I'll try separating the speakers out farther. I haven't done it yet because of obstructions but with some work I can spread them out.
As I said in the first post the floor is carpeted and has a pretty thick pad beneath it. The walls are drywall. The room is about 17 feet wide and 30 feet deep. Ceiling is at two levels, about 9 feet over the speakers (drop ceiling) and about 7.5 feet over the listening area (drywall).
I do believe it is a room issue because both sets of speakers with two amps have the same nasty hollow vocals and mid freq spike.
I have a set of Cambridge Soundworks bookshelf speakers in the family room + subwoofer that sound great--very clean and transparent. I may try the M60s in that room just to see how they sound.
