10pi vs 90 vs 9

[Guest Bret]

The friend of mine with the 10pi's was very recently able to purchase a pair of 90s. I have many hours of familiarity with his 10pi's and his equipment and room. We have some specific noises on specific recordings that we listen to for comparison purposes. Sometimes it isn't a question of better / worse, but different. Sometimes it is a question of better or worse.

There is a bongo we listen to. On my 9s you feel like you could take the player's fingerprints. On the 10pi's it sounds like maybe he's wearing latex gloves. Other things are like that, as well. There's just more detail in the 9. We fired-up the 90s and the fingerprint-level detail reappeared. The detail is not available on the 10pi's in any of the placements we've tried regardless of crossover setting.

But both the 9 and the 90 have irritatingly small "sweet spots" compared to the 10pi that will give you a full house image (although not necessarily perfect) from anywhere in a much larger area.

I consider the 10pi to be a great speaker system, much better than a 3a in all but barrel-chested bass response (purely an opinion-call). Call the 3a Pavarotti and the 10pi Bocelli.

After hearing the 10pi's next to the 90s, though, I have to wonder. . . Are they (the 10pi's) suffering from something? Is the crossover going bad? OR, is it possible that the eyeball midrange is deteriorating?! Could it be that the 10pi just isn't up-to playing like a 90 or a 9, period, and never was?

Other observations - the 10pi has a greater tendency than the 90 to give you the impression sound is coming from far beyond the cabinets, back, high, and to the sides (early reflection artifacts?) The 90 provides a very unsatisfying experience anywhere but in the sweet spot, but it is a wholly better experience than the 10pi from the sweet spot.

I may be describing room acoustics more than speaker performance now comparing the AR-9 and the AR-90. Other people have described the AR-90 as being possibly "more detailed" than the AR-9. I find that to be true even though my 9's room is very bright and "alive" and the 90's room is probably average (carpeting, etc). Is it driver-placement? Forgive me if words fail, but the 90's sound "accurate" (not clinical) and the 9s sound "theatrical" or "dramatic." Between the two systems there seems to be a great difference in "warmth" (rolloff?) with the 9s sounding "older, warmer," despite the fact that of the two amplifiers his is decidedly "warmer" sounding no matter which speakers his is connected to.

Another observation and I don't know how this is even physically possible; the off-axis vertical energy limits of the 90 is somewhere between astounding and ridiculous. The top end simply disappears at a 30 degree (or so) angle above the horizontal plane. It seems to be the aural equal of the horizontal spread of light peeking between clouds at sunset, or maybe the plane of light an oscillating laser produces in a smoke-filled room on it's way to whatever screen it's projecting on. Although I still find the "shaft of sound" irritatingly small on the horizontal plane, it is nowhere near as cleanly clipped-off as on the vertical. If you are listening to the 90s, don't stand up.

Having said all that, at this point in my listening, to my ear the AR-90 may be an even better "deal" at four times the price of the AR-2ax than the 2ax. I've seen these go from anywhere from $250-$400 a pair while the 9 seems to be selling in the $650-800 range. If shipping weren't an issue I would still pay $200-300 more for a pair of AR-9s (personal choice about superlatives). If shipping is added to that, well, the 90 is. . . , is what? Cheap, in relative terms?

In absolute value terms an AR-90 a $400 (working) pair is a mind-bending value. At $500 shipped it's still a bargain. If THIS pair of 90's and THIS pair of 10pi's are representative of the class as a whole, and we're talking sound not collector's item, it would be folly to pay $500 for a pair of 10pi's while a pair of 90s are available for the same money.

In my ears' opinion, there is more difference in the 90s and the 9s than that last 5Hz in the 9s specs can account for. The crossover points for the woofers are the same, the drivers are the same except for the 10" vs 12" woofers, but still, something else is different. Does the 9 suffer from the bi-ampable crossover? Does the 90 gain something? Are the 9s too tall? The 90s not tall enough? Are my ears bad?

And why can't I have it all; the energy pattern of a 10pi with the detail of the 9/90? Is that what the 303 does?

Opinions? Observations? Jokes?

Bret

[ar_pro]

Happy Thanksgiving, everyone!

