Jump to content
The Classic Speaker Pages Discussion Forums

Steve F

  • Content Count

  • Joined

  • Last visited

Community Reputation

0 Neutral

1 Follower

About Steve F

  • Rank
    Advanced Member

Recent Profile Visitors

12,457 profile views
  1. Steve F

    Question about tweeters on VR30

    The Kortec tweeter should work well in the VR30. There would be no reason to use the AMD on the Kortec, since, as you surmised, it is strictly for removing the resonances of a metal dome. In all the time I was at BA (1992-2003) we never had to replace a single VR tweeter due to burnout. Not one. Ever, from the time of the VR's introduction (fall 1994) until I left in March 2003. Not a single tweeter. VR20, 30, 40, VR950, 960, 970, 965, 975, VR12, 10, VR910, 920, VR-M50, 60, 80, 90, VR-MC, VR surrounds, MR90 sats, MR90 Center, probably a few models I'm forgetting. Not one tweeter. Ever. You (or the previous owner) must have driven the ever-lovin' cr*p out of these things. That tweeter was both bullet-proof and ruler-flat from 2kHz to 20kHz. It put every tweeter from every company I was at to total shame. Steve F.
  2. Steve F

    Acoustic Research Classic 30's

    When I was at BA, our head transducer engineer had previously been at AR and he was one of the lead system engineers for these Classic models. He did a lot of work on the 30. He did say that they were a bear to ship because of the unusual cabinet shape, the way all the panels sloped in and down. A lot of early shipping damage before they got the packaging straightened out. I only heard them briefly, during a tour of the AR plant when it was at 330 Turnpike St in Canton MA, just before they left for CA. They sounded clean and detailed, but I wasn't using my own "test" material and I couldn't form a definite opinion. I always wondered about the low end--with two 10" woofers, did this have 90-like bass? I have reason to doubt it. The AR3 Limited came out in the same timeframe as the Classics and the 3 was a very "audiophile-ish" speaker with a 12" woofer and a MTM array with 3" dome mids and a dome tweeter. It had that off-standing metal screen grill that made it look like an electrostatic speaker. Anyway, true to its early-90's timeframe, the Limited 3 was a 'lean' sounding speaker in the audiophile tradition, not a gutsy, powerful-sounding speaker like the 3a, 11 or 9/90. Can anyone give me a real, accurate assessment of the Classic 30's sound character? Steve F.
  3. Steve F

    An AR Christmas

    Wow. Not bad.
  4. Steve F

    TSW series one-offs?

    That TSW brochure is the very first one. There were others that followed. There was, in fact, a TSW710 with dual 8-in woofers. There was also a TSW brochure where all the speakers model numbers ended in '15,' not '10.' You probably have TSW710's. The TSW x15's were all dual-woofer units--315, 415, etc. Dual 5 1/4", dual 6 1/2", etc. I think the other speaker is one of those. I'll check to see if I can find that x15 brochure and I'll post pics.
  5. Steve F

    VR30 "2-and-a-half-way"?

    Thank you for the kind words. Except for those 2nd-gen CRs (which were in development when I was still there although not completed), I was involved with all the others. The Recepter was a really great radio. We had big arguments over that one, for many reasons. I voiced it, but at the last minute, the President came in and added 2 dB to the EQ below 100Hz. Now it's a little bass-heavy, in my opinion. Nonetheless, I have three of them scattered around the house. The very first production run will lose 20-30 seconds per month on the clock and after 6 months, the clock will be a few minutes slow. Annoying. It was because there was an inefficient circuit design that pulled a hair too much voltage from the timing circuit in order to power some other part of the radio. Starved for voltage, the clock runs just a tad slow. It was corrected on the second run. That's "inside info" you'll never hear anywhere else, that's for sure! The Micro90x sub-sat family was the best-selling (from a $ standpoint) family of products in the company's history. I was incredibly proud of those, although the President never wanted to do them and never really enjoyed their success. I really liked the VR-M series. I own 50's and 60's. The VR-M90 remains one of my all-time favorite floorstanding speakers ever. We were going to do a "VR-M100" at $4000/pr--would've been killer!--but 2-ch stereo was dying as HT was taking over, so we never did it. Steve F.
  6. Steve F

    VR30 "2-and-a-half-way"?

