valkyrie Posted March 3, 2017 Report Share Posted March 3, 2017 A few months back there was some discussion concerning which AR three way was the definitive, best sounding unit. As I recall the author had mentioned that he thought the AR-91 was that model, since it was the outcome of the ADD research and used the same midrange and tweeter as the AR-9 family. This discussion piqued my interest as I was looking for a nice AR three way with the 12" woofer to replace my second system AR-2ax. AR3/a are out of the question due to their high prices (> $1000). Rarely does one see an AR-10pi or an AR-11 for sale. Lo and behold - shortly after this topic appeared I found a "nice" set of AR-91 on flea bay. The guy wanted $600 - but this was a cherry set - with the original absorptive pads on the baffle - all of them. Very rare. Cabinets were good - no chipped veneer - some water stains on the top of one speaker - but overall very good. That small still voice told me; "BUY THESE". So I took a flyer and did so. Received them in good shape and put them into play. I was amazed at how good they sounded - just knocked back. The woofer had been new surrounds and I "suspect" that the crossover had been updated - they had that brighter, more forward sound that I associate with a freshened crossover caps (I do not know for sure whether or not this is the case - I have not been into the speakers). So I took them to my audiophile friend's house - and we tested them in his dedicated listening room. Full ARC stack (including the REF-40 preamp and the mono-bloc 210 watt tube amps). A very nice setup. My friend has a FR measurement system so we ran some pink noise plots on these beauties. BTW: there was NO ATTEMPT on our part to optimize the location of the speakers for the room - it was strictly "first seat available" which, in this case meant they were located about 6' apart on a TV stand - with a giant flat screen between them. The rake (or toe in) was arbitrary and the attenuators were set to zero dB. Here is a picture of the setup - looking towards the speakers from the position of the mike - the 91s are on the shelf on each side of the flat screen (I cannot seem to place a photo "in line" so the first attachment is the test setup. The mike is on a boom leaning over the couch with its position about where a head would be. The black panels to the side of the 91s are a set of Tympani I-D (the model without the ribbon tweeter) and the two small speakers on stands are Spendor SP1-2 (English three way from the same approximate era). All of these speakers were compared to the 91s. But first here is the F/R plot - again - no attempt was made to optimize speaker setup - and the speaker cables were BB 14 gauge - no upscale stuff. But the ARC stack was first rate by any standard. The humps and bumps from 120 Hz or so down were no doubt room driven. But really good performance from a very old speaker (I figure about 36 years young). This plot was a done with smoothing - but I cannot remember the value. Overall an excellent performance - both objectively and subjectively imo. Subjectively the 91s crushed the Spendor speakers - rendering the Spendors as rather mechanical and unable to pull out musical textures in complex lines. Against the Maggies the results were equivocal. If you like the Maggie "sound", lots of sound bouncing around all over the place, limited dynamics, and not much in the way of bass - the Maggies were good - but my friend used every tweak and adjustment known to man in setting up the Maggies - while the 91s were just located without any effort at room optimization (and such makes a huge difference in speaker sound). Overall? The 91s are a great bargain - if you like the classic AR sound then that model is indeed a superb speaker. Quote Link to comment Share on other sites More sharing options...
DavidR Posted March 3, 2017 Report Share Posted March 3, 2017 The 91 is no slouch. Quote Link to comment Share on other sites More sharing options...
valkyrie Posted March 3, 2017 Author Report Share Posted March 3, 2017 No - the 91 is amazing - a real treasure from AR. Now I am prejudiced towards the AR sound - have been all my life. But to my ears, the 91s are much superior to the AR-3/a models. Brighter, greater clarity, a more tilted up sound. Those are some really excellent speakers. As previously pointed out the 91s were never on the radar - never reviewed, never much mentioned by anybody - sort of in the shadow of the Mighty Nine and the 90 models. BTW: The room that was used for measuring is NOT FRIENDLY to wide dispersion speakers like an AR. My friend is one of those audiophile types who listens "near field" and has lined the room with cabinets containing books, records and CDs to suppress/absorb/diffuse off-axis sounds. Just his style of listening - and John Atkinson the editor of StereoPile has the same setup - the long axis of his room is absorptive/diffuse - lined with all kinds of crap. The result being a relatively dead sounding room. Many of the "audiophile" types like that kind of environment - it allows them to enjoy speakers that are not very dispersive. You only hear the main beam in the "sweet spot". Not my way or preference. I think if those 91s were placed in a more reflective room (like my own) and some optimization were done on their positioning that they would be giant killers. They easily held their own against a Magnepan Tympani I-D - which to some is the best speaker that Magnepan ever made. I am amazed at how good the 91s sound. Quote Link to comment Share on other sites More sharing options...