Bret, I have a hunch that the room/loudspeaker interface is really at work here...my original 9's were used in a medium-sized room, up against the front wall, and the sweet spot was decidedly narrow for a full-range, dynamic-driver system. My current pair of restored 9's are on spikes in a much larger room, and are pulled out about two feet from the front wall...the listening experience is dramatically different, with TWO distinct "sweet spots", tighter bass (extension is still there in spades, just no trace of plumpness in the mid-bass region), and a good sense of high-end balance.

My nephew owns a mint-condition pair of 9's, and we carefully auditioned them against the AR-90, as both systems were being sold as close-outs, back in the early '80s - as I recall, the 9 was the hands-down choice, especially when considering low-end response, and overall dynamic range.

I've always felt that the AR family tree (having shown both a consistant philosophical and engineering evolution up to that point) divided after the 3a, with one branch producing the LST series and the 10pi, and the other leading to the 9 and 90. Any thoughts on this?

[Guest Bret]

>with TWO distinct "sweet spots"<

Room reflection?

[AR-9 has]> tighter bass (extension is still there in spades, just no trace of plumpness in the mid-bass region), and a good sense of high-end balance.<

Mine are plenty "plump" where they sit. I can temporarily get rid of that by pulling them well away from the wall, but I can't leave the speakers sitting there. I can't "spike" either. They're on a wood-veneer floor, the floor is glued to concrete.

I'm sure you're right about the room's influence. This room really stinks for these speakers. It has lots of volume, but it's way, way too reflective. Now if I could just get the wife to let me hang some tapestries. . . or fuzzy Elvis posters.

Hopefully we'll get a chance to bring the 90s to my room (since they are 40lbs/ea lighter) and I'll be able to do an A/B comparison in the same room.

Maybe this room is going to have to have a pair of LSTs to bounce early and often.

Ah, about "dynamics." I cautioned my friend (Hi, Don - he reads but doesn't post which I wish he would so you'd have his perspective, too.) that the 90s, just like the 9s, are louder than you think they are. They produce extreme volumes so effortlessly that sometimes the only way to get a sense of how loud they are is to check for vibrating exterior walls. . . the ones on your next door neighbor's house. If it is still standing, of course.

Bret

[Guest Bret]

>I've always felt that the AR family tree (having shown both a consistant philosophical and engineering evolution up to that point) divided after the 3a, with one branch producing the LST series and the 10pi, and the other leading to the 9 and 90. Any thoughts on this<

Sorry, meant to comment before and forgot.

Isn't what you said pretty-much a matter of historical fact? The ADD guys did the LST then the 10pi then left for N.A.D. with those that didn't go developing the verticals? Tom or Steve or Ken could probably straighten us out on that.

Bret

[tysontom]

>>I've always felt that the AR family tree (having shown both

>a consistant philosophical and engineering evolution up to

>that point) divided after the 3a, with one branch producing

>the LST series and the 10pi, and the other leading to the 9

>and 90. Any thoughts on this<

>

>Sorry, meant to comment before and forgot.

>

>Isn't what you said pretty-much a matter of historical fact?

>The ADD guys did the LST then the 10pi then left for N.A.D.

>with those that didn't go developing the verticals? Tom or

>Steve or Ken could probably straighten us out on that.

>

>Bret

Bret,

I wasn't following this thread too closely, so I got caught out. The Advanced Development Division folks really had nothing whatsoever to do with the development of the AR-LST; that was Roy Allison's design with help, of course, from others on the staff. The LST came about three years before the ADD was formed. As you probably know, the LST was designed in response to needs from the professional recording and broadcast industry wanting the sonic accuracy of the AR-3/AR-3a, yet needing more power and better acoustic-power response. The rest, they say, is history. The LST was one of the last designs of Roy Allison before he left, and his new Allison: One was very similar to the original design of the AR-LST except for the woofer design. Allison and several of the original AR officers (e.g., Abe Hoffman, Sumner Bennett and others) had 5-year contracts with Teledyne after its purchase of AR in 1967, and by 1972 they had departed. Of course, Allison Acoustics was created shortly thereafter.

