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tysontom

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  1. tysontom

    ADS L1590

    >OK, I'll bite - you have me curious. My impressions are from owning both, although some of the arguments are moot as at extended levels either box will drive the tweeters into protection - the limiting factor. I'd be doing A/B listening comparisons right now to confirm (I am actually wired for that), but my wife is home ;). In my system, if I were running only the 1590s, I would want a subwoofer. With the 980s, I run a sub only for protection... Jeff, I think you are confusing deeper bass with "more" bass, as in the 40-80 Hz range, such as double bass or guitar bass or what have you, and it sounds to me like you are getting a peak output in the 980 in that region above resonance, and likely you are not getting this same bump in output in the 1590. And by the way, you would never need a subwoofer with a properly working 1590, not with its bass extension. That said, I think the 1590 has a lower "Q" (more damping) at resonance than the 980, thus making the bass seem to you to be a bit weaker when compared to the 980 side-by-side. This is the only explanation I can give you for you feeling that the 980 is stronger in the bass than the 1590. If you carefully matched the output level from both the 980 and 1590 speakers (only one channel at a time) at around 300 Hz, and then swept frequency downward with a audio oscillator (a high-quality one such as a Hewlett-Packard instrument), you would see that output continues further into the deep bass with greater linear output in the 1590 than with the 980; it's that simple. If you are driving the tweeters into protection with a 200-watt amplifier, you are likely clipping the amplifier, causing excessive output into the tweeters; you are essentially over-driving the amplifier. The 1590/2 can easily handle 500-watt peaks, and the 980 can handle 300-watt peaks, so there is no reason to think the speakers are in protection mode with this amplifier setup unless the amp is over-driving. You might also have your bi-amp setup incorrectly wired; in any event, there are more opportunities for problem with bi-amping something like this than by simply using a larger single amplifier through a single input connection. Most importantly, bi-amping does not improve sound quality; it simply allows more power to be applied to the speaker. Bi-amping also increases the opportunity for mistakes and out-of-phase wiring issues. >I had attributed the difference to excursion, curious to hear they're similarly spec'ed. Always appeared visually different to my eye, and recall the 980 as readily able to blow out a match ;). Yes, the voice coils on both of these systems are very similar, and both have about the same excursion. To keep efficiency at decent levels, ADS would never have gone overboard on the excursion travel on the 12-inch woofer in the 980. If they had used a longer voice coil to increase the excursion to 1-inch, for example, the efficiency of the system would have dropped by half, and the midrange and tweeter drivers would not properly match the efficiency of the woofer. It would make no sense whatsoever to design a speaker in that fashion. >As to the ear, the other aspect is cabinet volume vs driver area - 980 has the advantage there: L980 = cabinet volume 3838in^3, driver area 113in^2 = ~34in^3 per driver in^2 L1590 = cabinet volume 4227in^3, driver area 157in^2 = ~27in^3 per driver in^2 This argument isn't valid because it does not take into account the individual speakers' parameters, such as damping, free-air resonance, and so forth. Remember, the two 10-inch 1590 woofers have the approximate radiation area of a single 15-inch woofer vs. the 12-inch woofer in the 980, and with similar excursion, the displacement-volume numbers are in favor of the 1590 >I presumed the dimensions of the cabinet should matter too, as there is wave action (and reaction) inside the box as well. Also please realize the power handling for the 1590 was across two drivers, same rating on L980 for *one*. Granted, it's probably commonality in the crossovers that lead to the consistent rating, if you are sure the voice coils are that similar... >Granted frequency specification is similar (I recall a modest edge to L980 LowF) and I do not have matching A/B documentation, but the L1590 spec's down to 28db at +/-3dB. Attached is a sweep from an L980... I don't understand what you mean by "wave action and reaction inside the box." That is a new one on me. The power-handling on the L1590/II is 500 watts, and the 980 is 300 watts, peak. The earlier spec for the first 1590, using slightly different woofers, was also 300-350 watts peak, but the later series II version is 500 watts. The 980 has always been 300 watts peak maximum power. Note, again, that the low-frequency edge is clearly in the 1590's favor with its lower bass resonance! This is the physics of what is happening; it's not my conjecture. By the way, the response graph you attached is not the (acoustical) output of an ADS L980. It is the electrical current or voltage across the crossover. It shows the energy path through the crossover, but not the acoustical output of the speaker itself. It therefore does not show you anything about the low-frequency output of the speaker itself. >As to pricing, I think the market was not really seeking office-fridge sized bookshelves ;), and the stands added some to the equation. I believe studio reference was the big target for the L980s. The real market was towers, and buying new then the 1290 would have been the value leader with the wifely acceptability thrown in. The ADS 980 was designed to be a competitor with the likes of Acoustic Research's AR-3a, AR10Pi, AR-11, Large Advent and so forth, but it was marketed to be a "studio monitor," to enhance its place in the speaker market place, and insofar as it was priced slightly above those speakers. It was somewhat larger to get a low bass resonance, which was set a around 40-42 Hz, similar to the AR-3a/AR-11. The 980 was also priced much lower than the 1590 as well, so you would expect it to not perform quite as well. Let me finish my comments by saying that I don't doubt your admiration for the 980. It is a wonderful loudspeaker, but you should understand that the 980 is not equal to the 1590 in low-bass output, extension or low distortion. I have always liked the sound of the 980, and I think it is one of ADS's better efforts. Compared with the 1590, it might be close, of course, but not equal and certainly not superior. I have spent this time simply to try to set the facts straight in this discussion about these two speakers. I am not trying to criticize or dispute your impressions, but I wanted to be sure that anyone else reading this would realize that the L1590 is a more potent system over a wider range, for good reasons, than the L980. --Tom Tyson
  2. tysontom

