Modern woofer for AR-2AX?

[Guest jlaplante]

Hi all -

I see talk of upgrading tweeters and mids to modern components, but very little about upgrading woofers. Based on the following T/S specs posted by Carlspeak on this forum for the 2AX...

Fs = 28 Hz

Qts = 0.51

Vas = 6.35 Cu ft.

Mms = 29 gms

Eff = 89 dB.

(http://www.classicspeakerpages.net/IP.Boar....php/t1929.html)

...I dug up two candidates that look like they would work well in a 2aX:

Morel 1077

Morel 1075

Opinions?

I am not averse to woodwork, or crossover work. These are for a pair of older 2A's that have been upgraded with AB-Tech mids and tweets, so they are essentially 2aX's now, but the xovers are still stock.

[Carlspeak]

I feel there is a fundamental difference between classic AR woofers and mids/tweeters that argues in favor of their (woofers) continued use. Wereas, those early mids/tweeters were in their early stages of development when the 2a's and 3a's were designed and we see now how they have deteriorated in their performance over time, woofers OTOH haven't. So, I guess if you don't have or can't get a pair of original AR2ax woofers, then by all means seek alternatives.

I suggest you get one or both of those woofers you feel match my 2ax measurements well and install it in your 2ax box and evaluate it both subjectively and objectively and let us know what you find.

Just looking at woofer specs won't tell the whole story about how it will ultimately perform. It's a starting point. I wouldn't venture a WAG as to how those Morel's will perform.

BTW, ABtech sells a replacement woofer for the 2ax. However, they don't seem to share their dirver specs. If you can get ABT to divulge the T/S parameters on their 2ax woofer, please share them with us. If your going with ABT mids and tweeters, I have to ask why you didn't go with the ABT woofer as well? With either the Morel or ABT woofer, you will probably have to find a proper inductor to work with those also.

[JKent]

Two questions:

1) You said these are AR 2a speakers with the original xo. Would you please let us know what the xo components for the 2a are? A member asked me this question yesterday, and I don't know the answer.

2) Are your woofers missing, damaged, or just old? The early AR 2/2a/2ax woofers with the cast aluminum frames and cloth surrounds are truly great and desirable woofers. I fully agree with Carl--If they are still good or can be repaired KEEP THEM!

Or send them to me

Kent

[Guest jlaplante]

I feel there is a fundamental difference between classic AR woofers and mids/tweeters that argues in favor of their (woofers) continued use. Wereas, those early mids/tweeters were in their early stages of development when the 2a's and 3a's were designed and we see now how they have deteriorated in their performance over time, woofers OTOH haven't.

Good advice, well taken. OTOH, even AR modified the woofers slightly over time, didn't they? Mine are the old cast aluminum 6-hole variety.

So, I guess if you don't have or can't get a pair of original AR2ax woofers, then by all means seek alternatives.

I have the originals, one cone is torn, but they both look pretty worn and I would want a recone at a minimum. I am tempted by the modern developments in cone materials, magnet & VC design, etc. and like to ask myself if Edward Vulchar (sp?) were doing this today, wouldn't he also want to use the best materials? Of course that assumes it is even possible to get a woofer that is truly designed for acoustic suspension.

Is it just that nobody does true acoustic-suspension designs with 10" or 12" drivers anymore?

I suggest you get one or both of those woofers you feel match my 2ax measurements well and install it in your 2ax box and evaluate it both subjectively and objectively and let us know what you find.

Just looking at woofer specs won't tell the whole story about how it will ultimately perform. It's a starting point. I wouldn't venture a WAG as to how those Morel's will perform.

Oh man, I am really tempted to do exactly that. Money is the limiting factor. Will let you know if I do.

Carl - are confident about your T/S specs on the 2AX? Have you tested more than one? Are there some essential parameters missing that one must know about in order to be sure?

BTW, ABtech sells a replacement woofer for the 2ax. However, they don't seem to share their dirver specs. If you can get ABT to divulge the T/S parameters on their 2ax woofer, please share them with us.