The mid-70s ADD folks did have many people involved with earlier products, such as C. Victor Campos, who had returned to AR in 1974 (I think) after an initial stint in the AR Music Room in NYC around 1960-1963. Campos contributed quite a lot at AR and worked on refining and developing the AR-10Pi and subsequently the AR-9/90 (although he was not the designer in either case), and he also was responsible for the mid-70s live-vs.-recorded demonstration using the AR-10Pi and drummer Neil Grover. SteveF I think witnessed one of those live-vs.-recorded demonstrations, and could probably elaborate on his impressions. Coincidentally, Campos was around AR during the first AR-3/Fine Arts Quartet concerts, and learned a great deal about doing them at that time. In the end, however, the ADD products were simply the next generation of product design for Acoustic Research after the pre-Teledyne products had run their course.

The 1978 "Verticals" were primarily the brain child of Tim Holl, I am pretty sure, with input from many of AR's elaborate engineering staff both in Norwood and in England and Holland. These engineers took many innovative ideas, borrowed a couple from Allison (woofers close to the floor-wall boundary), and developed the next-generation AR speakers such as the AR-9 and AR-90.

--Tom Tyson

[kkantor]

Tom's account seems accurate to my memory. Along with Tim, I would add Bob Berkovitz as a key originator of 9x concepts.

[kkantor]

Because the perceptual implications of detailed response differences are not, to this day, fully understood, system design remains an inexact and wholistic process. It's difficult enough to get two speakers of the same model to sound alike! Changing cabinet dimensions, woofer diameters, relative distance to the floor, all have sonic impacts.

The tradeoffs between radiation pattern, envelopment, listening window and imaging precision is a favorite subject of mine. I'd be happy to discuss it here in as much detail as you would like. However, since this a massive subject that is not amenable to quick answers, let me see if I am allowed to upload an old AES paper that would give you a backgrounder on my opinions first.

[kkantor]

PS- while there is no stopping entropy, there are several reasons why the dome mids tend to have a longer life than the woofers, abuse aside. This is related to the stiffer materials used for the compliant parts in midranges, and to the lower mechanical stress they undergo.

[Guest Bret]

>The LST was one of the last designs of Roy Allison before he left, and his new Allison: One was very similar to the original design of the AR-LST except for the woofer design.<

Well, of course it was. In fact, it's obvious once you think about it; which I hadn't. That looks like an Allison design and follows his philosophy as I understand it.

To the best of your recollection, was an LST *built* after the 10pi became available? My memory says that it was, but I could be confusing "built" with left-over-inventory at the retail level.

Also, I want to remember that first the AR-9, then the 90, became available a year or more *before* the 91, 92, etc. But again, I may be thinking "retail level."

For some reason it is stuck in my mind that the 10pi was introduced well before the 11 (therefore 3a's were still around) and that the 9 was introduced after the 10pi was gone but before the 11, 12, 14, etc were done away with and the other "verticals" were available. Almost as though the ultimate of the next generation were offered first.

And while we are at it, what was the top-of-the-line speaker the moment before the MGC-1 rolled off the assembly line? I seem to remember the 9 was either gone or going.

Oh, and thank you, Tom. The richness of my educational experience at your expense is greatly appreciated. Much of my history with AR was daydreaming about how nice it would be if I could afford whatever the top of the line was at the time.

Then I discovered girls and somehow speakers had trouble competing. "Warm" and "smooth" and "top-end / bottom-end" took-on entirely new meanings. (not to mention "flat , response, curve. . .") Oh, if I'd only known then what I know now.

Bret

[Guest Bret]

>let me see if I am allowed to upload an old AES paper that would give you a backgrounder on my opinions first.<

I would appreciate your perspective so I look forward to reading the paper. I hope my almost non-existant physics education is up the task of understanding it.

What very little I know about the speaker systems primarily designed by you (or teams lead by you), I can't get a "handle" on where you stand on this whole imaging issue. Seems like you've done several from different schools of thought.

I'm glad that a guy with as many credentials, as much experience, so many awards and accolades, so many successful designs and business dealings, impressive positions and titles, and with so many other things to do as you must have takes the time to contribute to a public forum where I'm allowed to hang-out.

