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Roy Allison AR-3a AR-LST & Mark Levinson Cello Amati speakers


mluong303
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I just located this letter from Mr. Roy Allison to me in December 2000 and would like to share his answers to everyone who love his speakers. My questions to Mr. Allison were:

1. The original AR-LST has 5000uF capacitor and later changed to 2500uF. What was the advantage to the sound?

2. I really would like to get rid of the fuse, 5000uF / 2500uF cap, six position switch to flat frequency response and the auto transformer in the AR-LST crossover since all these parts have their own problem associate with aged! Is it safe for me to do that? Will it matter if I place the 6uF and 40uF capacitors at the positive input terminal instead of the negative terminal as shown?

3. The Pots in the AR-3a as well as many other AR speakers in that era often being Oxydized by moisture and polluted air. They would never work as new even being stripped apart to fully polished and lubricated. Is it safe to by-pass them? If not what resistors should I use to get the flat frequency response for both the midrange and tweeter?

Minh Luong

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Thanks for posting this Minh, nice to have Roy Allison confirm, essentially what I said in this post:

http://www.classicspeakerpages.net/IP.Boar...amp;#entry64275

There is no reason why the 3a style pots would not work for level controls,

or better something like a 5 position switch, as an alternative to tri-amping as

was stated by Roy Allision.

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There are serious mistakes being made on these Cello Amati speakers! Should you ever need Cello/AR drivers to convert them back to their original condition, just drop me an email and I should be able to bring them back to their original shapes and sound quality.

Minh Luong

mluong303@aol.com

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I just located this letter from Mr. Roy Allison to me in December 2000 and would like to share his answers to everyone who love his speakers. My questions to Mr. Allison were:

3. The Pots in the AR-3a as well as many other AR speakers in that era often being Oxydized by moisture and polluted air. They would never work as new even being stripped apart to fully polished and lubricated. Is it safe to by-pass them? If not what resistors should I use to get the flat frequency response for both the midrange and tweeter?

Thanks for the info, Minh...

I just double checked with John O'Hanlon to be sure, and it appears Roy Allison mistakenly reversed the 2 ohm and the 14 ohm (pot replacement) fixed tweeter resistors in the AR-3a drawing. The 2 ohm resistor should be in series, and the 14 ohm resistor should be in parallel with the tweeter. The drawing shows it the other way around.

Given the typical condition of original 3a tweeters these days, a 15 or 16 ohm parallel resistor with little or no series resistance is probably more appropriate for the tweeter anyway.

Roy

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There are serious mistakes being made on these Cello Amati speakers! Should you ever need Cello/AR drivers to convert them back to their original condition, just drop me an email and I should be able to bring them back to their original shapes and sound quality.

Minh Luong

mluong303@aol.com

Hi Minh;

What are the Allison tweeters doing in the speaker cabinet?

Are those Allison midrange drivers as well?

Vern

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Hi Roy and John

Thank you for pointing out the mistake. Can you post the corrected drawing with resistors at the right places plus your suggested fixed resistors crossover. I know you do more tweaking and listening than I do so whatever inputs you can offer will be helpful to others.

Vern,

The tweeters, midranges and 10" woofer with step down adapter are all Allison drivers. What are they doing in the Cello Amati speakers, I have no idea and it would be nice if the original owner who modified these speakers can explain his purpose and personal believe...

Minh Luong

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The tweeters, midranges and 10" woofer with step down adapter are all Allison drivers. What are they doing in the Cello Amati speakers, I have no idea and it would be nice if the original owner who modified these speakers can explain his purpose and personal believe...

