tysontom

Adams: Once again, AR lowered the crossover on the AR-3a from the earlier AR-1 and AR-3 levels because the new midrange could operate lower in the midrange, thus keeping the woofer out of the higher frequencies. This was always the goal. The problem has to do with off-axis response, smoothness and linearity of the large woofer cone; the lower crossover was not related to vocalist clarity or midrange intelligibility. With the AR-3, the lowest Villchur could operate the 2-inch phenolic-dome midrange was ≈1000 Hz, thus the 1 kHz crossover. The AR-3's woofer thus had to operate up to 1000 Hz, and even though the woofer is flat, on axis, from 38-1000 Hz within ±1½dB on axis, the off-axis response is compromised. With the 1½-inch AR-3a soft-dome midrange, the resonance frequency was a half-octave lower; therefore, AR could lower the midrange crossover was set to 575 Hz. The result was improved dispersion in the midrange and upper-bass frequencies. What Roy Allison is referring to is the boundary dip that is caused by a reflected, out-of-phase low-frequency wave from the woofer cone that bounces off the floor or wall and returns and partially cancels the front wave, causing a dip in the response at certain frequencies in the upper bass. By placing the woofer(s) close to the floor-wall boundary, and crossing over below that frequency, the dip can be avoided. The AR9 was also designed with this in mind, of course, with the two woofers close to the floor on each side (instead of in front up high). This has come to be called the "Allison Effect." There is still debate on the efficacy of trying to remove the dip (do recording studios compensate in recordings for a dip they may or may not get from their studio monitors?), as it may cause some "softness" in certain frequencies, but in general that dip is there and can be avoided. It is possible that you are losing some intelligibility around the frequency of the boundary dip. If you re-mount your AR-3a speakers flush with a wall or bookcase, you can avoid this problem. —Tom

Adams, in response to your comments above about Zilch. "Zilch" "Zilch," Evan R. Flavell, who died about seven years ago from lung cancer, was definitely one of the more knowledgeable and accomplished home-style speaker testers. He was a major JBL-style contributor to AudioKarma's Speaker Forum, and his measurements always seemed reasonably accurate for the type of testing he was doing. He certainly understood what he was doing, but his preference was near-field fr testing more than acoustic-power testing, and it appears that he preferred flat on-axis output from a speaker rather than rolled-off highs. Nevertheless, he did a lot of polar-response and off-axis testing as well. At one time, Zilch had been a conditioning coach for the swim team at UC Berkeley and developed a "swim bench," a dry-land exercise device for swim teams. He was an engineer and held several patents in the field of exercise equipment. Zilch used his engineering background to delve into the field of audio-loudspeaker design, and he developed (and marketed) a crossover network to incorporate a constant-directivity horn-tweeter, the "Econowave," as a replacement device to add the benefit of a "flat curve" to replace the old "rolled-off" high frequencies of speakers such as ARs, EPIs and Advents, etc. This system has apparently had (and perhaps still has) a good following, and the system actually sounds pretty good from my brief experience. I think Roy C of our forum has had experience with that setup with very satisfactory results, and Roy might elaborate on the Econowave design. Insofar as Zilch was marketing his Econowave horn tweeter replacement, he had an ax to grind concerning speakers like ARs, and he frequently offered rather extensive measurements made on some of the old speakers, including many ARs. His measurements were generally much more comprehensive than most of the other DIY measurements and these were not terribly different from the anechoic measurements done in AR's anechoic chamber. DIY Measurements of the AR-3a What this comes down to is that for years the AR-3a, and many other AR classic speakers, have been tested a dozen different ways from Sunday by numerous and enthusiastic DIY audio testers—most folks equipped with inexpensive digital software and non-calibrated electret microphones—in an effort to quantify that the AR-3a speaker wasn't really all that great or to explain that the speaker system might have been overrated because it didn't measure so well, even though it seemed to sound great. Of course, no two tests were the same and few resembled each other, and virtually none was governed by the old standards of measurements used in the hi-fi industry! The fact that the AR-3a received such great commercial success and stellar reviews (except for CU's comments at one point) only compounded the dilemma. One thing stands out: there is 100% disagreement by most "weekend warriors" on the measurement standards used to test the speakers. Chart speed, levels, vertical resolution, smoothing and testing conditions in general rarely resemble each other. Some amateur reviewers tested the AR-3a outdoors and some indoors; some were done at 1 meter for the entire system while other tests are tested at 2 or 3 meters. Some testers tried rta measurements while others tried full-system frequency response tests, most with the notion of proving why the speaker sounds "rolled-off" in the high frequencies, yet ironically, most testers agree that the speaker always sounded much better than it appeared to measure. It appears that most amateur testers also strongly believe that what you measure when you put a microphone in front of a speaker is what the speaker "is doing." —Tom

