b&k or Bryston or McCormack?

The Ascent is no big deal to drive, a 1 ohm dip at high frequencies will not present a problem and is not a difficult load. There are not huge impendance swings with this speaker -- this is the real challenge -- so, without question, any of the amps you mention should be fine. Why am I so sure? I'm driving CLS's with a McCormack DNA1 Deluxe and am quite happy. (Can I do better? "Yes". But this the amp I had on hand. There's more possible with a high current/voltage tube amp and a REL sub-woofer -- my next moves -- but since this amp drives the speakers without effort, images well and makes damn fine holographic music I have no doubt whatsoever that whichever of the amps you mention will do a good job.) Just pick the one that sounds best to you. The person who advised bi-amping (imho one amp for the panels and one for the woofers is the way to go) is right on. This makes a huge difference with the Logan hybrids and gives you a great deal of flexibilty -- pick the best sounding amp for the panels and another for the bottom end. By the way, I hear that the Ascents do a much better job of integrating the woofer and panel than the SL3. Let us know how you make out.

I have owned the DNA1, B&K, and the Bryston 4BST. In my system, the Bryston was the most controlled in the bass and the most transparent in the midrange. The DNA1 was close. The B&K was warmer however. A very fine color, but pleasant. Almost tubey. You should use a tube preamp to get a little warmth also. The amp I would use with that speaker is the Aragon 4004 or the 8008 I think they call it now. The 4004 has worked well with ML speakers and can drive that wicked load. If you can find an ARC D300, that is a good amp with that speaker also. Even better than the Aragon, but more money. Try before you buy.

have had theBryston 4b for years,is real good for power-hungary speakers as those,yet is also open and clear,cant speak for those other amps,can only say you will be satisfied splendidly for the money,bob

In a direct comparison using all of the same components and speakers, a Bryston 4B (original model, non ST model) had a harder time driving some very low efficiency / low impedance speakers than did my old Classe' 70 amp. Keep in mind that the the 4B was rated for 400 wpc @ 4 ohms while the Classe' was only rated at 150 wpc @ 4 ohms. Needless to say, i found this pretty perplexing given the excellent reputation of the "built like a tank" Bryston's. It's possible that the Classe's dynamic headroom of 3 db's helped it out quite a bit, but it still sounded measurably better than the 4B. The 4B had just came back from their U.S. service facility after a complete overhaul and very thorough inspection, so i know it was up to factory specs. I also found that a Yamaha M80 sounded much better than the Bryston 4B when used in the same system. The Yamaha is rated for the same appr. power, but was much cleaner sounding all the way around. Needless to say, i sold the Bryston within a very short period of time. Just my observations ( for what they're worth ). Sean >