Personal Reviews

[frankmarsi]

Any one see this? I'm sure some one has, or am I too late?

http://www.polkaudio.com/forums/archive/in...hp/t-12475.html

I'm sure some have seen this?

http://www.stereophile.com/loudspeakerreviews/995ar/

Just staying in touch with you guys.

FM

P.S. I'm still sick over my LST tweeter replacement problem. I don't want the overly aggressive sound of the AB tech replacements of which I foolishly bought 18 of 2 years ago in a dull moment of AR tweeter panic, and I don't need the related weaknesses, but great sounding originals which are more rare than ever before and can't handle my power demands.

Any newer members with any suggestions?

FM

[johnieo]

Ken Kantor is currenly working on a tweeter crossover design for the AB-Tech replacement tweeter. Many including you have found it not to sound at all like the original AR-3a tweeter with the original crossover. The AB-Tech is more sensitive and has a big resonance peak below the crossover frequency.

When Ken is finished, you might consider trying that crossover modification and seeing how it sounds. The LST tweeter crossover is similar to the AR-3a, but with four drivers in a series/parallel arrangement in series with the same 6-uF capacitor as in the AR-3a.

Cheers,

[RoyC]

Frank,

John beat me to the post :-)!

Hang in there, your purchase was not in vain.

At the moment I am listening to a pair of modified 3a's that John and I have collaborated on for use with those tweeters, while awaiting further guidance from Ken. Even at this point they sound quite nice, like a slightly "crisper" version of the originals to me...and as you know, I was NOT a fan of the AB Tech tweeter to begin with.

You will have no choice but to dig into your cabinets, but I promise you won't regret the outcome. A few crossover changes and additions are absolutely required to tame the beast.

Roy

[soundminded]

>P.S. I'm still sick over my LST tweeter replacement problem. I

>don't want the overly aggressive sound of the AB tech

>replacements of which I foolishly bought 18 of 2 years ago in

>a dull moment of AR tweeter panic, and I don't need the

>related weaknesses, but great sounding originals which are

>more rare than ever before and can't handle my power demands.

>Any newer members with any suggestions?

>FM

>

OK, while you're waiting for the second coming, here's an idea that you can try that probably won't satisfy you but it is cheap and easy and will do something. It will roll off the high end. Try adding various capacitors right across the speaker input terminals. You can do this at the amplifier output if it's more convenient (probably is if your speakers are hanging on a wall) or anywhere in between. I'd get a pair of each of the following values, 1/2, 1, 2, and maybe a 4. all are 100 volt non polarized and are in microfarads. If you buy the regular cheapo NPCs like I do, this shouldn't set you back more than about $2 or $3 plus shipping from Parts Express. Since the equivalent capacitance is the sum of capacitors in parallel, start with 1/2 mfd and then go up in 1/2 mfd increments. If you try it, let me know what happens. Your other alternative which will give you far more control is a 1/3 octave equalizer (27 or 30 band.) That will set you back probably about $125 to $200 or so. BTW, if you try the equalizer and get exactly the response you want but are one of those guys whose religion forbids the use of equalizers on Sunday, Monday, Tuesday...., once you have the response curve you want, an equivalent passive circuit can be engineered for the crossover network to give the same results without an equalizer. Don't be surprised if it takes a lot of parts to do it though.

[kkantor]

Hey, this is all finished, and I thought James (at my lab) sent it out some time ago. I'll look into this Monday. Meanwhile, feel free to discuss details here. The 2nd-Order we came up with is a go!

-k

www.kenkantor.com

http://kkantor.spaces.live.com

[soundminded]

