More opinion time here, so don't take my words as gospel...
I believe that 1900cu ft is too small for M80's. As others have said, M80's need room to breathe. My main den is about 3150 cu ft (14x25x9), and I think even that is sort of on the small side for M80's. Might be why the bass response for me isn't as great as others report.
Our bedroom is about 1800cu ft (off the top of my head). I have a pair of M22's being powered by a tiny T-Amp, fed from an iPod dock. No sub, just raw, full-range M22's. The setup sounds fantastic. I'm extremely pleased with it. More than I thought I would be, actually. The smallness of the room, combined with ample sound deadening from the bed, drapes, etc, really 'warms up' the M22's. They'll play fairly loud before the T-amp runs out of juice. I've never tested it with my SPL meter, but it'll play to the point where you'd have to raise your voice to carry on a conversation in the room, with a lovely amount of bass. Very good for classical music. With an amp that puts out more than the meager 9 watts (or whatever) that the T-Amp does, I'm sure they'd go much, much louder.
