AR-2ax questions

[gcrimmins]

I just purchased a pair of AR-2ax speakers because I wanted deeper bass than the AR-4x's I've been using for about 15 years. I have a couple of comments and questions about the speakers.

I was pleasantly surprised to find that all of the tweeter and midrange pots works fine, and the woofer surrounds seem to be in good condition. It looks like the woofer surrounds are cloth. Their serial numbers are 14059 and 14051, if that helps anyone date them. I thought it interesting that the grill cloths have the square "AR" badge in one corner and then a brass "a" in another corner. But the tags on the back say "AR-ax" which is what they appear to be. I wonder if this means they were built early in the production of this speaker and they didn't have the new "ax" brass tags.

One of the speakers seems to work fine, and the other one had two problems. One if fixed, the other has me stumped. There is a hardboard disk between the woofer surround and metal frame. The hardboard disk was coming unglued from the metal frame, resulting in a clicking and vibrating sound. I glued it back down and it seems to work fine now. BTW, what type of adhesive should I have used for this? The second problem involves the midrange driver. I'm hearing some distortion or vibration from it during loud passages. I can best describe it as sounding a bit like a kazoo. I only notice this on louder passages. I don't know if the problem only occurs at this time, or if it's too quite to notice other times. I can image this being a problem with the midrange driver, or perhaps that it's causing something nearby to vibrate. Any ideas on how to get to the bottom of this sound and fix it?

Now I just have a couple of comments on the differnce in sound between the AR-4x and AR-2ax. First, as I had hoped the AR-2ax has much better response in the low bass. Music containing an electric bass, piano, pipe organ, etc. sounds much better. These speakers really do a respectable job reproducing the pedal notes on an organ, so I can only imagine what the AR-3a must be like. Second, when I first hooked up these speakers they seemed a bit thin, I think in the upper bass/lower midrange area, but I'm not certain. Compared to the AR-4x's, they just sounded a bit thin like speakers do when the volume is too low. I turned up the volume which helped, but then the midrange seemed almost overpowering. I turned down the midrange pots, which helped a bit. The more I listen to the speakers the less I notice this, but I find it interesting that this was my initial reaction. Might this in part be due to the frequency of the crossover between the woofer and midrange, which looks to be quite high compared to the AR-5 and AR-3a? Finally, could there be any problem with my receiver not having enough power for the AR-2ax? It's an old 10wpc Sansui 221. This doesn't sound like much power, but I almost never turn it up more than 1/3 of the way. Anyway, thank you to anyone who endured all of my questions and comments. I'd appreciates any comments or answers that anyone has.

One last thing. I found these speakers by putting a want ad in the local newspaper. The seller of the speakers was a man who buys and sells estates. He said he's starting to see a fair amount of electronics and speakers from the 1960's. So if you're looking for classic AR speakers, you might look for someone like that in your area.

--Geoff

[dynaco_dan]

>I just purchased a pair of AR-2ax speakers because I wanted

>deeper bass than the AR-4x's I've been using for about 15

>years. I have a couple of comments and questions about the

>speakers.

>

>I was pleasantly surprised to find that all of the tweeter and

>midrange pots works fine, and the woofer surrounds seem to be

>in good condition. It looks like the woofer surrounds are

>cloth. Their serial numbers are 14059 and 14051, if that helps

>anyone date them. I thought it interesting that the grill

>cloths have the square "AR" badge in one corner and then a

>brass "a" in another corner. But the tags on the back say

>"AR-ax" which is what they appear to be. I wonder if this

>means they were built early in the production of this speaker

>and they didn't have the new "ax" brass tags.

>

>One of the speakers seems to work fine, and the other one had

>two problems. One if fixed, the other has me stumped. There is

>a hardboard disk between the woofer surround and metal frame.

>The hardboard disk was coming unglued from the metal frame,

>resulting in a clicking and vibrating sound. I glued it back

>down and it seems to work fine now. BTW, what type of adhesive

>should I have used for this? The second problem involves the

>midrange driver. I'm hearing some distortion or vibration from

>it during loud passages. I can best describe it as sounding a

>bit like a kazoo. I only notice this on louder passages. I

>don't know if the problem only occurs at this time, or if it's

>too quite to notice other times. I can image this being a

>problem with the midrange driver, or perhaps that it's causing

>something nearby to vibrate. Any ideas on how to get to the

>bottom of this sound and fix it?

