AR OEM drivers

[fordf250]

I don't know how many people know about the fact that new drivers are available, manufactured to original AR, OEM, specifications, and materials; three drivers are available: 12" woofers, complete with linear sided basket frames, upper mid range dome tweeters (I believe they are 1.5"domes), and the high range dome tweeters ( 1.0"domes?).

As I understand it, from the company marketing these products, the construction information was provided by an AR technical manager, who was a long term AR employee.

You can gain more information, about speaker repair, or purchasing these products, at www.simplyspeakers.com.

Hope this information helps, in cases where our old units are being delicately mothered along (I own 2 AR9's and want to keep them going as long as I am going!)

[genek]

These appear to be the same service parts offered by ABTechservices. If so, whether they meet OEM specs has been a matter of discussion here for a long time.

[fordf250]

These appear to be the same service parts offered by ABTechservices. If so, whether they meet OEM specs has been a matter of discussion here for a long time.

I was not aware of the ABTechservices-I'm sure you are right about the OEM specs-but than again which set of specs? My original woofers had the square magnetic structures-when my foam surrounds went bad-and I didn't know about having surrounds being able to be replaced-I ordered 4 relacement drivers from AR (they were still in operation) and the one's I received had the round magnetic structures-they are still in operation, as the surrounds are still holding up. I am aware that AR had several different batches of 12" woofers, subsequent to the original square magnet ones-with varying native resonance points.

I guess the only way to be sure is to refoam, and or recone, what one has, if one is sure that it is original-until there is nothing left.

[Mexicomike]

Looking at the website I suspect that they are "original spec" only in the sense that they will bolt in place. I'm confident they do NOT meet the AR specs re response/dispersion. Further, they do not list actual response with a + - db range which makes a "response" spec essentially useless. Saying a speaker responds to 20khz just means it may "twitch" it doesn't tell you anything about it's actual performance. From everything I have read, virtually nothing made since can match the dispersion capability of the factory AR3/LST tweeters/midrange.

Sadly, it would make no financial sense for a current make of speakers to produce factory matches of classic AR tweeters and Mids. So I suspect that nobody actually does.

[RoyC]

Looking at the website I suspect that they are "original spec" only in the sense that they will bolt in place.

Hi Mike...I agree!

Unfortunately, AB Tech is the only "official" source of new AR replacement drivers, mostly selling wholesale to retailers like Ebay's "Vintage AR" (Larry Lagace), "Simply Speakers", and other re-sellers.

Last year Larry brought over the latest, Chinese sourced, ABT AR 12" woofer (AR-3a, etc) replacement to measure on my Woofer Tester (WT2) program. It measured very poorly with respect to its intended use...but it fits the unique cabinet hole. Larry now routinely replaces the spider and the surround to make it perform a bit more like the original. Another example is the ABT $13 AR "potentiometer", which is simply a common 8 ohm l-pad, available from many other sources at a third of the price.

Roy

[Mexicomike]

Hi Roy,

You know...re the woofer, I was thinking...

If I remember right, Mr Vilchur took an off the shelf woofer (can't recall the brand) and "made it" into an acoustic suspension woofer by replacing the surround with mattress ticking. Maybe he modded the suspension too? So the woofer thing seems possible by modification. Can't see what could be done to mids and tweets though - at least as far as mechanical changes to current models.

[KlausDK]

The last 12" AR replacement woofer I saw (Ordered about 1½ year ago) was a circular basket woofer that had been cut to flat sides, with something like a chain saw. It had rubber surround and was ordered and delivered directly from AB Tech. With all respect, not anything like, what I would have installed in my AR speakers.

BRgds Klaus

[Carlspeak]

I've got lots of measurements on original AR drivers accumulated over time. Particularly woofers and mids. If anyone has any spare ABT OEM drivers to send me I'd be glad to conduct an in depth measurement protocol including EIC baffle response plots.

[RoyC]

The last 12" AR replacement woofer I saw (Ordered about 1½ year ago) was a circular basket woofer that had been cut to flat sides, with something like a chain saw. It had rubber surround and was ordered and delivered directly from AB Tech. With all respect, not anything like, what I would have installed in my AR speakers.

BRgds Klaus

Hi Klaus,

Apparently there have been a few ABT varieties since the demise of the Tonegen 12" replacement. A couple of years ago Larry brought over a 12" rubber surround woofer he obtained from ABT with cut flanges, just as you described. It had "NHT" stamped on the magnet, and actually measured reasonably well as a replacement. He was not able to purchase more than 2 of those, however. For the next order ABT sold him some laughable specimens, also with cut flanges, very small magnets, and extremely stiff suspensions...which he immediately returned to ABT. The latest offering appears to have the right size magnet and basket, but fs measures around 40hz (it is supposed to be around 20hz)! Replacing the spider, voice coil, and surround puts it back in the ballpark, bringing the retail price to nearly $200 each.

Carl, At this point I am willing to bet any new AB Tech driver you measure will significantly differ from the AR data you have accumulated.

Roy

[Carlspeak]

Hi Klaus,

Carl, At this point I am willing to bet any new AB Tech driver you measure will significantly differ from the AR data you have accumulated.

Roy

You're probably right Roy. The question is how much different?

It's understood the measurements would be a 'snapshot in time' since, as you have witnessed, there is strong evidence of lot-to-lot variation.