Whatever the reason: I'm all for it and am happy to take advantage.

Thank you.

By the way, as heartfelt as all the above is, I'm tellin' ya', I can hear the difference in amplifiers. . . no brown-noser, I. :-)

Bret

[Guest Bret]

>Because the perceptual implications of detailed response differences are not, to this day, fully understood<

Ah HA!

Let's understand them. I've got the Neurologist and an ear for the etherial; your P.E.T. scanner or mine? ;-)

Bret

[tysontom]

>Tom's account seems accurate to my memory. Along with Tim, I

>would add Bob Berkovitz as a key originator of 9x concepts.

>

Ken mentioned Bob Berkovitz, and not enough can be said of this man’s accomplishments at AR, and in audio and acoustics in general. In the 1965 issue of *Stereo Review,* Berkovitz published a very interesting article, “What the Music Demands of the Amplifier,” in which it was demonstrated how much power was needed to reproduce musical instruments at their original acoustic-power levels. At that time Berkovitz was product-development manager at Mattes, an early manufacturer of high-power, solid-state amplifiers. While it wasn’t mentioned, the speaker used was an AR-3 and towards the end of the article Berkovitz commented, “No information was taken regarding distortion, frequency response, phase shift or other characteristics of the elements of the recording and playback system. It is worth noting, however, that all those present during the session were impressed -- subjectively -- both by the accuracy with which the loudspeaker system appeared to reproduce the music, and by the extremely close correspondence between the photos of the waveform of the actual performance and those of the output waveforms of the loudspeaker.” This article was written a few years after AR had conducted the now-famous live-vs.-recorded concerts across the country. The accuracy of the AR-3 was now becoming well known, and this article was yet another confirmation of that speaker’s excellent design.

After leaving Mattes, Berkovitz actually joined AR and worked in public relations (I believe) from 1967 to 1970. He joined Dolby Laboratories, and then returned to AR from 1974-1982 as Director of Research (an interesting sidebar, Dolby Labs was close to Ampex Corporation, and Ampex used AR-LSTs). His numerous contributions to AR and to acoustics in general are too many to describe here in detail; he wrote many important papers on audio, presented on many topics at AES and ASA. Berkovitz and Allison co-authored an important paper in 1970, "The sound field in home listening rooms," which described the low-frequency, boundary-effect phenomenon that formed the basis for Roy Allison's designs, and subsequently to some degree, the design of the AR “Verticals.” In the early 1970s, Berkovitz and others at AR developed a remarkable 16-channel digital, time-delay system (AR-7s). While at AR and other places, he developed software for acoustics measurement, loudspeaker design and development, etc. He held several patents, including four-channel recording system (Quadraphonics Corp), patents with Dolby and four or five patents with Acoustic Research. He has lectured at Boston University, MIT and in several foreign countries. To say he is talented is a gross understatement, and he has done all this with only a degree in History and Art from University of Illinois. To my knowledge he has no formal training in engineering or math or science -- all self-taught. Berkovitz is now Chairman (and Co-Founder) of Sensimetrics, a company specializing in speech analysis and electroacoustics.

Bob Berkovitz's name is in the news again. Among his many other talents, Berkovitz is also apparently a noted forensic-acoustics expert, and he recently studied the JFK assassination recording (the Dallas Motorcycle police officer who left his mike "keyed" during the whole incident), and determined that what was once thought to be the so-called "4th gunshot sound" on the tape was unlikely to be one. This seems to contradict the 4-shot conspiracy, since the original evidence pointed to three shots. His conclusions have apparently been taken seriously.

--Tom Tyson

[Steve F]

"…To the best of your recollection, was an LST *built* after the 10pi became available? My memory says that it was, but I could be confusing "built" with leftover-inventory at the retail level.

Also, I want to remember that first the AR-9, then the 90, became available a year or more *before* the 91, 92, etc. But again, I may be thinking "retail level."

For some reason it is stuck in my mind that the 10pi was introduced well before the 11 (therefore 3a's were still around) and that the 9 was introduced after the 10pi was gone but before the 11, 12, 14, etc were done away with and the other "verticals" were available. Almost as though the ultimate of the next generation were offered first.