Having had many exchanges with John Atkinson on another web site, I make no apologies for saying that I do not like or trust him or his magazine and I do not usually read it. I've certainly never paid money for it. However, taking its review of AR 303 at face value it appears to have a 5 db peak at its system resonance frequency which seems to me to be around 60 hz from the graph. This is not at all consistant with AR1/AR3/AR3a/AR10pi which are flat to resonance at 42 hz and I can hardly believe this peak and higher fs is the design intent of AR 303. If this is real, it may be due to a difference in the stuffing. Was it fiberglass? Even the tightness of the packing and the diameter and length of the fibers can affect system Q and fs and if it is a different material, well that would also change things a lot. Was this the same driver used in other AR 12" bookshelf speaker systems? Also uncharacteristic is the reported lack of clarity in the upper bass. I'm also at a loss to understand the high frequency rolloff. If this is the same tweeter used in AR3a something is very wrong with the waterfall diagram especially in light of AR3a tweeter's remarkable dispersion which as Tom pointed out is only down 5 db 60 degrees off axis at 15 khz. I still cannot find another tweeter which comes even remotely close. I also don't understand the suckout he described which I assume refers to a cancellation trough in the midrange tweeter crossover region. He specifies it as down 23.32 db 45 degrees off axis at 5682 hz. If that is real, what was the purpose of the vertical alignment of the drivers? The results are also inconsistent with AR3s demonstrated ability to perform well on live versus recorded demonstrations, AR303 presumably being an even more accurate reproducer. Since we have the designer available here, perhaps he would care to comment on the data in this review. Perhaps Stereophile's test set up is flawed. If so, this would invalidate every other measurement they report. That would not come as a surprise to me if it is true.

[ToastedAlmond]

That was my initial response over at the Polk Audio Forum.

Yours truly,

GG (of the Jersey Grands)

[dynaco_dan]

>Having had many exchanges with John Atkinson on another web

>site, I make no apologies for saying that I do not like or

>trust him or his magazine and I do not usually read it. I've

>certainly never paid money for it. However, taking its review

>of AR 303 at face value it appears to have a 5 db peak at its

>system resonance frequency which seems to me to be around 60

>hz from the graph. This is not at all consistant with

>AR1/AR3/AR3a/AR10pi which are flat to resonance at 42 hz and I

>can hardly believe this peak and higher fs is the design

>intent of AR 303. If this is real, it may be due to a

>difference in the stuffing. Was it fiberglass? Even the

>tightness of the packing and the diameter and length of the

>fibers can affect system Q and fs and if it is a different

>material, well that would also change things a lot. Was this

>the same driver used in other AR 12" bookshelf speaker

>systems?

Hi there;

I do not agree with your comment here in part only, Soundminded.

It is too bad that the original Cambridge AR anechoic chamber was not available for the AR-303 woofer, etc test as well.

I did subscribe to Stereophile magazine for several years during the mid-late '90's.

I did not know anyone who could afford their recommended high-end products, at least, not in my life.

Honestly, I could not afford the lowest reviewed annual product each year, with two exception's, Marantz CD-63SE cd player and PBJ Kimber Cables.

I am sure that there was and is hifi buffs that can afford them though.

I do remember reading that one of their staff did not like either one or the other, either the AR-3A or AR-LST, but had never actually heard them, if my withering memory serves me right.

I read a few small articles that John Atkinson wrote.

I think he is also a musician to some degree.

He may be biased, as I am also.

I personally would love to sit down and have a simple hifi discussion with him, if that was possible.

Also with our own, Ken Kantor.

Also uncharacteristic is the reported lack of

>clarity in the upper bass. I'm also at a loss to understand

>the high frequency rolloff. If this is the same tweeter used

>in AR3a something is very wrong with the waterfall diagram

>especially in light of AR3a tweeter's remarkable dispersion

>which as Tom pointed out is only down 5 db 60 degrees off axis

>at 15 khz. I still cannot find another tweeter which comes

>even remotely close. I also don't understand the suckout he

>described which I assume refers to a cancellation trough in

>the midrange tweeter crossover region. He specifies it as

>down 23.32 db 45 degrees off axis at 5682 hz. If that is

>real, what was the purpose of the vertical alignment of the

>drivers? The results are also inconsistent with AR3s

>demonstrated ability to perform well on live versus recorded

>demonstrations, AR303 presumably being an even more accurate

>reproducer. Since we have the designer available here,

>perhaps he would care to comment on the data in this review.

>Perhaps Stereophile's test set up is flawed. If so, this

>would invalidate every other measurement they report. That

>would not come as a surprise to me if it is true.

[soundminded]

You can converse all you like with John Atkinson at the Audio Asylum mostly on the section called "Critic's Corner." Personally I no longer post on that site and haven't for some time now. Keep in mind that both the site and John Atkinson are in the business of promoting among other things very expensive and exotic products of highly dubious value such as audiophile wires. The first time I saw a Stereophile magazine in the early 80s they didn't even have measurements in it. You are right about them favoring products which are very expensive. Since my experience with these is that they at best only offer marginal improvement over far cheaper alternatives and therefore a poor value for money, they don't interest me. Even the cheaper products they review strike me as offering a poor value for money. I also don't consider myself an audiophile and so am not taken with most of the advertising hyperbole which has guided the thinking of many who are and those who sell to them.

