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About tysontom

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  1. No, not meant to be rhetorical. If you prefer spaciousness (and sit back within the listening room and not right in front of the speakers), then the wide-dispersion speaker will be better for you. You will get a better sense of ambiance of the recording space, much akin to sitting back somewhat in a symphony hall or large musical stage. I've always felt that if you want the best of both worlds, spaciousness and "imaging," headphones (which are "binaural") provide a good solution, as you hear what the microphones recorded without the second, or double, reverberation of the playback environment..
  2. Dear Adams, As we've said previously, all things being equal, the 1½-inch dome midrange driver will have wider dispersion in the treble frequencies than the 4-5-inch cone driver, simply by virtue of the smaller radiating diameter. Domes typically are better behaved in the higher frequencies with fewer break-up modes, but it also depends on how high the cone driver is taken in the system before being crossed over to the tweeter. Subjectively, if you sit close to the speaker and the speakers are aimed at you, the 4-5-inch cone will have a more focused sound (the so-called "image") than the wider-dispersion dome driver; however, further back into the room, the 4-5-inch driver will have lost the sense of spaciousness due to the lack of off-axis energy and the diminishing direct output (as a function of distance to the speaker from the listener). In effect, unless the cone driver is over-bright in direct output, it will lose total acoustic output the farther back you get from the speaker and can actually begin to sound dull due to the lack of total acoustic-power output in the room. Therefore: · Dome has a more diffuse, less-focused sound close to the speaker; · Cone has better "image" but less spaciousness back in the room. Which is better is up to you. Do you like spaciousness or intimate detail sound? —Tom Tyson
  3. Ha, ha! Both contenders have begun "bouncing" off the ropes a bit, slugging it out. AR-3a 3½-inch dome midrange vs. Boston Acoustics 3½-inch neodymium-magnet cone midrange. No winner, no loser, but now it has become an almost purely academic argument. To a degree, the debate has come down to a subjective-versus-objective, "philosophical" debate. The Boston Acoustics 3½-inch midrange was likely an excellent driver, and no one questions that assumption; in fact, it may be the finest transducer the world has ever known, but what is not known is its actual quantitative performance, how smooth or rough its output, warts and all. However, I do believe what my friend Steve tells me, and therefore I must have faith that this BA driver is/was a stellar performer. Faith! But I am also a skeptic when it comes to electro-mechanical devices, and I like to see the proof of performance. I fall into the old school on measurements. I am conflicted. With quantitative loudspeaker measurements, a company can back up its performance claims to some extent with lab results, thus reinforcing its claims for "performance excellence," but this trend was never very popular (and grew worse) in the consumer high-fidelity loudspeaker industry, showing precious little correlation with speaker sales. Alternatively, speaker measurement tended to open a can of worms. It cost a lot of money and required additional engineers, and it exposed vulnerabilities—someone would have to answer for that; therefore, most consumer speaker companies steered clear of big anechoic chambers and such. Avoid such testing... "like the plague." I am reasonably confident that the Boston Acoustics speaker company also did not place much credence in advanced-measurement equipment and research; certainly if it had, the public would have seen more of the output from the labs, or we would have test results here on the little 3½-inch cone midrange driver. Of course, there were tests done and measurements made, but no in-depth, detailed acoustics measurements in the AR manner (the pro-audio folks did these measurements). BA had very innovative products and commercial success; research, not so much. Had there been, the company would likely have capitalized on it and published even the most rudimentary response graphs, distortion curves, power curves and so forth, making a strong case for a family of fine reproducers. They would say, "Not only do our speakers sound great, they also measure well!" The lack of this type of testing was steeped with tradition going back to the KLH and Advent days under the guidance of creative-genius Henry Kloss. There were virtually no lab measurements from those companies, either. No anechoic chambers, no holes in the ground to measure woofer performance, etc. Kloss was not a trained acoustics engineer, and he believed not in quantitative acoustical measurements beyond very basic in-room measurements. He was, however, a creative, very bright "tinkerer" with a exceptional ear for "voicing." He knew a good thing when he heard it, and usually he was right. He therefore taught his disciples the art of speaker "voicing." This philosophical lineage dribbled downhill from KLH to Advent and on to Boston Acoustics, founded by the former Advent