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tysontom

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  1. Why does it even matter?
  2. Clearly the serial numbers are incorrect (and the date-stamp font is also incorrect along with the absence of the "C" in the serial number) for some reason, but I don't know why this would be unless the original serial numbers were pretty far apart and the seller felt that this might detract from their value, which it really won't. Consecutive serial numbers in AR speakers really don't mean anything, and it's fairly rare and usually "coincidental" that two have consecutive numbers. Serial numbers far apart do have significance with regard to components, crossovers, etc., but these two appear to have been built pretty close together. Send some pictures of the two speakers with their grills off, side-by-side. Also, pictures of the other crossover, if possible. These AR-3s are definitely early versions, likely dating to 1960-61. If you look at any of the drivers (the midrange or tweeter, particularly but sometimes on the woofer), you can usually find a date stamped on the back plate of the magnet circuit. Try to locate a stamped date. The presence of the oil-filled, mil-spec surplus crossover capacitors (the best kind, actually) clearly proves that these speakers date back to the earliest versions. Someone appears to have changed the level controls, however, as they don't look original to the AR-3. Woofer details are also present that show the orange surround color (before AR added lamp-black to the treatment), the damping ring around the outside of the woofer cone just inside the surround, and that sort of thing. The woofer has the Gen 2 cone annular rings and foam damping rings, which came about a year or so after the introduction of the AR-3, probably late 1960 or early 1961. The terminal strip is early, too, as mentioned before. I'm thinking that the original serial numbers for these speakers would be something in the C 04500 to C 07500 range or so. If both speakers work properly, then you're in fine shape with only the fraudulent "sequential" serial numbers and the wrong grill cloth material and relatively crude "3" pins. It doesn't appear that any drivers have been changed from the pictures you show, but I haven't seen both speakers. Look on the woofer magnet back plate to see if you can find a date stamp. --Tom Tyson
  3. I agree with Gerry 100%. Bi-amping is somewhat of a solution to which there is no problem. Years ago, with under-powered amplifiers, audiophiles often resorted to bi-amping speakers to get higher output levels with lower distortion. However, with the ADS L1590-2 -- as with most modern loudspeaker systems -- the passive crossover is an integral part of the design of the loudspeaker, and to bypass the crossover can be problematic. In fact, ADS spent about two years researching improvements in the design of their tower speakers (the 1090, 1290 and 1590 in the Series II version) to make them even better, and most of the improvements came in the crossover itself with driver enhancements. Therefore, removing or bypassing the crossover altogether can lead to serious spectral-balance issues, when using an outboard active crossover, which could result in some frequencies favoring others along with a serious issue with the shape and slope of the acoustic-power response into a room. Many times, audiophiles feel that they know better than the designers, and they can improve on the original design, but this is usually a false premise. In other words, the engineers at ADS knew very much what they were doing when they designed and improved these speakers; why screw with their professional work? Place the speakers in an acoustically "proper" listening room, large enough to appreciate the bandwidth of the speakers and a room properly damped with furniture and floor treatment. Again, use an appropriately powerful and stable power amplifier. If the crossover is left in place, however, separating the woofer section from the treble section does not accomplish much of anything, and to get the proper balance is sometimes difficult. There is always the issue of getting the two section out of phase along with the relative balance of the output. With an adequately powered amplifier; i.e., an amplifier with 200-300+ watts output, the sound of the 1590 should be fine without the need to bi-amp. I drove my ADS L1590-2s with several different high-powered amplifiers over time, but mostly I used a Threshold 500-watt amp or McIntosh MC2500, and there were times when the Mac "Limit" lights flashed on peaks, meaning that peaks were greater than 1kW into each channel. I did have a good friend with a pair of L1290s, and he chose to biamp his setup with the crossover in place. He struggled to get the sound properly balanced, and ultimately he returned it to a single-amp operation. With my ADS L1590-2 system, I never once detected any weakness, distortion or lack of clarity from these speakers, a hallmark of the excellent design of the ADS speakers. I did mount them back within about a foot of the front short wall and away from the room corners in my large, well-damped listening room of about 15' x 23' or so. I was always amazed at how clean and effortless these speakers sounded, with clear, balanced output and low-distortion deep bass. --Tom Tyson