DavidDru Posted March 3, 2017 Report Share Posted March 3, 2017 Great, now I am off to look for some 91's. Thanks. Quote Link to comment Share on other sites More sharing options...
ar_pro Posted March 3, 2017 Report Share Posted March 3, 2017 The '91 had the misfortune of being developed in the shadow of the AR-9 and AR-90; and although it stood as an improvement on the earlier AR 3-way systems, it's almost as if it didn't matter to anyone at the time. And sadly, its looks didn't help. It lacked the aesthetic appeal of the classic AR-3/3a, or even the more "modern" appearance of the 11 or 10pi, which were standard-bearers for Acoustic Research. Instead, the '91 was put forth as a solution to a problem that didn't really exist for people who wanted a 3-way bookshelf system. If anything, there's a certain amount of irony in the fact that with the AR-91, Acoustic Research had managed to un-invent their 12" bookshelf system. Note in the photo how Valkyrie's pal has positioned the '91s - very much different from what AR had in mind! Quote Link to comment Share on other sites More sharing options...
genek Posted March 3, 2017 Report Share Posted March 3, 2017 Wasn't the entire 9 series designed to be floor speakers? I wonder how the listening would have gone if they hadn't been up on the shelf. Quote Link to comment Share on other sites More sharing options...
lARrybody Posted March 4, 2017 Report Share Posted March 4, 2017 Congratulations Valkyrie on those AR91's. Would like to see some closer photos, especially of the acoustic blankets. Yes it is very rare to find a pair with them in place. I like many others here read arpro's post last July about the 91 being a sleeper. I started looking for a pair. In August a pair was listed on CL and located less than a mile away in my town. I went back and forth with the owner, but they did not come with grills or acoustic inserts and had a few scratches. The guy was firm on his price, and said he would part them out before negotiating on the price. Then in November a pair was listed on the auction site in Avon (30 miles away) with a starting price of $340.00 and local pickup only. I won the auction being the only bidder. They appear to be in excellent condition cosmetically, with just a few snags in the grill cloth. The acoustic inserts are missing and recreating them will be the only challenge in their restoration. Thus my interest in yours being in place. If you ever open them up I would be interested in what the crossovers look like. I plan on working on mine this spring when nice weather returns. LarryinIN Quote Link to comment Share on other sites More sharing options...
JKent Posted March 4, 2017 Report Share Posted March 4, 2017 Nice find Larry but in the spirit of "can you top this?" I'll just rub in the fact that back in 2011 AR_Pro alerted me to a pair of nice 91s in a town near here (in fact, the town I grew up in) for $75. They were fine as-is but I didn't like the look of the re-foam job so I sent them to Bill LeGall. Then rebuilt the crossovers and of course did a little (but not much) work on the cabinets. Total cost was under $250. Woohoo! I have these set up in my shop, driven by the Adcom 555 II. Very nice. These are keepers! If they would fit in my living room they'd be there. I didn't bother replacing the felt around the mid and tweet and I think they sound good but I suppose you could adapt the rings sold by Madisound for the tweets and make some for the mids out of foam. Beautiful speakers! Good luck with them! -Kent Quote Link to comment Share on other sites More sharing options...
ar_pro Posted March 4, 2017 Report Share Posted March 4, 2017 I believe Kent's record could stand for awhile, although Larry's $340 is still pretty good, as the asking price for the '91 keeps going up! As more & more people become aware of the quality of this excellent speaker, and how favorably it compares to the now relatively expensive AR-3a, I wouldn't be surprised to see its popularity continue to rise. The foam inserts from the AR-90 can also be used with the '91, but only the tweeter insert from the AR-9 will fit the '91. I've seen these inserts on eBay priced from about $20 all the way to $100/set. The crossover is pretty straightforward, especially if you don't get into replacing the resistors, with just 5 capacitors hot-glued to the masonite board. Based upon my recent experiences with the AR-91 polyfill, if anyone decides to temporarily remove the stuffing from their '91, please - please! - take the opportunity to weigh it for posterity! Quote Link to comment Share on other sites More sharing options...
