Welcome, Mike. If a recording is "bright", an accurate receiver such as the Yamaha and accurate speakers such as Axioms will reproduce it brightly, as they should. Only inferior speakers cover up some of the problems with bad recordings. Your 630 should have enough power for the M60s in your room, but if you're looking for updated features, not just more power, you could consider the Yamaha 1400.

-----------------------------------

Enjoy the music, not the equipment.