And while we are at it, what was the top-of-the-line speaker the moment before the MGC-1 rolled off the assembly line? I seem to remember the 9 was either gone or going…"

OK Bret, here it is, one more time:

The 10Pi, 11 and MST were introduced together in early 1975 as the first models of the Advanced Development Division (ADD). The 3a was definitely still being produced when the 10Pi and 11 were introduced, because I remember writing to AR and asking them how could a 3a list for $295 (in 1975 it did) and the 11 also list for $295? They gave me some double-talk answer, but the point is, both the 11 and 3a were in production together for a short time, no question about it.

(As an aside, I will be forwarding the letters I received back from AR in the 1972-1976 time frame to Mark so he can scan and post them on the site. This will be a truly unique insight into AR at that time—not available anywhere else--and I’m sure everyone will find these letters to be interesting reading.)

The 16, 12, and 14 were introduced in 1976. I remember A-B’ing the 12 and 14 with the Large Advent at a store in Harvard Square MA in the summer of 1976 and thinking to myself, "Finally! The smooth, accurate AR sound, with the ‘not enough highs during a retail demo’ problem solved at last!" They were terrific speakers, but the big rush of the stereo buying bubble had already peaked, and the 14 never did catch the Advent the way AR had hoped. But AR’s marketing saga is a separate issue, one that I have dealt with at length in a previous post several months ago.

The 9 came along in 1978, the 90 in very early 79. The 91 and 92 came in late 79/early 80 (I bought my 91’s in the summer of 1980).

The 9LS (the next generation 9) was an ’82 introduction.

BTW, the LST’s positioning as a "professional monitor" was nothing more than really inspired marketing, probably the only time in AR’s history that they really used some imagination when presenting one of their products. How did that line in their brochure go? (I could get the exact quote, but I’m upstairs, and I don’t feel like walking down to the basement to look it up.) "While the LST is intended as a professional monitor, it is also available by special order to those individuals who want such a precision instrument in their homes." Yeah, and I’ve got a bridge in Brooklyn I want to show you. While there is no doubt that AR was more than willing to sell the LST for studio use, the whole "available only by special order" rap was designed purely to add some exclusive zing to a product that was very expensive and strange-looking.

And it worked beautifully. The LST sold better than such an expensive speaker had any right to, and was a tremendous commercial, as well as engineering, triumph.

Manufacture of the LST began in late 1971. The LST-2 was introduced in early 1974.

The MGC-1 was an '85 intro (see Stereo Review June '85 for the test report). The 9LSI was around then, with the 50 to be intro'd in 1986.

Steve F.

[Guest Bret]

>OK Bret, here it is, one more time:<

I appreciate your willingness. There have been so many corrections and questions about the time-line that's posted that I'm never sure if what I'm looking at is the corrected version or the version that's been corrected in posts.

Makes it tough on those of us who have to remember what we read instead of what we lived, sometimes.

I have no recollection, for instance, of ever seeing an AR11 and an AR 3a on display in the same store. I *do* seem to remember seeing an LST and an 11 on display at the same time.

You had told me before that the MST was an ADD product and contemporary to the 10pi; that's how I got confused with the LST and 10pi. (hard to understand why ADD would bother with an MST, looking back at it) I won't make that mistake again.

I liked the 14, BTW, not merely as a demoable speaker but I enjoyed listening to it. But then, I like listening to my 17s, too. Not quite the same experience as the 9s.

In fact, within the past couple of days I was sitting in the bedroom with the 17s on thinking how much better they sound than they would seem to have any right to sound.

The other AR speakers that I always thought that about were the Partners. Particularly the Rock Partners (although I hated the name) made me think they needed to be much larger to sound as good as they did.

Thanks again, last time, promise.

Bret

[tysontom]

>

>OK Bret, here it is, one more time:

>

>BTW, the LST’s positioning as a "professional monitor" was

>nothing more than really inspired marketing, probably the only

>time in AR’s history that they really used some imagination

>when presenting one of their products. How did that line in

>their brochure go? (I could get the exact quote, but I’m

>upstairs, and I don’t feel like walking down to the basement

>to look it up.) "While the LST is intended as a professional

>monitor, it is also available by special order to those

>individuals who want such a precision instrument in their

>homes." Yeah, and I’ve got a bridge in Brooklyn I want to show

>you. While there is no doubt that AR was more than willing to

>sell the LST for studio use, the whole "available only by

>special order" rap was designed purely to add some exclusive

>zing to a product that was very expensive and strange-looking.