team of Andy Kotsatos* and Frank Reed. Nevertheless, this company was very successful, and a lot of this success can also be attributed to the marketing and design thinking of our friend Steve! On the flip side, what you did see from the old Acoustic Research was the good-and-the-bad measurements from AR's anechoic, free-field and reverberant measurements. On top of that, all of the measuring instruments at Acoustic Research were calibrated regularly to assure compliance with ASA and US Bureau of Standards (now known as the National Institute of Standards and Technology). Rigorous test methods all the way. So, at this point we know exactly what is going on with the AR 1½-inch dome driver. We know whether or not it has any peaks and dips along the way, both on- and off-axis, and we know its strengths and weaknesses. We don't know this about the BA 3½-inch midrange driver. We assume—and have faith—that it performs superbly, but there is no hard-core evidence that it does. Now, the AR-3a edge-molding "window-frame, horse-blinder" effect is real in one sense: near-field measured response. But diffraction occurs at nearly 90˚ off axis from the drivers, so it is not a major problem, even in the near field; importantly, diffraction is a major issue if one listens to the speakers from 3-5 feet away. Once back in a listening room, edge-molding diffraction, lobing, crossover interaction and other anomalies are literally swamped and cannot be measured or even identified, as all of the reflections from the output of these drivers is blended into a seamless acoustic-power response output. It is certainly true that the AR-10π and AR-11 improved on the diffraction issue, but it is imperceptible back in the reverberant field. What might have been an improvement in reduced diffraction is also offset slightly with less-stellar dispersion of the newer cloth-dome tweeter. So, where does this leave us. These are two top-notch midrange drivers, but we don't have all the data we need to know the true performance of the BA driver. * Andy Kotsatos was "Andy Petite," a name that evolved from his father's nickname, "Le Petit," acquired as a restaurant owner in New York. —Tom
  4. This is a interesting discussion, but it is more subjective than objective. Without frequency-response and power data on the BA midrange unit, there is no way to know how well that unit would actually compare with the 1½-inch AR-3a dome mid. It might actually outperform it, but we don't have hard data. "And it was a far superior performer at the lower end of its band" might also be true, but that is a subjective description and not a completely valid argument. Technically, of course, a low-resonance BA 3½-inch cone driver with a larger surface area—and likely an underhung voice coil—should perform much better at lower frequencies than the AR midrange. Nevertheless, the AR-3a midrange is uniform and very flat within its operating region of 575-5kHz, and our discussion was originally about dispersion and ultimately, power response. It's just that at the lower end of its operating range, the AR-3a midrange won't blow you out of the room. At normal levels, there is never a problem. It is also true that AR recognized the need for greater power-handling in the midrange, and raised the low limit on those drivers in the newer AR9, AR90 and so forth, to reduce the stress on the midrange. At 30˚ to perhaps 45˚ off axis, the 3½-inch BA cone midrange should do well within its range; however, beyond that angle, there is a question as to how it would perform compared with the AR dome midrange, and flat power response requires very wide dispersion at all frequencies. You have hit on one of the big differences between the early manufacturing processes and later, more automated production, when you described the "rejected" drivers at AR during production. The rejection rate of AR midrange drivers was not as high as you describe—the ¾-inch tweeters were—but it was obviously higher than speakers built with higher automation in later years. Although the 1½ MR used in the AR-3a was less "hand-made" than earlier drivers, it still was tested for any quality issues and rejected if it didn't meet certain standards. AR did have barrels of rejected drivers that were destined to be rebuilt and returned to inspection, but in later years, production methods greatly improved for the high-fidelity industry, for sure. In the end, the performance and quality of the product are what counted, and this required more QC intervention with the more hand-assembled speakers of the 50s-80s than later automated production. Time does "move on," but this is really not our discussion here. —Tom