    ADS L1590

    What you are saying isn't possible. Maybe it feels like more bass to you, and perhaps the 980 is more efficient or has a lower impedance (making it louder for the same volume control setting) but the two 10-inch woofers in the 1590 can move as much air as a single 15-inch woofer, and we both know that a 15-inch woofer is larger and can move more air than a 12-inch woofer, all things being equal (voice coil excursion, etc). The 980 may also have a bass rise down close to resonance, and this would make it seem to have more bass output, but this is not like ADS to have this problem. The 1590 woofers also have a lower resonance than the 980, so the 1590s can also get lower in bass. Both the 1590 woofers and the 980 woofers use a 2-inch-diameter voice coils with about the same linear excursion. So do the math: the 1590 is inherently more potent in the bass than the 980. I'm not saying that for one reason or another, you are not actually hearing more bass from the 980; I'm just saying that technically, the 980 cannot move as much air as the 1590. The 980 is more akin to the Acoustic Research AR-3a in bass output; both of those speakers are closer in performance with about the same resonance, same woofer size, etc. More importantly, why would ADS have ever designed a large bookshelf-type speaker (studio-type) in their product line that costs significantly less than the 1590 to have better bass output? That doesn't make sense, and ADS would have been ridiculed in the industry if this were the case. --Tom
  3. Additional thoughts on Tmc's AR-2axs: Tweeters: · Measure tweeters for dc resistance with voltmeter to determine if they are the correct impedance (i.e., ≈2-4-ohm dcr would be 4-ohm version for AR-11, 10Pi; ≈5-6ohm dcr would be correct 8-ohm impedance for AR-2, AR-5, AR-12). · If you intend to keep the black-fabric-dome tweeters, check with Roy C about any changes made to crossover or changes that need to be made to crossover to make tweeters compatible. The tweeter level control will need to be somewhat lower with this tweeter compared with the original, as it is about 3 dB more efficient. Take a close-up picture of the tweeters for us to study the detail of the dome; Roy is probably correct about this being an AB Tech replacement tweeter. I have an old, but comprehensive AB Tech part-number list on file, and I can cross-reference the tweeter if you also can find the part number on the back of it. · To keep the original AR-2ax "tonal balance," try to locate two original-style AR-2ax (AR-5 and AR-LST/2) 8-ohm tweeters, either front-wired or back-wired. If the crossover had been changed by the service company in the 90s to accommodate the new black-cloth dome tweeters, be sure to return to the original crossover values. Midrange Drivers: · There do not appear to be any issues with these original 3½-inch midrange drivers, and you probably don't need to do anything to them. These were great midrange drivers, and this is one reason why the AR-2ax has such good focused-imaging properties when compared with the AR-5 or AR-3a, etc. Much voice and music intelligibility in the AR-2ax is due to these drivers. They don't disperse the sound as well as the AR-5 or AR-3a 1½-inch dome, and thus the AR-2ax is definitely not as 3-dimensional as the other two, but in terms of clarity and image stability, the 2ax is great. Woofers: · It is possible that these woofers were the last of the yoke-magnet versions, but these could have the larger ferrite-magnet assembly. Sometime during the 1973-1975 time frame, AR updated the earlier AR-2ax woofer (and the 8-inch woofers as well) to the new magnet assembly Either way, the voice coils, cone materials, acoustical parameters and so forth should be very close, and the bass performance should be nearly identical. · The woofers will have a free-air resonance of ≈26Hz, plus-or-minus, and the AR-2ax system should have a system resonance of ≈58 Hz, plus-or-minus. It is possible that the "refoam" job done by your service company was botched, and that the surrounds are a bit too stiff. Remove the woofers and gently push them in to check for compliance to see if they move freely, which they should. If they feel stiff and resistant to movement, you may have an issue with compliance; however, that is very unlikely. Normal AR-2ax bass response will be about 3 dB down at 48 Hz, which means that you should sense relatively strong bass output down into nearly any frequency where there is music. Bass drum and double-bass sounds come through quite clearly with the AR-2ax system, and you should be able to slightly "feel" the bass on this low-frequency output—not as strongly as with the AR-3a, of course, but not too far from it. · Proper bass performance is completely dependent on where the speakers are mounted in a listening room. The AR-2ax speakers should