Modern replacements for AR 3A Tweeter / Midranges

[Guest aroostookme]

Hi:

I have a great pair of AR 3A's.

I really am not crazy about the sound or look of the classic tweeters and midranges.

I am wondering if anyone has replaced or knows replacements that work with the AR 3A crossover and are from major suppliers like Vifa, Scan Speak, Seas, Focal, Morel and the like.

If you've done this or know a modern amswer I'd appreciate it. I do not want to replace the tweeter and mid with the AR models.

Thanks.

[ar_pro]

Can I have your tweeters and mids?

[kkantor]

Many people would be happy to trade you various speakers for your 3a's. Why destroy something precious? Why not get a speaker you like, and sell your 3a's to someone who collects or covets them?

Plus, if you really want a platform to experiment with drivers on, there are some boxes which would might be more convenient to work with than your AR's.

One man's opinion....

[Guest palomar]

One thing you might want to consider would be to buy a pair of small, full-range speakers that you really like, place them on top of the ARs, and use the AR's as subwoofers. I don't know if all of the AR3a's let you disconnect the mids and tweeters, but the ones I've seen let you disconnect a wire from a third terminal, and just use the woofer.

You could either get a new set of speakers (I've heard that something like small Paradigms offer excellent sound except for the deep bass), or get a good value on a pair of used speakers that you like.

There are a couple of things that might be an issue. One is that the AR woofers are 4 ohms, so you'd probably need to insert a simple, very low frequency crossover between the AR and full range speakers, otherwise your overall impedance could drop to dangerously low levels for many amps.

And the other issue would be level matching. The ARs, being 4 ohms, are going to draw twice as much power as the full-ranges if they are 8 ohms. Given that the ARs are pretty inefficient, and that we're only talking 3 dB, this might not be a big deal.

This may be more trouble than it is worth to you, but I don't think the cost would be much more than replacing the mids and tweeters - maybe even less if you got a good deal on some used speakers. And the advantage would be that you'd know what the add-on speakers sound like. It would be much harder to assess what the resulting mid and tweeter swaps would sound like until you're done. Plus, you'd still have your original ARs, should you ever decide to sell them.

Gary

[soundminded]

>Can I have your tweeters and mids?

I'd like to bid on your liver and one of your kidneys. :-)

Aroostookme, if you read my thread on competing with professional speaker designers to go them one better, you know you have a tough uphill battle on this one. First of all, from your question, I have to assume you are a tinkerer and not an engineer (which is perfectly OK.) You are competing against a very well engineered product which was the result of over a decade of research and careful calculations, measurements, and manufacturing. To improve on their product, you will need a good understanding of speaker design, lots of patience, and a well trained and practiced ear, especially if you don't have any measuring equipment. There are no drop in replacements or near replacements that I'm aware of. There are dome midranges and tweeters you can buy but you will be hard pressed to find a tweeter with the dispersion of the AR 3/4" unit. Down only 5db 60 degrees off axis at 15 khz, I don't know of any others in that league. Most dome midrange drives are 2" not 1 1/2. And most are 8 ohms. You could put an 8 ohm resistor in parallel with one and the same for an 8 ohm tweeter and hope for the best. Mounting could be a problem too. I think you will need to maintain the box sealed as there isn't a sealed sub enclosure for them and you'll want models with sealed backs to avoid interaction from the woofer's pressure waves. You'll also need a midrange with a very low Fs to match the crossover at 525 hz (or is it 575 hz?)

Personally I think you'd be better off starting from scratch with a woofer like this 12" Dayton model in about a 2 cu ft sealed box.

http://www.partsexpress.com/pe/pshowdetl.c...tnumber=295-464

I'd also add an 8" or 6" lower midrange too. If you damage your AR3as or cannot return them to their original condition, their market value should you decide to sell them would be substantially lessened.

BTW, using the AR3a as a subwoofer only with an outboard speaker is IMO not a good idea unless you modify its crossover point to match the other speaker. A separate subwoofer plate amplifier with an adjustable crossover is one way to do that.

Good luck.

[stan461]

I have replaced the tweeters in AR3as and they sound terrific. I'll post pictures of the tweeters soon. They really work well. Better? Well thats a matter of taste and/or opinion. The old tweeters? I'll just keep them. I don't find that it's the end of the world to swap drivers. Just not a big deal to me.

