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Gerry S

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  1. I always felt the "bi-amp" option that ADS offered to consumers was a mistake. There is more opportunity to screw up the sound than to improve it (I once owned a pair of 910's using just the built in passive crossovers). Effective bi-amping requires pretty detailed knowledge of the raw drivers individual performance. It also requires test equipment to set amplifier gain levels, as well as the crossover frequencies and slopes. Pro's use bi-amping in sound reinforcement for increased output capability and reliability, and when the performance space has been defined. With pro use,the cost and complexity of additional amplifiers and electronic crossovers is justified over the long haul. With consumer use, I don't think it's justified, from either a cost or performance point of view. Let's assume the ADS passive crossover was properly designed, and yields what is generally acknowledged to be "good sound". With bi-amping, audible changes to the system should be SUBTLE. The primarily benefit should be less audible distortion as the woofer amplifier "clips" (overloaded) with heavy bass content. The distortion generated with this clipping is produced by the woofer(s) only, where it's mostly inaudible. It's inaudible because woofers naturally rolls off highs, and the passive crossover reduces the highs further. The trouble with bi-amping occurs when any additional filtering created by the electronic crossover upsets the INTENDED "blending" occurring between upper woofer frequencies and midrange lower frequencies. Not to mention any changes in the "radiation pattern" at the crossover frequencies. I'm not saying that bi-amping isn't a valid way of improving sound. I'm saying that in the hands of the average consumer, it's not likely to do so. Gerry S
  2. The T1030 crossover pictured above is a genuine BA part. It is a "quasi-second order" SERIES network between the woofer and midrange. With this type of network, any change in X-O values affect both the woofer AND the midrange SIMULTAINIOUSLY (because the drivers are effectively in series). It is much harder to "voice" because of this inter-dependent relationship. Note that If you disconnect either the midrange or woofer from the crossover, you will get no sound from either! The T930 Series 2 also used this "quasi-second order" configuration. I'm pretty sure the T830 Series 2 also used a quasi-second order network. The midrange and tweeters should be identical for the T930, T930 Series 2, T1000, T1000 Series 2 and T1030. There is NO "Series 2" T1030 (probably because it's hard to "improve" the T1030). Lessons learned from the T1030 development work resulted in the Series Two versions of the T930 and T830.
  3. Gerry S

