ar_pro Posted May 21, 2015 Report Share Posted May 21, 2015 I've had these AR-91 cabinets for several years, and they were in such bad condition - chipped & gouged veneer, dented corners, and Acoustic Blankets that looked like they'd been chewed by a wolverine - that I'd come close to tossing them a few times.Over the past few months we've been working on converting the third floor of our house into a dedicated listening room that'd give us more space for our main speakers & system, and get them out of the way of curious guests & children. This move would also serve to eliminate the TV/audio conflict that happens from time to time.We were going to look around for a pair of speakers to combine with the Mac integrated amplifier, turntable & media player that would remain in our family room, when it dawned on me to do something with those old AR-91 boxes. eBay and Craigslist supplied a pair of square-magnet woofers, a pair of AR-9 tweeters, and a set of AR-91 mids. I also picked up a second set of crossovers in case there were any issues with the ones in the '91 boxes.The decision to change the look of the speakers was something that I'd been thinking about for a long time. Some might recall the several AR-9 rehabs that my son and I had done over the years, where we removed the felt blankets and vinyl faceplate stickers to reveal a clean, walnut-faced appearance.In all honesty, some of the cosmetic choices that Acoustic Research made in the era of the AR-9 leave me cold. Love or hate the effect of the blanket, it was always stone ugly, and when combined with those dissolving foam inserts, the result was inelegant, at best. On the '91, there's a partial blanket, the same foam inserts, a useless plastic panel (with a vinyl sticker!), and a painted, unveneered front face to deal with.Being unwilling to re-veneer that big box, I decided to bondo, prime & paint the whole thing. Having had experience removing the blanket from the AR-9, I didn't anticipate the work involved to rid these 91's of theirs. The usual method is to get a good grip on the blanket with a pair of pliers, and slowly separate the felt from the cabinet surface - this has worked very nicely in the past. That said, on these blankets, it seems as if AR had used some sort of surplus Cold War-era Warsaw Pact armor adhesive, originally designed to field-patch a Russian tank. It took several applications of chemical stripper, and hours of sanding to remove every trace of the blanket! Never again.For the finish, I went with several coats of sanding primer, and three coats of automotive urethane paint in satin black and clear-coat that I had sprayed at a local body shop. The tweeter faceplates, midrange trim rings, and woofer cosmetic ring were painted flat black, giving a nice uniform appearance to the drivers, and all of the mounting hardware was cleaned & sprayed, as well.The idea to do something different with the front panel evolved over time - I'd been doing some reading on textured finishes, and decided to experiment with Krylon stone spray paint. Over several test panels, it became clear that the differences in the color and material sprayed from each can of Krylon was so variable, that I'd have to use several cans to get the effect that I wanted on both speakers. In the end, there are five coats of Krylon on each front panel, sprayed from seven different cans; and there are four coats of clear acrylic sealer as a finish. Krylon calls the finish "obsidian", but I think I prefer "asphalt roofing shingle" - it's just the appearance that I was looking for.I'd removed the stuffing over the crossover to swap out the original caps (all Parts Express Dayton replacements), test the switches (the ones on the AR-91 are much better than those on the AR-9), and double-check the binding post connectors. The orginal grill connectors were removed & replaced with new ones from PE.One note for anyone working on AR speakers from this era: the cabinet stuffing is starting to change - puffy clouds of particles can be seen if the stuffing is disturbed or removed - handle with care, caution and a dust mask!All of the drivers went in without a hitch, although I needed to re-set a few of the woofer T-nuts. The worker who was responsible for originally fitting these did a crap job - he might be the same guy who randomly stapled the crossover boards, with 50 on one side, and 3 on the other - I'd like to hit him with my Graig Nettles Louisville Slugger.We had a pair of speaker stands constructed out of 5/4" steel tubing - they're sand-filled & spiked, and topped with a slab of Pennsylvania bluestone - that raise the tweeter to the same height as the one on an AR-9. The Mac amplifier provides 200 watts/channel, and we're using a NHT B-12D powered sub, crossed over at 40 Hz for extreme LF support - most of the time, you wouldn't know it was there, as the AR-91 bass is outstanding.In a nutshell, I'm very pleased with the result - I can't imagine any current-production loudspeaker approaching the performance of this AR-91 at anywhere near what was spent on the rebuild. Link to comment Share on other sites More sharing options...
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