>

>Now I just have a couple of comments on the differnce in sound

>between the AR-4x and AR-2ax. First, as I had hoped the AR-2ax

>has much better response in the low bass. Music containing an

>electric bass, piano, pipe organ, etc. sounds much better.

>These speakers really do a respectable job reproducing the

>pedal notes on an organ, so I can only imagine what the AR-3a

>must be like. Second, when I first hooked up these

>speakers they seemed a bit thin, I think in the upper

>bass/lower midrange area, but I'm not certain. Compared to the

>AR-4x's, they just sounded a bit thin like speakers do when

>the volume is too low. I turned up the volume which helped,

>but then the midrange seemed almost overpowering. I turned

>down the midrange pots, which helped a bit. The more I listen

>to the speakers the less I notice this, but I find it

>interesting that this was my initial reaction. Might this in

>part be due to the frequency of the crossover between the

>woofer and midrange, which looks to be quite high compared to

>the AR-5 and AR-3a? Finally, could there be any problem with

>my receiver not having enough power for the AR-2ax? It's an

>old 10wpc Sansui 221. This doesn't sound like much power, but

>I almost never turn it up more than 1/3 of the way. Anyway,

>thank you to anyone who endured all of my questions and

>comments. I'd appreciates any comments or answers that

>anyone has.

>

>One last thing. I found these speakers by putting a want ad in

>the local newspaper. The seller of the speakers was a man who

>buys and sells estates. He said he's starting to see a fair

>amount of electronics and speakers from the 1960's. So if

>you're looking for classic AR speakers, you might look for

>someone like that in your area.

>

>--Geoff

Hi Geoff

I like to rattle.

Your stepping up from AR-4X's to 2Ax's and wondering what about the AR-3A's, reminds me of an ice skating show I saw years ago.

We had a local Canadian skating champion Karen Magnussen living here years ago.

Any ways, this Ice Capades type show was, the best of the best ice skaters, here in Canada.

This was a first time experience for me to see, as I can't ice skate if my life depended on it.

I am not a Wayne Gretski that's for sure.

As the show started, local amateurs, which I thought were really great put on a wonderful display.

As each act came on the ice you could see a little more precision, a little bit stronger performance.

Now I believe his name was Toller Kransten (spel) was a champion extraordinaire, came on the ice and I thought they can't get any better than this, but I was wrong.

Then Karen Magnussen came out, and wow, just when you thought you had seen perfection, she wowed the audience with even far greater precision, power and authority.

She was a Canadian Figure Skating Champion.

Now that you know about ice skating here in Vancouver, "on with the show".

This is how I would compare AR speakers going from AR-4X's up to the AR-LST's.

Others may not use ice skating as an example but I think you can see why I did.

I never have too much excitement over AR classic speakers.

Your amplifier at 10 watts is what you now own, and you can use it at lower sound levels which shouldn't clip.

Maybe 25 watts recommended minimum would be a tad better up too maybe 100 watts per channel or more.

I always recommend fusing your investments with open fuse blocks and 1 amp fast blow fuses, or read the AR fusing information sheet in the excellent library.

You can use what you have, until an upgrade may be available in the future.

I went from AR-4X's to AR-3A's in one jump, the 3A's were their best at the time.

The AR-LST's came out later, which I now own.

Good luck.

Have a great day.

[gcrimmins]

Hi Vern,

Thank for the great ice-skating analogy. Makes sense. I thinks it should also serve as a warning not to listen to an AR model better that what I own unless I intend to buy a pair. I'm sure I could be happy with the AR-2ax's for the rest of my life. But if I heard AR-3a's or AR-LST's I'd probably fall in love with them. And then I'd be in trouble with my wife. Seriously, thank you for your comments, and the reminder to fuse the speakers. I haven't done that, but will do so.