Minh Luong

Dear Minh,

The only reasons I could imagine anyone making this type of alteration would be to (1) improve the already superb dispersion and (2) increase the already prodigious power-handling capability of the LST/Amati. The only peculiar thing is the use of that woofer which, by the way, does not appear to be an Allison woofer. Nevertheless, I believe that the Allison tweeter is the only tweeter ever made that can outperform the AR-3a 3/4-inch tweeter with respect to off-axis dispersion. I think the midrange is somewhat better off-axis than the AR-3a, and can also be crossed over at significantly lower frequency (375 Hz). The Allison tweeters had a "pulsating" characteristic that made radiation from the edges of the diaphragm somewhat asymmetrical, and thus there was increased output from the “flexing” nature of the edges of the diaphragm (refer to US Patent No. 4,029,910 “Wide Dispersion Loudspeaker with Flexing Diaphragm.” I’m not sure if this patent went forward). On the other hand, I don't think the Allison drivers were better performers, overall, than the AR drivers with regard to transient response, distortion and flatness of response.

The AR-LST (not necessarily the Cello Amati) had such wide dispersion that to use a tweeter with even greater off-axis extension doesn't seem particularly rational, and to down-rate the woofer from the potent 12-inch AR woofer to a 10-inch version makes little sense, particularly in a 2-Pi setting.

--Tom Tyson

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Dear Tom

Thank you for the comment and input.

You said: "The AR-LST (not necessarily the Cello Amati)..."

Why Not? Can you express what you think!

If someone else who had read bad review on the Cello Amati speakers performance somewhere on the InterNet please copy and paste the link for me. I would appreciate to find out what I had missed...

The main problem with these modified Cello Amatis was the crossovers are the one designed for use with the AR drivers so by swapped out all the AR drivers for the supposedly better designed Allison drivers will definitely degrade the sound quality and screw up the tonal balance more than helping them. I really wish to hear from the owner point of view...

Minh Luong

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Dear Tom

Thank you for the comment and input.

You said: "The AR-LST (not necessarily the Cello Amati)..."

Why Not? Can you express what you think!

If someone else who had read bad review on the Cello Amati speakers performance somewhere on the InterNet please copy and paste the link for me. I would appreciate to find out what I had missed...

Hello Minh,

I apologize if I upset you about the Cello Amati -- wasn't inteded to to do that. What I meant was that the LST, with its original AR-3a hard-dome 3/4-inch tweeters, had better dispersion than the first-version Amati (with the soft-dome 3/4-inch tweeters) and significantly better dispersion than the later version Amati with the larger tweeters. It's not that any of these designs was deficient in off-axis performance: the Amati is far better than most speakers, but that the LST was clearly the best in terms of acoustic-power response of these particular speakers. I have heard from several insiders that the LST was actually flatter in response (particularly acoustic power) than any of the Amatis, but I have never seen a comparison in print. Actually, I've never seen any sort of performance test report on the Amati, so I don't know the press reaction to this very limited-production and extremely expensive loudspeaker.

If you think about it, Mark Levinson took an already excellent loudspeaker -- one developed and refined by Roy Allison in AR's anechoic chambers and reverberant chambers -- and set about modifying the original design with different crossover and other changes, eventually changing the drivers themselves. The build-quality was extremely high, and perhaps the high cost could be justified on this basis. I don't believe he ever used the AR-3a tweeters, for whatever reason, and chose to use the AR-10/AR-9-style soft-dome versions, which had been tried and abandoned by AR in a test version of the LST (I believe that Victor Campos tried this combination and a picture of this version is shown in one of the pieces of LST literature). Since the autotransformer allowed essentially flat output, the additional efficiency in the soft-dome tweeters was unnecessary, and the off-axis performance was compromised slightly. On top of all this was the exorbinant pricetag for the Amati!

--Tom Tyson

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Hi Tom

I am going to break apart you post and answer to what you said and hopefully this will clear up the misconception of people who have a hard time understanding the Cello Amati speakers.

" I apologize if I upset you about the Cello Amati -- wasn't inteded to to do that."

No problem, I don't get upset but willing to listen and learn if there is anything I had missed? I want to find out where the discrepancy was! I would like to present what I know and to set things straight so to stop the people who love to copy what you said and spread the wrong info to mislead others.