Atkinson's own positions are often difficult to understand in terms of rational logic. For example, he says that when he masters a recording he will sit for hours at a work station using a 64 band digital equalizer tweaking his recordings so that they are within one tenth of a decibel of what he considers ideal but when listening to a recording, he would not so much as nudge a bass or treble control to tame a shrill or boomy recording. In fact I'm sure the type of equipment he listens to doesn't even have a bass or treble control or any like thing. Go figure.

I consider Stereophile Magazine very inferior to the consumer hobbyist audio magazines I used to read many years ago, Stereo Review, High Fidelity Magazine, and Audio Magazine. I respect all three of their laboratories for their reliable work, Hirsch Houck Labs which tested for Stereo Review, CBS Technology Center which tested for High Fidelity, and Audio Magazine's own laboratory. Reports like the one cited for AR 303 give me reason to wonder just how accurate their reports are. Hopefully, the designer will comment on their test results.

[roundhome]

ok ? if you have two speakers with old tweeters and you placed new ones in two other speakers and made the crossove mod would they sould close enough in a quad set up

Jim

[dynaco_dan]

Hi Jim;

I believe that Ken Kantor has some important information coming up in a few days that may answer that exact question for you.

Standby please.

[ToastedAlmond]

When the venerable Len Feldman died, and his estate made some of his electronics available, I felt it was a great opportunity to really pick-up a piece of audio history. I contacted his wife and managed to buy a pair of Auratone 5c's, that I would hope were on his test bench for years and years performing test duties.

I'm not sure I'd EVER be in a big rush to own anything that was owned by ANY of the Stereophile reviewers. No history there.

[RoyC]

...just dug out a Julian Hirsch/Hirsch-Houck Laboratories review of the AR 303 that appeared in a June '95 Stereo Review magazine.

In a head to head comparison with the AR-3a, the AR 303 compared very favorably.

Some excerpts:

"..we are indebted to collector Thomas Tyson for the loan of a pair of virtually mint-condition AR-3a speakers for comparison with the new models, both in listening and measurement."

"Not surprisingly, there were more similarities than differences...composite response curves were amazingly alike. The AR-303 had significantly flatter response at the high frequencies, however, about 3 to 5db stronger than the AR-3a above 6khz."

"There was no doubt that the two were close relatives in the bottom octaves. In fact, their was little or no audible difference between them in the deep bass."

"The AR 303's woofer was true to its heritage, producing only 5.5 percent harmonic distortion at 20Hz with a 90db sound-pressure level (the AR-3a and my old AR-1 were in the same range, generating around 6 percent distortion)."

"The AR 303 can deliver a clean, ear-popping output all the way down to 20Hz....Certainly no other current full-range speaker that I know of in the AR-303's size range can match its low-frequency capabilities."

"The AR 303, with a pedigreed descent from the earliest acoustic-suspension loudspeakers, is not only a fine reproducer, but a bargain as well."

All in all a very interesting and enjoyable article for 3a and 303 fans.

Roy

[soundminded]

This review is entirely at odds with Stereophile's review. It only makes sense that a modernized version of a venerable older design would show only improvement retaining all of the virtues of its predecessor. This is one reason why I have no respect and give no credibility to Stereophile's reviews or opinions. So whose facts and opinions should I trust, Julian Hirsch's or John Atkinson's? Are you kidding? BTW, when Stereo Review, High Fidelity Magazine, and Auidio Magazine reviewed the same products, their results were usually remarkably similar, both in their measured performance laboratory data and their expressed opinions.

[soundminded]

This review is entirely at odds with Stereophile's review. It only makes sense that a modernized version of a venerable older design would show only improvement retaining all of the virtues of its predecessor. This is one reason why I have no respect and give no credibility to Stereophile's reviews or opinions. So whose facts and opinions should I trust, Julian Hirsch's or John Atkinson's? Are you kidding? BTW, when Stereo Review, High Fidelity Magazine, and Auidio Magazine reviewed the same products, their results were usually remarkably similar, both in their measured performance laboratory data and their expressed opinions.