George, I don't disagree with your statement. The graph you attached shows predictably the effect of measuring anechoically into a 4π, 360˚ solid angle, as you noted, which shows the attenuation in bass as though the speaker was being suspended from a rope in the middle of a room. Also, the grill molding affects the system measurement fairly dramatically, but at different angles. All of these things add up to the difficulty in testing "full-system frequency response." On the other hand, MurphyBlaster's measurements of the AR-3a were more or less random, and it is difficult to separate meaninful speaker performance from interaction, diffraction and so forth. For this reason, I think the MurphyBlaster response graphs were not useful. —Tom

Ligs, In my opinion, this MurphyBlaster AR-3a measurement really doesn't mean a great deal. With all due respect, this guy is/was an economist by training and a speaker-DIYer as a hobbyist. I'm sure his intentions are creditable, but I have no idea how he got that measurement or what it means. Like so many hobbyists, this guy gets some measuring equipment and soon considers himself an expert in the field of acoustic measurements. Notice that the curve is all over the place with apparently reflections and interaction from any number of things. You cannot decipher anything whatsoever about the performance of the speaker from those response curves. For example, he says, "...The woofer also had a big humb at the top of its range, whcih colored the sound. Still, it sounds better than you might think...." —Tom Tyson

Adams, You have completely misinterpreted the AR-3a response curve above, and you're "reading into it" what you think you are experiencing in your setup at home. The "blue zone" and the "green zone" are not at all what you actually hear: the tracing above shows superimposed individual-driver response curves all on one chart for reference purposes, done for transparency by Acoustic Research. There is a huge amount of interaction and blending that occurs with drivers at the crossover frequencies, and that "Diminished-output-of-important-voice-and-harmonics-and-overtones" insert you put at the top is actually meaningless and incorrect. You need to look at the power response or rta response to see what you are or are not hearing from the speaker. These curves give a better idea of what you hear from the AR-3a —Tom Tyson

Adams, Regarding the settings of the level controls on the back of the AR-3a (and other AR speakers of this vintage), most people do leave the midrange close to the "dot" or center position with the tweeter at or near full tilt. Even with the midrange output down somewhat from the woofer level, with the control set to max, the overall output sometimes makes the speaker seem too bright, probably due to the very wide dispersion at all frequencies. But the controls were designed originally to tailor the speaker's balance to match the "liveness" of the listening room. Placing two AR11s, AR58s or even AR-3as back-to-back on the floor would not emulate the AR9's bass extension, simply because the system resonance (fc) of the 11s, 58s, etc is higher at around 43 Hz and the AR9 has a lower system resonance of around 32 Hz, thus has a more extended bass output. Placing two AR-11s back to back will increase bass output in the region of bass resonance (making the two sound a bit bass-heavy), but the resonance frequency remains the same (due to the AR-11 box size, "Q" and other factors), and bass response falls off at the rate of 12 dB/octave below resonance. A bass equalizer would have to be used to flatten and extend the output below resonance. Even with that, however, the output would not be quite as smooth as the AR9 in the 20-200 Hz range due to the AR9's purpose-built crossover for the two 12-inch woofers. Overall, the harmonic distortion and so forth would be equal, however. --Tom Tyson