  4. The serial number stamp doesn't look authentic, and it lacks the "C" as mentioned earlier.
  5. Add to the mix that the grills and the "3" pin are not original.
  6. The serial numbers for this pair of AR-3s are inconsistent with the physical appearance of the speakers themselves, for some reason. SNs 43896 and 43897 would have been manufactured in the 1964-1965 time-frame, yet these speakers look like 1959-1960 models with their early front terminal strip and the treated-cloth surrounds without the later-added lamp-black treatment for the woofers. How are the cabinets different? With consecutive serial numbers, it would indicate that the speakers were built virtually at the same time. Consecutive numbers aren't particularly rare, but AR speaker were never intentionally shipped out from AR as a "pair" with consecutive numbers. The most unusual thing is the lack of the standard oval-shaped, flush terminal strip rather than the earliest version mounted above the baffle. The serial numbers strangely do not have the "C" in front of the serial numbers. This is unusual, and it's hard to determine what's going on. The drivers are also earlier, but in seemingly excellent, unmolested condition from the one image. More pictures would be very helpful. --Tom Tyson
  7. Norman, Welcome to this forum! That is an interesting story about your experience at the AR Music Room on the west balcony in GCT. I had forgotten that the room was air-conditioned, but now that you mention it, I do recall that it felt very comfortable up in the room. I spent quite a lot of time up there in 1966 and again in 1968, two trips I made to the New York High Fidelity Music Show. Those were fun memories that I had there, too, along with attending the hifi show. At the time, my girlfriend lived in Manhattan, so we all had a great time! I got to know Walt Berry quite well during that time and his assistant Barbara. During those years, AR had over 100,000 people a year visit the room, but no sales were ever allowed to be made. In 1994, AR made a return visit to GCT, but this time renting the east balcony. By now, the old AR building was long-gone, but AR rented the east balcony to celebrate "AR's 40th Birthday Party," a celebration and trip down AR memory lane that included most of the "who's who" in high-fidelity audio history at the time. --Tom Tyson
  8. The tweeters are also wired in a series/parallel fashion, so there are some slight variations between even properly working tweeters. If one tweeter is defective, it will affect the output of the others as well.
  9. Notice, too, that the very first AR-10 Pi speakers (the prototypes, that is) were called "AR-Pi-One," and they had slider switches for the environmental control rather than the later toggle switches. By the time of production, the name was changed to AR-10Pi; and in the ad shown in this message string, the AR-10Pi is actually shown with the slider switches, so perhaps serial number 0001 had sliders instead of toggle switches. One of the important contributors to the AR-10 was C. Victor Campos of AR (he recently died, sadly). Victor and I used to talk for hours about AR and KLH, and Victor had actually worked at AR during two different periods, once in the early 1960s and then in the mid-1970s about the time of the new Advanced Development Division speakers (AR-10, AR-11, AR-12, 14, AR-MST, etc.). He worked on the cabinet design of the AR-10 Pi, and during its development, AR technicians were having some difficulty making the access doors, which tended to bind, close properly. Victor was somewhat impatient, and he insisted that the engineers stop screwing around and just install ball-bearing pivots for the door hinges! Of course, this would have cost a fortune and was immediately nixed by management, so the engineers got to work and fixed the existing bearing surface for the solid-walnut door, and it worked fine forever more. Victor was also very interested in the 1978 AR9 "D", an experimental 4-way "powered" AR9 speaker that was sadly never actually put into production! What good did come of the AR9D: the birth of NAD electronics! --Tom Tyson
  10. This is a great tribute to a very knowledgeable AR man! I couldn’t agree more, and I have been dealing with Acoustic Research products nearly all my life, and I would run something by Roy before deciding on it when it comes to the vintage Acoustic Research products! Roy has had such broad experience because he has seen and worked on so many Acoustic Research speakers! Roy is also a fine gentleman, very gracious and thoughtful – and very nice, too! What a huge asset to this forum of AR devotees! --Tom Tyson
  11. The AR-10π with the black face is a very early version (looks like serial No. 0051) of the original model. The first production models of both the AR-10 and AR-11 -- the first models of the "Advanced Development Division" line -- had the face painted black. Subsequently, veneer was used on the front panel of the upscale AR-10.