Does anyone have a suggestion on how to diagnose the funny sound the sometimes comes from one midrange driver?

--Geoff

[dynaco_dan]

>Hi Vern,

>

>Thank for the great ice-skating analogy. Makes sense. I thinks

>it should also serve as a warning not to listen to an AR model

>better that what I own unless I intend to buy a pair. I'm

>sure I could be happy with the AR-2ax's for the rest of my

>life. But if I heard AR-3a's or AR-LST's I'd probably fall in

>love with them. And then I'd be in trouble with my wife.

>Seriously, thank you for your comments, and the reminder to

>fuse the speakers. I haven't done that, but will do so.

>

>Does anyone have a suggestion on how to diagnose the funny

>sound the sometimes comes from one midrange driver?

>

>--Geoff

Hi again Geoff

If I can be very honest with you and everyone else, A - B'ing between speakers in this case, but with anything, can leave you either very happy with what you have, or yearning for the better model.

Usually, it leaves you yearning for the better model, it can become a compulsion.

If you have the lesser speaker at your friends or brothers house, he may rub it in, that his is superior.

You may leave their house with your speakers in hand, sulking, as your friend gloats over his winning that battle.

It actually can be an illness, hifiitis, I believe it's called, you start to have wild fantasies of upgrading and not having a WAF (wife acceptance factor) problem.

Reality sets in, and you also can do, as a very brave reader named Tom does, he doesn't try to figure out how to get upgrades by the wife, he just does it.

Mind you he's in the doghouse a lot and probably sleeps on that extra couch a lot as well, but, he is, "The Hifi Guy", master of his house, maybe.

I think I also came across without ice skating this time, I think everyone gets the idea though.

Now I'll try to drop my humour for a minute, to help you with the second question.

The midrange driver sounds like it's voice coil may be rubbing or I have seen the voil coils actually become un-glued and slip back off of the form.

Either way I can't give you any good news.

If you try switching your amp to mono, just have one speaker connected and try this as you increase the volume.

Next change speakers and repeat the same steps.

Change amp channels as well to eliminate both speakers and both amp channels.

The distortion, if only one speaker, will follow with each move.

This also eliminates amp distortion as well.

Please keep us posted, if needed drivers are available used.

Good luck, Geoff.

PS Taking your wife out now for a nice dinner might get her in a more receptive mood, improving her WAF a bit in advance.

lol

[Guest dartmouth12]

Just been going back through all my speaker receipts etc looking for contacts to get replacement AR-2ax tweeters (RoyC has kindly offered to help out and I'm still chasing a couple of places in OZ). Anyway I noticed on one of my repair bills that a "buzzing" midrange, turned out to be a faulty cross-over so your culprit might be there.

Darryl

[tysontom]

>

>I was pleasantly surprised to find that all of the tweeter and

>midrange pots works fine, and the woofer surrounds seem to be

>in good condition. It looks like the woofer surrounds are

>cloth. Their serial numbers are 14059 and 14051, if that helps

>anyone date them. I thought it interesting that the grill

>cloths have the square "AR" badge in one corner and then a

>brass "a" in another corner. But the tags on the back say

>"AR-ax" which is what they appear to be. I wonder if this

>means they were built early in the production of this speaker

>and they didn't have the new "ax" brass tags.

With the square AR logo and "a" pin, and the "AR-2ax" printed on the label, it tells us that these speakers were most likely in the 1964-1969 range with the 6-bolt Alnico woofer and the 3-1/2-inch midrange drivers and 1-3/8-inch tweeter. However, with the low serial-number sequence, it is possible that these might have been AR-2a's that were updated, but it's hard to tell. Note that all 10-inch, 4-bolt woofers had urethane-foam surrounds, not cloth. Only the 6-bolt Alnico woofers had cloth surrounds.

(1) Is the grill material a tweed-like weave or is it the beige-linen material? (2) Are the "AR-2ax" inscriptions on the back actually printed on the label, or is the "x" added to the "AR-2a"? (3) Do both speakers have the single, 3-1/2-inch midrange driver, and is there an adapter board with the midrange driver mounted in the center of it? (4) Do both woofers have the adapter ring with 4-bolt woofers in the 6-bolt hole? Can you send an image or two of the speakers?