    I was the new product development manager for the VR Series when I was at BA from 1992-2003. I supervised the engineering and did all the voicing on the speakers. I do not remember the two 7" drivers being much different, if at all. The "woofer-only" lower driver may have had a larger dustcap just to distinguish it visually. The dustcap would only affect the upper-end of that driver's response around 1.5-2kHz or so, which wouldn't make any difference in that driver, since it was rolled off around 800Hz. Both woofers handle the bass and the system is a conventional dual-woofer ported system. It's just that the lower woofer is rolled off with a choke above 800Hz, so you don't have the two 7" drivers interfering with each other in the midrange. "2 1/2-way" means two woofers, only one of them going up into the midrange, and then a tweeter. It was not a BA-exclusive design. Several AR TSW's in the 80's, like the TSW410, were 2 1/2-ways. Currently, the Paradigm Prestige 75-85-95 are 2 1/2-ways. Pretty well-known design approach. BA moved from Lynnfield to Peabody in 1996. The VRs came out in late 1994 and were discontinued in 1997 or 8. Great speakers, all of them. The 40 is truly great, but the 30 was quite excellent as well. 40-50 solid watts/ch is enough in a normal-sized room as long as you don't want heavy-metal at ear-splitting levels. They're closer to 4 ohms, regardless of what the specs may say. Steve F.
  7. Steve F