be mounted, either vertically or horizontally, on a shelf or stand at least one foot above the floor, against a wall. The speaker should not be located adjacent to a large opening into another room, such as a large archway. One speaker can be mounted in a corner. That is, the proper flatness and extension in bass will be determined by the speakers' placement in the room, particularly when mounted up off the floor but snugly against the wall (the front wall or facing wall into your room), and better yet with perhaps one AR-2ax mounted in a corner if the room simply doesn't support bass very well. If you pull the speakers out from the wall into the room, bass response will definitely get weaker, leaner and suffer accordingly. It is probably best to mount the speakers along the "short" wall rather than the "long" wall of a room, as this supports bass better as well. · Woofer polarity is also of paramount importance. If one woofer in one speaker is wired out of phase with the speaker in the other cabinet for some reason (service technicians sometimes don't realize this mistake), the bass will have a disjointed, diffuse sound, and low frequencies won't be properly reproduced. To quickly check polarity of the woofers in the speaker cabinet, you should enlist the help of your husband to do the following: solder a short length of wire to each end of a type-D flashlight battery. Remove the grill panel from the speaker, and have one person observe and the woofer. Then, take the stripped ends of the wires and touch the positive (+) terminal battery wire to the No. 2 terminal (this is the positive input terminal) on the back of the speaker. Observing the woofer cone, it should move out away from the cabinet. Then do the same thing to the other speaker, and it should also do the same thing. This way you know that the speakers have the same woofer polarity. It is also possible that something is miswired in the crossover or the woofer leads were reversed when the tech re-foamed the woofers, but check this first. Also, be certain that the speaker wires from the amplifier are in the proper polarity, too, such as the positive amplifier terminal is the same on both speakers. It makes no difference if the negative connects to the No. 1 or No. 3 terminal as long as both speakers are wired the same way; however, it's always best to try to keep the positive to the positive and the negative to the negative just for neatness and clarity. · Be certain that the woofer is sealed properly in the cabinet. If gaskets are used and are in good shape, you are likely sealed well for the proper acoustic-suspension seal. Air leaks can occur at the midrange and tweeter, too, so check everything for a good acoustical seal. The box does not have to be air-tight; this is an "acoustical seal" for the frequencies in use, not a hermitic seal, so if you gently push in on the woofer cone, it should not immediately return to the center position. It should slowly return to the center position within about a half-second or a second. This effect is not as pronounced on this speaker as with the larger AR-3, AR-3a, etc., but you can tell if the woofer has a good seal. · The fiberglass material in the speaker is likely fiberglass, not rock wool, in your version of this speaker. You will recognize the material once you open the speaker. Rock wool was used back in the middle 60s due to a shortage of fiberglass, and it works equally well for the purpose, but it is harder to handle. Be certain that you have the same amount of fiberglass in both speakers, and that it is distributed pretty much the same way in both speakers. Hopefully, the service people didn't change any of this. Speaker Grills: · The replacement grill material you use appears to be dense and somewhat thick, and it may not be acoustically transparent. The original linen grill material was dense enough to block the appearance of the drivers behind the grill, but open enough to allow sound energy to emerge without too much degradation. If you take your grill panel and hold it up to the light, such as window light or the sun, etc., you should see at least 50% light through the grill when compared with pure light. If it looks like the grill is blocking more than this, you should probably consider an original grill material. AR ran out of the original beige-linen grill that was used for all AR speakers in the Cambridge era from around 1965 until 1972, and then AR went to a thicker, white-linen material that was okay but not nearly as transparent as the original. Crossovers and Level Controls: · It is possible that your crossover networks are still within spec. There is no way to know for sure other than by disconnecting one lead of each capacitor and measuring the capacitance of each capacitor and determining if it is over 15% out of spec. The chokes (coils) are rarely out of