  5. Steve, Great discussion! That 3.5-inch midrange BA driver description sounds fascinating and quite impressive. It was undoubtedly a stellar performer with little or no stress under normal circumstances. It is very true that the AR-3a midrange can be stressed if pushed (but generally there is negligible distortion in the midrange at any reasonable output level). The voice coil has marginal overhang in the gap, but there is considerable flux outside the immediate gap, too. Nevertheless, the the dome is small and can move only so much air, especially as the lowest-operating frequencies required of it. Do you have any measurements on the BA 3.5-inch driver, on and off-axis? It would be interesting to compare its anechoic-frequency curve, on- and off-axis up to 60 degrees vs, the AR 1.5-inch midrange to compare output linearity. Insofar as the BA 3.5-inch MR used a neodymium slug-type magnet, it would mandate a large-diameter voice coil just to have room for the magnet assembly within the speaker driver itself. Yoke and slug magnets are also somewhat susceptible to demagnetization from the voice coil if power or heat is sufficiently high enough, but this was more of a problem with woofers, and not so much of a problem with neo magnets, though high heat is a problem (thus the big heat sinks used by BA). There were often reports of some yoke-magnet woofers and mids losing magnetization because of excessive current through the voice coils, as the coils were directly adjacent to the magnet itself. Also, the 1.5-inch MR diameter should not be conflated with an AR-2/5/6 woofer's 1.5-inch diameter voice coil; the windings on the AR 10-inch woofer were much larger bell wire with a much longer coil height, and the woofers were capable of several times as much actual input current. Nevertheless, a 1.5-inch voice coil in a 3.5-inch driver is impressive. I wonder what constitutes "noticeably directional?" Is it beyond 30 degree off axis, 60 degrees? I think it is just the point at which it becomes noticeable, and that might be just a few degrees off axis at higher frequencies. The beauty of the AR-3a 1.5-inch dome midrange is that it does well out to 60-75 degrees off axis -- well beyond its intended operating band. When I look at AR's 3.5-inch midrange driver, as used in the AR-2ax, early 2x and AR-4, the 30-degree performance is pretty much equal to the 3a dome up fairly high, but the wider the measurement angle, the dome is much better; thus the superior acoustic-power response of the smaller-diameter driver. It's all an academic argument, but fun to contemplate. So, therefore, the 5-inch driver is clearly no match for the 1.5-inch driver in off-axis performance, but the 3.5-inch MR is a much closer match. The answer as to linearity and smoothness when comparing those two would reside in the anechoic-chamber measurements themselves. For sure, if power levels get too high with the AR-3a, the dome midrange can run out of excursion, yet it is amazing that the AR-10Pi could sustain 800+ watt peaks during the Neil Grover live-vs.-recorded drum demonstration! You were there, too! This is the same midrange, though these may have had Ferrofluid! I do know that the tweeters had Ferrofluid. Victor Campos told me that the bulk of the high-energy peaks went to the midrange/tweeter units (mostly drum "rim" shots), and that no drivers were lost due to thermal damage during the actual demonstrations. Two woofers were damaged because of the Dunlap-Clarke Dreadnaught 1000 amplifier-bias failure. --Tom
  6. Thanks Ligs. That certainly is a pretty curve, but.... The problem is not so much the 30-degree off-axis performance; the real issue is how it performs 60- and 75-degrees off axis. This is where the small dome has a huge advantage. The problem with any cone driver is that you cannot make a 1.5-inch cone driver that can handle sufficient power that would otherwise be able to compete with the 1.5-inch AR dome midrange. It's down to the physics of the moving system size, and a dome driver has it handled. In addition, these should be anechoic-chamber measurements of both types of drivers to get true comparisons, avoiding the various smoothing and gait settings that are necessary when measuring in free field or rooms. There is no real standard here. In essence, room measurements are helpful but do not necessarily tell the true picture of what the driver is doing -- warts and all. Thoughts? --Tom Tyson
  7. ____________________________________________________ I took the measurements (from that link) of the Infinity Reference r152, with its 5-inch woofer/mid and 1-inch semi-horn tweeter, and I compared the off-axis measurements to those of an AR-3a midrange measured in AR's anechoic chamber in 1967 made around the time the AR-3a was commercially introduced. Some observations: The graph (chart) used for the Infinity measurement is "spread" a bit in the horizontal plane, giving a picture of a smoother-appearing output across the band; The Infinity was only measured out to 30˚ off axis and not beyond (the AR-3a was measured to 60˚ off axis, a much more difficult measurement; The Infinity measurement was not a true anechoic measurement, but rather a "gaited" measurement, and although extremely close, it is not a true "apples-to-apples" comparison, but definitely close enough to make a quality judgment. The AR-3a measurement was taken from 575Hz (lower crossover) to 5 kHz crossover to the tweeter. Taking these characteristics into account, the AR-3a midrange is flat, ±3 dB, 575 to 5 kHz at 30˚ off axis and ± 4.5 dB, 575 to 5 kHz, 60˚ off axis! The 5-inch Infinity woofer-midrange, assuming ≈3 kHz crossover, is ±6 dB, 600 – 3 kHz at 30˚ off axis. This comparison demonstrably shows the superior on-and off-axis performance of the AR-3a 1½-inch dome midrange, and that it is flatter, off-axis, even at 60˚ off-axis, up to a higher frequency than the 5-inch cone woofer-midrange driver in the Infinity. There is really no comparison. That said, it is very important to understand that acoustic-power output is not nearly important today with speaker designers as in the past. It is more academic today, but in terms of true acoustic performance, the small dome midrange will easily out-perform a 5-inch cone midrange in dispersion, and that was the purpose of the original message! It might be possible to say that the AR-3a dome is a more accurate reproducer, but that might open another can of worms! —Tom Tyson