Adams, I didn't take your comments to be terse and dismissive. No apology needed! I thought your comments were measured and reasonable. Also, your equalizer settings are not a problem from what I can see. The big thing that is happening here is the effect of wide dispersion of the AR-3a at those midrange frequencies and how it affects the perceived clarity of voice or instruments. It also occurs to me that if you are mounting your AR-3a on a stand or table (above the floor but back against the front wall), your AR-3a will be susceptible to the "Allison Effect," a boundary-caused dip of several dB as the reflection from the wall behind the speaker (and the floor) interact with the direct output of the woofer and cancel (null) certain frequencies to some degree, usually around 300 Hz or so. This could impact intelligibility at those frequencies, of course, and the way to fix this problem is to mount the AR-3a flush with the wall or in a bookcase flush with books around the speaker so that the woofer sees a true 180 solid angle. It's not always easy to do it that way! With the AR9, the idea was to get the woofers to operate close to the floor-wall boundary to get maximum reinforcement and minimum boundary dip, such as the wall and floor, and to limit the pass band of the woofers for smoothest response. Therefore, with side-mounted 12-inch woofers operating up to 200 Hz, there had to be a lower midrange driver (requiring a 4-way configuration) to handle the mid-bass frequencies. This also allowed a higher crossover into the 1½-inch midrange dome to improve its power-handling capability, and so forth in the design of the AR9. It was definitely a step forward in design. The AR-3a has been criticized in the past for its somewhat "heavy" sound, and some of that problem was due to a crossover issue during the changeover from the Alnico woofer to the newer ferrite woofer in the 1969-1970 time frame. Also, the relative balance of the midrange output to that of the woofer seems to give a slight sense of heaviness, but it is very minor. The reduced output of the tweeter also added to this, but the overall acoustic-power output of the AR-3a is very smooth and linear, though downward-sloping through the midrange and treble. Ironically, the acoustic-power response of the AR-3a in the highest frequencies is greater with less drop-off than most speakers (for example the original Large Advent) that are "brighter" and more forward-sounding than the AR-3a on axis! —Tom Tyson

Aadams, Out of curiosity, what "equalizer" are you using with your setup and why? Do you have a picture of your AR-3a/AR9 listening-room setup? The AR-3a woofer is not going to contribute much to the overall sound of a vocalist because, as you noted, most of the overtones are going to be well into the midrange frequencies. The woofer will reproduce the fundamental energy very accurately, of course, but the midrange is where most of vocal energy (the overtones) are reproduced and what you would hear. The AR-3a's dome-midrange driver reproduces these higher frequencies with nearly perfect perceived "clarity," insofar as this driver has nearly perfect transient response and is linear and flat with low distortion at normal listening levels. However, it also has much better dispersion in the 600 Hz range than the AR9's 8-inch LMR cone driver, so there will be more interference effects and reflections from the floor and walls, grill molding and so forth, than the AR9, and this could reduce "intelligibility" somewhat. This is typically never heard back in the reverberant field. The AR9's 8-inch lower-midrange driver operates from 200 Hz to 1200 Hz, so it covers a big range for vocalists, and this driver is more directional and will "image" better than a small dome driver. In addition to all this, the average output level from the AR-3a's midrange driver is down 2-4 dB from the 12-inch woofer's level, whereas the output of the AR9's 8-inch lower-midrange driver is even with respect to its woofers. For the AR-3a, this slight difference in spectral balance likely gives the sensation of slightly less output in that critical voice frequency range. I realize that you are not trying to criticize the AR-3a, but this discussion is largely academic, and it has little to do with the perceived accuracy the AR-3a reproducing music. You stated, "...Perhaps keenness for speech is why I have not read of Live vs Recorded tests being done with vocalists." There have been several LvR demonstrations done with vocalists, but AR used a string quartet, classical guitarist, drum solo and a 1910 Nickelodeon for its well-known public demonstrations. The reason the quartet was chosen was the difficulty in reproducing the ensemble tone and acoustic-power balance, which proved to be difficult to accurately reproduce and as a result, easier for listeners to detect differences in the live and playback sessions. Even with this, few listeners could reliably detect the switch-overs. Voice reproduction is difficult, but probably not as much so as a string quartet. —Tom Tyson