spec, of course, unless thermally damaged somehow, and you would know this immediately. You could, of course, go in and change all of the capacitors to be sure, but that is overreacting. I have found many old AR speakers that had crossovers still fairly close to spec. Also listen to your speakers to see if you detect any distortion or anything unusual in the output of the drivers. Again, Roy C is a great resource in helping you determine what you may need to know here. · Level controls are the primary source of headaches in these old AR speakers. By the time your speakers were made, AR had adopted an improved version of the Aetna-Pollock level control that had been used for so many years, and the wiper-spring tension was significantly increased. This control is characterized by the aluminum shaft end on the back side of the speaker, and I suspect that you have this version, and that is has not been removed and replaced. Even the improved control did not completely stop the contact issue. If the controls still work, even if scratchy, the best thing to do would be to get some contact-cleaner spray and try to get it on the wiper surface. To some degree, you can let it run down the shaft from the outside, but getting inside is the better way to do this. You can also turn the control back and forth repeatedly to "clean" the contact surface if you still have fairly good electrical contact. As a last resort, you could remove the controls and manually burnish and polish the surfaces to improve the contact. This usually always works as long as the controls haven't been badly corroded over time due to moisture, etc. --Tom Tyson
  4. TMC, your AR-2axs were made after 1973, likely in '74, so the invoice you have would be "1975." If you look as the clerk's sloppy handwriting, you can see that it is a "5." AR moved from Cambridge to Norwood, Massachusetts in 1973, and your speakers are definitely Norwood models. The label on the back does show 10 American Drive, and this would be Norwood. Anytime you see the blue label on the back, you also know it is a Norwood-built version. Norwood versions also had Velcro-attached grills, and your's have that feature. These also still have the "tweeter terminal strip" (adjacent to the incorrect tweeter), and these attachment points were present on a lot of the early Norwood AR speakers. In this case, AR had moved to back-wired tweeters, but they probably had a lot of baffle boards (the front panel that holds the speakers) with the earlier front-wired terminal strips. This strip would not have actually been used unless these had some left-over front-wired tweeters. In any event, it has nothing to do with the quality of the speaker! I am pretty sure that the tweeters are the later AR-12 (or possibly AR-11) tweeters; i.e., these tweeters were used in the 1976 AR-12 if they are the 8-ohm version, or they are the AR-11/AR-10Pi versions if they are 4 ohms. In any event, they are not correct unless a crossover adjustment has been made for them. You should first determine the impedance, and you will need to remove one or both of them and measure the dc resistance ("dcr"). The proper dcr measurement should be in the 6-ohm range; if they measure 2.5-3.0 ohms, they are the AR-11/10Pi versions. All of these 3/4-inch tweeters will mount in the same cutout, so it is very easy to interchange tweeters. It is likely that these black tweeters are significantly brighter in output than the original versions, and this isn't always better. If you can attach a close-up picture of one of the tweeters, that would be helpful. Anyway, you have a wonderful pair of speakers, and you should definitely rebuild them as close to original as possible. Properly working, a pair of AR-2ax speakers is very accurate and natural-sounding, and except for the last 1/3-octave of bass, they are the equal of the bigger AR bookshelf speakers in smoothness and overall sound. Because of the 3-1/2-inch midrange cone driver, the 2ax actually images slightly better than the AR-3a and AR-5, but lacks a little of the spaciousness of the latter! Anyway, if you do stay with the retrofitted tweeters, contact Roy C. on this site for advice on the best way to correct the crossover for the tweeters. For the best acoustical (or "spectral") balance, you might want to try to locate some original 8-ohm AR-2ax 3/4-inch dome tweeters. You can find either an early set of AR-2ax (or AR-5 or AR-LST/2) front-wired tweeters or a pair of later-model back-wired tweeters, and you can make them work with your cabinet either way. Quite frankly, the early front-wired tweeters were somewhat better built, but either type will work. Roy C can also help you get these old tweeters re-wired with new voice coils and suspensions. We will all help you in any way possible to get these back to their original sound! --Tom Tyson
  5. tysontom