  8. Steve, what a provocative topic! Where has the dome midrange gone? How about, where has the high-fidelity loudspeaker gone? It's all a moot point today. This is a very interesting subject and, for sure, very controversial. In my opinion, I think it comes down to the philosophical differences between speaker designers Henry Kloss/Andy Petite (Kotsatos) and those of Ed Villchur/Roy Allison, and how each perceived speaker quality and a speaker's sound in a listening room. The answer lies somewhere in the midst of what is important to the listener, acoustic power or near-field frequency response. Is flat, forward-sounding speaker output with average acoustic-power output better than rolled-off near-field response with better acoustic-power response? A louder, more forward-sounding speaker sound usually trumps the more laid-back, "reticent" sound when listened to in the near field. For many years, Acoustic Research studied the sound of concert halls and what the listener hears in the reverberant listening environment. Much of this research by AR was done in conjunction with Leo Beranek of Bolt, Beranek and Newman (now Raytheon BBN Technologies). BBN studied the acoustics of concert halls all over the world, and their research offered a great body of data in helping AR determine the sound reaching the listener's ears in concert halls, etc. In essence, flat acoustic-power output in a listening room, though slightly downward-tilting to a degree, was closest to the experience of live music in a concert hall. But not everyone listens to classical music; nevertheless, any type of music from jazz to rock will have a widely dispersed spectral balance, especially the farther back in the room one listens, so acoustic power applies to all types of music in one form or another. Also, a speaker with very wide dispersion will have a relatively flat acoustic-power (or integrated-power) response when measured in a typical listening room. A speaker with less midrange and treble dispersion will have a rolled-off power response in that same environment, a function of less sound reflection off the boundaries of the room. Important: a "bright," forward-sounding speaker with relatively even on-axis frequency response across the spectrum, but embodying average dispersion and average acoustic-power response, will invariably sound duller and less three-dimensional back in the reverberant field; alternatively, the rolled-off, reticent-sounding speaker with excellent dispersion and power response will sound brighter and more "spacious" back in the listening environment. Therefore, I would add, a 3-way BA speaker with a 1-inch dome tweeter and a 5-inch midrange could not approach the acoustic-power response of an AR-3a in the reverberant field, but the BA will surpass the AR-3a up close. Dispersion is a function of the frequency wave length and the radiating-diaphragm diameter, and the smaller the radiator diameter, generally, the wider the dispersion down to the frequency at which the driver is omnidirectional. AR designed dome tweeters—not so much because of their small diameter—but because they were driven at the periphery of the diaphragm (the edge of the moving system), which gave significantly better control over the moving system with fewer break-up modes, lower distortion, better transient behavior due to the lighter mass of the moving systems and so forth. This translated into lower distortion, greater clarity and greater smoothness. The small size does give better dispersion, naturally, but a 1-inch dome will not give better dispersion than a 1-inch cone driver! So the dome design is more than just dispersion. An AR-3a 1½-inch dome midrange dome will produce wider dispersion throughout its higher-frequency operating range than any 5-inch cone midrange, despite the superior sensitivity and on-axis output advantage of the cone driver. In the near field, particularly, the cone driver will typically be more efficient, brighter and more forward-sounding than the AR-3a midrange dome. The AR-3a's small midrange dome does has limited excursion, as the voice coil has very little overhang in the gap and simply cannot produce very high output. It is sufficient for nearly any type of music for home use, but not by any means sufficient for high-output sound-reinforcement levels. Typically, a 5-inch midrange driver can belt out much great output, simply because it has a significantly larger moving system to move more air, greater overhand with more excursion and a voice coil wound with heavier wire, allowing higher electrical and acoustic power levels. The AR-3a dome uses a very large magnet with a lot of gauss, but the small dome simply can't move much air. Under duress, therefore, the AR-3a midrange can burn out, whereas the 5-inch midrange will distort badly before