Aadams: I think you are missing the point somewhat, and what you are saying is sort of getting in the weeds a bit. This is also listening up too close to these speakers. Up in the direct field, you will unavoidably encounter interference and diffraction effects, especially from the AR-3a, but from the AR9 as well. Back in the listening area you would not be able to easily make the distinction you mention. More importantly, you would have to set up the AR-3a and the AR9, side-by-side, and carefully balance the output levels and then switch back and forth to make that determination (probably best done with Double-Blind Tests). I understand what you are saying, but you can't go on assumptions or perceptions. In the reverberant field, you are not likely to be able to clearly make those distinctions anyway, and if you were at the original venue of the recorded performance, and you were listening to the integrated output of the entire recording, you would also not be able to clearly make those distinctions. There is little doubt that the AR9 has somewhat better integration of sound through each individual speaker, and the 8-inch lower-midrange driver on the AR9 is better suited for mid-bass in the 200-700 Hz range than the 12-inch AR-3a woofer up to 575 Hz, but I am confident there would not be huge, noticeable differences. Also, the AR 12-inch woofer is very linear and flat within its pass band. It is not "muffled" or lost in the frequencies it is reproducing; it is not missing notes or failing to reproduce sounds in its operating range. There is no ringing or overhang or other damping issues. I think you are getting caught up in some interference effects by listening too close to the speaker. On the other hand, if you are looking more for more "imaging" and more detailed, up-close, intimate sound of the performers or the instruments, then neither of these speakers is going to be the best solution for your listening, although the AR9 images better than the AR-3a. —Tom Tyson

Ligs and Aadams, Thanks for the comments and thoughts about the distortion levels and crossover points. The important thing to note is the very low distortion for all of the AR woofers tested, and this was typical throughout years from all testing laboratories and magazine reviews, etc. From the very beginning in 1954, AR designed its speaker components by using accepted scientific testing methods—repeatable by anyone following these test methods—to have the lowest-possible harmonic distortion and the flattest frequency response that AR could design. The results from these measurements were widely published for all the world to see, something fairly unique in the high-fidelity loudspeaker industry during the day. In fact, for many years after the first AR-1, Acoustic Research was the only hi-fi manufacturer I know of to publish detailed distortion, frequency-response and acoustic-power response tests for all of their speaker systems. Reluctantly, a few other speaker manufacturers did follow suit after AR's early success in the market place and with critical reviews, but the main reason that most manufacturers did not publish such information: lack of comprehensive testing equipment, anechoic chambers and a real fear of the outcome of those measurements and possible public backlash. The point I was making to Ligs was that there were often variances in the method of testing, and this could cause slight differences in results. AR maintained that by using the accepted standard testing methods of the day, for example RETMA STandard SE-103 and 61 IRE.RP1 Recommended Practices for Loudspeaker Measurements, anyone could accurately replicate the same results that AR got with their testing measurements. By the way, McIntosh Laboratories' Roger Russell did extensive lab measurements for their speaker products (though they did not publish all of the results), and McIntosh later built and maintained one of the largest anechoic chambers in the industry for this purpose. As for the crossover points on the three-way AR speakers, the lowest crossover was always chosen based on the lower frequency-response linearity of the midrange speaker. The issue was dispersion of the large woofer cone but not so much the distortion of the woofer at its higher range, as it actually gets lower and lower the higher it goes up to its operating limit. For example, the AR-3 has a 1kHz crossover from the 12-inch woofer to the 2-inch dome midrange speaker, and this was the lowest frequency that the midrange could operate. AR would liked to have a lower crossover, but the 2-inch dome could not do it; with the AR-3a and the new 1½-inch midrange with its lower resonance, the crossover was changed to 575 Hz., thus improving the off-axis response at those frequencies. Therefore, the crossover was based mostly on the operating range of the respective drivers, and there were very few compromises made to dispersion. AR could easily have used a low-resonance cone midrange in the AR-3 to go much lower, but the dispersion and linearity of the 2-inch AR-3 dome was considered much more important to the overall accuracy and sound quality of the speaker, and AR was unwilling to give up that accuracy in the design. —Tom Tyson