The fact that the woofers have the adapter flange (adapts the later foam-surround 10-inch, 4-bolt woofer to the earlier 6-bolt hole) indicate that the woofers were replaced or that this was at the end of the 6-bolt sequence. I don't believe that production units were made with the adapter flange, only replacement units. The 6-bolt Alnico woofer production ended around 1969 or so.

http://www.classicspeakerpages.net/dc/user_files/628.jpg

AR-2a with two 5-inch midrange drivers (prior to 1964) and 1-3/8-inch dome tweeter. Woofer is later (1970) urethane-foam version mounted with 6-to-4-bolt adapter ring.

http://www.classicspeakerpages.net/dc/user_files/629.jpg

Examples of the two types of 6-bolt Alnico-magnet, cast-frame woofers used in the 1957-1969 AR-2 series. These woofers utilized a treated-cloth surround, with the later ones characterized by a dark surround.

http://www.classicspeakerpages.net/dc/user_files/630.jpg

Example of the later 4-bolt, stamped-frame 10-inch woofer used in the 1970 and later AR-2x/AR-2ax speakers.

>Finally, could there be any problem with

>my receiver not having enough power for the AR-2ax? It's an

>old 10wpc Sansui 221. This doesn't sound like much power, but

>I almost never turn it up more than 1/3 of the way.

I would almost certainly think that the loose flange you mentioned was the primary culprit in the noise you heard, but the 10-watt Sansui is definitely inadequate except for playing at very low levels. You might check to see if the Sansui, in fact, puts out 10 watts RMS from 20-20 kHz; it most likely doesn't, and this could be a problem of amplifier distortion into the AR-2axs. You could have a rubbing voice coil in the 3-1/2-inch midrange unit, but that is fairly unlikely.

--Tom Tyson

[tysontom]

Disregard my previous message regarding the adapter flange. I did not read the original message closely, and now it is clear that the masonite ring that attaches to the surround had come unglued -- a not uncommon occurrance. Any good glue -- even white glue or carpenter's glue -- would probably suffice to hold the masonite ring in place.

My assumption is that these speakers have the singe, 3-1/2-inch midrange driver, is this correct?

--Tom Tyson

[gcrimmins]

Hi Tom, thank you for your response to my message.

>(1) Is the grill material a tweed-like weave or is it the

>beige-linen material?

Mmmm...not having seen both, it's hard for me to say. It's a rather open weave beige cloth. Some of the fibers seem to vary in width, creating a texture to the cloth. Maybe I need to post a photo.

(2) Are the "AR-2ax" inscriptions on

>the back actually printed on the label, or is the "x" added to

Yes, AR-2ax is printed on the label. The x doesn't appear to have been added.

(3) Do both speakers have the single, 3-1/2-inch

>midrange driver, and is there an adapter board with the

>midrange driver mounted in the center of it?

Both speakers have six-bolt woofers that appear to have cloth surrounds. The woofers are bolted directly to the cabinet with no adapter. At the upper left is an orange 1-3/8" tweeter. To the right of the tweeter is a 3-1/2" midrange. The midrange is bolted directly to the cabinet with no adapter. It is covered with a piece of cream felt/insulation/something with a coarse diamond-pattern screen over the top.

Can you send an image or two of the speakers?

Yes, I'd be glad to do that. It may take me a couple of days to get the photos taken and posted.

>fact, puts out 10 watts RMS from 20-20 kHz; it most likely

>doesn't, and this could be a problem of amplifier distortion

>into the AR-2axs. You could have a rubbing voice coil in the

>3-1/2-inch midrange unit, but that is fairly unlikely.

I did as Vern had suggested earlier, and tested the speakers with the amplifier in both stero and mono mode, and swapped the speakers side-to-side. No matter how things are set up, the sound follows the same midrange driver. I don't hear the noise all the time, and it's only on louder passages, and maybe just in a certain frequency range. It's hard to tell. The sopranos in a very loud choir passage cause the sound, for example. As I said, it's kind of a vibrating, kazoo-like sound. So I'm guessing it must be a problem with the driver, or maybe something else vibrating? Does this help anyone narrow down the problem? Is there any way to test the midrange driver.

