I suggest dumping the playing of music from a DVD player and buy a dedicated cd player - Cambridge Audio or NAD for your price range. Don't listen to people who will tell you otherwise, just try it and see.
If you want soundstage depth or perhaps even more dynamics, get rid of everything that stands in between your speakers. Not practical, I know but try it one day. Lower frequency depth? Not sure what would cure that - definitely a better amp, perhaps M60s but probably unlikely since you already have a sub.
Invest in some cheaper used separates from Audiogon or something like that. Older NAD separates are pretty cheap and warmer. This will improve your music performance. Finally, don't take advice from anyone who hasn't heard the stuff they are talking about.