"The heavy 12" AR woofer, while it has very low distortions at low frequencies, has relatively high distortions at higher frequencies." Ligs, the graph you show above is from CBS Labs test of the AR-3a (that picture, by the way, with no attribution, looks like the one I supplied some time back; it even has my file number on it). Your comment about the "heavy 12-inch AR woofer having relatively high distortions at higher frequencies" is vague, incorrect and appears to be based on assumption. "Relatively high" compared to what? You have to understand the measurement conditions before you can make such a statement. First of all, the input-power level for this particular measurement extended to very high; you would never see such sustain-wattage figures for normal listening. In addition, CBS Labs tested into full space in an anechoic chamber and did not test using the normal 2Pi steradians solid angle for their measurements, thus the distortion is at least twice as high. It would be akin to listening to your speakers hung from a rope in the center of a room; bass response suffers without boundary reinforcement, and the woofer has to work harder without a boundary for reinforcement. Nevertheless, the comments made by the lab on this distortion was that it was the among the lowest ever measured for a loudspeaker; so even with the high-power measurements, the distortion level was considered very low when compared with other loudspeakers, which holds up well even to today. --Tom Tyson

Rather than criticize and attack the old AR management team in hindsight, "...Astonishing that otherwise intelligent people like Villchur, Allison and Landeau (Gerry Landau) could be so incompetent when it came to sales and marketing," I was really trying to get CSP reader's experiences of dealers disparaging AR (and by the way, there were other companies, such as Dynaco, treated this same way, too) in comparison to more profitable in-store products. We've been down this AR-bashing road many times in the past, and I was not trying to reopen that part of the discussion. Again, this is what I was asking: "Give examples of experiences you've had in dealer showrooms where AR speakers were intentionally maligned, "bad-mouthed" or "doctored" in order for a dealer to steer an unsuspecting customer to another product." It is a bit insulting to accuse these (now gone) AR management people of "incompetence" when, in fact, the company did remarkably well for the first twenty years of operation. AR outlasted most of its competitors as well. It is easy to look back fifty years and criticize the way a company ran its organization; anybody can do that, and what worked then is not directly comparable to the way business worked twenty or thirty years later. Actually, in the beginning, AR had a strong network of dealers—especially in large cities—but over time the company, now commercially successful, was unwilling to accede to the typical demands of most hi-fi dealers of the day, for example: 1. product discounts as high as 40-50% or more with additional large-volume discounts; 2. kick-backs (spiffs) to sales reps for "pushing" their products; 3. rebates (in some cases) from the manufacturers for exceeding "quotas" in sales; 4. extended-payment terms with manufacturers (many dealers had on-going cash-flow problems); 5. ability to "transship" products to other (often unauthorized) dealers; 6. the usual co-op advertising (which AR actually always did to some degree):. 7. expectation not to be told what they should stock in inventory or what or how to demo, and the list goes on. So who could blame the dealers! They run a business, and they're in it to make a profit, pay employee salaries and keep the lights on and so forth; therefore, they expected the manufacturers to give them favorable terms to be able to sell products and be profitable. The better the terms, the more likely a dealer will be happy and push that manufacturer's products, but in long run the manufacturer has shoulder the brunt of those terms, and many manufacturers could not survive the true cost of doing business. Among those, by the way, were Advent, KLH, Fisher and EPI. "Remember, AR wouldn’t have needed those AR Sound Rooms [or rental programs] so people could hear “how they really sounded” if their basic marketing policies were decent enough so dealers supported them and demo'ed their speakers properly. Think about that for a moment." What a croc! A hi-fi dealership is not an altruistic endeavor to enlighten the would-be customer. It is a business, and the dealers would "push" a product that sold well with the right amount of incentive, and incidentally, KLH, EPI, Advent and many others gave the dealers this incentive to keep favor with them. Some dealers were even taught methods of competitive "trade disparagement" rather than simply talk about the virtues of one's own product or how best to demonstrate it. You might ask how I know this. I owned a hi-fi dealership during the mid-1970s, and we carried such products as Bose, AR, Allison, Epicure, Advent and KLH. I know how the system works. But a quick look at AR's Music Rooms: The AR Music Room in Grand Central in New York alone brought in over 100,000 visitors each year, but the company policy was to demonstrate AR products and answer questions, but never to initiate sales of any kind. To do so was strictly against company policies. It was simply a listening room for the public at AR's expense. Of course, by doing this, AR knew that people could listen and evaluate in a "sales-free" environment and make decisions without the usual sales rep's pressure to sell products. This type of commerce-free environment simply did not exist in a dealer's showroom; the dealer was there to make money first (and foremost) and to please the customer second. So, therefore, I kind of wish I hadn't mentioned this topic and will refrain from it in the future. —Tom Tyson