>

>

>And it worked beautifully. The LST sold better than such an

>expensive speaker had any right to, and was a tremendous

>commercial, as well as engineering, triumph.

>

>Manufacture of the LST began in late 1971. The LST-2 was

>introduced in early 1974.

>

>The MGC-1 was an '85 intro (see Stereo Review June '85 for the

>test report). The 9LSI was around then, with the 50 to be

>intro'd in 1986.

>

>Steve F.

>

I think SteveF is correct in most of what he has described in the introduction of the various models. The LST comments deserve further clarification, I believe, as to AR’s intent and the success of this product.

First of all, the AR-LST was originally designed in response to numerous inquiries from the recording industry for an accurate monitor with flat on- and off-axis frequency response, capable for use in studio monitoring and acoustic-laboratory work. Prior to the AR-LST, several studios used AR-3as and AR-3s for monitor speakers, and AR found itself constantly replacing burned-out tweeters. The AR-LST, with more than double the power-handling capability of the 3 and 3a and a much-superior acoustic-power response, would actually fill the bill quite well. It should also be said that Roy Allison was the probably last person on earth that would put “marketing” ahead of common-sense engineering in designing the LST, but AR obviously eyed the nonprofessional user as well.

When AR introduced the AR-LST, it established something known as the “Professional Products Division,” an entity within AR that was ostensibly dedicated to professional products. The first LSTs were indeed sold to recording studios, laboratories and other for professional uses; but once magazine test reviews and critical acclaim of the LST became known to audiophiles and the like, demand for the speaker for consumer-use rose quickly. The LST was offered for sale to “nonprofessionals,” and the procedure for purchasing the speaker was quite different from consumer AR products. The speaker was at first only offered at certain dealers, and rarely did these dealers have the speaker on display. Dealers were not required to demonstrate the LST, whereas there was a dealer “policy” (never enforced, of course) requiring dealers to demonstrate the other consumer products. The nonprofessional wanting to purchase a pair of LSTs would therefore place an order with an AR dealer. A check for the list price, $600 each, was to be made out to Acoustic Research, Inc., and the dealer would forward the check to AR. AR would subsequently ship the AR-LSTs directly to the end-user’s address, freight prepaid. There was no discount, although the dealer was I think reimbursed at the regular AR dealer discount. The LST was never listed in the regular AR dealer price schedules, although the procedure for purchasing the speaker was described in the back of the 1974 schedule outlining the procedure the dealer would follow to purchase the speaker (contacting the rep in their area).

I don’t know how long this lasted, but I do know that I purchased my first pair this way in 1972. Few dealers ever stocked LSTs, per se, but I think that the speakers could be purchased directly from the dealers toward the end of the run.

--Tom Tyson

[Steve F]

While my comments about the LST’s marketing were made with tongue planted firmly in cheek, I know that there is far more than just a grain of truth to them. I know how the professional marketing of consumer products works, first hand.

Bear in mind that JBL had the vast majority of the studio monitor market in the 1970’s. Remember their L-100 advertising theme of that time period? "Wednesday for horns. Thursday for vocals." They pegged the entire appeal of the L-100 Century as being the consumer version of their professional studio monitor. AR had a small following in the so-called "professional" market, but they weren’t a major player by any means, and there was no great call for their products by the recording industry.

The entire "direct order from AR… for those individuals who want such a precision instrument etc. etc. …" gambit was one of either phenomenal naivete or truly inspired marketing. It was probably somewhere between the two. The LST became more and more a top-of-the-line consumer speaker when it became apparent that the major studios were not going to adopt the LST, and that AR was not, as industry insiders like to say, "going to save the world from bad sound."

None of this is meant in any way to denigrate the integrity of Roy Allison’s (or AR’s) motives or incredible engineering success with the speaker.

Steve F.