[Carlspeak]

Here are some much earlier posts regarding the AR303 which may add to the current dicsucsion or, refresh some memories.

enjoy!

http://www.classicspeakerpages.net/dc/dcbo...ing_type=search

It's all about the music

Carl

Carl's Custom Loudspeakers

[soundminded]

According to Stereophile's data, despite the local impedence maximum at around 38 or 39 hz, the maximum acoustical output is clearly at 60 hz. This is the true system resonance frequency according to the graph but it makes no sense. The graph is also clearly for an underdamped system atypical for AR speakers. The well known linear falloff below resonance begins at almost exactly 60 hz, not 39 hz.

"In the bass—measured in the nearfield with the microphone capsule almost touching the woofer dustcap—there's a moderate rise in the midbass"

Aren't these measurements usually made at one meter from the speaker? Do we have a case of the well known "proximity effect" distorting the microphone's measurement? It looks like that might be the case. (It is a fact that bass frequency response for microphones increases when the source of sound is very close to it.)

"There is also a distinct step in the curve just above 1kHz. This kind of response shape would usually be associated with some audible nasality. The 303, however, seemed relatively uncolored, suggesting that the on-axis peak'n'dip is probably compensated for by the opposite behavior off-axis."

This is almost imposible to understand as this step occurs right in the middle of the midrange driver's pass band with no other irregularities. It is also not credible that a drop in response on axis would be accompanied with a rise in response off axis at the same frequency as the reviewer hypothesizes. There are also no abrupt changes or anomolies in the speaker's impedence in this region. What's more there is virtually no change in output in the region of the crossover frequencies where it is more likely to be if there were a problem with this speaker system. The whole thing just doesn't add up.

[frankmarsi]

>Hey, this is all finished, and I thought James (at my lab)

>sent it out some time ago. I'll look into this Monday.

>Meanwhile, feel free to discuss details here. The 2nd-Order we

>came up with is a go!

>

>-k

>

>www.kenkantor.com

>

>http://kkantor.spaces.live.com

Hey Ken, any word from the front?

I'm waiting with high hopes to lift me out of my AB-tech

tweeter regrets.

FM

[frankmarsi]

>Hey, this is all finished, and I thought James (at my lab)

>sent it out some time ago. I'll look into this Monday.

>Meanwhile, feel free to discuss details here. The 2nd-Order we

>came up with is a go!

>

>-k

>

>www.kenkantor.com

>

>http://kkantor.spaces.live.com

Dear Ken Kantor, I'm just wondering if you've had a chance to locate the

paper and information regarding the electrical installation of the AB-tech tweeters in the AR-LST and AR-3a's? As you may have noticed I'm dragging my heels on installing these replacement tweeters in my cabinets until I come about a complete plan to do it correctly.

Any advice and coaxing you can pass-on is greatly appreciated by me and I'm certain other 'site' members.

Respectfully, Frank Marsi

frankmarsi@verizon.net

[frankmarsi]

>>Hey, this is all finished, and I thought James (at my

>lab)

>>sent it out some time ago. I'll look into this Monday.

>>Meanwhile, feel free to discuss details here. The

>2nd-Order we

>>came up with is a go!

>>

>>-k

>>

>>www.kenkantor.com

>>

>>http://kkantor.spaces.live.com

>

>

>Hey Ken, any word from the front?

>I'm waiting with high hopes to lift me out of my AB-tech

>tweeter regrets.

>FM

SECOND MESSAGE 8-6-07

>Hey, this is all finished, and I thought James (at my lab)

>sent it out some time ago. I'll look into this Monday.

>Meanwhile, feel free to discuss details here. The 2nd-Order we

>came up with is a go!

>

>-k

>

>www.kenkantor.com

>

>http://kkantor.spaces.live.com

8-6-07

“Time To Start Thinking Again”.

“No, it would seem that I again want to hit the restart button at 50. Once again undertake a risky and exhausting journey. I must build something yet grander and enduring. I must build on my past, and apply it to social landscapes and problems that excite and concern me. “

Thanks Ken! Profound and prophetic words, I thought I was the only person who felt this way.

My “restart-button” has been in ‘stand-by’ mode for about 57 years just waiting to get going and actually start to feel good about most things to some degree.