AR tried the "Speaker Rental Plan" for a short period of time in the early 1960s. As part of the customer-centric culture at AR, it was well received by potential customers but not with dealers. In the words of Thomas Huxley, it was "a beautiful hypothesis slain by an ugly fact." Major pain in the tail for dealers even though they received additional compensation for their effort. For $2 a week, a customer could rent a pair of AR-3s! If they didn't like the speakers, they could be returned to the dealer. Of course, the speakers became "used" right then and there, and likely the unusually heavy AR-3 speakers would get a few scratches along the way. Some big-city dealers in New York, Boston and Chicago tried this plan, but it was soon dropped because of dealer complaints. Most did indeed stay "sold," but it was not a popular thing with dealers. --Tom Tyson

Martin, this is precisely what I meant! I've had several experiences through the years, and I think others have experienced the same thing. It was the old "trade-disparagement" and "bait-and-switch," tricks that dealers would do, and Acoustic Research got it the worst of about any speaker company, probably due to AR's very casual attitude about dealers. While in the Air Force out in El Paso, Texas—after I was humiliated by the little AR-2 experience—some friends of mine and I started visiting the various hi-fi showrooms around the area. I had heard that a large JBL Sound dealership had a single AR-3 setup in their main listening room to compare with their Ranger Paragon, JBL's top-of-the-line speaker and easily one of the most beautiful pieces of audio cabinetry ever designed. Sure enough, there was a single AR-3 well out from the wall, on the floor hooked up to the speaker selector switch! The salesman said that you could quickly tell how much "superior" the JBL speaker was than the little AR speaker! I looked at the back of the single AR-3, and both level controls were turned almost all the way down, and the speaker sounded pathetically dull and bass-heavy (sitting on the floor). So... the 20% efficient Paragon vs. the single 0.5% efficient AR-3 on the floor out from the wall, being switched back and forth! What an insult. The salesman said they only had that one AR speaker, but they wanted to show customers the superiority of JBL speakers! After a spirited argument, we were asked to leave the dealership, not the first time for that, either! —Tom Tyson

