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Dan Mui

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Everything posted by Dan Mui

  1. The unity of KEF sound is likely that the bass output is from the front top slot of the cabinet. I think it is only exclusive to Model 107, not other KEF models with the band-pass design in that era (late 80s/early 90s).
  2. It is time for me to write a comparison between my AR-90s, BA-T1030s and recently acquired vintage KEF 107-1s. I previously wrote about my AR-90 vs. BA-T1030 in this forum back in late 2020. I got my KEF 107-1s in excellent condition approximately three months ago from a seller who no longer uses them. My seller got them for free from the original owner, who is an internationally renowned individual. The seller sold them to me at well below market value. Since they are not the kind that you bi-amp, they were new likely built circa 1986 to 1988. The KEFs do not have the KEF Kube. I disassembled the speakers and refitted the 4-10” woofers with new surrounds. I touched up the already beautiful solid (does not look like veneer to me) rosewood cabinets. The crossovers are in like-new condition without any signs of leakage. All the components, including nuts and screws, are top-drawer stuff. Fit and finish of the speakers are the best that I have ever worked with. It took me nearly two weekends (25 hours) to finish. About a month ago, I inspected the mid- and high-range crossovers of the AR-90’s carefully. They were in great shape physically and I found no leakage. I then listened to the high- and upper mid-range of the AR-90 carefully with respect to the Optimus Linaeum tweeters on top of the AR-90. Other than a bit less sensitive than the added-on tweeters, they sound alike. Sound I have listened to the KEF 107-1 and the AR-90 (mostly) in the last three months using the same Sony S-Master Pro Class-D STR-DA7100es receivers and Denon DVD-2900s. The Sony Class-D has no distortion or noise to speak of. Far quieter than any tube or Class A/B amplifiers that I had. The Sony is very natural, yet analytical. The sound of BA T-1030 went to another room which displaced the AR Holographic Imaging M6. I sold the AR M6 to a friend, who is very happy with them. I compensated for the lack of the Kube by increasing the bass & treble (a bit too recessed) by 3dB on the Sony. The 3dB boosts are sufficient without making the music sound over boosted. The bass boost is somewhat more noticeable. I keep Linaeum tweeters sitting on top of (AR-90) or behind (KEF) each pair of speakers. The Linaeum and the KEF are nearly identical in sound and volume (matching sensitivity). Less so for the AR-90 as it is less sensitive than the KEF (87 vs. 90dB). Here are my observations. 1. KEF 107-1s have more holographic and out-of-the-box sound, depth, better (maybe even more precise) imaging and very musical and sound very natural. The small heads on top of the band-pass bass cabinets eliminate the issue with sound reflection from the surrounding sides of the cabinets. The AR-90s use acoustic blankets but are not as effective with respect to the heads of KEFs. The KEF sound is noticeably darker (but not greatly) than the AR-90 even with the boost in the treble. In a quick comparison, one might even think the AR-90 sounds more entertaining and has more flares. However, longer listening session will point otherwise. Both speakers are very musical, and I guess (to say) that AR might voice the AR-90 to satisfy a wider spectrum of audience (East plus a bit of West coast sound). To my ears, the KEF is another level above the AR-90 in terms of musicality, soundstage, imagining & naturalness. Both female and male voices are a bit more realistic from the KEF. The KEF bass is top quality, solid but musical without feeling like listening to a quality boombox in a house or car. There is hardly any pressure from the bass even at much higher volumes. The bass, mid-range & treble are so well integrated that there is more unity than the AR-90. This might have to do with the all drivers are in the box of the AR-90s. 2. The BA T-1030 speakers’ sound in-between the AR-90 & KEF 107-1. They are closer to the KEF 107-1s sound-wise than the AR-90s. However, they still sound more so within the box, less holographic and a bit more brittle/less sweet than the KEFs. Simply put, the KEF uses high quality drivers and parts. Their crossovers were well-designed, which contribute to the quality of the imaging. I briefly heard a pair of an earlier Harbeth Monitor 40 from the BA-T1030 seller several years ago. I thought the BA-T1030 sounded better, but now I realize that the BA T-1030 may be just more entertaining but not necessarily better or correct. However, I love all three pairs.