Thanks for the help,

Geoff

[tysontom]

>Hi Tom, thank you for your response to my message.

>

>>(1) Is the grill material a tweed-like weave or is it the

>>beige-linen material?

>Mmmm...not having seen both, it's hard for me to say. It's a

>rather open weave beige cloth. Some of the fibers seem to vary

>in width, creating a texture to the cloth. Maybe I need to

>post a photo.

>

>(2) Are the "AR-2ax" inscriptions on

>>the back actually printed on the label, or is the "x" added

>to

>Yes, AR-2ax is printed on the label. The x doesn't appear to

>have been added.

>

>(3) Do both speakers have the single, 3-1/2-inch

>>midrange driver, and is there an adapter board with the

>>midrange driver mounted in the center of it?

>Both speakers have six-bolt woofers that appear to have cloth

>surrounds. The woofers are bolted directly to the cabinet with

>no adapter. At the upper left is an orange 1-3/8" tweeter. To

>the right of the tweeter is a 3-1/2" midrange. The midrange is

>bolted directly to the cabinet with no adapter. It is covered

>with a piece of cream felt/insulation/something with a coarse

>diamond-pattern screen over the top.

>

>Can you send an image or two of the speakers?

>Yes, I'd be glad to do that. It may take me a couple of days

>to get the photos taken and posted.

>

>>fact, puts out 10 watts RMS from 20-20 kHz; it most likely

>>doesn't, and this could be a problem of amplifier distortion

>>into the AR-2axs. You could have a rubbing voice coil in

>the

>>3-1/2-inch midrange unit, but that is fairly unlikely.

>I did as Vern had suggested earlier, and tested the speakers

>with the amplifier in both stero and mono mode, and swapped

>the speakers side-to-side. No matter how things are set up,

>the sound follows the same midrange driver. I don't hear the

>noise all the time, and it's only on louder passages, and

>maybe just in a certain frequency range. It's hard to tell.

>The sopranos in a very loud choir passage cause the sound, for

>example. As I said, it's kind of a vibrating, kazoo-like

>sound. So I'm guessing it must be a problem with the driver,

>or maybe something else vibrating? Does this help anyone

>narrow down the problem? Is there any way to test the midrange

>driver.

Geoff,

Actually, your description brings a lot of clarity to the question of which AR-2ax speaker. You clearly have the standard 1964-1969 version of the AR-2ax, with the 6-bolt Alnico woofer, the 3-1/2-inch midrange and the 1-3/8-inch "fried-egg" dome tweeter. I don't know how I managed to "read-into" your first description so much the first time, but I somehow thought you had a factory-updated AR-2a-to-AR-2ax conversion.

Also from what you describe, you appear to have a distorting 3-1/2-inch midrange driver, probably due to a rubbing voice coil. If you look around on eBay, there are usually one or two of these drivers being "parted-out" at any given time. Oops... I just looked, and of course there are none presently on eBay, but keep an eye open in the "Vintage Loudspeaker" and "AR Speakers" categories. You could have a crossover problem, but it would not necessarily manifest itself the way you describe, with a clear distorting sound. To completely isolate the 3-1/2-inch midrange driver from the crossover, you could swap the drivers from one cabinet to the other -- a pain, but this way you can test each driver against a known good crossover. You will have to unsolder the leads, or you can alternatively cut them and then use self-insulating butt-spices to re-attach (T&B 14-16 AWG is excellent) the wires. Be sure to scrape off the Mortite from both the back-side of the midrange flange and the cabinet surfaces; roll the Mortite into a ball, then roll it back and forth to form a "pencil-shaped" mass that you can then re-apply to the flange before retrofitting the drivers. Be certain not to push down hard on the phillips screws as you remove them: you can accidentally dislodge the "T-Nut" on the back side, and getting this straight is not always easy.