As I have written before, I have also relaced the crossover capacitors with Solen caps and I can easily hear the improvement. Night and day. That's a no-brainer in my book.

[roundhome]

Hello I would be happy to trade you a pair of nice jbl L100 speakers for your AR3s I like the sound better.

Jim

[Guest denmarkdrivers]

I'm not too farmilliar with AR3a's but im curious, If the drivers surround is rotton how many of you would save the driver?

How many of you would try to find a driver of simular quality and technical value to replace it ?

Are some drivers better suited to be repaired in general ?

My experience with trying to repair drivers is, they never sound the same after a repair.

Could just be the way it was repaired i saposse.

I would have a hard time wanting to save a rotting cone or surround. The AR3a's must be really nice, they also sound like a challange when trying to rehab them to original specs.

[dynaco_dan]

>I have replaced the tweeters in AR3as and they sound

>terrific. I'll post pictures of the tweeters soon. They

>really work well. Better? Well thats a matter of taste and/or

>opinion. The old tweeters? I'll just keep them. I don't find

>that it's the end of the world to swap drivers. Just not a big

>deal to me.

>

>As I have written before, I have also relaced the crossover

>capacitors with Solen caps and I can easily hear the

>improvement. Night and day. That's a no-brainer in my book.

>

>

Hi Stan;

What voltage rating Solen caps did you use, please?

[stan461]

>Hi Stan;

>

>What voltage rating Solen caps did you use, please?

Here is what I purchased :

Item # CP6 6.0 mfd Polypropylene 400V $2.65 Solen

Item # CP50 50.0 mfd Polypropylene 400V $12.90 Solen

Item # M140 140 mfd electrolytic 100V $2.75 Bennic

Checking Madisound's website, it looks like the prices have stayed the same.

[dynaco_dan]

>Here is what I purchased :

>

>Item # CP6 6.0 mfd Polypropylene 400V $2.65 Solen

>Item # CP50 50.0 mfd Polypropylene 400V $12.90 Solen

>Item # M140 140 mfd electrolytic 100V $2.75 Bennic

>

>

>Checking Madisound's website, it looks like the prices have

>stayed the same.

Hi Stan;

Thank you very much for the complete and detailed listing of the caps, Stan.

The reason I asked for the voltage rating is, somewhere in the recent past, I read, that there was an audible difference, good or bad I don't remember, in the same brand and value caps, but different voltage rating.

I can't be certain, but, I believe it was the Solen brand.

I did write a few months ago about a suggested cap swapout with an AR-4X, because of it being an established, referrence standard and recognized speaker system.

I could have also mentioned either AR-6, KLH SIX, Larger Advent, EPI 100, Dynaco A-25 or other 2 way speaker system.

My point was not the particular speaker, but, a simple 2 way system using different replacement caps.

If a replacement cap for a speaker is needed, then a brief audible test by a member of several readily different branded available capacitors, a reasonable sonic evaluation and opinion posted would be welcomed by all, I am sure.

I would love to do such a test, but, Solen is basicly the only brand available here, and to order anything from the US is very costly.

I also don't have the disposible income like I used to.

If the tweeter cap was out of the circuit and the contact points brought out through the woofers putty trough, a switch or switches could be also used to switch between the different caps as well.

A 3 way system adds too many variables for ths initial report, but that would be another interesting challenge afterwards.

In other words, if Solen caps in particular were considered to offer an increased improvement over several other tested caps, then a referrence standard would be available, for now.

A standard product which is probably more worldly available, rather than a super exotic expensive cap, and limited availablity to a smaller group.

If the, super exotic cap, happened to be the chosen preferred cap, then we would have a preferred list to make our choices from.

As I have read in just Stereophile magazine alone, over the years, sometimes speaker systems initially sounded just awful right out of the box.

A week or two, with speakers face to face, out of phase, being fed signals to break in the speaker and or caps, altered the sound quality, for the better.

Perhaps this is the capacitor forming, I don't know this technical aspect enough, to comment further.

If a few members agreed, that when, Solen, or whichever brand, 6.0 uf - 400 v P-P caps, were definitely the ones that gave the highs the most clarity and openness, for example.

[stan461]

I will get another chance to test the re-capping shortly.

I have a pair of large Advents that are pretty harsh on the top end. Let me see if a Solen re-cap helps them.

I think Solen caps are just fine. The old caps were those wax jobs. They were 30+ years old and I have to believe there must be some improvement in capacitor manufacturing in the last 30 years.