I tried to get both AB tech and vintage_ar to disclose specs, but I just get a runaround. I'm tempted to buy one just to measure it, as well as one Morel, then dump them on eBay.

If your going with ABT mids and tweeters, I have to ask why you didn't go with the ABT woofer as well? With either the Morel or ABT woofer, you will probably have to find a proper inductor to work with those also.

The AB mids and tweets were bought ten years ago when the woofers still seemed okay. I soldered the level controls out of the circuit. They improved the sound somewhat, but at that time, I had bigger worries than hi-fi sound, I just needed something to work.

Today, I am catching the fever that you all share on this forum, and it is fun! I figure the AB tech mids + tweets are good enough, but even those I would reconsider replacing if you guys convinced me hard enough!

I have been a speaker builder all my life, but primarily pro sound stuff. These 2A's were bought when I was in elementary school and I still remember the first day that dad brought them home. What a revelation!

[Guest jlaplante]

Two questions:

1) You said these are AR 2a speakers with the original xo. Would you please let us know what the xo components for the 2a are? A member asked me this question yesterday, and I don't know the answer.

Will tear into them this weekend and let you know.

Two questions:

2) Are your woofers missing, damaged, or just old? The early AR 2/2a/2ax woofers with the cast aluminum frames and cloth surrounds are truly great and desirable woofers. I fully agree with Carl--If they are still good or can be repaired KEEP THEM!

Or send them to me

Damaged AND old - one cone is torn, but not major. I was pulling the grill off and lightly bumped the cone and tore it. I was figuring a recone at a minimum - doesn't the paper and surround deterioriate with time? Are these older units packed with rock wool? It is dark yellowish looking fiberglass stuff. Does that stuff affect cone life?

[JKent]

Will tear into them this weekend and let you know.

Damaged AND old - one cone is torn, but not major. I was pulling the grill off and lightly bumped the cone and tore it. I was figuring a recone at a minimum - doesn't the paper and surround deterioriate with time? Are these older units packed with rock wool? It is dark yellowish looking fiberglass stuff. Does that stuff affect cone life?

Those cast-aluminum woofers are worth fixing. "everyone" seems to agree that Millersound is the place to get speaker drivers fixed. Here is the website:

http://www.millersound.net/about.htm

I think that yellow stuff is probably yellow fiberglass--which is good. Be sure to check the EXCELLENT booklet from CSP members, "Restoring the AR3a". It will have a lot of info relevant to your 2ax restoration, INCLUDING how to identify the dreaded rock wool:

http://www.classicspeakerpages.net/library...ring_the_ar-3a/

Good luck!

Kent

[soundminded]

There are no single right or wrong reasons for visiting this site (within the rules and bounds of civility.) Many people who come here want to restore their AR speakers and other equipment to as close to the way it was when it was new as possible. There is nothing wrong with that. The problem with that however is that it is impossible to restore some of the parts such as the midrange and tweeter drivers to their original performance and the more contemporary designs have not been developed along the same line of engineering goals as AR's, mainly in the area of wide dispersion of midrange and tweeter drivers. Similarly, woofers have not generally been developed along AR's original lines. Many today are designed for ported systems and are not suitable for replacements for AR drivers. That is a shame because AR's basic design is still in the opinion of many the best, remarkably so even after 50 years. I was amazed at how well the AR2a 10" die cast frame woofer performs. There are no direct substitutes even though the best manufacturers quietly use acoustic suspension designs without any fanfare about it. There are also no pristine examples of AR speaker systems to compare re-engineered knockoffs to even in a laboratory.