" What I meant was that the LST, with its original AR-3a hard-dome 3/4-inch tweeters, had better dispersion than the first-version Amati (with the soft-dome 3/4-inch tweeters) and significantly better dispersion than the later version Amati with the larger tweeters. It's not that any of these designs was deficient in off-axis performance: the Amati is far better than most speakers, but that the LST was clearly the best in terms of acoustic-power response of these particular speakers."

The Cello Amati speakers have never used stock AR-10Pi/AR9 coated soft dome tweeters since day one but instead they were special ordered paper dome tweeter with butyl latex/coated fabric suspension with embedded ferro fluid for high power handling but with the off-axis dispersion characteristic of the original AR-3a tweeter. The midranges were ferro fluid filled as well compare to the none ferro fluid filled midranges in the original AR-LST therefore the Cello Amati speakers actually can handle even higher power than the original AR-LST speakers and the dispersion characteristic is basically the same for both models. The later Cello Amati Pro also used 3/4" coated soft dome Dynaudio tweeters (not the larger 1"+ tweeter as you may think, see attached photos for the difference) so to preserve as much of the dispersion characteristic as the AR drivers Amati but the crossover were totally changed due to the introduction of the more expensive Dynaudio drivers to kick it up a notch.

" I have heard from several insiders that the LST was actually flatter in response (particularly acoustic power) than any of the Amatis, but I have never seen a comparison in print. Actually, I've never seen any sort of performance test report on the Amati, so I don't know the press reaction to this very limited-production and extremely expensive loudspeaker."

I imagine these insiders must be hard cored Roy Allison followers and will not give Mark Levinson any credit but making judgement based on their personal believe and what they think. I used to be one of these people myself for many years but eventually feel I should let go my blind following and personal assumption but to find out the real truth. But then I could be wrong about this so please let me know who said that if you don't mind! Mark Levinson is an excellent salesman himself so not often he will ask for helps from the magazine reviewers or the press to promote his gears. I like him because he really knows his stereo components well and has a true understanding in music recording and sound reproduction.

" Mark Levinson took an already excellent loudspeaker -- one developed and refined by Roy Allison in AR's anechoic chambers and reverberant chambers -- and set about modifying the original design with different crossover and other changes, eventually changing the drivers themselves. The build-quality was extremely high, and perhaps the high cost could be justified on this basis."

If it was for ego boosting, I had already spent my money on a set of Wilson Audio WATT/Puppy speakers and running my mouth all around town! Why bother with the Cello Amatis? I love Cello Amati speakers simply because they carry on the original AR sound, tradition and tonal balance with tremendous cares in built quality and details. They are very expensive due to the very limited run. The Cello Amati was not designed or modified by Mark Levinson, Tom Colangelo or Paul Jason as many Cello owners around the World tend to believe in! I just hope one day Mark Levinson will reveal his old friend's name so no one will have to guess who the real designer was but Please keep in mind Roy Allison was the original designer for the AR-LST which the Cello Amati speaker was based on.

" I don't believe he ever used the AR-3a tweeters, for whatever reason, and chose to use the AR-10/AR-9-style soft-dome versions, which had been tried and abandoned by AR in a test version of the LST (I believe that Victor Campos tried this combination and a picture of this version is shown in one of the pieces of LST literature). Since the autotransformer allowed essentially flat output, the additional efficiency in the soft-dome tweeters was unnecessary, and the off-axis performance was compromised slightly."

Mark Levinson did request AR to order the original skillful technicians to build the modified AR-3a tweeters for him to implement onto his Cello Amati speakers. See attached pictures. This is one of the reason why the Cello Amati speakers were priced so high! Never under estimate Mark Levinson's capabilities and abilities to carry out his thought! He is the true founding father of high end stereo equipments. I don't have the extra money to spend on his electronics but that will not stop me from admiring his products and creation.

Is the b&w AR-LST picture shown the picture you mention about Victor Campos experiment of soft dome tweeters on the AR-LST? This is a technical drawing and beautiful rendering but not a true photograph at all. Hopefully Victor Campos can tell us what he did or had found out in the experiment with the AR-10Pi tweeters on the AR-LST speakers if such test had been done?

