Tyson

Fig. 1 Neil Grover/AR-10Pi Internal Construction

Fig. 2 Neil Grover/AR-10Pi Wiring

[genek]

Very simply: Why do you think the Classic ARs were and are so popular?

Actually, what I was hoping for was a technical characterization of their sound leading to someone building a new speaker whose is indistinguishable from that of the original, similar to the many attempts that are being made to chemically analyze and duplicate pricey French wines such as Chateau Margaux. Attempting to explain popularity is just going to get us more dueling unprovable theories.

[Steve F]

Actually, what I was hoping for was a technical characterization of their sound leading to someone building a new speaker whose is indistinguishable from that of the original, similar to the many attempts that are being made to chemically analyze and duplicate pricey French wines such as Chateau Margaux.

Attempting to explain popularity is just going to get us more dueling unprovable theories.

No, it's not. I gave very specific, plausible reasons in my post, and I'm sure the rest of the Forum could come up with many more. It'd be interesting reading.

Your desire for "a technical characterization of their sound leading to someone building a new speaker whose (sound) is indistinguishable from that of the original" is also very interesting, but it is a completely different topic than the one I asked.

Perhaps you should split the thread. I want to know from this august group of widely varying ages, viewpoints, and experiences to what do they attribute the Classic ARs' enduring popularity?

Simple question. Distinct topic from yours.

Steve F.

[genek]

No, it's not. I gave very specific, plausible reasons in my post, and I'm sure the rest of the Forum could come up with many more. It'd be interesting reading.

Your desire for "a technical characterization of their sound leading to someone building a new speaker whose (sound) is indistinguishable from that of the original" is also very interesting, but it is a completely different topic than the one I asked.

Perhaps you should split the thread. I want to know from this august group of widely varying ages, viewpoints, and experiences to what do they attribute the Classic ARs' enduring popularity?

Simple question. Distinct topic from yours.

It really isn't, because you can't arrive at a consensus on a "factual basis" for the speakers' popularity while everybody's still arguing about what they really do. But there's no reason to split the thread between the questions, because as I have already said, I've concluded that my question will never be answered anyway. Maybe you'll have better luck with yours, but I think it more likely that in any discussion that is not narrowly focused on the tech, certain posters will inevitably start taking their usual personal potshots at each other and I'll end up closing the thread. Again.

[genek]

I've split Steve's request for peoples' opinions on AR popularity off to a new thread so it won't get lost in "beam or not beam." Let's see how long it lasts there.

[Steve F]

I have one of the original tapes that was made by AR of Fine Arts Quartet, and in this particular tape (this was an early tape recording of the musicians, AR-3s and the audience's reaction during an actual concert), Leonard Sorkin, First Violin, stopped the music about half-way into the concert. He said, "…by the way, could we have a show of hands on how many people could detect the switchovers from our live playing to the reproduced music through the speakers?" There was a rather large showing of hands. He said, "…well, I'm sorry to tell you this, but except for the first two bars, the entire part was playing through the AR-3s."

Image One: AR Live-vs.-Recorded concert

The caption in this AR pic is another example of the amazing class and dignity that this company had during the 50's-early 70's time frame. They actually call out Briggs and Wharfedale and cite their L v R demos as well.

In the 1970-72 brochure, on the 3a page, they quote Consumer Guide saying, "In our opinion, one of the two finest speakers available today." AR puts an asterisk next to the quote, and at the bottom of the page, they say, 'The other is the KLH-12.' !! They give their no. 1 rival a nod of respect--in their own brochure!

What company has ever done this, in any industry? Can you imagine a BMW ad, citing their 3-Series Car and Driver magazine "10 Best" selection for the Xth year in a row, and BMW saying in their ad, "And the Honda Accord was selected best family sedan for the Xth year in a row also."

Not a chance.

But AR was so classy, so 'above the fray,' that they routinely did this kind of thing and it conferred amazing, understated credibility on the company.

The Classic-era AR was a once-in-a-lifetime company, from every angle.

Steve F.

[Zilch]

I haven't heard from anyone else, but since Zilch has posed the same question, I'd love to hear his and others' responses, in very specific terms, as I tried to do in Post #49 in this thread.

And I have provided my answer a dozen times, including here, at least to the extent that I understand it, and that is constant directivity, and ultimately, even Howard agreed to the terminology. That's also what the Linkwitz postings were about.

Soundminded just said the same thing, though he apparently has zero clue that it is easily accomplished today, having earlier opined that the example I previously posted, a pioneering Speaker Dave design from 1980, in fact, could not possibly work....

[Zilch]

I'll say it again, also for the dozenth or more time, that wide and very wide-angle dispersion adversely affects both spatial and sonic quality, which Howard also concedes. "Concert hall realism" doesn't give a whit about either, but there is a very real sense in which Howard is a victim of his preferences -- wide dispersion requires a "perfect" listening space; it puts the room in control of the result. Even then, only multi-channel can make that work optimally, as Howard further concedes.

The more contemporary answer is to minimize the influence of the room rather than rely upon it, and that is easily accomplished, two-channel even, via more moderate dispersion constant-directivity sources, which sacrifice neither localization nor spaciousness when suitably deployed in ANY room.

AR's LvR successes are not evidence of the superiority of anything. What IS compelling is that science, the industry, and the marketplace itself have each and all long since repudiated and abandoned the very principles those successes are herein alleged to have established as transcendent.

If there is merit in these early designs, that may best be found by looking elsewhere than to these outmoded theories....

[speaker dave]

Result: no change in spectral balance at all with either procedure. I also tried it at arm's length (about two feet), and then I could hear a slight difference, and I mean slight. Frankly, I was surprised, because I actually thought the differences would be seriously audible. The differences between so-called identical speakers when compared this way were audible, and yet this test of yours was not even close to that kind of contrast.

So, good try, but I was not impressed. Yeah, I sure did learn something: I was correct the first time.

Howard Ferstler

Well I tried the ruler test again with my long suffering wife doing the honors. My home theater is a largish bedroom. The system was a Snell XA75 with a 1" dome with slight "added directivity" from a wide flare. I could certainly hear the effect of the ruler very readily when I did it myself at arms length. I normally sit about 12 feet away. From that position it was still easily audible as a single pitch moving up and down in frequency as the ruler got closer and farther from the dome. It wasn't "dramatic" and I'm not sure that it would be a strongly noticeable effect if it weren't for the constant motion. Still, it is an aberation that degrades the response of the dome and one that you would want to correct if at all possible. (Well, I would.)

I was surprised that I could hear it from the back corner of the room at about 19ft away. Both the listening position and that corner were to the right of the speaker while the ruler was on the left side. This would be the side that reflected energy would favor. It was also nearly as audible on the back left corner, which could not be a reflection but would have to be a diffraction effect.

If you want to hear other reflection effects an interesting one is to hold a piece of paper over a hard surface such as a stone or marble counter top. Ripple your fingers over the back of the paper to create a constant crinkling noise. While doing that move the paper up and down from the counter surface. You will hear distinct pitch effects that will swing up and down in frequency. The direct sound and the reflection off of the hard surface have a time difference that is constantly changing due to the up and down motion. This creates a variable pitch comb filter.

You can also hear pitch changes from floor bounces if you do deep knee bends at a distance form your speakers. Carpet is surprisingly reflective.

Fun with science.

David