    AR-5 store speakers

    I grew up in central CT. Big jazz lover. Used to go to Integrity 'n Music all the time. Amazed that they're still there. That's nice. Are you from CT? Bought my first 'good' speakers--AR-2ax's--from Fred Locke Stereo in Avon CT in Feb 1972. They were huge Infinity dealers and were quite annoyed that I preferred the 2ax's over the Infinity 1001's. Steve F.
  8. You better be ready to defend the statement about “Allison” himself saying that the 3a needed 5dB more tweeter output for flat response. There are many fanatical AR defenders here who are going to jump on any criticism of the 3a as sacrilege and imply that its performance was essentially perfect in its day and if functioning at factory-designed level today, would still be among the very best speakers available anywhere in the world. In fact, AR’s own system curves of the 3a’s own drivers shows that on-axis, the 3a tweeter is down at least 5 dB from the woofer. Off-axis, the reduction in level compared to the woofer is even more, of course. Full credit to AR for publishing such honest and accurate curves, both the technical specs curves of the individual drivers overlaid into a system curve and the Berkovitz-Allison curves done for the AES paper on listening rooms. Both show the tweeter down 5dB. Even the Technical Paper on the 3a , which has a “full system” response (not individual drivers), says that the amplifier’s treble control needs to be advanced to 2:00 for flat response. AR's own curves show exactly why the 3a sounded the way it did— powerful bass with very low THD, widely-dispersed mid and HF, reticent overall tonal character. A total lack of harshness. Advance the treble control to 2:00—about a 3-4 dB increase for most amps—and the 3a sounded incredible. Play it too loud with that tonal adjustment and you blew the tweeter. Today’s hard paper ¾” tweeters? Likely down another 3-5dB from factory level, at best. That’s my WAG. I’d have them rebuilt by Chris, not go the HiVi route. Something about that original ¾” tweeter that’s just so nice. Steve F.
  9. This is a fascinating set of curves by Julian Hirsch at Electronic World magazine. Electronic World published parallel test reports by Hirsch to the ones published in Stereo review, but the EW reviews revealed more of JH’s technical results, including a speaker’s frequency response curve, which Stereo Review never published (as a matter of policy). Presumably SR felt that a frequency response curve was too subject to misinterpretation by SR’s emotionally-charged hobbyist readership, while their sister publication of EW had a more mature ‘technical” readership, so the publication of detailed technical specs/graphs was deemed ‘safe.” This is a deep dive, so stay with me here or else I might as well be writing a private letter to Tom Tyson. When the AR-5 was introduced, it generated a bit of controversy because Julian’s review in Stereo Review made note of a deep dip in the 5’s frequency response at around 2000 Hz. He said it gave the speaker an unacceptably distant sound and only with the mid-range control advanced all the way up did Julian say the speaker sounded good. (He actually used the word “superb,” but only with the mid control advanced “to the reviewer’s liking.”) Roy Allison, the 5’s designer, took vociferous objection to Julian’s findings. He insisted to Julian that the 3a and 5 used essentially identical MF and HF drivers and their x-o topology was nearly identical, so it would actually be impossible for the 5 to have this trait and the 3a not to. He further insisted that in all of AR’s tests, measurements and listening, the only difference between the 5 and 3a occurred below about 45hz or so. Their response and sound was identical from the mid-bass on up. There was no mid dip on either speaker. Julian didn’t buy it, saying that he measured the 5’s dip in two completely different set-ups and the 3a did not have the dip. Julian never actually gave a reason for the 5’s apparent problem, but he insisted it was real and different from the 3a. Julian and Roy’s disagreement was aired in public, in succeeding issues of Stereo Review in Julian’s Technical Talk column. To Julian’s credit, he gave Roy ample space to have his say, and in all candor, Julian liked AR so much he probably wanted to hear a legitimate explanation that would take AR “off the hook.” Nonetheless, like any good scientist, Julian stuck by his findings, since he measured them according to his own legitimate methods. The AR-5 was caught from a marketing standpoint between the prestigious, highly-reviewed top-of-the-line 3a and the amazing 90%-that-anyone-would-ever-want value of the 2ax, at half the 3a’s price. So the AR-5 was already struggling from a sales standpoint. This review—a tenuous, conditional recommendation, with a serious wart—didn’t help the AR-5 at all. Now, to the matter at hand. This is a frequency response of the four main AR speakers in early 1970s—the 4x, 2ax, 5 and 3a—superimposed on each other and normalized to 1000Hz. These curves were made by Julian for EW magazine and published, although it’s not clear if these are the actual curves made for the test reports or whether these are additional curves made at some later date, just for interest’s sake. Here’s the really interesting thing: The 5’s and 3a’s curves are within about 1dB of each other all the way from around 90hz on up! Within 1 dB! The AR-5 has no dramatic, egregious 2000Hz “dip” in the midrange. None. And these curves were made by Julian. Explain that, Julian: The 5 and 3a are essentially identical above the mid-bass, exactly like AR says they are. Julian? Julian? Here’s another interesting thing: the 2ax upper mid response is a few dB lower than the 5/3a’s, which is exactly how they sounded relative to each other. I A-B’d the 3a and 2ax in my home many times and the amount of increased inner-mid detail on the 3a vs. the 2ax was apparent, just