Well, I have say enough to clarify as much as I know how so hopefully my explanation will clear up the confusion others may have for all these years on the Cello Amati speakers.

Minh Luong

mluong303@aol.com

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" ... Meanwhile another high-end giant was doing his part for the Audio Preservation Society. Mark Levinson, the man created by many as having invented the modern high-end movement, added a line of speakers to his Cello range, the first based on a near-forgotten model from one of the most venerable of all hi-fi brands: Acoustic Research's AR-LST. You have to be old enough to remember the days of Labour governments to recall this product, known for staggering performance which couldn't be accessed by the amplifiers of the day. Levinson revived the LST, knowing that the modern amplifiers such as his Cellos could milk the speaker for all it was worth. And, to everyone's surprise, Acoustic Research was more than happy to let this crazed audio maven raid its parts bin. "

by Ken Kessler of Hi-Fi News & Record Review

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Dear Minh,

I’ve been away for a few days, so I’m just now getting back to check messages, etc. I have commented below on your post regarding the Amati.

[You said] “I am going to break apart you post and answer to what you said and hopefully this will clear up the misconception of people who have a hard time understanding the Cello Amati speakers.”

[You said] “No problem, I don't get upset but willing to listen and learn if there is anything I had missed? I want to find out where the discrepancy was! I would like to present what I know and to set things straight so to stop the people who love to copy what you said and spread the wrong info to mislead others.”

Minh, I know you are passionate about the Levinson-Amati speakers, and that is great. There is no intention whatsoever on my part to “mislead others or spread the wrong,” as you say. But in my opinion, the original price of the Amati speaker (wasn’t it between $10,000 and $15,000 per pair at the time?) was excessively expensive, especially considering the performance level, which may or may not have been lower than the AR-LST. Even the Amati speaker stand ($5,000 I believe) was more than four-times as expensive as the original AR-LST speaker pair! How can that be justified? I have *never* seen response graphs or objective test reports on the Amati speaker -- so I would simply ask you to provide whatever evidence you can give that the Amati was equal to or an improvement over the AR-LST. As you know, the LST was tested extensively in AR’s reverberant and anechoic chambers, and its performance was quantified with results that were widely published throughout the world. Its level of performance was therefore established over time, not merely by people bragging about it, but by objective reports and measurements. A lot of people did not like the LST, and it had its share of criticism, but at least it was tested and measured carefully. I don’t recall ever seeing a single test report or response graph on the Amati or the Amati Pro, and that is where I ask you to help me out by supplying some documented evidence of that speaker’s performance.

[You said] “The Cello Amati speakers have never used stock AR-10Pi/AR9 coated soft dome tweeters since day one but instead they were special ordered paper dome tweeter with butyl latex/coated fabric suspension with embedded ferro fluid for high power handling but with the off-axis dispersion characteristic of the original AR-3a tweeter. The midranges were ferro fluid filled as well compare to the none ferro fluid filled midranges in the original AR-LST therefore the Cello Amati speakers actually can handle even higher power than the original AR-LST speakers and the dispersion characteristic is basically the same for both models. The later Cello Amati Pro also used 3/4" coated soft dome Dynaudio tweeters (not the larger 1"+ tweeter as you may think, see attached photos for the difference) so to preserve as much of the dispersion characteristic as the AR drivers Amati but the crossover were totally changed due to the introduction of the more expensive Dynaudio drivers to kick it up a notch.”

I guess I stand corrected on the issue of the tweeter used on the first Amati; it looks very similar to the “B” generation AR-10Pi/AR-11 tweeter. However, it would be helpful to me to see a high-resolution image of this tweeter (close-up) to see how the paper dome was integrated with a cloth suspension, as you describe. By the way, the second-generation Amati Pro ¾-inch coated soft-dome Dynaudio tweeter is inferior in dispersion to the hard-dome AR-3a-style tweeter for two reasons: 1) soft-dome designs don’t respond as well off-axis as hard-dome tweeters and 2) the Dynaudio tweeter is recessed in a small “semi-horn” type appendage which enhances on-axis efficiency at the expense of off-axis response. The soft-dome “semi-horn” approach isn’t wrong, per se; it is the modern way to manufacture dome tweeters these days, as dispersion is less important to contemporary speaker-driver engineers as on-axis sensitivity. For Levinson to “kick it up a notch,” makes me wonder why you would want to take a basically flat-response speaker (the original AR-LST) and make it even brighter. Does that make it more accurate? The definition of accuracy is the faithful recreation of the original sound, not adding to or subtracting from the original program source.