When you replace AR components with others, you are engineering a new speaker. There is nothing wrong with that, I do it myself. Although I lived through the AR golden era, there is nothing sacrosanct about the original parts or designs to me. Edgar Villchur himself was looking to create the most accurate sound he could and I don't think he would have had any problem altering his design towards that end. If I were to replace an AR 10" woofer myself, the one I would consider first is the Dayton RSS265HF-4. It will handle 350 watts RMS (far more than the AR 10") has an Fs of 22 Hz, lower than AR's, a Vas of 2.12 which makes it suitable for the small AR2 series enclosure, and a Qms of only 2.80. Its Qts is .39 but its sensitivity is only 87 db and it is only 4 ohms. it may require using a router to make it fit the AR woofer opening too. The crossover network will also need some changes. Achieving an overall system Q of .707 may require adjustment of the amount of stuffing too. There is lots of help and technical advice on line for all this. Personally, I'd bring the crossover network outside the enclosure at least until I was satisfied with it. Even the experts tweak their crossover designs before they decide on what to manufacture and sell. None of these problems are insurmountable but they will require patience and persistance to solve them. The one area of concern is that this driver is designed as a subwoofer and has a plastic cone. The upper bass lower midrange may not be to your liking. In that case an additional lower midrange speaker may be the answer, probably about a 4" or 6" high quality paper cone driver (certainly not the Jensen 5" table radio speakers used in the AR2a midrange. This would entail a larger design change of course. It's the kind of solution AR used in AR9 and its lower cost models of that era such as the AR90. The similar RSS265HO-4 has specs slightly closer to the original and can handle even more power, 600 watts RMS. I would not try the TIT280C-4 Titanic MKIII. I don't think it is a close enough match. Neither is the ST255-8 10" series II. I don't have any data for the Morel 1077 but I do have data for the 1075. I don't think it is a good match. Its Vas is too high 4.35 and its Xmax is only 4.24. It is also very expensive. It has a plastic cone but it is 8 ohms. Others here have other favorites. I think one contributor likes Audire.

[Guest jlaplante]

Thanks very much soundminded, that's exactly the info I am looking for. However it is very eye-opening. Given the plethora of OTS drivers out there, one would think a close substitute would be easy to find, but I think you have cleared that up.

After your advice and many others here, the picture clearly emerges that these woofers are really the best I will get for this cabinet without reengineering everything.

I took the previous poster's advice and called Bill LeGall at Millersound yesterday. He offered to do a bang up job on reconing those woofers, guaranteed they'd sound better than new. From stuff I read on the net, this guy really knows his stuff and is a perfectionist.

Right now, I am leaning strongly toward this path. I even suspect AB tech replacement woofers now!

With this change in philosophy toward original parts, I posted this thread about how to get the 2A crossover upgraded to 2AX.

So the direction that looks good now is the woofer recone, sticking with the AB tech drivers in the short term along with upgrading the crossover to 2AX specs, plus any mod that is needed to bring the AB tech drivers into "OEM" performance.

Then long term maybe I will pursue Carlsound's Super-Mod philosophy for the 2AX to improve on the mid and tweeter, but it sounds like uncharted territory for the 2AX.

Has anyone pursued mid+tweet+xover upgrade on a 2AX?

[Pete B]

Peerless 1727, but it is out of production:

http://www.classicspeakerpages.net/IP.Boar...amp;hl=peerless

[Guest jlaplante]

Peerless 1727, but it is out of production:

http://www.classicspeakerpages.net/IP.Boar...amp;hl=peerless

Thanks Pete. Looks like a good possibilty but probably hard to find.

Oh well, I'm going to try the recone route first and see how it goes.

So I opened up my other cab this morning to start the whole job, and a heart-dropping moment. The original woofer is gone! I apparently already replaced it when doing the mids+tweets about 12 years ago. Sad to think it is sitting in a landfill somewhere, wish I knew all this then. Guess I'll start looking around for a replacement...

[Pete B]

http://www.madisound.com/catalog/PDF/peerless/830668.pdf

Have not tried it myself.

[Pete B]

http://www.madisound.com/catalog/product_i...products_id=417

Eclipse 1038R Again have not tried it, but it is well known to be excellent, and I believe that

you can buy it without the amp. It is a dated, low cost driver.

Here also: http://www.meniscusaudio.com/products/Meniscus.htm

[Guest jlaplante]

1) You said these are AR 2a speakers with the original xo. Would you please let us know what the xo components for the 2a are? A member asked me this question yesterday, and I don't know the answer.

Please see this new thread I have started to document my progress; all the crossover details are there now, including photos and schematics:

My AR-2A to AR-2AX conversion

Thanks!