--Tom Tyson

[RoyC]

Here are some photos of a recent 2ax restoration. They are very early 1970's vintage (serial numbers are just over 200,000). The cabinets were refinished, grill cloth replaced, the original pots refurbished, and new surrounds installed on woofers. The wax block 4uF/6uF caps were replaced (as they were out of spec in both speakers) with 4uf polys for the tweeters and 6uf mylars for the mids.

By this time the AR-2ax had a #7 woofer coil instead of the original #5 and and less fiberglass stuffing....similar early 70's changes have been noted in the AR-4x and the AR-3a.

Roy

[RoyC]

Forgot to post the photo of the AR-2ax badge..

Roy

[Pete B]

Excellent work Roy, those sure do look nice. They look to be the same vintage as mine. I was wondering where you got the grill cloth?

The woofer cone looks darker toward the outside, was that some sort of treatment? Mine do not have that look.

The foam edge looks wide, is that a 5/8" wide roll?

Pete B.

[RoyC]

Thanks Pete!

>I was wondering where you got the

>grill cloth?

Its a type of linen I've been experimenting with. I bought it in a crafts store. Its VERY close to the mid to late 70's AR material, but the search never ends.

>The woofer cone looks darker toward the outside, was that some

>sort of treatment?

It must be an AR thing. I have collected a number of the 10 inch woofers from that era and many look that way. Attached is a photo of a Sept. 1972 2ax woofer awaiting a surround which has the same coloring. The two areas of the cone do not feel or appear otherwise different.

The second photo is of a 1971 AR-5 woofer (essentially the same as the 2ax woofer) refoamed by Millersound. Bill does fine work and dyes the cone.

>The foam edge looks wide, is that a 5/8" wide roll?

Yes..

Roy

[Guest mc]

Excellent work, Roy - especially nice finish & details. Can you please give us the name of your crafts store, and its location?

[Guest dartmouth12]

Can anyone tell me the vintage of my AR2ax's - they're in the shop at the moment awaiting new tweeter (thanks Roy) and pot repairs (fingers crossed they can do it). I've attatched an image of the rear label sticker that was salvaged when I first got them.

I'm curious as to the age because my speakers were walnut finish as the label states but they had a raised black (painted) timber "bevel" approximately half the thickness of the cabinet timber on front edge of the cabinets. All the images I've seen of AR-2ax's have had a flat leading edge with none of this additional trim.

Check out the diagram attatched - what's the verdict?

PS you can tell I'm getting a bit carried away with this! The actual finish is/was not dissimilar to what good old powerpoint has done in this case (what's going on Mr Gates?).

Darryl

[RoyC]

Hi Darryl!

I have a pair of early to mid '70's AR-3a cabinets with the same design. Tom T. identified them as the non-US or "European" version.

Your speakers are probably early to mid 70's vintage as well.

If you notice the spelling of the word "metre" on your label. That spelling would be "meter" in the US. In fact it was "feet" and not "meter" at all in the US.

Roy

[tysontom]

>Thanks Pete!

>

>>I was wondering where you got the

>>grill cloth?

>

>Its a type of linen I've been experimenting with. I bought it

>in a crafts store. Its VERY close to the mid to late 70's AR

>material, but the search never ends.

>

>>The woofer cone looks darker toward the outside, was that

>some

>>sort of treatment?

>

>It must be an AR thing. I have collected a number of the 10

>inch woofers from that era and many look that way. Attached is

>a photo of a Sept. 1972 2ax woofer awaiting a surround which

>has the same coloring. The two areas of the cone do not feel

>or appear otherwise different.

>

>The second photo is of a 1971 AR-5 woofer (essentially the

>same as the 2ax woofer) refoamed by Millersound. Bill does

>fine work and dyes the cone.

>

>>The foam edge looks wide, is that a 5/8" wide roll?

>

>Yes..