OTOH, I feel it would be a worthwhile effort to get the data and publish it on the web so prospective buyers can at least be aware of what they are getting themselves into.

[tysontom]

Hi Roy,

You know...re the woofer, I was thinking...

If I remember right, Mr Vilchur took an off the shelf woofer (can't recall the brand) and "made it" into an acoustic suspension woofer by replacing the surround with mattress ticking. Maybe he modded the suspension too? So the woofer thing seems possible by modification. Can't see what could be done to mids and tweets though - at least as far as mechanical changes to current models.

Mike,

You're correct that EV purchased (two) off-the-shelf Western Electric 728B full-range drivers, and on one he modified the surround with the help of his wife (she sewed the half-round surround out of mattress ticking) and used this for his experimental acoustic-suspension woofer. He loosened the spider, too, to lower the free-air resonance (fs). This first experimental woofer had a very low free-air resonance, but later versions were up to the 14-17 Hz range. The second 728 was left unmodified and mounted in a conventional infinite-baffle arrangement in order to compare the performance of the two systems.

--Tom Tyson

Western Electric 728B

[tysontom]

Mike,

You're correct that EV purchased (two) off-the-shelf Western Electric 728B full-range drivers, and on one he modified the surround with the help of his wife (she sewed the half-round surround out of mattress ticking) and used this for his experimental acoustic-suspension woofer. He loosened the spider, too, to lower the free-air resonance (fs). This first experimental woofer had a very low free-air resonance, but later versions were up to the 14-17 Hz range. The second 728 was left unmodified and mounted in a conventional infinite-baffle arrangement in order to compare the performance of the two systems.

--Tom Tyson

Western Electric 728B

By the way, anyone care to guess why Villchur used the 728B for his prototype 12-inch acoustic-suspension woofer?

--Tom Tyson

W.E. 728B Loudspeaker

[frankmarsi]

By the way, anyone care to guess why Villchur used the 728B for his prototype 12-inch acoustic-suspension woofer?

--Tom Tyson

W.E. 728B Loudspeaker

Hi Tom T., was it one of the best available for him to experiment with? Maybe he had a few in his collection and respected their quality?

O.K. I give up. All I know is that when the NY city tore down the old Staten Island ferry terminal in 2005 (built in 1948, finished in the early '50s), I pondered the thought

that all of the 24 P.A. domed hanging enclosures with-in the terminal might have been the Altec speaker (Western Electric 728B full-range drivers) that was

used in the early AR speakers and those garner bu-ku bucks these days. I have read that they were widely used in such applications. I felt gee, if I were more aggressive I'd ask and take all of the debris from that sound system from the demolition dumpster, but I didn't even try, henceforth I will never know.

In other 'news', I'm into 'heavy', I'll say it again, 'heavy' vinyl LP use these days, hey, isn't that what the first generation of AR's were brought up on besides 1/2 track tape or better? I surmise that the early designers of AR speakers must've listened awfully hard to their prototypes when using vinyl as cartridges were not as good as they are today, even early Denons, etc. I put on an occasional CD every so often, but damn, the LP's always win my heart. Some CD's sound great like; "Round-Up" by "Erich Kunzel" on "TELARC" and are a treat to listen to their depth and a must for AR speaker owners as they are good 'show-off' discs, especially if you're 50 to 95 yrs. young. And hey "Vern" if you ain't got no fuses to replace, I have more than 40 fuses in the ready for my LST's and 3a's, let me know what you need (LOL), no crap, it's the only way to keep these babies going as I do get very 'carried away' pretty often.

I do have the vinyl versions of other "TELARC", remarkably enough, they're tough to find, but some are dangerous disks to play and can be disheartening if your T.T./cartridge is not entirely and precisely tweaked,-mine are as accurately as I can with good tools (my original 1973 Shure Scale, supplemented by digital scales, remarkably both types always coincide,especially when I'm in a determined mood to do so. I track most of cartridges at 1 and one third grams), but I'm not about to 're-tweak' my tables just for one disk as I have before like for the "War of 1812" cannon shots which requirer 'upping' the tracking weight and anti-bias. Can anyone attest to to the actual 'crazy' looking tracks I refer to here?

P.S. Tom, might you take a shot at answering a question for me? I have always been in love with my AR's midrange speakers as being one of the most natural sounding speakers to my ears, question is; will they ever degrade and die because of the materials used in them might dry-out, my hunch is they will eventually, of course, but hopefully not in my remaining years? I have 20 midrange back-up units from mostly 1972 to 1980, (along with 16+ woofers and 48 back-up tweeters (AB-Tech's, HV's and AR-11's and even two 303 tweets), completely insane I must admit, but that's me from my generation and generations before, always preparing for the worst, is there anyone out there that nuts?) but I still dumbly lose sleep at night hoping they won't. Perhaps others will come forth with their opinions too?

[Mexicomike]

Ah yes, the Telarc 1812 canon shots. Interestingly, my Oracle TT and Signet TK10 or Shure V15 IV cartridge at the time both had trouble with that at 1.5 grams. Now the Oracle/Signet/Shure is long gone. But I kept my old AR TT though I didn't use it at all once I started "upgrading" TTs.. And you know what? The old AR TT and an Ortofon Super OM 30, (which I bought a couple of years ago) tracks the canon shots just fine at 1.5. Maybe I should have tried the AR with the Shure back in the day and saved a lot of money on ever-more expensive TTs/cartridges!