[You said] “I imagine these insiders must be hard cored Roy Allison followers and will not give Mark Levinson any credit but making judgement based on their personal believe and what they think. I used to be one of these people myself for many years but eventually feel I should let go my blind following and personal assumption but to find out the real truth. But then I could be wrong about this so please let me know who said that if you don't mind!”

The comment regarding the LST’s performance compared to the Amati was made during one of the long-past Chicago CES Shows by a respected industry insider and a member of the Boston Audio Society, but I have *no* intention of naming any names! The comments were made “off the cuff,” and were only comments of people who had made comparisons of the AR-LST and the original Amati speakers. I felt the comments had credibility, but I never thought much more about it.

[You said] “Is the b&w AR-LST picture shown the picture you mention about Victor Campos experiment of soft dome tweeters on the AR-LST? This is a technical drawing and beautiful rendering but not a true photograph at all. Hopefully Victor Campos can tell us what he did or had found out in the experiment with the AR-10Pi tweeters on the AR-LST speakers if such test had been done?”

No, you are looking at the wrong picture (see attachments).

--Tom Tyson

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Hi Tom

"There is no intention whatsoever on my part to “mislead others or spread the wrong,” as you say."

I didn't said it was you but the people who love to copy what you said and spread the rumor that really steer others who know less off track. Anyway, I had said all I could and know how and not planing to go any further in term of showing proofs and graphs since I have none on hands! I have nothing to do with Mark Levinson and he is not my God neither! I just being honest and said what I know and express myself clearly as personal experience for owning both the AR-LST and Cello Amati speakers so people know what they are. I used to own 7 pairs of AR-LST speakers so that if you want to say I am passionate, it was about AR-LST and not Cello Amati speakers. I have never bad mouth about the AR-LST or try to promote the Amati speakers. The bottom line is, It was totally a personal preference of mine and that is all it came down to.

The pictures you attached seems like the picture of the back of the AR-LST brochure I scan the front of. It was really dark and small and I can hardly see anything! So much for high resolution scans!

The original price for the Cello Amati was $10000 with AR drivers and $16500 for the Amati Pro with Dynaudio drivers and Paul Jayson was the designer for the Amati Pro(Sorry for miss-spelled his last name in the previous post!)

Tom, a friend is more I need in life than a pair of speakers no matter how much they Cost!

Minh Luong

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Dear Minh,

I’ve been away for a few days, so I’m just now getting back to check messages, etc. I have commented below on your post regarding the Amati.

[You said] “I am going to break apart you post and answer to what you said and hopefully this will clear up the misconception of people who have a hard time understanding the Cello Amati speakers.”

[You said] “No problem, I don't get upset but willing to listen and learn if there is anything I had missed? I want to find out where the discrepancy was! I would like to present what I know and to set things straight so to stop the people who love to copy what you said and spread the wrong info to mislead others.”

Minh, I know you are passionate about the Levinson-Amati speakers, and that is great. There is no intention whatsoever on my part to “mislead others or spread the wrong,” as you say. But in my opinion, the original price of the Amati speaker (wasn’t it between $10,000 and $15,000 per pair at the time?) was excessively expensive, especially considering the performance level, which may or may not have been lower than the AR-LST. Even the Amati speaker stand ($5,000 I believe) was more than four-times as expensive as the original AR-LST speaker pair! How can that be justified? I have *never* seen response graphs or objective test reports on the Amati speaker -- so I would simply ask you to provide whatever evidence you can give that the Amati was equal to or an improvement over the AR-LST. As you know, the LST was tested extensively in AR’s reverberant and anechoic chambers, and its performance was quantified with results that were widely published throughout the world. Its level of performance was therefore established over time, not merely by people bragging about it, but by objective reports and measurements. A lot of people did not like the LST, and it had its share of criticism, but at least it was tested and measured carefully. I don’t recall ever seeing a single test report or response graph on the Amati or the Amati Pro, and that is where I ask you to help me out by supplying some documented evidence of that speaker’s performance.