Roy,

It appears that your AR-2ax models were very early 1970 versions as characterized by the 1-1/8-inch-thick front baffle board. The thick front panel was a vestige of the early AR-1/AR-2 development, and carried forward until the 1970-1971 AR-2ax cabinets, which then reverted to the standard 3/4-inch baffle. Originally, the thick front baffle was used to drop the woofer a few millimeters in order to prevent the cone from coming into contact with the grill cloth in the early versions, and to provide a mounting flange for the T-Nuts. I believe that a thin plywood panel (3/8-inch) was laminated to the backside of a standard 3/4-inch panel to achieve this thickness. The thick-panel speakers are characterized by drivers in which the mounting flange is recessed slightly below the front edge of the baffle. Later, of course, the flange hole was routed out of the 3/4-inch portion of the speaker hole.

The treatment on the cone was one of many that was used in an effort to constantly improve the smoothness of this driver. This sort of improvement, though probably barely audible, was part of AR's quest to quantitatively improve driver performance in order to reduce cone break-up at higher frequencies. Some of the AR 10-inch cones of this era had cone materials that were very pliable, and many have commented that they felt that the material was not sufficiently stiff to work properly. The opposite is true: the relatively soft material helped prevent cone breakup at its higher frequencies, and at the same time allowed the cone to operate as a "piston" within its operating range.

On the re-foamed 10-inch woofer, which incidentally looks very nice, it's interesting to note the use of (1) 5/8-inch half-round surround and (2) the cardboard piece on the frame edge. The 5/8-inch surround is good, but probably larger than it needs to be, and I'm not sure that the original even had that large a surround. The linear excursion of the AR-2ax 10-inch woofer is approximately .375-inches, so the large surround can't hurt. The cardboard piece (or is it rigid foam?) that Millersound put on your woofer flange serves no useful purpose on an AR woofer, and it is similar to those used in the early days as a mounting flange for speakers that were mounted *from the inside of the cabinet,* such as the early Electro-Voice, Altec Lansing, Jensen and University systems of the 1940s and 50s. Later, some speaker manufacturers used these cardboard pieces to permit the speaker to be placed "face-down" on a surface and thus not damage the surround, but I suspect that the AR surround will still touch the surface if placed in that manner. It's generally the rule to never place an AR driver "face-down" on a flat surface anyway, as this can damage the surround. Also, dyeing the cone might be questionable, as well, if it changes the texture or density of the cone material, thus affecting its frequency response in the higher-operating range. The cone is probably best left alone.

--Tom Tyson

[Guest postjob62]

Tom and Roy:

First of all, Roy, those are gorgeous 2ax's! Wow! Any info as to the particulars on that linen would be appreciated. Perhaps the craft store has an Atlanta branch.

I find myself a little confused which is not too unusual.

Roy said his 2ax's were serial # 200,000 range and thought to be "very early 1970's". Tom said they appeared to be "very early 1970". I have a pair that are obviously newer style (see pic) with serial # 171,000. My memory is not unexpectedly a little foggy during that time period, but I'm pretty sure I bought them after college graduation in 1971. Might have been closer to 1973. The backs are plywood and the labels are the old style, not the newer skimpy ones. If the "new stlye" 2ax started in 1970 at around #125,000 could Roy have serial # 200,000 from early 1970? And could my serial # 171,000 been after 1971 or am I indeed foggy? How many 2ax's would they have built in a year?

By the way, I had these repaired about 12 years ago and obviously the woofers were refoamed. Looking at the ribs on the woofer cones, were the cones also likely replaced at the same time or could these be original?

Ed

[Guest Ken Perkins]

I was looking in the fabric department a Walmart a month ago and found some thin linen material that's virtually identical to the linen fabric used by AR and Dynaco in the 70s. It's very thin and acoustically transparent and beautiful as far as the look and texture goes and is the closest thing to original I've ever seen. It's not as thick or course as the material Advent used and is sort of an off white/light creamy color. Wish I could give you the SKU number but it was easy to spot and not expensive at all.

[tysontom]

>I find myself a little confused which is not too unusual.

