First of all, make sure you've got enough (5+ feet) space behind the speakers, then experiment with toe-in. The curved panel rewards extensive experimentation with positioning. Also, damp your room properly and manage first reflections.
As above, Parasound do not make the best electronics for ML's. I have a pair of Sequel 2's and have done very well with a Sumo Nine +, NEW A20.1's (vertically biamped, but still underpowered for HT, fine for stereo) and now Atma-sphere M60 Mk2's. My Bryston 3B was OK, but probably not optimal. Fortunately, I had a big room at the time.
Changing power cords (or even better, using power conditioning) can also help. Changing preamps may be necessary, too, but try these other things first. Don't give up!
As above, Parasound do not make the best electronics for ML's. I have a pair of Sequel 2's and have done very well with a Sumo Nine +, NEW A20.1's (vertically biamped, but still underpowered for HT, fine for stereo) and now Atma-sphere M60 Mk2's. My Bryston 3B was OK, but probably not optimal. Fortunately, I had a big room at the time.
Changing power cords (or even better, using power conditioning) can also help. Changing preamps may be necessary, too, but try these other things first. Don't give up!