For many years—perhaps from the very beginning—AR had a difficult time selling their products in typical audio salon showrooms. In fact, from 1954 until around 1974, AR made no attempt to cultivate good dealer relationships. Nevertheless, and despite the lack of dealer success, AR outsold nearly every other speaker manufacturer worldwide for many years without a strong, formal dealer network. How was this possible? AR products traditionally had the highest ratings and best reviews, but a prospective speaker buyer would never know it to visit the typical, small hi-fi showroom where one usually encountered a negative vibe in a showroom when an AR speaker was being demonstrated. Many times, dealers would "doctor" the speaker, reverse the polarity, turn-down the level controls or place the speaker inappropriately or disadvantageously for good A-B demos with competing products. Some dealers felt that customers would enter a store, make a decision to buy an AR product and simply go out and order it from the Allied Radio or Lafayette catalogs. Was it due to.... 1. Low dealer profit margins? 2. Lack of dealer salesman "spiffs" paid by AR? 3. Lack of dealer promotionals? 4. Lack of dealer co-op advertising? 5. AR's lack of "hand-holding" and blasé attitude towards dealers? 6. AR's traditional laissez-faire method of doing business? 7. Other reasons? Give examples of experiences you've had in dealer showrooms where AR speakers were intentionally maligned, "bad-mouthed" or "doctored" in order for a dealer to steer an unsuspecting customer to another product. —Tom Tyson

I contacted Bose and the "end" date was indeed September, 2016! So, 48 years... almost 50! Anyway, that was a good run with several-hundred thousand units built before it was over! The 901 was a true icon in the industry! --Tom Tyson

Let me add that the discontinuation of the 901 may have occurred over a year ago. It looks like it may have happened back in September, 2016!

I just learned that the Bose 901 is no longer being made available from Bose Corporation. This would be the end of a glorious 50-year run for this fine old speaker, and it's probably safe to say that if founder Amar Bose were still alive, no one would dare discontinue this model regardless of low the sales volume! This is sad news, but nothing is forever, at least after the founder of the company has died. I also think the AWMS (Acoustic Wave Music System) is also discontinued. --Tom Tyson

Brad, thanks for that clarification on the "Shop Talk" show on WBUR-FM. I apologize for misstating that detail in my short tribute about Victor Campos; I was actually unsure of his exact participation and relied on something I read from another source. I was originally aware of his work on "Adventures in Sound," but I let the two programs run together in my description. Thanks again, —Tom Tyson

C. Victor Campos C. Victor Campos, 84, from Framingham, Massachusetts, an alumnus of Acoustic Research from 1960 until 1963 and again from 1974 until 1979, died on December 11, 2017 after an extended illness. Victor briefly worked at AR's Music Room in New York in 1959 and later worked in customer services and assisted Ed Villchur with the production of the Live-vs.-Recorded series in the early 1960s. In 1963, Victor went to competitor KLH Research and Development Corporation to work in customer service and engineering under Henry Kloss, but he returned to AR in 1974 working with the Advanced Development Division's new speakers. During these years, Victor produced a superb series of FM broadcasts out of Boston, "Adventures in Sound" and "Shop Talk." These broadcasts were done with master tapes without compression, usually challenging a FM listener's high-fidelity equipment; i.e., if you did not possess AR heavyweight loudspeakers in your system, you were likely to sense distortion during playback! These were superb reel-to-reel tapes done on Ampex AG-440 machines and similar high-end transcription recorders. In the mid 1970s, Victor produced the excellent Neil Grover (drums)/AR-10π live-vs.-recorded demonstrations that showed the extremely capable and accurate reproduction of the AR-10π, especially reproducing the bass drum at high levels. This was a very difficult demonstration—in ways more difficult than the Fine Arts or Gustavo Lopez demonstrations—requiring enormous amplifier peak levels of over 800 watts per channel to reproduce the peak acoustic levels. Steve F on this site attended at least one of those demonstrations and can elaborate on the effectiveness of that demonstration. Much of the credit for the success was due to Victor Campos' understanding of amplifiers, loudspeakers and tape recorders, and he was able to produce excellent results during these LvR demonstrations. Before Victor left AR (he was also at Adcom and NAD through the years), he was very instrumental in the development of the AR9 tower loudspeaker. Initially, Victor wanted the AR9 to be a "powered" speaker complete with built-in amplifiers for woofers, midrange and tweeters, but he was not successful in that quest! At times, Victor could go overboard: when the AR-10 was being developed, a problem occurred with hinge on the fold-out solid-walnut access door on the front. It would bind and stick. Victor wanted to quit "experimenting" and simply cut to the chase: add ball bearings to the hinge! Of course, this was much too expensive, and a proper hinge was developed which worked well without problems. His influence was felt! Victor was an intelligent but sometimes impatient person, yet he accomplished a great deal in the years he was at Acoustic Research and KLH. He will be greatly missed! —Tom Tyson 12Dec2017