[You said] “The Cello Amati speakers have never used stock AR-10Pi/AR9 coated soft dome tweeters since day one but instead they were special ordered paper dome tweeter with butyl latex/coated fabric suspension with embedded ferro fluid for high power handling but with the off-axis dispersion characteristic of the original AR-3a tweeter. The midranges were ferro fluid filled as well compare to the none ferro fluid filled midranges in the original AR-LST therefore the Cello Amati speakers actually can handle even higher power than the original AR-LST speakers and the dispersion characteristic is basically the same for both models. The later Cello Amati Pro also used 3/4" coated soft dome Dynaudio tweeters (not the larger 1"+ tweeter as you may think, see attached photos for the difference) so to preserve as much of the dispersion characteristic as the AR drivers Amati but the crossover were totally changed due to the introduction of the more expensive Dynaudio drivers to kick it up a notch.”

I guess I stand corrected on the issue of the tweeter used on the first Amati; it looks very similar to the “B” generation AR-10Pi/AR-11 tweeter. However, it would be helpful to me to see a high-resolution image of this tweeter (close-up) to see how the paper dome was integrated with a cloth suspension, as you describe. By the way, the second-generation Amati Pro ¾-inch coated soft-dome Dynaudio tweeter is inferior in dispersion to the hard-dome AR-3a-style tweeter for two reasons: 1) soft-dome designs don’t respond as well off-axis as hard-dome tweeters and 2) the Dynaudio tweeter is recessed in a small “semi-horn” type appendage which enhances on-axis efficiency at the expense of off-axis response. The soft-dome “semi-horn” approach isn’t wrong, per se; it is the modern way to manufacture dome tweeters these days, as dispersion is less important to contemporary speaker-driver engineers as on-axis sensitivity. For Levinson to “kick it up a notch,” makes me wonder why you would want to take a basically flat-response speaker (the original AR-LST) and make it even brighter. Does that make it more accurate? The definition of accuracy is the faithful recreation of the original sound, not adding to

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Dear Minh,

I’ve been away for a few days, so I’m just now getting back to check messages, etc. I have commented below on your post regarding the Amati.

[You said] “I am going to break apart you post and answer to what you said and hopefully this will clear up the misconception of people who have a hard time understanding the Cello Amati speakers.”

[You said] “No problem, I don't get upset but willing to listen and learn if there is anything I had missed? I want to find out where the discrepancy was! I would like to present what I know and to set things straight so to stop the people who love to copy what you said and spread the wrong info to mislead others.”

Minh, I know you are passionate about the Levinson-Amati speakers, and that is great. There is no intention whatsoever on my part to “mislead others or spread the wrong,” as you say. But in my opinion, the original price of the Amati speaker (wasn’t it between $10,000 and $15,000 per pair at the time?) was excessively expensive, especially considering the performance level, which may or may not have been lower than the AR-LST. Even the Amati speaker stand ($5,000 I believe) was more than four-times as expensive as the original AR-LST speaker pair! How can that be justified? I have *never* seen response graphs or objective test reports on the Amati speaker -- so I would simply ask you to provide whatever evidence you can give that the Amati was equal to or an improvement over the AR-LST. As you know, the LST was tested extensively in AR’s reverberant and anechoic chambers, and its performance was quantified with results that were widely published throughout the world. Its level of performance was therefore established over time, not merely by people bragging about it, but by objective reports and measurements. A lot of people did not like the LST, and it had its share of criticism, but at least it was tested and measured carefully. I don’t recall ever seeing a single test report or response graph on the Amati or the Amati Pro, and that is where I ask you to help me out by supplying some documented evidence of that speaker’s performance.