it gives up, and this is likely at a high output level. So what does all this mean? To Andy Kotsatos, the AR-3a midrange was a "joke," so he says, but philosophically, Andy was from the Henry Kloss school-of-thought to build a speaker that sounds good both in the near field as well as "ok" in the far field, despite the small differences that might be measurable. Near-field clarity and brightness was important in the high-fidelity showroom—thus to Andy and Henry—not the reverberant field. Kloss found this out immediately after leaving AR in 1957, and he sold his KLH speakers directly against AR speakers (some of which he helped design!) by demonstrating that the AR speakers were low in treble output and low in sensitivity. In most hifi showrooms, people listened a few feet away to speakers mounted on shelves or on speaker stands, and many decisions on "speaker quality" were made based on this method of audition. The end game in the design of all of the BA and Advent loudspeakers (not to mention KLH and others earlier) was subjective "voicing" in a listening room by Andy (and Henry Kloss before that), deciding how loud or how bright, etc. Then, for the fun of it, they place an AR-3a up on the shelf and sit back a few feet and listen to that speaker: reticent and hard to take at 5 feet away, correct. All sorts of interference effects, lobing and interaction, coupled with an output that is 3-7 dB down from the woofer level at close range. Therefore, the speaker is a "joke" in their minds. To them it is overrated, "lousy" and probably "stinks" and is "no good." People in a showroom will be able to hear this. KLH and Advent dealerships across the globe were "coached" on methods of dealing with the "AR" sound, and since there were many more mail-order outfits selling AR with its "laissez-faire" pricing policy (other manufacturers insisted on fixed suggested retail prices), there were relatively few dedicated AR dealers to defend the AR speakers. Still, AR outsold everyone in the 60s. Neither Advent nor Boston Acoustics did much, if any, anechoic-chamber or free-field measurements, and certainly there were no power-response measurements. Not even driver response curves or system anechoic curves from Advent, KLH or BA were ever published in any literature to my knowledge, so we have no way of knowing how good these speakers measured at the time. They sounded good, of course, and these speakers sold extremely well in the late-60s and into the 70s, eventually outpacing AR sales. So Advent, KLH, Advent (and many other) product-design decisions were driven heavily on market demands by dealers; AR, on the other hand, with its mail-order sales through the mid-60s didn't care about hifi showroom effects, and relied on reviews and critical acclaim and so forth. AR won this battle in the 1954 through 1967 era, but after Ed Villchur sold AR and after Roy Allison and others left AR in the early 1970s, things changed a bit at the company. --Tom Tyson
  9. It was definitely an AR-1 cabinet, and the back panel is original, but there was no way of knowing if it had all of the original drivers. AR never had a burlap/cane grill like the one shown -- and would never have sold one with a grill like that -- and the comment by the seller that it had never been opened is surely false. Someone along the way had been inside and then replaced the grill. AR did put special grills on speakers, and on special order would install other materials other than what the company supplied, but burlap is notoriously poor for that purpose. I'm surprised that anyone would buy it without seeing the having the original AR grill, but many buyers simply don't know what is original and what is not. --Tom Tyson
  10. There is really no prettier loudspeaker than the lacquered-mahogany AR-3. Here are a couple of other pictures for reference: The lacquer finish is not glossy so much as it is semi-glossy, smooth with no grain showing. It is akin to the Steinway piano finishes, done the same way. The speaker (one of two) looked shiny, but it was due to the flash used. --Tom Tyson
  11. Hi Luigi, You're right that it is the "New-Look" Mark II version, but I think the AR "Advanced Development Division" marketing people probably used whatever they had to make the cutaway versions. The "ADD" moniker went away pretty soon after the "New Look," too. These cutaway versions were also very early in the Mark II process, but there are no serial numbers on either of the display speakers. AR also made a beautiful, single AR-3 cutaway, but it was apparently dismantled at some point. This speaker was on display in the AR Music Room in New York's Grand Central Terminal. It was powered by a 5 Hz sine wave, with the woofer slowly pumping back and forth to show the acoustic-suspension principle. There was a Plexiglas AR Turntable, but it too was destroyed. Fiberglass was used well into the later versions, but I don't know the date of change to polyester. Another thing: fiberglass can be placed in "squares," to appear to be neatly packed inside the cabinet, whereas polyester would be all over the place. The woofer voice-coil former is Nomex, commonly used in this woofer, but late in the 70s AR began using aluminum for the former. Aluminum dissipates heat better, yet Nomex can stand higher temperatures. --Tom
