I have a music dvd that behaves stangely. Without the center speaker installed the sound volume cuts down in some parts as if the amp couldn´t handle the high volumes. With any center speaker installed the sound is just fine. This happens only with this one dvd. For aesthetic reasons I´d like to have a "phantom" center speaker set-up but because of this I have to keep the center speaker. It doesn´t help if I set center "none" in the amp. Does the problem originate to the way the dvd was mixed?