[You said] “The Cello Amati speakers have never used stock AR-10Pi/AR9 coated soft dome tweeters since day one but instead they were special ordered paper dome tweeter with butyl latex/coated fabric suspension with embedded ferro fluid for high power handling but with the off-axis dispersion characteristic of the original AR-3a tweeter. The midranges were ferro fluid filled as well compare to the none ferro fluid filled midranges in the original AR-LST therefore the Cello Amati speakers actually can handle even higher power than the original AR-LST speakers and the dispersion characteristic is basically the same for both models. The later Cello Amati Pro also used 3/4" coated soft dome Dynaudio tweeters (not the larger 1"+ tweeter as you may think, see attached photos for the difference) so to preserve as much of the dispersion characteristic as the AR drivers Amati but the crossover were totally changed due to the introduction of the more expensive Dynaudio drivers to kick it up a notch.”

I guess I stand corrected on the issue of the tweeter used on the first Amati; it looks very similar to the “B” generation AR-10Pi/AR-11 tweeter. However, it would be helpful to me to see a high-resolution image of this tweeter (close-up) to see how the paper dome was integrated with a cloth suspension, as you describe. By the way, the second-generation Amati Pro ¾-inch coated soft-dome Dynaudio tweeter is inferior in dispersion to the hard-dome AR-3a-style tweeter for two reasons: 1) soft-dome designs don’t respond as well off-axis as hard-dome tweeters and 2) the Dynaudio tweeter is recessed in a small “semi-horn” type appendage which enhances on-axis efficiency at the expense of off-axis response. The soft-dome “semi-horn” approach isn’t wrong, per se; it is the modern way to manufacture dome tweeters these days, as dispersion is less important to contemporary speaker-driver engineers as on-axis sensitivity. For Levinson to “kick it up a notch,” makes me wonder why you would want to take a basically flat-response speaker (the original AR-LST) and make it even brighter. Does that make it more accurate? The definition of accuracy is the faithful recreation of the original sound, not adding to or subtracting from the original program source.

[You said] “I imagine these insiders must be hard cored Roy Allison followers and will not give Mark Levinson any credit but making judgement based on their personal believe and what they think. I used to be one of these people myself for many years but eventually feel I should let go my blind following and personal assumption but to find out the real truth. But then I could be wrong about this so please let me know who said that if you don't mind!”

The comment regarding the LST’s performance compared to the Amati was made during one of the long-past Chicago CES Shows by a respected industry insider and a member of the Boston Audio Society, but I have *no* intention of naming any names! The comments were made “off the cuff,” and were only comments of people who had made comparisons of the AR-LST and the original Amati speakers. I felt the comments had credibility, but I never thought much more about it.

[You said] “Is the b&w AR-LST picture shown the picture you mention about Victor Campos experiment of soft dome tweeters on the AR-LST? This is a technical drawing and beautiful rendering but not a true photograph at all. Hopefully Victor Campos can tell us what he did or had found out in the experiment with the AR-10Pi tweeters on the AR-LST speakers if such test had been done?”

No, you are looking at the wrong picture (see attachments).