    ADS L730 Mods

    As a loudspeaker designer (retired), I wouldn't do "mods" for ADS loudspeakers. As is, they are well built and well designed. Unless you possess the technical knowhow, as well as access to necessary test equipment, ANY change you make will most likely just ALTER system performance; NOT "improve" it. These are loudspeaker SYSTEMS, where each driver is meant to work with their associated drivers, and in that particular enclosure. If you change/substitute just ONE driver (woofer, midrange, tweeter), you've essentially changed the whole system (probably for the worst). Even if a driver swap is miraculously "successful", you would have to do the same for both speaker systems to get reasonably matched "stereo performance". I believe that "modifying" any loudspeaker system for personal preference can be fun. But if the mods are made to a "classic", that product is no longer a classic.
  4. Honestly, I can't remember. If I had to guess, the newer version had the terminals on the back. Here's how I would test/distinguish them just by LISTENING TO THEM (preferably using pink noise). Keep in mind that crossovers determine the "radiation pattern" where the various drivers "meet", aka "crossover". With the original, smoothest response between the midrange and tweeter is pretty much "on axis" of the midrange/tweeter drivers. When listening "sitting down" or "low" to the floor, response is uniform. However, as you stand up, the sound balance can change noticeably, perhaps by seeming perhaps "duller". That's due to a "dip" in in the response (at/near crossover) as you move up from the speaker axis. The newer version minimizes this "lobe"; not much tonal change between listening "sitting down" and "standing". Listening evaluations can be performed using just ONE speaker (instead of a stereo pair). I prefer "pink noise" as a source, since it's repeatable and continuous. Lacking that, music with mid/high frequency content should reveal differences. Listen in the "near field" (about 2 meters away) so that the drivers "integrate" fully, but before the room alters what you hear. Listening to "a stereo pair", the newer version should have a more "focused" central image with a mono source (pink noise or a vocalist). That "focus" is also better maintained as you "stand up". Again, the differences are most noticeable when listening in the "near field". .
  5. Please refer to: Boston T1000 vs T1030 Started by morkys, Mar 16 2009 10:01 AM The driver alignment difference alone would make replicating the T1030 "sound" on the T1000 difficult (if not impossible) in the "near field". The T1000 and T1030 use identical drivers and enclosure volumes, but the crossovers are NOT interchangeable. That's because the two systems have different physical driver alignments, requiring a different approach to crossover design. As far as specifics, the T1000 crossover uses three "parallel" networks (one each for the woofer, midrange and tweeter section). The T1030 uses a "quasi-second series" network between the woofer and midrange sections, a parallel network on the tweeter. The crossover frequencies and slopes are also different, resulting in different "near" and "far-field" responses. As far as replacing caps, I don't think it's necessary. It could actually be detrimental to system performance and reliability (because of changes to the crossover frequencies). I would not operate both systems in the same room because of likely acoustical interference between the two. Also, each system has an impedance of 4 ohms at low frequencies; operating both systems at once (from the same amp) would tax the amp.
  6. Regarding T 830: no change in drivers, just crossovers.
  7. The A400 isn't meant to be be "pulled away" from the wall behind it. Doing so will weaken the bass considerably. Nor was it designed to be "toed in" (which pulls the speaker slightly away from the wall behind it. The T1030 can be used near or close to walls, but also several feet away to minimize wall reflections which can slightly "blur" the stereo image. You can also toe theT1030's in..also to minimize blurring the "first arrival" stereo image. I personally believe that speaker spacing is best between 6' to10' apart depending on size of the room (for either system) and how far you can sit behind the speakers and still have good imaging AND good, smooth bass at the listening location. There is no hard/fast rules to exact distance..depends on the room and aesthetics.
  8. Dear Mystery. Regarding post #11. The A400 was "before my time" at BA. It was Andy Kotsotas's VERY FIRST SPEAKER when he founded the company. I did listen briefly to the A400 flagship, but did not use it as "a reference" while doing the design work for the T1030. Note that they are VERY different speakers as far as loudspeaker placement is concerned. The A400 was designed to tackle the "Allison effect" by having the woofer very close to all the boundaries (for smoothest bass into the room). The wide baffle minimized diffraction from the cabinet edges. For the system to work as intended, it must be placed against the wall. With a smaller "footprint", the T1030 was designed to give the user greater flexibility in it's room placement options. When I "voiced" the T1030, I gave particular attention to it's "nearfield imaging" capabilities. I don't know whether Andy did the same for the A400. I do know that the A400 was/is highly regarded in the audiophile community. For all I know, the A400 could "image" as well or better than the T1030. Again, I have not "A-B 'ed" the two to see which is "better". IMO, really pointless to do so because it's really like compairing apples to oranges. I've found that when comparing two systems that are competantly designed, the differences heard can be attributed as much to the recordings and room acoustics as to the speaker themselves. Sometimes, these two variables can SWAMP differences in "design philosophy". Which is why I don't pay much thought to exotic (expensive) cables and such.
  9. todtubbi.... "The T930's make a very nice 2.0 system for my big screen tee-vee, but I want to upgrade to 5.0 (I'm thinking that with the T930's I shouldn't need a sub--do you agree?)" As good as the 930's bass is for music,"Movie Bass" is a whole other animal. It can't hurt to add a powered sub for "home theater". I personally use a Hsu Research model with fantastic results.
  10. Gerry S

    ADS L1590

    I remember reading brochures on the Series II. On paper, it seemed to have enough engineering improvements to justify it as a replacement for my 910's. So, I went to listen to them...forgot where. What I saw was impressive: tall, elegant towers with all drivers vertically aligned. Metal grills designed for minumum difraction. Compared to my relatively "squat" 910's, they certainly LOOKED more apealing to me. But, when I heard them, I wasn't "hit-over-the-head" impressed. If I AB-ed them at length, and at home, I might have thought differently. When I asked about the price, THAT'S when I decided the audible improvements (I did hear some in that showrooom setting) were not large enough to warrant lugging them home for extended listening. I think I would have been impressed if I did. Having done my share of crossovers at BA, I can attest to how important ADS's improved crossovers can be in determining overall sound quality. At the same time, many improvements can only be heard if the system is properly set up, AND quality recordings are used to reveal these improvements. I believe under normal conditions, many of these improvements would be inaudible or very subtle. I know that there IS a "night and day difference" between an AR 3a and a AR10 pi. Despite having similar/identical drivers, I could easily and repeatedly distiguish one from the other blindfolded. Probaly not as much between the AR 10pi and the AR 9 as far as tonal balance...probably reasonably similar! However, the AR 9 would have been my speaker of choice (tremendous dynamic capabilities AND "imaging") if I had to own something "vintage". I can't help but wonder if I would feel the same way about the ADS Series II if I had purchased them. The ADS Series II towers (an idustrial designer's speaker) LOOKED more advanced than the AR 9 (an audiophile/enginner type product). I wonder.... which product sold better?
  11. Gerry S

