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Another Curbside Rescue


Rich W

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I got a call from a musician friend of mine a few weeks back. "I found a pair of speakers by the curb of someone's home - they looked similar to a pair you have at your place (my AR-17's), so I grabbed them. They're AR-11's. Do you want them?". First words out of my mouth: "holy s**t". I couldn't get my hands on them fast enough.

As it turns out, aside from the usual shot woofer surrounds, and missing foam screens, both speakers were in immaculate condition. Cabinets were in great shape, one or two minor dings - a little light sanding with 400 grit and an application of Watco's Danish Oil and they'll be good to go. But it gets better - every driver was operational! Obviously, the previous owner thought that once the surrounds were gone, these speakers were basically junk.

I got right to work, ordered surrounds from Larry at Vintage-AR, and started rebuilding the crossovers since I ad the right caps on hand. Used a combination of Bennic, Dayton and Solens to get the job done. The existing Callins caps literally crumbled to pieces as I removed them, the large can 120uf for the woofers looked salvagable at a measured 130uf, but I replaced them anyway. Removed disintegrating foam from around tweeters. Re-foam of first woofer went without a hitch, then I did something so incredibly stupid with the second - I inadvertantly applied too much power to the 27 hz test tone I use to center the driver and blew the voice coil clear out of the magnet structure - and no amount of manipulating would get it back in place. I caused even more damage in the process,

Once I got over my self-loathing (it pains me just to write this), I completed the restoration by borrowing a woofer from one of my AR-3a's until I get another woofer (any member who has an woofer of this vintage - not re-foamed is fine - please PM me) .

I'm not going to go into detail about how great these speakers sound - it's the classic AR-3a sound with a more extended high end, so enough said. In addition to some photos, I've included a reverberant field response curve, which includes the usual 70 hz dip my room exhibits on the left channel. I was a bit surprised by the minor midrange dip in both speakers, it almost looks like the woofer and mid are not in phase. I suspect it's a side wall cancellation effect. My 31-band EQ made easy work of this - fortunately the dip is almost exactly centered on the 615 hz band slider. There are absolutely no ill effects with the sound. Another interesting thing is that I had to cut both midrange and tweeter levels in the right channel to -6 db (full cut), and -3 db (midrange) and -6 db (tweeter) in the left channel to get flat response (with the usual rolloff at the highest frequencies which is to be expected with far field measurements). Since I listen primarily to classical music, flat response in the 2K to 5K range still sounded too hot. 31-band to the rescue again to recreate the "concert slope", and these things sound just like a pair of AR-3a's with more air on top.

These are keepers!

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Great catch!

I can't imagine your original woofer is beyond repair. But it might not be cheaper than a used replacement.

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Nice speakers, Rich. I, however, have one piece of advice for you ..."shims". :)

Your woofer can be repaired.

Roy

Hi Roy,

I've always had good luck with the test tone / non-dust cap removal method. Obviously, my luck ran out. Since my damaged woofer is currently residing in a landfill in Medford, it's going to be hard to repair. From your post, tossing it might have been even dumber than the original knuckle-heading thing it I did.

Rich

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Hi Roy,

I've always had good luck with the test tone / non-dust cap removal method. Obviously, my luck ran out. Since my damaged woofer is currently residing in a landfill in Medford, it's going to be hard to repair. From your post, tossing it might have been even dumber than the original knuckle-heading thing it I did.

Rich

Hi Rich,

Bummer...It is likely the voice coil could have been saved. Along with a new surround, a new spider may have been the only other item required.

I do much of Larry/Vintage AR repair work these days. We always use shims (same as those included in your kit) for centering the vc. They are also good for setting the height of the cone for an easier, more precise repair. Larry tells me not to get involved in re-foam debates because test tone and other methods are "good for (his) repair business". :) Based on what I've been seeing lately, he is probably correct.

I'll keep an eye out for a woofer.

Roy

.

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................ always use shims (same as those included in your kit) for centering the vc. They are also good for setting the height of the cone for an easier, more precise repair. .......

Roy

.

Yup

Best advice right here.

BTW, nice score!

Would this work> http://www.ebay.com/itm/ACOUSTIC-RESEARCH-Original-AR-9-12-034-Woofer-Also-AR9LS-Speaker-AR-11-AR-98LS-/251593356149?&_trksid=p2056016.l4276

I've been wondering how the AR11 would match up against the AR91s I just got (also being tossed because of foam rot).

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lucky f-in b@$t@rd.....AR11's are on my short list of "dream speakers"......those powered by a nice marantz 2325 would probably cause me to miss days of work because I'd be refusing to leave the man cave....

and yes, never throw out old woofers....someway somehow that either can be, or will be able to be repaired in the future...;)

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lucky f-in b@$t@rd.....AR11's are on my short list of "dream speakers"......those powered by a nice marantz 2325 would probably cause me to miss days of work because I'd be refusing to leave the man cave....

and yes, never throw out old woofers....someway somehow that either can be, or will be able to be repaired in the future... ;)

Hey michiganpat,I'm sure that Marantz would do the AR-11s justice. I'm running mine off a rebuilt Pioneer SX-1010 which is about 105 watts a channel, a few watts less than your Marantz. The sound quality with good source material can only be described as effortless and without any restriction (I was just listening to Hans Zimmer's score for the Da Vinci Code, which has one of the widest dynamic ranges I've ever heard on a CD). I'm definitely going to fuse them though. Those tweeters are hard to come by (a lot harder than a woofer!).

Rich W

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Yup

Best advice right here.

BTW, nice score!

Would this work> http://www.ebay.com/itm/ACOUSTIC-RESEARCH-Original-AR-9-12-034-Woofer-Also-AR9LS-Speaker-AR-11-AR-98LS-/251593356149?&_trksid=p2056016.l4276

I've been wondering how the AR11 would match up against the AR91s I just got (also being tossed because of foam rot).

Hi David. Yes, that would do. All the flat-sided AR woofers are pretty interchangable. My AR-3a's have one woofer circa 1974 and the other circa 1990 (Tonegen replacement). To my ears, there is no perceptable difference in sound character between the two speakers.

Rich W

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Hi Rich,

Bummer...It is likely the voice coil could have been saved. Along with a new surround, a new spider may have been the only other item required.

I do much of Larry/Vintage AR repair work these days. We always use shims (same as those included in your kit) for centering the vc. They are also good for setting the height of the cone for an easier, more precise repair. Larry tells me not to get involved in re-foam debates because test tone and other methods are "good for (his) repair business". :) Based on what I've been seeing lately, he is probably correct.

I'll keep an eye out for a woofer.

Roy

.

Thanks Roy,

Shims it is going forward.

Rich W

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