On further thought, it occurs to me that the slots are on the outside of the dome/voice coil, and thus may not necessarily affect air movement inside the dome. I also suspect that the early domes before Ferrofluid might be less affected by the space under dome than later ones with fluid. The gap would allow a small amount of air to pass inside the voice coil past the pole piece. With Ferrofluid (on both sides of the coil), air would be trapped under the dome.

Many of the new-style (cloth) AR-10/AR-11 3/4-inch tweeters used the same magnet assembly and top plate as the original AR-3a tweeter, thus having three slots around the pole piece that were used for the foam suspension in the 3a tweeter. Since no foam was used in the AR-11 dome, air can escape from under the dome into the pole-piece/magnet cavity below the dome. This would in essence increase the volume under the dome. --Tom

Right. It was strictly a figure of speech, not a "literal" interpretation. I thought that would be self-evident. The point was made that no tweeter can possibly be rated (on its own) for 75 watts, and that was the point I was trying to make with reference to the new AR replacement tweeter. That new one is not likely to have significantly better power rating than any of the older AR 3/4-inch tweeters. It is simply a matter of mass, dome weight and the voice coil weight. To significantly increase power-handling capability, the coil must be heavier, and this is unacceptable in a good tweeter. In terms of instantaneous bursts of energy, I think the AR-LST was originally tested to 5,000+ watt peaks at one point without any ill effects, but this is strictly short-term bursts of energy. The AR-3a 3/4-inch tweeter can probably sustain a little over 5 watts, long-term steady-state energy, before burning out. The later Ferrofluid 3/4-inch black-dome tweeter could probably take 8-10 watts long-term energy, but not much more. --Tom

Thanks for these suggestions! I'm going to look at all of them, but I'm thinking that a single-volume book (size unknown at this point, of course) makes the most sense. Getting one book off the ground will be hard enough, let alone multiple volumes. I do plan to discuss somewhat the history of the "New England" high-fidelity industry, largely how AR—literally overnight—changed the face of the loudspeaker industry and formed what became known as the "New England Sound," and how this small company brought down many component-speaker giants in the hi-fi industry during the early post-war years. Such a book would therefore have to be much more than just the interest in the products themselves, of course, to attract any readers at all. I think this book should also explain the culture of Acoustic Research and its people. But product details are important to anyone interested in high fidelity. I agree with everyone here (and some email messages) that the book should have a catchy title and the subtitle to get readers interested. One grave reality: a book such as this might go "begging" to find enough readers to make it even remotely interesting to a publisher. This worries me the most, and it has occasionally dulled my enthusiasm, knowing the time it would take to do it right. The high-fidelity industry—in the grand scheme of things—is/was simply tiny. There are a few small biographies and generic audio-history books, but none is considered important or a big seller by any means, and most appear to have been self-published by individuals or by the firm about which the book was written. Ed Dell, who originally published a do-it-yourself audio magazines such as Audio Amateur, Speaker Builder and Glass Audio (before audioXpress and Voice Coil) used to have almost the entire list of audio-specific books for sale at the back of his magazines, and this was during the heyday of hi-fi audio, so this is a slight dilemma. —Tom