Since so much sound comes from the center speaker, you may want to replace yours with a center speaker that can better hold its own more with your full range Magnepans. The default surround mode for stereo DPL II-C (like DTS NEO:6-C) steers an awful lot of the sound to the center channel. DPL II-M (and DTS NEO:6-M) on the other hand, steer less to the center and more sound to the mains instead.

Enjoy!