  12. Great message! Thanks for this further clarification. One note: after the initial 200003 woofer, AR did change the compliance slightly to prevent the often-occurring back-plate voice-coil incursions. This early 1969-1970 ferrite woofer (Roy and I can't determine precisely when the new ferrite woofer appeared in the AR-3a) was extremely compliant and prone to striking the bottom plate of the magnetic structure under very hard low-frequency input power. This took an excursion of a little over an inch, peak-to-peak. Sometime after AR moved to Norwood (1973), AR did revise this woofer to (1) eliminate the butyl-rubber coating on the surround, (2) change the dust cap and (3) slightly stiffen the spider to control excursion beyond the .5-inch linear travel. Perhaps this corresponds to the drawing changes. I did notice that the AR-11 woofer, for example, was slightly stiffer at extremes than the AR-3a ferrite woofer. This did not materially affect the driver resonance or harmonic distortion, but it limited the excursion a bit more at extremes than the first edition in an effort to prevent flattening the voice coils under duress since the woofer did not have an extended back plate ("bumped"). AR also went to the aluminum bobbin for this woofer in the mid-1970s, and most of the later ones were aluminum rather than the earlier DuPont Nomex-treated-paper formers, even though the latter probably dissipated heat better into the magnet structure. --Tom Tyson --Tom
  13. I didn't mean to repeat the details of my first message!
  14. Pete, I don't know the details of how spiders are made other than they are formed under heat and pressure in a mold. I believe the majority of spiders are made from linen or similar materials, then coated for longevity and stability. I saw a YouTube video recently where some guy had a collapsed spider on a large subwoofer driver, and he sprayed water on the material while keeping the cone "centered" with spacers. He used a shrinkable-tubing heat gun to quickly evaporate the water and to hopefully cause the spider to shrink and return to its original shape. It looked to me like it partially worked, but there were definite sags in the spider that never went completely away; and if the surround material was treated, I don't know how the water could penetrate past the coating to get to the fibers. AR once had a recommendation that to get the sags out of a linen grill cloth, the best way to do that was to use a fine mist spray of distilled water on the fabric and then hold a light bulb (back in the incandescent days) close to the fabric to allow it to shrink and thus draw up the slack and sagging. Of course, that did work quite well, but the surround is a different deal altogether. Once badly stretched, it's likely that there would be no fix other than to replace the spider. --Tom
  15. Are my AR9’s getting “old?” Steve F I bought AR9’s in 2010 in Boston from their second owner, a young EE who had graduated from MIT. He had re-surrounded the woofers and LMRs and had re-capped the x-overs. I’ve never opened up the cabinets to check his work, but the speakers sound great and I have no aural reason to doubt the quality of his work. I think the 9’s are remarkable speakers. They do everything at least very well and some things the best I’ve ever heard. I haven’t tired of them in 9 years, nor do I find their performance lacking in comparison to more “modern” speakers. I do a fair number of speaker reviews for the website Audioholics.com and I compare every speaker that comes my way to the 9. There are some very good mid-priced tower speakers out there these days, but even so, none surpasses the 9, in any area. But I am nagged by the suspicion that my 9’s are aging. I fear the aging is gradual and subtle, such that I don’t notice, and the 9’s margin of ascendancy over other speakers I’ve compared it to side-by-side is great enough that a slight diminution in their absolute performance is not enough to significantly affect their competitive standing. ________________________ There is likely more reduction in your hearing acuity in the intervening ten years than reduction in output fidelity in the AR9s, but without actual before-and-after response measurements to verify it, there is no way of knowing whether or not your AR9s have declined in output and fidelity, or if distortion has increased over time, etc. But, intellectually, academically, I can’t help but think there are areas in which my 40+-year-old speakers have slipped, even if just slightly. Specifically: 1. The woofers’ and LMRs’ spiders. Yes, they have been re-surrounded (by all subjective audible and visual measures, correctly), but the spiders are original. 40 years old. Surely, they have stretched and sagged a little over time. Maybe, just maybe, the spiders are not exerting quite the same degree of control over the cones’ motion as was the case when they were brand new. Could be that the woofers and 8” LMR are just ever-so-slightly looser and floppier than before. A tiny amount, but certainly possible. Sagging of the woofer spiders is more a function of gravity, not so much a function of wearing out during operation, in the 200003-0 woofer, although the strength of the spiders has probably diminished over time due to constant movement. If, however, the voice coils don't rub, or that there is no tear or rip in the spider fabric, you should be fine. The only true function of the spider in this woofer is to center the voice coil both longitudinally and vertically—hold it correctly in place—thus to bring the cone back to the center resting position and and prevent it from rubbing the pole piece. It therefore exerts very little force on the woofer cone. The air in the enclosure does most of the restoring of the woofer to the center position; the spider/skiver only do about 10-15% of that anyway. Remember: the electrical signal driving the woofer cone does not provide the necessary restoring force of the cone to keep it centered; that falls on the suspension system. Therefore, if there is no rubbing, banging noises, rattles, obvious distortion, off-center cones or physical rips... I wouldn't worry too much about the spiders. On this woofer, the spiders are loose but fairly durable, but they certainly will sag if the speaker driver (or the speaker enclosure) is stored face-up or face-down for prolonged periods. 