  3. Stimpy, That is always in my mind (for last few years) but the Linaeum tweeters really help. They outperform both AR90 & T1030 tweeters abd best with acoustic music.
  4. I finally decided to write my experience with my current three pairs of speakers. I am not audiophile but a serious listener. Most of my music is from the 70’s soft rock to classical acoustic music. They are all driven by two Sony STR-DA7100es Class D amplifiers and 2 Denon DVD-2900 players. 1. Acoustic Research AR90 bought new in early 1982. I replaced all 6 drivers (4-10” & 2-8”) with foam surrounds. One 10” driver needed to be replaced by supposing AR driver from then A-B Tech after a couple years of coil rubbing (after new surround). I added Optimus Linaeum tweeters on top to get better highs (40-1389). 2. Boston Acoustics T1030 bought used in 2018 late summer in excellent condition. I was planning to get KEF Reference Model 3 (or KEF similar) but none were available. I read the glorious Audio Magazine review for the BA T1030 and a pair was locally available. All new surrounds done in 2016 or so by previous owner. I added Optimus Linaeum tweeters (40-1389) as well. I still want to get a pair of KEF just to try out eventually. 3. AR Holographic Imaging M6 in fair condition. I replaced all 4-8” (210mm) woofers with rubber instead of the original foam. Repainted with 7 to 8 layers of spread paint in light flat Black (more like dark charcoal grey) for the cabinets. I think the bass comes from a band-pass design similar to KEF in the late 80’s. Sound Quality: Of the three pairs, the most balance sound comes from my AR90 with the Linaeum tweeters. Without the Optimus Linaeum tweeters, the sound is somewhat recessed and confined within the cabinets. It also lacks depth by itself without the Linaeum tweeters. Being a dipole, the tweeters also produce wide dispersion of high frequencies. The bass can go low but not very tight. I believe that this is because they can reproduce lower frequency well and is distracting it from the tightness. An increase in overall volume would help to tighten up the bass noticeably. AR90 has the advantage of being a 4-way design to achieve the most balance sound. The 8” lower midrange seems to achieve that goal well. Midrange appears to be a bit cloudier than both AR HI M6 & BA T1030. All in all, they are still very good speakers. However, they are not the most accurate speakers of the three above. BA T1030 are the most accurate speakers to my ears. They are similar to the AR90 but seem to be even more natural with piano and vocals (somewhat less accented). Their bass are strong, tight but not as low as the AR90. Vocals are very good & a bit less accented & less bright than the AR90. The seller/owner has a pair of older Harbeth 40 for music. He demonstrated them to me after the sale. Vocals were even better and more solid than the T1030 but the musical instruments sometime became too “dark”. I am sure that they sounded more correct and accurate but they sounded sometimes less “attractive” than the T1030. I sometime can hear a bit of plastic (plastic vs. paper woofers) sound coming out from the T1030 woofers when driven louder. AR HI M6s are truly holographic speakers. I can’t say whether they are correct in the sense of space and imaging but they do the trick very well. They sound nearly without the speaker box boundary. Bass is very strong and tight but not as low as the AR 90. I would say that the lower bass limit is similar to the BA T1030. Midrange is clean & clear but sound a tiny bit like a speaker phone. The band-pass design crosses over at 150 Hz for the 2-8” woofers (in each cabinet). Maybe it is because the lower crossover frequency, I hear an upper bass discontinuity. It is not noticeable when playing by themselves, but since they are parked next to my AR 90, the discontinuity is evident. Switching them back & forth can pin point that rather easily. I also hear a tiny bit of metallic sound coming out from the tweeters. These are “bright” enough that I don’t need to add the linaeum tweeters. If the recording is recorded without aggressive brightness, I can tolerate them but just about the maximum limit. However, I listen to my AR 90 more because they are easier to listen to for a longer period of time. This is also very similar to Boston T1030 without listening fatigue. Other speakers that I had were Martin Logan CLS (driven by ARC amplifier D90), Carver Amazing Speakers (ARC amplifier D90) and Polk Audio SDA-1c. Thank you! Dan
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