[tysontom]

>I have a pair of large Advents that are pretty harsh on the

>top end. Let me see if a Solen re-cap helps them.

Stan,

I don't believe that crossover caps will entirely fix the "harsh-on-the-top-end" problem. The original Advent tweeter had some roughness in the high-frequency region that accounted for some of that problem. An "independent" (shall remain nameless) anechoic test of the Advent tweeter done in 1974 showed good smoothness from 800 Hz to about 2 kHz, with a broad 3 dB rise up to 3150 Hz. After this point response fell steadily at 3.5 dB out to 12,500 Hz, with two dips and peaks separated by 8 dB each in the area above 7 kHz with the tweeter on axis and mounted in a flush baffle radiating into 180 degrees anechoic solid-angle. The response was down 10 dB at 20,000 Hz., on axis. Tests were actually conducted with and without the crossover in place, and the results were similar above approximately 1500 Hz.

The fact that the woofer's response was good, and the midrange smooth, accounts for much of the favorable comment on this speaker, but the tweeter's output in the higher frequencies did have some problems, it seems.

[soundminded]

>>I have a pair of large Advents that are pretty harsh on

>the

>>top end. Let me see if a Solen re-cap helps them.

>

>

>Stan,

>

>I don't believe that crossover caps will entirely fix the

>"harsh-on-the-top-end" problem. The original Advent

>tweeter had some roughness in the high-frequency region that

>accounted for some of that problem. An

>"independent" (shall remain nameless) anechoic test

>of the Advent tweeter done in 1974 showed good smoothness from

>800 Hz to about 2 kHz, with a broad 3 dB rise up to 3150 Hz.

>After this point response fell steadily at 3.5 dB out to

>12,500 Hz, with two dips and peaks separated by 8 dB each in

>the area above 7 kHz with the tweeter on axis and mounted in a

>flush baffle radiating into 180 degrees anechoic solid-angle.

>The response was down 10 dB at 20,000 Hz., on axis. Tests

>were actually conducted with and without the crossover in

>place, and the results were similar above approximately 1500

>Hz.

>

>The fact that the woofer's response was good, and the midrange

>smooth, accounts for much of the favorable comment on this

>speaker, but the tweeter's output in the higher frequencies

>did have some problems, it seems.

Thank you. Now that there is a reason to explain it, I will admit that the few times I heard this speaker I didn't like it and I didn't think it was accurate. Now I know why and the technical explanation confirms what I heard.

BTW, you were right about other manufacturers using a semi horn to one degree or another to load their dome tweeters. I looked through catalogues at dozens and dozens of them and every single one of them had it to one degree or another and because of the way they are made, there isn't much you can do about it. Too bad, it means that in the dispersion department, the AR 3/4" still reigns supreme. 45 years and none better. What does that tell you about the state of this art?

[Steve F]

<

Product design today, especially in the audio industry, is guided more by intent and less by capability. Audio engineers today are at least as well educated as in years past. They still know and obey the same laws of physics and acoustics. And they have far greater diagnostic/measuring/analyzing equipment at their disposal. If today’s dome tweeters don’t disperse as well at 15-20kHz as the 1970’s-era AR dome (and there’s no disputing that the AR dome was superior in that regard), it’s not because today’s engineers are less capable or that the collective technical competence in the loudspeaker industry has somehow slipped in comparison to their counterparts 30 years in the past.

The reason is that there is a different design intent. It’s not because of a lack of execution ability. If the design goal at BA or Klipsch or B&W or anywhere else was to produce a single-tweeter loudspeaker with the widest possible HF dispersion, the advanced engineering and manufacturing capability available today could do it.

But design goals change. The super-wide dispersion, somewhat diffuse-sounding smooth power-response designs of Roy Allison and Ed Villchur were beaten in the marketplace by the more sharply focused, less widely-dispersed designs of AR’s competitors. The disadvantage in retail showroom conditions during A-B comparisons of AR’s wide dispersion products (coupled with AR’s poor sales/marketing policies) compared to the Advents had something to do with it. This has been covered at great length before and I don’t want to waste the readership’s time and space going over that again here.

Then in the 1980’s, the ‘audiophile/imaging’ fad took hold, and super-wide dispersion speakers were “out.” That was a marketing trend, not an engineering limitation. I’m sure the talented, capable folks at, say, ProAc loudspeakers could have done a wide-dispersion speaker if that was their primary intent.