    Request date of birth AR2

    Georgio, those are very nice early examples of the wonderful AR-2! And your cabinets are plywood bottom panel with veneered (walnut, it appears but possibly cherry) NovaPly for the other panels along with the solid-stock grill molding. Only the AR-2 had this unfinished plywood panel, as the AR-2a was finished on all sides. Both the AR-2 and AR-2a were designed to be placed horizontally for best dispersion from the tweeters. I'm thinking these are Cherry, but I can't tell for sure. Henry Kloss worked on the design of the AR-2 throughout late 1956, and he had the speaker about ready to go around January, 1957. The Carbonneau 5-inch tweeters (the same units used in the Kloss-built Baruch-Lang corner speaker) were treated by Kloss to smooth and dampen the response, and the end result was a relatively smooth, clean treble up to around 13-15 kHz. There was a problem with the woofer, though, and it would ride out of the gap under high power. Thus, the AR-2 could not be shipped when planned. In February, 1957, however, Kloss was gone from AR without fixing the problem of the woofer, thus delaying this important new product. Edgar Villchur had to redesign the woofer before it could ship, and it was in late March or early April, 1957 before it shipped. Monthly production figures were pretty high, and I think your pair dates to about 1959-1960. Only way to know for sure would be to pull a woofer to see if there is a date on it, but it's not worth disturbing the system for that bit of trivia. Great speakers! --Tom Tyson
  6. tysontom

    An AR Christmas

    Not bad at all!
  7. tysontom

    An AR Christmas

    This wonderful Christmas poem was sent to me several years ago by a great AR friend (who reports here frequently): T'was the night before Christmas And all through the room, 3a's were playing, Their bass tight with no boom. As Nat sang "Chestnuts..." He sounded so near, Those dome drivers Were playing so clear. From high notes to low notes It sounded so good The melody came through Just as it should Now Santa loves music, And his gifts are so right, "AR speakers for all And to all, a good night!" Merry Christmas! --Tom Tyson
  8. tysontom

    ADS L1590

    Huh? Are you saying that the L980, with its higher-resonance enclosure and single 12-inch woofer, has great power-handling, etc than the L1590? That does not make sense, but it's entirely possible that I didn't understand what you were trying to say. --Tom
  9. tysontom

    Original AR 3a's???

    Roy, while I have seen very few veneered-plywood cabinets, I certainly can't argue with your empirical evidence! So I certainly stand corrected, but I believe that plywood was a rare exception for veneered cabinets. Again, when it comes to the history of old AR products, anything goes. Years ago, AR spec'd mdf panels for veneered cabinets for the various reasons I stated earlier, such as (mostly) lower cost, panel smoothness, dimensional stability and so forth. I suspect that if mdf panels were in short supply, the cabinet shops, such as F.B. Hicks of Cambridge, Cab Tech of Nashua and Pine and Baker of Cambridge at Lechmere Square would use what they had to fulfill requirements. --Tom
  10. tysontom

    Original AR 3a's???