DavidR Posted March 4, 2017 Report Share Posted March 4, 2017 5 caps (4, 8, 24, 40 and 100). The 40uF is hidden under a resistor at the bottom of this picture. Attached is a picture of the xover I did for my 91's Quote Link to comment Share on other sites More sharing options...
JKent Posted March 4, 2017 Report Share Posted March 4, 2017 17 minutes ago, DavidR said: 5 caps (4, 8, 24, 40 and 100). The 40uF is hidden under a resistor at the bottom of this picture. yeah. And I bet the silver cans are still good (but I changed them). Quote Link to comment Share on other sites More sharing options...
DavidR Posted March 4, 2017 Report Share Posted March 4, 2017 One of my 24uF metal can caps measured over 40uF. Attached are the cap readings for my 91's AR91 cap values.pdf Quote Link to comment Share on other sites More sharing options...
JKent Posted March 4, 2017 Report Share Posted March 4, 2017 3 minutes ago, DavidR said: One of my 24uF metal can caps measured over 40uF. A little surprising because I'd have bet money the Callins PVC caps would be way off and the metal cans (Sprague??) would be OK. Guess we were right to replace 'em all. Quote Link to comment Share on other sites More sharing options...
ar_pro Posted March 4, 2017 Report Share Posted March 4, 2017 1 hour ago, DavidR said: 5 caps (4, 8, 24, 40 and 100). The 40uF is hidden under a resistor at the bottom of this picture. Attached is a picture of the xover I did for my 91's Yes, five caps - doh! Quote Link to comment Share on other sites More sharing options...
DavidR Posted March 4, 2017 Report Share Posted March 4, 2017 Kent, the metal cans in mine were also Callins. I think Sprauge was out of the picture shortly after the 9 series speakers began. I think its hit or miss with the old Callins. Quote Link to comment Share on other sites More sharing options...
lARrybody Posted March 4, 2017 Report Share Posted March 4, 2017 What a wealth of information here. I was just curious in what had been done to Valkyrie's crossovers. You guys sure do pretty work. About the foam material. I am assuming it is some type of open cell foam. I measure it to be 1/2 in thick. Hand cutting the foam from sheets with a template may be possible, but the pictures I have seen have a camfer around the driver opening. This could be problematic to reproduce. Maybe a jig with a router? Anyway I am thinking this may be acceptable material to use. http://www.foambymail.com/SFF-/speaker-filter-foam-30-ppi.html Am I even close? Quote Link to comment Share on other sites More sharing options...
ar_pro Posted March 4, 2017 Report Share Posted March 4, 2017 Larry - The original diffraction foam had a certain stiffness to it, with large cells - it was slightly flexible, but not limp. There is a chamfer on both the tweeter and midrange inserts, and the thickness was just enough to bring it flush with the Acoustic Blanket. The foam in your link doesn't look bad, at all. Here's a couple of AR-90 & AR-91 photos that show the shape & chamfer, and what looks to be a home-made attempt on an AR-91. Quote Link to comment Share on other sites More sharing options...
ahannan Posted January 27, 2018 Report Share Posted January 27, 2018 On 3/4/2017 at 1:11 PM, larrybody said: What a wealth of information here. I was just curious in what had been done to Valkyrie's crossovers. You guys sure do pretty work. About the foam material. I am assuming it is some type of open cell foam. I measure it to be 1/2 in thick. Hand cutting the foam from sheets with a template may be possible, but the pictures I have seen have a camfer around the driver opening. This could be problematic to reproduce. Maybe a jig with a router? Anyway I am thinking this may be acceptable material to use. http://www.foambymail.com/SFF-/speaker-filter-foam-30-ppi.html Am I even close? I just measured the PPI of the original foam on an AR90 and it looks like 28 +/- a pore ... Quote Link to comment Share on other sites More sharing options...
Saso Knez Posted February 2, 2020 Report Share Posted February 2, 2020 Hi! I was googling the AR91s. I have a pair that were owned by my late father. They need some work with estetic damage to the fabric cover and lacquer. As dear as they are to me, I need the space in my small house. If anyone is interested, please mail me at saso@aformx.si I am in the EU. Thanks. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.