I have a pair of M3s for my music system. (modest - Technics SADX 940, Cambridge Audio D500SE CD, Maple Audio Ambience interconnects, M3 speakers, Velodyne CT80 sub.)
The M3s are incredible speakers. The M3s have 6 1/2" woofers (+ 1" tweeter). M22s have a pair of 5 1/4" woofers (+1" tweeter.) The M50s have a pair of 6 1/2" woofers and again a 1" tweeter. Because the M3s just knocked my socks off, I'm going with a pair of M50s for my home theater/music system because they both use the 6 1/2" woofers. I'm hoping the M50s play like super M3s.
(HT system - Onkyo 797 receiver, Panasonic RP56 DVD, waiting for M50s up front, Merak MC6H center, Merak MT66 sides, Mission 77ds rears, Velodyne CT100 sub.)
BTW, I've heard great things about the HSU subwoofer.
As long as I'm blathering, I'm thinking of upgrading the Merak horn tweeter center (which I love) to the VP150, and the side Merak MT66s with the QS8s.
