I installed the V-trac horns, BMS 4592 mids, Beyma CP25 tweeters and ALK Universal crossovers in my 1987 Klipschorns replacing the stock drivers and crossovers last weekend. I’ve got at least 15 hrs of playing music on them, the sound has pretty much stabilized, so I thought I would share my impressions so far. I have not finalized the attenuation setting for the midrange drivers yet. I started at X-4 (6.2 dB attenuation), and subsequently tried 0-1 (12.5 dB), 0-2 (9.5 dB), 1-4 (7.4 dB) and now 0-3 (6.7 dB). I’ll probably leave it at 0-3, but might go back to 1-4.
The rest of my system: Scott 299 integrated receiver (run in triode, “Platinum” modification by Sam Kim), Rega Saturn CDP, and MIT Shotgun S3.3 speaker cables.
First of all, the V-trac, driver and crossover changes improved the speakers way more than I expected. And I expected substantial improvement. Bottom line: I can’t recommend the upgrades highly enough. The K-horns have been DRAMATICALLY improved across the board, without any downsides that I have identified so far. The modifications were expensive, but at least for me, I feel like the huge improvement in the sound more than justified the cost.
Now for the details. The most obvious change is one of much greater clarity. It’s almost like a substantial amount of distortion, “grain” and harshness is now gone, yielding a much lower noise floor and making the music more emphasized. Individual orchestral instruments are now easier to follow. Lyrics are easier to understand. Voices are much more natural. Instruments have more accurate timbre. There is more “air” around instruments and more sense of the acoustic space. There is also a bit more liquidity and midrange warmth. Altogether MUCH easier to listen to for hours. The biggest problem I have is wanting to turn up the volume too loud. I think before the upgrades, I listened at lower volume levels because of the grain and harshness. That’s much, much reduced now, and a big improvement.
Before the upgrades, I thought the K-horns had a very wide if somewhat indistinct and unstable soundstage. I have the speakers in exactly the same place and the soundstage has improved a LOT. Wider, deeper, stable and more natural.
For those who may be curious, I don't have any experience with with any other driver/horn/crossover modifications. And I don't foresee any need to: these K-horns sound wonderful!
There is one other thing I would like to comment on, and that is the bass performance of the stock speaker, which I did not replace. About a month ago, prior to installing the upgrades, I switched out my Kimber 8TC speaker cables for MIT Shotgun S3.3 cables. Holy cow! For those of you who feel like the K-horn is somewhat bass-shy (and I formerly felt that way), you might want to try MIT cables. I feel like I almost have too much bass now. At least in my system, the MIT cables made a dramatic (and welcome) change. Very highly recommended.