--Tom Tyson

I think Mark Levinson was an early experiment which proved that audiophiles would pay big money for the prestige brand cache even if there was nothing substantive in either engineering or materials which justified those prices. The entire high end audio mystique is built around this now long proven fact that many people think that if something costs more to buy and is carefully marketed, it must be better. There is no reason to believe that the European made drivers are superior or even equal to the AR manufactured drivers but because Amati/Levinson said they were, there were more than enough people willing to pay for them. Funny how this is always justified as "research" when in fact it is invariably nothing than laughable tinkering and marketing when compared to what real scientific research and engineering are about. In recent years, it seemed to me that excluding the box, you could reverse engineer many high end loudspeaker systems for around 5% or less and certainly under 10% of their manufactured cost by simply buying the drivers at retail. What's more, the crossover networks could be made equal or superior using off the shelf active crossovers and multi-amplification than the passive designs ordinarily employed. Most of the drivers are either off the shelf or minor variants of off the shelf units so that when replacements are needed, the speaker system manufacturer becomes the sole source and can charge what he pleases. I'm talking about TOTL speakers from companies like Von Schweikert and Wilson which cost over $100,000. Frankly, whether objectively or subjectively judged I would expect the AR equipped driver version of the Cello Amati/LST to outperform the foreign made driver version but that's just a guess. Certainly we have discussed the inferiority of the semi-horn loaded dome tweeters in terms of dispersion before and this seems exactly correct but the very purpose of the design of LST was to devise a speaker system which further improved the lateral dispersion of AR3a's already excellent dispersion, otherwise why not just build it as another rectangular prism? This is why the HiVi tweeter cited in the other posting is no match for the AR3a/LST tweeter. The graphs linked in that posting tell the story. The HiVi tweeter is down 8db at 15 khz 30 degrees off axis compared to its on axis response (84 vs 92) while the AR tweeter is down only 5 db 60 degrees off axis. By comparison, the HiVi essentialy fires most of its top octave as a narrow beam. One would expect a considerable change in tonal balance as one moves in a circle from one extreme at 180 degrees left of the speaker to the center to 180 degrees to the right from an LST using the HiVi replacement tweeters compared to one with the original AR manufactured tweeters. I'd also expect the possibility of reflected hot spots from high frequency reflectons off the side walls as a consequence of the inner and outer tweeters' beaming characteristics.

I would like to have been a fly on the wall the first time Sidney Harman got the amplifier design teams from Mark Levinson and Crown in the same room after he owned both companies and asked them to debate why a Mark Levinson amplifier should cost five to ten times as much as a comparably performing Crown amplifier. What a heated argument that must have been. Of course, Sidney Harman would have no problem raking in all those extra windfall profits on the Levinson units if people were still willing to pay the price. (Would you trade your Crown Reference amp for a Levinson? I wouldn't.) If there's one thing Sidney is fond of, it's big profits. :rolleyes:

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  • 2 weeks later...

The main reason I choose the Cello Amati over the AR-LST was due to all drivers, crossover components and cabinets are 20 years younger so they will definitely last much longer than the original AR-LST for my music enjoyment. I dislike the extra fuse, auto transformer and step dialer and the huge cap that is no longer necessary in today amplifier technology(that was why I ask Roy Allison if I can get rid of them all together in early '90?) I did save my last pair of AR-LST for serious break apart operation but at the end just give up on it since I don't want to kill the historical valued AR-LST just for my own curiosity...! AR did help Mark Levinson to built the tweeters, midranges and woofers. Alex Barsotti did see Mark many times during those years in AR factory in MA...

Minh Luong

post-101112-1202426845.jpg

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  • 3 years later...

I just located this letter from Mr. Roy Allison to me in December 2000 and would like to share his answers to everyone who love his speakers. My questions to Mr. Allison were:

1. The original AR-LST has 5000uF capacitor and later changed to 2500uF. What was the advantage to the sound?

2. I really would like to get rid of the fuse, 5000uF / 2500uF cap, six position switch to flat frequency response and the auto transformer in the AR-LST crossover since all these parts have their own problem associate with aged! Is it safe for me to do that? Will it matter if I place the 6uF and 40uF capacitors at the positive input terminal instead of the negative terminal as shown?

3. The Pots in the AR-3a as well as many other AR speakers in that era often being Oxydized by moisture and polluted air. They would never work as new even being stripped apart to fully polished and lubricated. Is it safe to by-pass them? If not what resistors should I use to get the flat frequency response for both the midrange and tweeter?

Minh Luong

Hi Minh

I was very happy to read all of this tonight.

Very gracious of Roy Allison to even remember and be willing to share all this so many years after leaving AR.

He was MR AR when he was there for sure.

I believe because of his excellent communication with me that I fell in love with all AR products.

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  • 1 month later...

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