2. I’ve never checked the condition and seal of the LMRs’ tubular sub-enclosure. A tube of heavy-duty cardboard is actually quite a strong structure, but I wonder if they’re still properly sealed against the backside of the baffle board. These speakers have been moved around a lot, from location to location. Glue dries out over time and becomes brittle. Wouldn’t surprise me if the glue seal has cracked slightly and there is a small air leak in one or both LMR enclosures. I think the seal for this sub enclosure was carefully crafted when originally designed, so it shouldn't cause an issue. You could always remove the 8-inch LMR driver and check the seal. No problem here. 3. Slight thickening/degradation of the ferrofluid in the UMR and tweeter. Again, they sound ok, but their output may be slightly compromised and/or the distortion/VC travel slightly impeded compared to factory-fresh units if the FF has degraded even a little. This may be a concern, and there is likely some drying out over time. The problem seems to be worse in many other brands than with the AR series, but no one knows how long it will take for the oil to dry out. Removing all of the old Ferrofluid and replacing it with the proper amount of new stuff is extremely problematical. On the other hand, we don't often hear of this problem as a serious concern with this series of AR speakers. 4. Mediocre 1978 crossover component quality and garden-variety internal wiring. This is both a design and an aging consideration. The x-o’s have supposedly been re-capped (by an MIT EE!) and they sound fine, but still, I wonder if there are any age-related issues with the x-overs. The internal wiring and binding posts that AR used were hardly audiophile quality by today’s standards, but does that matter? It could, even if just a little tiny bit. AR9 crossover components were actually of high quality, mostly Sprague capacitors and large-gauge coils and so forth, and the wiring was more than large enough in gauge with high-temperature insulation. The mediocrity might be in the (lack of) "neatness" of wiring, using very few Ty-Raps to bundle cables together and nicer-appearing crossover boards like those done by some boutique manufacturers during the day. The extra cosmetic things only cost money, and no one looks inside anyway. Nevertheless, the wiring is more than adequate for proper electrical performance. Also, most newer crossovers are usually completely board-mounted and circuit-board soldered, so the appearance of "hand-made" wiring is absent in the newer designs. 5. An undistinguished cabinet. These two 12” woofers can and do generate a great deal of internal cabinet pressure and panel vibration in a sealed enclosure. Are the cabinet glue joints still as strong and vital as they were in 1978? The panel thickness is ¾” all around and the internal bracing is minimal. If these speakers were done today by a high-end speaker manufacturer, the side panels where the woofers are mounted would be 2”-thick MDF, the front baffle would be 1” MDF and the inside would have top-to-bottom windowpane bracing. Does that matter? Probably a little. The AR9 cabinet is not heavily braced, but it is adequately braced for the need. AR extensively tested for that during the development stages, and the bracing was used that provided adequate cabinet damping. Oh sure, additional bracing would help to make the cabinet sides more inert, but there is probably negligible audible benefit and very little measureable benefit from doing that; again, it adds cost. The truncated top-back of the cabinet adds huge stiffness, too. As you know, I had a pair of B&W "Matrix" 801 Series II speakers, which I liked very much, and the cabinet was heavily crossed braced with a high-dollar, honeycomb bracing insert. I still had my AR9s at the time, too, and without doubt I felt that the AR9 was cleaner in the deep bass than the 801s, and the 801s were equalized flat to 18 Hz. Did that bracing make that much difference? It no doubt helped this vented enclosure quite a lot, but the cost to build that speaker was very high and the selling cost was exorbitant, more than twice as much as a pair of AR9s. I personally felt that the AR9 was a superior loudspeaker overall. The thought has crossed my mind to send the woofers and LMRs to Bill Legall at Millersound and have them completely rebuilt. I’ve also though about duplicating the x-overs electrically, but with much higher-quality components and having new custom cabinets built with the same internal volume, the same stuffing arrangement and the same dimensions, but with thicker panels and better bracing. This is probably the last thing you should do. If it's not broke, don't fix it. New spiders, cone and new surrounds will most likely raise the resonance frequency of those woofers and likely change their frequency-response characteristics , and this will, for better or worse, affect the sound the speaker. Just my thoughts! Good topic for discussion, though! —Tom
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