These days, there is something else at play: There is a certain loss of the spirit of “discovery,” if you will, in the speaker business. Back in the 50’s and 60’s, everything was new. It was being discovered for the first time. Low-distortion bass from small enclosures. Wide dispersion, Accurate frequency response. There was an excitement, almost a fever, of doing everything as well as could be done, of pushing the envelope to new limits. I remember when engineers would excitedly discover that they could get an extra 2 Hz of bass extension simply by optimizing the amount and type of stuffing in the enclosure. 2 whole Hz and you’d have thought they had discovered water itself! But that was the mindset back then.

Not any more. Speaker design is so competently and reliably “nailed down” by modern engineering/measuring processes that a very credible bookshelf speaker can be virtually ‘mailed in’ by most good designers. And there are two other very important factors in play now that didn’t exist in the 3a’s day:

1. Convenience, not ultimate quality, is king. Now that playback quality has reached a pretty high default minimum level, it’s convenience that rules. The iPod is an excellent example. Not really as good as a CD, even to so-called untrained ears, but pretty darned good on an absolute basis nonetheless. Do people sample at the highest rate for best quality, even though that means fewer songs will fit? No, they sample at the lowest rate, to fit the maximum number of songs. Know why? Because to the average user, the lowest sampling rate still sounds acceptably good. Far better than their $29 GE clock radio. Good enough so that quality is not the issue. Quality has passed the threshold to where convenience now is paramount. But in 1969, we argued over every subtle difference between the Advent and the 2ax. Not anymore for today’s 25-40 year-old. Convenience is king because quality is more or less automatic and expected.

2. There is so much competition for today’s discretionary hobby/leisure time dollar that audio/sit-at-home music listening is yesterday’s pastime. Now there are computers, DVD, soccer moms, golf, you name it, all manner of activities and distractions that we, as 50-somethings, either didn’t have at all or didn’t have to anywhere near the same degree in the 60’s and 70’s. When was the last time you just sat down on a Saturday afternoon and spent 3 hours listening to music on your system? More importantly, have your adult children EVER done that? No, they haven’t. (At least mine haven’t, and if you’re honest, yours haven’t either.)

Given the current, permanently-changed state of the recreational-time market, and the new and different products used to fill that time, it’s not surprising that the 1970’s AR ¾” dome remains the dispersion champion. It will probably always hold the crown—-but not because today’s engineers are incapable of besting it. They simply have different goals.

Steve F.

[soundminded]

>If today’s dome tweeters don’t

>disperse as well at 15-20kHz as the 1970’s-era AR dome (and

>there’s no disputing that the AR dome was superior in that

>regard), it’s not because today’s engineers are less capable

>or that the collective technical competence in the loudspeaker

>industry has somehow slipped in comparison to their

>counterparts 30 years in the past.

>

>The reason is that there is a different design intent.

Very true.

>These days, there is something else at play: There is a

>certain loss of the spirit of “discovery,” if you will, in the

>speaker business.

Also true, sad but true.

Even within the limited paradyme of a 2 channel stereo system, the speaker still being the weakest element, I think far better speaker designs are possible. And if the day ever comes when they make an appearance, who knows if anyone will even care anymore.

[dynaco_dan]

>I will get another chance to test the re-capping shortly.

>

>I have a pair of large Advents that are pretty harsh on the

>top end. Let me see if a Solen re-cap helps them.

>

>I think Solen caps are just fine. The old caps were those wax

>jobs. They were 30+ years old and I have to believe there must

>be some improvement in capacitor manufacturing in the last 30

>years.

>

>

Hi Stan;

Thank you, Stan.

It wll be interesting to read, whatever changes or differences, if any, you can discern.

[dynaco_dan]

Hi Steve;

An excellent write-up, thank you.

[kkantor]

Good post, Steve. A few brief comments:

1- Trying to get flat power response out of a single 3/4" tweeter is like trying to get half-pregnant. In a truely reverberant environment, there just isn't that much difference between a 3/4" and a 1" over the perceptually relevant frequency range.

2- Often, the goal of a modern tweeter is to make the response MORE even over a certain listening window, at the expense of extreme angles. For example:

http://www.tymphany.com/datasheet/printview.php?id=115

3- Since AR bit the bullet on the efficiency wars, the dome tweeter was a natural. It was difficult for others to duplicate the dispersion of the AR unit without lowering their claimed sensitivity. I'm not saying there wasn't superb engineering behind that tweeter, there certainly was. But, like all commercial successes, the stars have to be aligned.