like these curves show. Also interesting is the 2ax’s apparently stronger extreme (above 10k) on-axis treble response: This is because the 2ax was really a 2-way speaker with a super-tweeter add-on, where the 3 1/2-inch driver (remember that was the tweeter in the AR-4 and ‘early’ 2x) goes full out, as high as it can go, and the 2ax’s ¾-in tweeter is brought in as HF reinforcement. In the 2ax, the 3 ½-in driver is essentially flat and level with the woofer all the way out to about 13-14kHz, so it is combining with the ¾-in tweeter for a pretty healthy on-axis treble output. In the 3a and 5, they are true 3-ways, where their mids are rolled off as the tweeter is brought in. The 2ax has both drivers pumping out HF above 5kHz, whereas the 3a/5 have only the relatively weak ¾-in dome doing all the HF work above 5khz. (“Weak” as in limited ultimate output level, not “weak” from a quality/performance/dispersion standpoint.) These curves show all of that quite clearly. And prove, once again, AR’s honesty, QC (the way the 3a and 5 mimic each other is pretty remarkable) and high performance. Steve F.
  10. This is an in-room curve of the 3a from the Berkovitz-Allison AES paper on Soundfields in domestic rooms. It’s a fascinating curve, because it demonstrates AR’s honesty and technical proficiency, attributes that put AR well ahead of other speaker companies of that time. First of all, it’s doubtful if any other company would let anything other than some phony-baloney hand-drawn ruler-flat response curve even see the light of day. Sure, this was an AES paper (not an ad in Stereo Review), but it was out there in the public domain. Nonetheless, AR had such high principles of broadening the general understanding of speaker behavior/performance and had such (justifiably) high confidence in the correctness of their design ideals and approach that they willingly let an imperfect-looking FR curve of their best speaker—warts and all—out of the secret confines of their marketing department. Let’s look at the curve a bit more closely. It’s the FR of an AR-3a in a home living room, with the Mid-Hi controls all the way up. The speakers were on stands, somewhat away from the room’s walls. This was not an uncommon usage scenario, although certainly not an optimum one. Using the speakers on stands, away from the walls, is a classic “4π” placement. This placement provides the least amount of bass reinforcement. The 3a (like all AR speakers at that time) was designed for 2π bookshelf placement (as in Tom’s bookshelf). You can see the woofer’s response falling off from the midrange level below 500Hz as the solid angle that the speaker “sees” transitions from 2π to 4π. (The 25” front baffle of the 3a serves as the 2π baffle for frequencies above around 5-600Hz. A 565Hz wavelength is 2 feet long, and 25 inches is…..it’s the math, the math…..). BTW, any box-type bookshelf speaker on a stand away from the walls will show the same mid-to-bass falloff as the 3a, when placed similarly. If you raise the under 200Hz woofer level up to the mid’s level (as the woofer level would be in a 2π setting), you can see that the speaker’s response from just under 40 Hz to a bit over 2,000 Hz is remarkably flat and accurate. This is the bass-midrange region, where virtually all the music lies. Above than, you see the falloff—but very smooth—in the upper-end response, partly due to AR’s willingness to sacrifice flat on axis upper treble for wide dispersion (in the days before ferrofluid-cooled tweeters) and party because RA’s somewhat misguided (IMO) view that the loudspeaker should intentionally introduce the particular coloration of the performance venue (in this case, the HF rolloff of major orchestral halls) into the domestic playback chain. In my opinion, the speaker should simply reproduce the electrical signal fed into it as accurately as possible. Nothing more, nothing less. It should be up to the recording engineer/record producer to impart any sense of the performance space into the recording, if desired. Not the loudspeaker. In any event, with the woofer level raised to the mid’s level as it would be in a 2π space, the 3a’s real-world, in-room performance is quite excellent. If you were to tweak the treble just a hair, it goes from quite excellent to unconditionally superb. This was quite a loudspeaker. Steve F.
  11. Let's inject a little logic and math into this discussion. Take 13560 (the speed of sound in inches/sec at sea level) and divide that by the piston diameter of the driver. That will give you the frequency at which the driver starts to become objectionably directional (when the diameter exceeds the frequency being played). 13560/11 (the piston diameter of a 12-inch woofer, minus the 1/2" surround on each side) = 1233Hz. A 12-in woofer is "good" to 1200. 1200! So an AR-3 crossing over at 1000Hz is just fine, no sweat. That is why the Large Advent with a 10/12-in woofer crossing over at 1000 always sounded fine, from a directivity standpoint. (I'm not talking tonal balance or anything like that, I'm talking directivity.) Will the dispersion improve if the driver is crossed over lower than its upper limit? Of course, but things are not as bad as they seem. 13560/4.25 (the piston diameter of a 5 1/4-in driver = 3190 Hz. A 1-in tweeter is good to 13,560, obviously, while a 3/4-in dome is good past 18kHz. Here's an interesting one--a 10-in driver (9-in piston) is directional at 1506Hz (13560/9 = 1506). So the AR-2, 2a, and 'old' 2ax were all "wrong" because they took a 10-in woofer up to 2000Hz, way past the point where it becomes directional. So does everyone here on the Forum criticize these speakers for being objectionably beamy in the midrange? Do we hear constant complaining from everyone about, "I just can't stand the way my 2a's beam that midrange. It's horrible! These are horrible speakers!" Nope. Not a peep. Ponder that. Steve F.
  12. Steve F