    ADS L1590

    Senior moments come and go. While it's still in my head: "another similarly powerful amp for the demonstrations" was (I think) a Luxman M4000. The Dreadnaught cost me $1500....very industrial looking. The Luxman cost several times that....more than the car I owned at the time. It almost weighed as much too..LOL
  12. Gerry S

    ADS L1590

    Tom, I never blew a 910 fuse either. I do remember the Dunlap-CLark "VU" meters "dimming" significanty when I "clpped them". The meters weren't "true" VU meters because their ballistics were a bit slower than what's called for. still good enough though ! At the "-20 db" level meter setting, 0 to +3 db "average" readings would clip the Dreadnaught. Strangely enough, none of the fuses on the amplifier blew either. And if the fans did come on , it was a very rare occurance. I actually owned TWO Dreadnaughts. When they eventually failed , it was an output transistor. I actually used the Dreanaught to develop the "improved" BA towers and found the Dreadnaught invaluable; revealed some critical performance criteria i wouldn't have noticed if I used the amps BA had in the labs at the time (big Adcom and NAD amps). But that's another story.
  13. Not to "diss" Steve (or Andy Kotsotos, who did the original 930), but the Series Two was RADICALLY different than the original. The crossover topology of the Series II bore NO resemblance to the original. For both far- field (reverberant) and "near field" listening conditions, the sonic differences between the two were large enough to think one was listening to different brands. If I had to characterize these diferences, the original had that "concert hall" warmth, while the Series II was more "detailed" or "analytical". The T830 also underwent a radical change in its crossover design (but retaining the original driver placement). I can’t remember if their was a model # change, but again, the audible differences were HUGE. Regarding these very pronounced audible differences, I’m not saying which is "better". The best analogy I can give is comparing the AR3a to the AR 9/10/11 seies. Some prefer the "original 3a sound" to the newer ones. With no access to sales data, I couldn’t tell you if the "improved versions" did well or poorly in the stores. Off course, since I voiced the "improved" versions, I naturally believe the later versions were "better" ...LOL. Of the three "towers", my personal favorite is the T830 (with the newer crossover)! It may not have the bass capabilities of its larger siblings but had the smoothest and most neutral sound in both the far and near- field. I’m theorizing it probably had better power response because of its smaller midrange driver. The 830 were also easier to move around for best placement. Add a powered sub and that would be MY ideal BA system for "stereo listening’ in it’s simplest form. The irony of my post is I never OWNED any of the towers mentioned despite my "re-working" the crossovers ("voiced them"). Maybe someday!
  14. Gerry S

    ADS L1590

    I actually WOUND these voice coils in their Wilmington ,MA facilities. I distinctty remember that black "goop" coating; a devil to work with. DCR tolerances were extremely tight (at least mine were). When I owned the 910's, never blew a driver despite using them for hard-rock & disco playback @ high SPL. My amp at the time was a Dunlap- Clark Dreanaught 1000 (rated @500 watts/ channel into 4 ohms from 20 -20 Khz CONTINUOUSLY) ! Think my ears became "non-linear" before the speakers did !
  15. Gerry S

    ADS L1590

    Tom (and former ADS engineers). I always wondered why they never "mirror imaged " them, especilally since they were "studio monitors". I know that they were "reverberant field" speakers, but still !!!!. Other "classical music" monitors of that period (KEF & B&W) did pay attention to imaging in the near field as well as diffraction issues. The grilll that came with them was reminiscent of the AR3a inset driver mounting with a big lip overhanging the baffle. At least the 910 grills were removable. I must say that the 910's were my biggest "high-end" dissapointment of all the speakers I've owned. Given the superb and expensive "build quality" of this model, a miirror imaged pair shouldn't have been that costly to make. Heavy MDF consruction, well braced,seperate chambers for each woofer, industrial grade printed circuit board and crossover components, fuses for each driver, etc. I can't help but wonder why they didn't go "alll out" to address my "minor quibbles" like imaging.
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