AR55
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A friend mine owns a pair of TSW 910’s, and about 10 years ago I had the opportunity to compare them to my 9LSi’s. I preferred the sound of my 9Lsi’s, but the 910’s were still very impressive. Comparing the two, I found the 910’s sound tended to be a little more forward and at times a little bright. The bass response of both 9Lsi’s & the 910’s was equally excellent. His 910’s bass response sounded the best when the speakers were placed about 4” from the back wall and had at least 12” of clear space provided on each side of the speaker.
I agree with Aadams that your speakers may be wired out of phase. I have attached a copy of the 910’s crossover schematic, to you help you confirm that your speakers are correctly wired. Note that the positive connection is typically adjacent to the label on the back of the woofer or is it marked with a red dot.
The poly fill is probably original. I wouldn't recommend removing it.
Another possible issue is that your drivers are not properly sealed to the cabinets. Often the old foam gasket has been lost or no longer forms a good seal. I use a gasketing tape sold by Parts Express - Parts Express Speaker Gasketing Tape.
AR-Drawing484 - 102116 - Crossover Schematic - AR910TSW - 1987.pdf
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Giorgio AR,
It looks like that in 1973, AR changed the 200005 tweeter from being front wired to back wired. This was done in Revision B to the Basket & Top Plate Assembly (part no. 205019) for the 200005 tweeter.
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I have a couple of pairs of AR speakers with 1¼” cone tweeters, and I thought it would be a good idea to see if I could find a pair of backups. I picked-up a pair of Tonegen made 210038 tweeters, thinking that they could be a direct replacement for the 200034 tweeters in my AR-28B’s. It turns out that they are similar to, but not the same as either the 200034 or 200038 tweeter.
Discovering this, I decided to see what I could find on the 210038 tweeters in the AR archive drawings. This evolved into a research project encompassing all of AR’s 1¼” cone tweeters. The following is a summary of my findings:
- 200005: the original 1¼” cone tweeter. It had its own unique, smaller metalworks and no Ferrofluid. It was used in the AR-4ax, AR-6, AR-7 & AR-8
- 200014-1 & 200014-2: 10-ohm tweeters that were exclusive to the AR-MST & AR-MST-1
- 200014-3: the tweeter that all later 1¼” tweeters appear to be derived from. It was used in the AR-7x, AR-17, AR-18 & AR-25
- 200034: not technically the same as the 200038 tweeter (different metalwork model number). The 200034 comes with a protective screen cover, but otherwise it looks identical to and was built to the same specifications as the 200038.
- 200038: an updated version of the 200014-3 (new cone & adhesives, but same voice coil & metalwork). Most of the AR speakers with 1¼” tweeters that came after the ADD series appear to have used this tweeter.
- 210034/38: Tonegen made tweeters. The 210038 tweeter was OEM for some of AR’s later models. Although similar to the 200034/38 tweeter, the 210034/38 tweeter is built to different specifications, and has a magnet that is physically 1/3 larger than the 200034/38 tweeter’s magnet.
If anyone’s interested, I have attached a more detailed writeup of my findings.
AR 1.25-inch Tweeter Research.pdf
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I recently came across a bargain priced pair of 3-way AR38BXi’s.
The speakers needed restoration. Most of which was fairly straightforward (the drivers needed re-foaming & the grille fabric needed to be replaced). There were, however, a few restoration hic-ups. One of the tweeters was defective & its replacement assembly didn’t immediately fit, plus a jury-rig fix was needed for a broken grille mounting pin.
The tweeter replacement wasn’t costly (found a 48BX replacement on eBay for just $40), but the installation could have gone more smoothly. The 48BX tweeter was attached to a “Twin Unit” mounting plate, and removing the tweeter would most likely break off its lead wires, so there it stayed. The problem arose when I tried to slip the 48BX plate into the 38BXi recessed cutout. It was 1/32” too long!! Fortunately, the plastic plate was easy to file down & the installed plate shows no signs of being reworked.
A broken mounting pin (ball) also proved to be more of a challenge than expected. The existing grille pins are slightly larger in diameter than any of the replacement mounting pins I could find. I tried expanding the pin’s diameter with some success, but it still wouldn’t grab. Ultimately, I resolved the problem by slightly drilling out the existing socket and installing a plastic sleeve that matched up with the smaller pin.
