Avalon Ascendants - How is the treble?

If your needing more fullness and detailed bottom end, I recommend you consider keeping your M30's and add a REL sub. This would save you some money, and if your still not satisfied, REL and Harbeth's hold their value very well on the used market.

The harbeth has certain midrange that is quite difficult to acheive in other speakers.
Its quite magical due to the radial woofers.
I would recommend adding the Rel sub with the M30 before you ditch it. It might well be worth it.

The M30's are quite good, and I'm not sure I'll do anything. Part of my interest in the Avalons is because I've been very happy with Steve Huntley's work from Great Northern Sound. He's now done both an ARC LS-15 for me, and I just got back my Wadia 860 from him. He likes the Avalons, so I thought I should consider them, and turned to Audiogon for some advice. But I sure can't argue with anybody who says the Harbeth mid-range is quite something...as is the treble on the M30's, also.

I went up to Great Northern Sound to listen to the Avalon Ascendants in the last 10 days, and can now answer my question myself. The short version is that I'm buying a pair, though not without a bit of uncertainty. I've gotten used to the Harbeths over the last few months, and they're lovely...very easy to listen to. Hard to get an offensive sound out of them (unless they are paired up with really problematic equipment, I suppose). However, the Avalons do two things I really like, and kind of miss with the Harbeths: They do holographic imaging about as well as I've ever heard, and they present a lot of sensuously satisfying detail in a relatively laid back manner. (They also have deeper bass.) I doubt that they will be as forgiving as the Harbeths are (although I was surprised how much they got out of a couple of torture-test CD's I used for the audition). (How I react to that issue is the part that makes me a little nervous--it seems that there is a bit of a price for increased detail, and I'm not completely certain where I stand after the Harbeths.) The tonal balance of the Avalons reminds me of the Vandersteen 3a sigs I used to have, but the upper mids and highs seem better laid out, cleaner, and richer. To be specific, one of my torture test discs is an EMI recording from the 60's of Barbirolli doing Delius. On the Vandersteens, the strings sounded dry, grainy, a bit muddy, and generally unpleasant. On the Avalons, I heard the orchestra laid out in front of me more clearly, and the strings sounded fine. Caveat however: I haven't heard the Avalons in my house. We'll see. But the equipment Steve Huntley used to demo them for me was similar to what I use at home: Modified Wadia front-end, and Joule and BAT tube gear, with Cardas cable. (I've got the GNSC Wadia front end, Joule pre-amp, and ARC VT100 Mk III on the 4 ohm tap, with Cardas cable.)

I'll report back for those that are interested.