4- The exact origins of the dome tweeter have long been disputed. For example, Peerless seems to have had a dome tweeter on the market in Europe around the time the AR was launching theirs. Who knows?

[stan461]

Here is what I tried. They work very well. I bought them on EBay and the ad said they were an AR3a replacement. I never looked up the specs. Anyway they came with an adapted which means I didn't have to butcher the cabinet. The pictures should explain better than I can.

[dynaco_dan]

>Here is what I tried. They work very well. I bought them on

>EBay and the ad said they were an AR3a replacement. I never

>looked up the specs. Anyway they came with an adapted which

>means I didn't have to butcher the cabinet. The pictures

>should explain better than I can.

>

>

>

>

>

Hi Stan, thank you;

Nice photos.

I see that it is a 6 ohm impedance tweeter.

In theory it will be maybe 2 db lower in volume that a 4 ohm tweeter.

Maybe with the adapters and a parallel resistor this may be a valuable replacement option.

[Guest gilbertparts]

>I'm not too farmilliar with AR3a's but im curious, If the

>drivers surround is rotton how many of you would save the

>driver?

>How many of you would try to find a driver of simular quality

>and technical value to replace it ?

>Are some drivers better suited to be repaired in general ?

>My experience with trying to repair drivers is, they never

>sound the same after a repair.

>Could just be the way it was repaired i saposse.

>I would have a hard time wanting to save a rotting cone or

>surround. The AR3a's must be really nice, they also sound like

>a challange when trying to rehab them to original specs.

I would replace the surround on vintage drivers. My experience with trying new replacements is dissapointing compared to repairing the vintage drivers. Also, when an old surround is replaced with new you really have to wait for the new surround to break in before making any judgements on the sound of the speaker.

[stan461]

>

>Hi Stan, thank you;

>

>Nice photos.

>

>I see that it is a 6 ohm impedance tweeter.

>

>In theory it will be maybe 2 db lower in volume that a 4 ohm

>tweeter.

>

>Maybe with the adapters and a parallel resistor this may be a

>valuable replacement option.

>

I'm a little concerned that I'm running the tweeter incorrctly. What resistor value would bring this up to specs?

How would I wire it in?

BTW. How can I measure the rsistance of a tweeter?

Thanks for any help.

[Guest Chartliner]

>Even within the limited paradyme of a 2 channel stereo system,

>the speaker still being the weakest element, I think far

>better speaker designs are possible. And if the day ever

>comes when they make an appearance, who knows if anyone will

>even care anymore.

Scanspeaks slitted drivers (controlling vibration distortion) and Vifa's ring tweeters-('reaching down to 2 khz so that the woofer doesn't have to reach up there, leading to stressed and ragged performance') as used in the Fidelity Acoustics, Krell, Sonus etc. speakers with 'transmission line' porting is an example of a better design, greater efficiency with very accurate sound.

http://www.fidelityacoustics.com/philosophy.html

[tysontom]

>4- The exact origins of the dome tweeter have long been

>disputed. For example, Peerless seems to have had a dome

>tweeter on the market in Europe around the time the AR was

>launching theirs. Who knows?

Ken,

I read in a textbook several years ago about a dome-type transducer developed in Europe -- and I saw pictures of it -- but I have been unable to find that information again. I don't know the date, but it seemed somewhat after the 1958 AR-3 period. I wonder what, if any, speaker system used that tweeter? I'm not aware of any patents on it.

Ed Villchur's dome tweeter patent covered the elastomeric suspension system rather than the actual dome itself. Although there appears to have never been a dome tweeter brought to market (certainly in the US) prior to the AR-3's domes, AR's patent attorneys felt that there were enough similar "dome-type" transducers (both loudspeakers and microphones) in prior art to consider it unsafe to try an outright patent on the dome itself. For example, Patent No. 2,084,945, issued in 1937, shows a rim-driven, dome-type driver facing into a short horn assembly. Nearly all compression-type drivers utilize dome, rim-driven diaphrams, and some early devices used dome-type drivers loaded into some type of mouth or small horn. None of these drivers, however, had been described as a stand-alone, direct-radiator tweeter for the purpose of low-distortion, wide-dispersion treble response.

--Tom Tyson