So, how does the restored 38BXi sound? Better than I expected, considering the BXi series less than stellar reputation on this forum. I used one my favorite 2-way speakers, an AR-15, for comparison. Both speakers have 8” woofers in similar sized cabinets, so I wasn’t surprised to find almost no difference in their bass response. Good, though not extremely deep. At the opposite end, I found the 38BXi to be brighter, maybe a touch too bright. Overall, though, the 38BXi’s sound is more detailed with better presentation of both male and female vocals. The differences aren’t great, but they are noticeable. Also, I briefly switched out a 38BXi with one of my AR-11’s. It wasn’t really a fair comparison.
38BXi’s sitting on top of a pair of AR-14’s
AR-15 & AR38BXi sitting on top a pair of AR-14’s. The 38BXi Cabinet is OK, but vinyl cladding just can’t compete with walnut veneer.
38BXi Mounting Plate 48BX Mounting Plate
Sleeved socket for new smaller mounting pin
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I happen to have a couple of AR-48B (200040-0). The surround mounts to the back face of the cone, and it doesn't have a shiny coating. My guess is that the coating on your woofer was added later.
I have no idea why AR choose to mount some surrounds on the front face of the woofer cone and others on the back face. While AR-48B's surround was factory mounted to the back face of of the cone, the surround on the 10"woofer (200004-2) found in AR-12 & AR-14 was factory mounted to the front face of the cone. You can also find examples of this with AR's 8" cones - 200050-0 back face - 200001-1 & 200037 front face.
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A few weeks ago, a friend of mine found a pair of AR9’s that, with one exception, were in excellent shape. It had a damaged 1½” dome midrange. I couldn’t locate an AR9/90 midrange for him, but I was able to find a nice used midrange from an AR-91. The only difference between the AR9’s midrange and an AR-91’s midrange turned out to be the plastic used for the semi-horn. While researching the AR library, I found that the dome midranges for the AR9, 90, 91, 92, 915 & 58s all appear to be functionally identical.
I also found that the AR-11’s 1½” dome midrange shares the same voice coil and the same metal work with the AR9...58s midranges. Before turning over the AR-91 midrange to my friend, I tried it out in one of my AR-11’s. The sound, particularly off axis, is slightly different than the 11’s midrange. I think the difference has more to do with the 91’s semi-horn then anything else. Is the sound better? I like my 11’s as they are, but I may be biased.
As an FYI – I also discovered that, much like the AR11's midrange, there looks to be little difference between the ¾” tweeter found in the AR-11B and the tweeters used in the AR9…58s. That also carries through to the tweeters in the AR38b, 48b & 58b.
By the way, the speakers really look great! I thought that I did a pretty good job with my restoration, but yours are definitely a step above.
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I don't know about the 48B's 4" MR, but the 38Bxi's 4" MR was made by Tonegen & it definitely has a cardboard/fiberboard gasket. It may not be exactly the same as the gasket on 48S, but it is there. That is torn cardboard not glue in the second photo. I had already removed the remains of the glue from the old surround.
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I am in the process of renovating a pair of 38Bxi's and wasn't able to remove the existing foam surround and glue without damaging the paper gasket. Let's face it. It's a 1/64" thick piece of cardboard. I'm just not sure what purpose it served. I can't see how 1/64" makes that much difference.
I may try to cut new gaskets, but if I can't, I'll just glue the new surrounds to the frame and not worry about it.
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My mistake - the schematic is correct. It does show the 72uF & 50uF capacitors in parallel.
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Note that the AR-11 schematic provided by DavidR has an error. The 72uF & 50uF capacitors should be shown in parallel. In the second generation AR-11B, AR changed these to a single 120uF capacitor. A capacitor that size isn't that common, so you may need to go with 2 - 60uF capacitors in parallel. I used Dayton Audio capacitors from Parts Express, but others have their own favorites.
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Sorry, I forgot to reply to your second question regarding the colored Danish oil.
I would try it out on the bottom surface of one of your speakers to see how it looks. If it looks good, finish the rest of the speaker with it. If it doesn't, no real harm done since few are likely to see it. You can then consider another option, such as linseed oil. I have never worked with it, but I know that others on the forum have had success with it.
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My USA made A-11A's & my USA made AR-11B's have an American walnut veneer. Since your pair were made in England, my guess is that they used European walnut. That being said, even if you get the correct veneer you may have to stain it to get it match the existing veneer. In my case, I had to re-veneered the bottom faces of a pair of AR-11A's. The top and sides of the speakers had a American walnut veneer, but when I sanded it down I discovered that it was slightly redder in color than the new Walnut veneer. Since it was the bottom of the cabinet, and would be seldom seen, I didn't bother trying to precisely match the color.