Sure, back in ’72 I thought I was the only person in my neighborhood that owned AR-3a’s, AR-Xa and a Dynaco amp and pre-amp, I probably was, -go figure. Who-ever thought there’d be such a thing as “ClassicSpeakerPages” to give me a sense of purpose and belief in the search for justice, truth in listening and ‘The Acoustic Research’ way?

Well Ken, you certainly got my vote for profound view points and or interpretations of life on that level.

Now what ever happened to the ABtech tweeter hook-up parameters for the AR-LST and AR-3a? If I gotta send you some of my home-made pizza dough in repayment, I will!

Just the same, thanks for any help in advance and I will certainly get back to you with my results.

Regarding the more esthetic aspects of life, well lets just say I consume many hours with such thoughts and I’m just talking about AR stuff here to kinda give me a break from all those profundities.

My friend and possibly your future friend too, Frank Marsi

[kkantor]

Thanks, Frank!

All the tweeter measurements and models are done. The write-up is mostly done, too, though work remains to format and label some of the curves.

Several people have seen this work, via private email. This includes John, Roy, Tom, Bret and Minh, all of whom have been very supportive of the project and who have donated time and components.

I think it would be great to start sharing the information here. Of course, I will upload the complete report when it is edited, but that sometimes gets bogged down. Meanwhile, there is plenty of useful data about adapting the AB tweeter, which the others can discuss at length. It can be made to work fairly well, without too much fuss.

-k

PS- It is my observation that many of the things I used to think were very private to me, little secrets, fantasies, tastes, ambitions, impressions, annoyances, shames, theories of everything, turn out to be surprisingly common. Hey, I guess that is why "marketing" works... I hope you run with your dreams or, at least, tip toe towards them.

[RoyC]

Frank,

Attached is an LST schematic from the Library.

I've indicated in red where an inductor and resistor will need to be placed in parallel with the tweeters to make your LSTs more compatible with the AB Tech tweeter. You can begin planning how to tackle your crossovers while Ken tweaks his data.

The single inductor and resistor shown in the first schematic can be substituted with 4 inductors and resistors of the same values in parallel with EACH tweeter, as shown in the second schematic. That approach, while allowing work to be done through the tweeter holes, would be more costly. It would also require care to be taken to install the inductors some distance away from the tweeter magnets to keep the inductors from being affected by them.

It appears the series tweeter capacitor will remain the same (6uf).

At our request, Ken tried to get as close as possible to the original tweeter's performance with minimal crossover changes in order to keep the conversion as simple as possible.

Roy

[dynaco_dan]

Hi there;

Thank you Roy and Ken Kantor for this topic posting.

I believe that you'll find that this is a schematic of AR-LST ver 1 and Frank also has AR-LST's ver 2, if I remember correctly.

Frank should confirm the schematic's colours is the same in the rear entry mounted crossover and Mallory switch as in the later front inserted crossover with the later supplier switch.

It is possible that the later ver 2 had different coloured wires.

Maybe not, I could be wrong.

Also the w-w resistor has not been added on the schematic yet.

This was an add-on by AR on the old blueprint that I had a copy of.

[RoyC]

Vern,

>Frank should confirm the schematic's colours is the same in

>the rear entry mounted crossover

I only used red to show where the added components should be placed in the circuit, not to indicate the color of the wire.

>Also the w-w resistor has not been added on the schematic

>yet.

Where is that located?

Roy

[dynaco_dan]

>Vern,

>

>>Frank should confirm the schematic's colours is the same

>in

>>the rear entry mounted crossover

>

>I only used red to show where the added components should be

>placed in the circuit, not to indicate the color of the wire.

>

>

>>Also the w-w resistor has not been added on the schematic

>>yet.

>

>Where is that located?

>

>Roy

>

Hi Roy;

I only mentioned the wire colours just in case there is a wire colour difference between cabinet versions.

I am only suggesting that these be confirmed prior to anyone quickly just cutting a wire lead inside.

You did a good job of placing identifying locations for Frank.

I lost almost all of data of my own during my last flood, I protected Wally's at least.

I had access to original AR AR-LST blue prints many years ago and the w-w resistor was an add-on afterthought by AR.

I do not remember where it went on the blue print drawing or it's purpose.

I do believe it was at least 10 watt and possibly 10 ohms.

Way back in time, when I first started writing here, I may have mentioned the size and value.