When you say there's a "little edge" to the music on the m80's when turned up over 90db, do they become unlistenable at this volume? Do they become sibilant? How about when listening to the m22s at that volume? I don't listen loud very often but I'd like to be able to crank them (m22s) up once in a while.
By a little edge, as I said, it sounds more like live music. I find that when I am listening to live music at loud volumes, rock concerts, etc. the M80s give that edgy sound you find at these venues, is it hard to listen to? Some people find it hard, I don't. I just keep cranking up the volume, the harshness or brightness or what ever you want to call it, really doesn't bother me. I do find some source material to be offensive when it is a poor recording, but I just don't listen to them as loud and they still sound very good and then there are those recordings that you just don't want to listen to at all.
You sound like me in that many other speakers that are said to be warmer etc., I find to sound muddy, muffled, less exacting, and I do not care for them as much as the Axiom detailed sound.
The M22s I think do not get as harsh/bright as the m80's at louder volumes, but it has been awhile since I really cranked up the M22's. The only way you will hear distortion from Axiom's or any other well made speaker, is due to a distorted source or trying to run too loud and the amp starts to distort.