    AR4x restoration (was a tale of misery)

    No wonder these have been referred to as giant killers and one member here gave them the label of "unfair speakers." Yes, that was what my Dad and I called them. He'd bought a pair in 1969 and a high school friend of mine bought Large Advents shortly after. Twice the size and twice the price of the 4x's. He'd come over to our house and hear the 4x's with familiar records and he'd say, "They sound so good--as good as my Advents. It's not fair!" A few years ago at a Boston Audio Society meeting, we had a small speaker "shootout," old and new speakers, any price but limited to 'small bookshelf' size. Mostly 5 1/4, 6 1/2 and 8-inch 2-ways. The 4x finished 4th out of 16! It was in the hunt all the way. The eventual winner was the Atlantic Technology AT-2, a 5 1/4-inch 2-way with their quite revolutionary H-PAS bass loading system. I think the last list price for them was $1200/pr. The AT-2 goes down to a legit 45Hz from a 16"-tall box and a 5-in woofer. It's overall voicing signature and tonal balance is remarkably similar to the 4x's, however and it's quite a nice speaker. That the 4x is still competitive with today's best says everything you need to know about its basic quality. I remember one of our members here (Speaker Dave--former head engineer at Snell) re-doing the 4x's crossover (without AR's original cost constraints) using the stock 4x drivers and attaining essentially a dead flat response from about 60-13kHz. "Not fair" indeed. Steve F.
  13. To avoid Thread Creep, I would agree with Aadams’ basic premise, that all things being equal, it’s generally advantageous to have a heavy, low-resonance woofer restricted to operating as low as possible, below 200-300Hz, max. “All things being equal.” We’ll let that rather vague qualification stand alone, in all its unspecified glory. (BTW, later 3a's--from around the foam/ceramic days, as opposed to cloth/Alnico days--had a crossover of 525Hz, not 575Hz. I think there was a woofer choke change then too.) As to the letter from Allison, I have seen this letter many times and it always struck me as strangely off-target. The 3a’s—or any AR speaker’s—goal was to reproduce the electrical input signal as accurately as possible. The goal of the 3a was not to replicate the spectral balance of any arbitrary symphonic hall or night club. Imparting a sense of the performance venue—if it is to be done at all—is the job of the recording engineer, not the loudspeaker. AR did not and should not have had any requirement for its speakers to impose the tonal characteristics of any particular performance space upon the playback process in a domestic living room. That entire concept is fallacious on its face. The response of the 3a may well have been uniform in a living room from 250 to 2500Hz, but its response in the succeeding octaves fell off precipitously. I reject “C” on its face as being flat-out untrue. AR’s own curves—like yours above—clearly show the mid level as being 2-3 dB below the woofer and the tweeter level being some 5 dB below the mid. So, the tweeter is about 7 dB below the woofer. Yes, yes, I know that these are “individual driver curves,” not an integrated system curve, but AR had the honesty to put the individual driver curves onto this graph in a real-life level relationship to the other drivers. This is a very accurate graph of how the 3a sounds. Why the heck do people think it’s a little “reticent” or “thick”? Because it sounds exactly as AR very honestly and accurately represents it to sound on this graph. They also say—quite honestly—on the 3a Technical Sheet that the amplifier’s treble control must be advanced to 2:00 o’clock for flat response. That’s about 5dB, exactly what I said the 3a needs for a treble boost and exactly how much more on-axis output the 10π/11’s tweeter has vs. the 3a’s. The 3a was a bit dull and its woofer level was a bit too high in relation to the other drivers. However, it had a whole bunch or other attributes that were really great, so if you could tolerate a down-sloping response tilt, it was a great speaker: unsurpassed bass from a 25” enclosure, super-wide dispersion, very low overall distortion and very smooth (albeit down-sloping) response. Far more good than bad. Far more. I’ll take it over almost anything in its size/price class and it has those classic looks too. But it’s not perfect. Steve F.
  14. What if some contrarian wise-*ss was to offer the opinion that it was all the tweeter? The AR-11 used the exact same midrange and woofer at the later 3a's, yet the 11 was never accused of sounding "thick and heavy." Indeed, the 11 is considered by most to be an exceptionally neutral, well-balanced speaker. That contrarian wise-*ss would say that perceived "heaviness" is primarily a function of spectral balance--the overall balance of lows-to-mids-to-highs, the general shape and slope of the FR curve. The 3a's slope is downward; the 11's is far more flat. Funny thing--when the treble control on your system is advanced to around 2:00 (say about 5dB more) when playing a 3a, its so-called "heaviness" miraculously disappears. Coincidentally, the 11 has about 5 dB more treble output from its tweeter than the 3a had from its. More treble output and the lower-midrange heaviness goes away. Spectral balance. (BTW, that's what the LST had over the 3a, too--and the LST used identical drivers and x-o topology as the 3a. It's a matter of spectral balance. The LST had none of the lower-mid heaviness that the 3a was accused of.) Steve F.
  15. Steve F

    The Venerable Bose 901 Discontinued After 50 Years

    I worked at Bose for a few years back in the early ‘90’s. Even then, in the beginning of the Home Theater era, Bose could see the writing on the wall for the 901. Stereo 2-channel was on the way out. The 901—complicated enough for the average Joe with its need to integrate the EQ through the tape rec loop in the system—was now a near-impossibility to use with home theater. Bose marketing/sales brass wanted to discontinue the 901 then, but Amar forbade it. There were two things that were bandied about re the 901: First, there was going to be a totally self-powered version (with the EQ’d amps in the pedestal stands, removing the need for the little outboard EQ box). This could be run directly off any line-level equipment and side-step the receiver completely. There were prototypes, but obviously, it never made it into production. The second option for the 901 was this: Amar was amenable to discontinuing the actual 901 Direct Reflecting 9-driver speaker that we all know, but he wanted any replacement (whether it was a standalone speaker, a powered speaker, a complete system, whatever) to be a) daring, envelope-pushing and TOTL, and b ) called the “901.” In other words, any new top-of-the-line Bose product had to be called the “901” if the original 901 speaker was discontinued. Alas, nothing worthy came along and so the original 901 speaker soldiered on, way past its relevance in the marketplace. In the last few years, retailers had stopped carrying it and it was available only from Bose directly, IIRC. Anyway, that’s some inside info on the 901 that you may find interesting. Steve F.