  12. Yes, yes. There I am explaining the intricacies of the Electro-Voice Interface A. That is Steve F "glazing over."
  13. Hi Luigi, I'm unsure of the details of the England and Holland production protocol; I do know that the drivers were originally produced in Cambridge, Massachusetts (and later in Norwood) and shipped to Europe. Later, some drivers were produced in Europe along with cabinets. I need to research this a bit to find out what happened. However, I honestly don't know how Teledyne AR worked the serial-number range. For example, I always understood that the orange tweeters were non-Ferrofluid drivers and that the black tweeters were Ferrofluid, yet the serial number of Jasper's (Patagora's) AR-10s fall into the Ferrofluid-tweeter range, another mysterious thing in the world of high-fidelity loudspeakers! I do agree with you that the "E" and "H" preceding the number indicated England or Holland production. Veering off topic a bit, Acoustic Research at first used an export service, Delrama, Inc., to ship products across the globe, but later expanded production and testing into Europe. Delrama became unnecessary, and I acquired quite a lot of NOS products that came from Delrama inventory, including the last existing AR-3a "cutaway" speaker. It was number 2 of 2 made, I believe; the first two were dismantled after the AR Music Room was discontinued in 1973. The AR-3a "cutaway" was a hand-made work of art made by Sumner Bennett with the help of AR's cabinet-maker. After this one, the "cutaway" AR-3a is extinct, but it will be protected. The AR-3a "cutaway" is similar to the AR-11 "Visible Speaker," another rare item. The AR-3a "cutaway" was used in Italy, Germany, England, France and Holland as well as in shows in Australia and China from time to time. It traveled the earth.for several years, starting in 1968, accompanying executives from Acoustic Research, such as Roy Allison, Sumner Bennett, Martin Borish and Gerald Landau. After AR went to internal, self distribution, Delrama was out and didn't know what to do with the AR-3a "visable," so I acquired it from them along with their existing inventory of NOS AR-3, AR-3, AR-3a and AR-1 service-replacement parts. I've given most of those parts to AR friends in need. The AR-11 "Visable" was an attempt by Teledyne AR to do the same thing with their Advanced Development Division speakers, and several (probably a dozen or more) of the "Visable" speakers were made available for franchised Teledyne Acoustic Research dealers in the US (and perhaps Europe, too). It could be purchased with a small sine-wave generator and amplifier and an AR metal speaker stand, but only a few dealers opted for this interesting sales aid. I apologize for straying off topic (original topic was the AR-10). --Tom Tyson
  14. As others have indicated, these are definitely AR-10π speakers—the original version—sometimes unofficially called the "Mark I" version. The original version is characterized by the use of the brass logo plate, the yellow-orange ¾-inch soft-dome tweeter, the earlier AR-3a-style woofer and the solid-veneer back panel (which easily delaminated in use and was later changed). Serial Numbers in the 4600 range. I think this particular pair are European (Holland) versions and judging by the serial number, this pair was likely built in October or November, 1976. In the US, AR began using Ferrofluid tweeters on September 22, 1976, beginning with serial number 6278, and this pair has a later serial number; however, most of the Ferrofluid tweeters were black rather than orange, so this might have had the earlier tweeters, perhaps shipped to Europe. The second version of the AR-10 with the "new look" came in June, 1977. —Tom Tyson
  15. Checking the crossovers might not be a bad idea, but the likelihood of bad capacitors is not high considering the quality of the components ADS used in this speaker. To check each capacitor, you will have to remove at least one lead from each capacitor (being checked) on the crossover board. It's also possible that something might have happened to the speakers before you acquired them, and they may have been subjected to excessive input power levels for extended periods, which could affect the crossover as well as the Ferrofluid in the voice coils. I can also see from the images that it looks like the woofers (at least the top one) may have been removed. The edge of the cabinet above the woofer seems to be slightly scratched, but it could be an optical illusion, as the picture is not completely in focus. If a woofer has been removed for some reason, the phasing and integrity of the wiring should be checked. Again, explain the amplifier being used, what type, rating, etc. I didn't look it up to see what configuration. Some amplifiers don't work well with these speakers. Thanks, and good luck with these speakers. I hope you get to the bottom of the issues! --Tom Tyson