    Wow! Thanks so much for sending that link! I have only seen a few AR-3s built after the very first ones that had all-plywood cabinets with wood veneer! These AR-3s, SN C 44135 and C 44136, are quite unusual, especially since they were built well into the mid-1960s, probably around 1965 or so! --Tom
  11. tysontom

    Original AR 3a's???

    I agree with Roy completely on most of his description of these nice AR-3as. What I see first is the different tweeter (definitely the Peerless 1-inch) on a custom mounting plate to fit the AR-3a cabinet, using the stock AR screws. The midrange has a similar custom mounting plate (using AR pan head screws instead of the flat-type), and the lead wires are under that flange piece, as Roy states. I wonder what happened to the original midrange mounting flange when the new mounting plate was added; apparently it was cut down in size and glued to the underside of the new mounting flange. The original midrange-driver flange cannot be removed without damage to the dome voice coil, etc. The woofer is an early ferrite version (long wire), but with a peculiar foam surround and a lot of glue, not too atypical. The cone surface appears to have been coated similar to treatments done on the AR-2ax woofers, so perhaps the cone is original and stock. The cone might have been one of the ferrite woofers with a damping ring (since removed), but I can't tell. At first, Roy Allison and Chuck McShane experimented with different, subtle treatments to the cone on nearly all of the AR woofers, so there were variations. I could be wrong, but I don't think these cabinets are "walnut-clad plywood." I think Roy might be referring to the front baffle and the rear panel, but not necessarily the veneered panels, as they appear to be original walnut-panel MDF cabinets with solid-walnut grill molding, completely stock from what I can tell. After the early AR-1 cabinets into the late 1950s, AR stopped using plywood cabinets (except for the front baffle and rear panel) for veneered-wood finishes. There might be exceptions, but I haven't seen any. The veneered cabinets were usually Novaply or MDF-type cabinets. The "Utility" plywood cabinets, however, were unfinished-pine plywood on all panels. The AR-3a-style grill mounting strip around the perimeter of the black-painted baffle board appears original, and there are traces of USM glue in places. I can't tell about the actual grill panels themselves, but the grill-cloth appears to be the Norwood-style white-linen material used after 1973 or so. --Tom
  12. tysontom

    AR-303A Rosewood Ser. Nos. 0000-0001 For Sale

    I don't know what finish was used. I will try to find out.
  13. tysontom

    AR speaker low frequency perspective

    Note that I have toned-down my original message! I got a little carried away!
  14. tysontom

    AR speaker low frequency perspective

    Aadams, it probably goes without saying that I will frequently jump at the chance to debate this subject -- I'm sure you know that by now -- but you are exactly right that I should have first asked where you were going with this post. As you left it, however, it was wide open to interpretation, and I was right in there. It might have been better for you to have described what you were trying to say in your first message; thus a debate could have been averted. I completely missed the 42 Hz blue line thing you mention above. I see the blue line, but I didn't see the reference to the 42 Hz in your image; I now understand that you were pointing to a specific piano key that represents 42 Hz, the approximate resonance frequency of the larger AR bookshelf speakers. I tend to get into a spirited discussion anytime I suspect something isn't correct, but I also realize that you are an AR buff, no argument there. Discussion and debate are good things and no harm meant, but I tend to raise the tension level sometimes, so I apologize for that. --Tom Tyson
  15. tysontom

    AR-303A Rosewood Ser. Nos. 0000-0001 For Sale

    Kent, the black "laminate" AR-303, the first version, was a non-wood laminate. It was a hard, "steel" Formica-type laminate, and the material was very durable but it tended to show fingerprints quite easily. There was also a cherry-veneer version of the first 303 which was real wood and, finally, a genuine-rosewood cabinet in some of the last AR-303 original versions. With the AR-303a, all were made with genuine rosewood veneer. Granted, this was not the rare, stripy Brazilian Rosewood, long banned for export, but likely Bolivian or another black rosewood species. The AR-303a manual also states, "The AR-303a Loudspeaker System is finished in a genuine rosewood veneer on all sides, accented by a unique gold logo and serial-number plate." --Tom
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