so in the living room, i have a 5.1 surround sound system with a 5-cd dvd player. verytime a movie plays, it goes into the surround sound mode and it fires at all speakers, dolby digital singal or whatever. but then, every 5 minutes or so, my sub punds and it goes into 2 channel mode, and then 2 min later the sub booms again and its back in dolby. what the hell? its annoying as all hell. how do i fix it? all sony stuff btw.