I later experimented a leftover piece of the new veneer and found that I could very closely match the color of the existing veneer, if I applied a light cherry stain to the new veneer before applying Danish oil finish.
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On 6/14/2021 at 6:03 PM, ar_pro said:
Whoever currently owns the Acoustic Research or Advent brand names might be missing out.
This is how far the AR & Advent brand names have fallen under Voxx:
Voxx uses the AR name on a line of outdoor speakers: Voxx - AR Speakers. Not exactly high end, but at least they are speakers.
Sadly, Voxx has relegated the Advent name to floormats: Voxx - Advent Floor Mats
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The only way that someone builds an new AR or Advent speaker that remotely resembles the new KLH Five is if Voxx sells the the brands. I believe that under Voxx's ownership the AR & Advent brand names are destined to just fade away.
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If you are looking to replace the foam surrounds yourself, Speakerworks and others sell kits. If not, there may be a local speaker repair shop in your area, or you could send them off to Millersound.
Make sure you keep track of the positive & negative wire connections, and you replace the seal when you reinstall the woofers into the cabinet.
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On 6/4/2021 at 5:50 AM, budney said:
Recently I picked up a pair of AR10 Pi for restoration, but unfortunately one had the wrong tweeter. One came with the original cream tweeter, but the other one was an AR3A tweeter. I'm now searching for a replacement original cream tweeter, which is proving quite difficult. I don't suppose anyone has one for sale? I'm not sure what my choices are other than finding an original replacement
I doubt that you will find a cream colored AR tweeter. I have never seen a working one come up for sale. You may have some luck finding the black, second generation tweeter found in the second generation AR-10B/11B. It doesn’t show up every day on eBay, but I wouldn’t be surprised to see one for sale in the next few months. I recently restored a pair of first generation AR-11A’s that had blown tweeters, and was able to replace the tweeters with a pair of eBay sourced 11B tweeters.
I don’t think that you will find an audible difference in the sound of the first & second generation tweeters. Other than cosmetics (black dome verses cream dome), it appears that the addition of Ferrofluid to the 10B’s/11B’s tweeter’s voice coil was the only change that AR made. This gave it more power handling ability.
If you can’t find an 11B tweeter, you may want to consider replacing one or both tweeters with aftermarket tweeters. I purchased a pair from Midwest Speaker Repair (Midwest Speaker Repair MT-4121 .75-inch dome tweeter) to use as backups, since I am now running 2 pairs of AR-11’s in my system, and didn’t want to risk not having a replacement if a tweeter blows. I compared the AR 11B tweeter to the MT-4121 tweeter, and felt that the MT-4121 may be a little bit brighter, but otherwise I could hear no difference.
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Anyone that has tried to replace the fabric on the 9LS/LSi & 98LS/LSi grilles knows how difficult it is to remove the plastic trim on the back of the grilles without breaking it. For those that are not lucky enough to have the trim come off in one piece or even a few of pieces, McMaster-Carr sells 3/64” thick x ½” wide black plastic strips. The strips are slightly wider than the original AR trim, but still a good fit.
The strips come in 5-ft lengths for $3.95, and are shipped in 4” diameter rolls. You will need to reverse roll them and set them aside for a few days to flatten them out. A minimum of 2 of strips are needed for each speaker. Below is a link to the McMaster-Carr site.
mcmaster.com - 1/2 inch plastic strip
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I agree with AR_pro. It looks like you have a veneer over particle board under that black paint. I would recommend sanding off some of the paint from the bottom of the speaker to confirm. If you do have a veneer under the paint, my own experience says that is worth the effort to refinish the speakers. A while back I acquired a pair of AR-15’s that also had been painted black. The photo below shows black paint vs. refinished. With that veneer, I could never understand why anyone would have painted them in the first place.
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I wouldn't mess with the spider. I recommend redoing the foam surround to see if that fixes the problem.
The 210037 woofer was a replacement woofer made for AR by Tonegen and should have nearly identical properties to the original square magnet 200037 AR woofer. I wouldn't worry too much about the 200037's magnet being slightly rotated.
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If go to the the Library and click: Acoustic Research - Special Sections - AR International - Brochures - AR "Extended Research" Brochure, you will find information on the 48Ls.
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I believe it is the European version of the AR-48b, which was manufactured from 1984 to 1985.