>

>Roy said his 2ax's were serial # 200,000 range and thought to

>be "very early 1970's". Tom said they appeared to be "very

>early 1970". I have a pair that are obviously newer style (see

>pic) with serial # 171,000. My memory is not unexpectedly a

>little foggy during that time period, but I'm pretty sure I

>bought them after college graduation in 1971. Might have been

>closer to 1973. The backs are plywood and the labels are the

>old style, not the newer skimpy ones. If the "new stlye" 2ax

>started in 1970 at around #125,000 could Roy have serial #

>200,000 from early 1970? And could my serial # 171,000 been

>after 1971 or am I indeed foggy? How many 2ax's would they

>have built in a year?

>

>By the way, I had these repaired about 12 years ago and

>obviously the woofers were refoamed. Looking at the ribs on

>the woofer cones, were the cones also likely replaced at the

>same time or could these be original?

>

Ed and Roy:

I looked through some documents and found that AR-2ax SN 202,320 was manufactured in Cambridge in November, 1972. AR-2ax SN 192,882 was manufactured in Cambridge in July, 1972. AR was producing approximately 2700 - 3000 AR-2x/axs-per-month during this period, so it would be consistent that your speakers were indeed built around November-December 1971. Roy's would have been built in the early Fall of 1972. AR moved from Cambridge to Norwood in 1973.

One thing I did notice: someone has retrofitted a different cone to your (Ed) AR-2ax. It has ribs, and I don't know whose cone it is, but the dust cap appears to be correct, so perhaps the cone was an OEM-replacement assembly that some repair stations used. All AR 4-bolt, 10-inch woofers were smooth-sided to the best of my knowledge. The early AR-6 had a ribbed cone on its 8-inch woofer, but I can't think of other AR woofers of that vintage that had ribbed cones. An authorized AR repair station would have simply replaced the woofer if the voice coil was rubbing, for example, so I suspect that the woofer was repaired by someone else. That woofer is probably fine, but I just wanted to point that out to you.

The tweeter in that AR-2ax had also been replaced. The replacement unit is a back-wired 3/4-inch, hard-dome unit with wires attached to the back of the tweeter evidentally taken through a new hole in the front baffle and then connected to the front-side, spring-loaded terminal strip. I suppose it works okay, but it's a convoluted way to fit the tweeter.

--Tom Tyson

[RoyC]

As always thanks for the insight, Tom!

The woofers from my speakers were stamped Sept 12,1972 and the serial numbers are 209,xxx...so you've nailed them.

The woofers have very "soft" cones. I have some earlier (late 60's) and late 70's versions with cones that are more rigid.

Roy

[RoyC]

Thanks for the compliment Ed.

The material for the grille cloth was purchased from Michael's. There should be one in Atlanta. Its a rather stiff linen ("tea dyed") used for needle point with a thread count of 28 per inch. The original stuff was a bit thicker and had a thread count of about 24. The thread count went up as time went on. Earlier cloth had a count of about 20 or 22.

I have never seen anything like it in a fabric store or department.

Roy

[Guest postjob62]

Thanks for the observations, Tom. Yes, I was asking about the woofers and suspected just what you postulate. At the time I had them repaired, I wasn't so much an AR "junkie" as I was just a guy with a set of old speakers I dearly loved and refused to give up on. It was an independent facility not associated with AR but as I recall drivers (parts) were still available from AR at the time. Seems like they wanted to just replace the entire woofer but I was afraid not to keep and repair the originals.

I suspected something might have been up with the tweeter wiring as well- good to know what has been done.

Ed

[Guest postjob62]

Roy,

I really appreciate the tip. There's a Michaels near my house, and my wife is there often. I'll head over this weekend and see if they have any.

Regards,

Ed

[tysontom]

>... The second problem involves the

>midrange driver. I'm hearing some distortion or vibration from

>it during loud passages. I can best describe it as sounding a

>bit like a kazoo. I only notice this on louder passages. I

>don't know if the problem only occurs at this time, or if it's

>too quite to notice other times. I can image this being a

>problem with the midrange driver, or perhaps that it's causing

>something nearby to vibrate. Any ideas on how to get to the

>bottom of this sound and fix it?

>

>

>--Geoff

Geoff,

Here is a link to a pair of AR-2ax, 3-1/2-inch midrange drivers:

http://cgi.ebay.com/2-Acoustic-Research-AR...1QQcmdZViewItem

--Tom Tyson