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About 10 years ago when I was looking for a set of AR metal stands for my AR-11B’s, I came across a pair of AR-11A’s selling for $350 on Craigslist that included the stands, as well as a set of replacement foam grilles. It was an all or nothing deal, so I agreed to include the 11A’s in the purchase even though they were not in the best of shape – I figured I could always part them out. The stands were put to immediate use, but I put off doing anything with the 11A’s themselves. Both of speakers had blown tweeters (one of the blown tweeters was a Tonegen replacement with an unfamiliar model number - 121130-0B). The midranges were good, but the woofers needed new surrounds and the crossovers were questionable. The owner had stored the speakers in his garage where they sustained significant water damage – buckled & peeling veneer on the bottom of the cabinets with some staining & delamination of the veneer on the sides. The rest of the cabinets were in fair shape with numerous nicks & scratches. Fortunately, the foam grilles were in their original box and were in excellent condition.
Recently I picked up a pair of crossovers and tweeters from a parted out an AR-11B on eBay. I now had the time & the parts to restore the 11A’s, so I pulled them out of storage.
Crossover restoration: Instead of trying to deal with the existing crossovers in the bottom of the 11A’s, I just removed them & replaced them with the eBay sourced, 11B crossovers. I kept the 11B’s original 120uF Sprague capacitor, but replaced the other capacitors (10uF & 40uF) with Dayton 1% tolerance capacitors. All the original red/black capacitors in the both 11A & 11B crossovers were out of spec, measuring between 19% & 55% over their original rated value. The 122uF (50uF+72uF) capacitors in the two 11A’s were close to their +/- 10% spec at 136uF & 140uF.
Existing Crossover Existing Crossover Removed 11B Crossover Installed with new Dayton 10uF & 40uF Capacitors
Cabinet Restoration: Removed and replaced the existing buckled veneer on the bottom of the cabinets. Re-glued & ironed flat the veneer that had delaminated along the bottom of the cabinets’ sides. Sanded off the existing finish (the exposed, unfinished walnut veneer was lighter & redder in color than I expected) and refinished the cabinets with 3 coats of Watco Danish Oil. The initial sanding had removed the water stains & all but a few of the deeper nicks/scratches. Wet sanding after the initial coat of Danish oil helped hide most of the remaining blemishes.
Water Damaged Veneer on Bottom of Cabinet New Veneer
Driver restoration: Installed the eBay sourced, 11B tweeters, adding new felt blankets over the tweeter face plates. The woofers were re-foamed curtesy of Millersound & the woofer’s rotted “outer gasket” trim was replaced with 1/8” x 1” adhesive backed, black foam. The finished product turned out looking better than I hoped & they sound just like AR-11’s should – detailed with tight, deep, undistorted bass. Flim & the BB’s can tell you a lot about your speaker's capabilities.
Restored Speakers
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I don't believe what you peeled off was put on by AR. The AR-17 cabinet had a real wood veneer with an oil finish (linseed oil or similar). It looks like you may have peeled off a poly type finish that was applied over the original oil finish. I am presently restoring an AR-11 that was varnished. In my case it was not possible to peel off the varnish. I sanded off the finish down to the bare wood veneer and then applied 3 coats of Watco Danish Oil, wet sanding after the first coat. AR veneers are fairly thick, but you still want to be careful that you don't sand through the veneer.
Bellow is a picture or a pair of AR-17's that I restored, who's finish only needed a few touch-ups with a Minwax walnut stain marker and a coat of Watco Rejuvenating Oil.
I also restored a pair of AR-15's that were painted black. In that case I sanded off the painted finish and applied a 3-coat, Watco Danish Oil finish. The picture below shows one speaker with the finish restored vs. one still painted black. Why anyone would have painted over that veneer is beyond me.
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Mine have actually held up quite well. The foam grilles for my AR-14's (same grille as 11/10pi) are 40 years old and still in very good shape and still grab the Velcro. The same is true for a pair of AR-15's I picked up a while back.
My AR-11's needed new grilles, but that was primarily due to mistreatment by the previous owners. The grilles were stained & torn. I was fortunate to find a replacement pair on eBay.
AR 17 parts needed
in For sale / Wanted
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If you can't find a 200001 woofer or a 200014-3 tweeter, here are other AR drivers that are acceptable options. Below are copies of the research into AR's 1.25-in tweeters & 8" woofers that may be of help:
AR 1.25-inch Tweeter Research.pdf
AR 8-inch Woofer-Midrange Research.pdf