ok...i've had my db-840 for 6 months or so and just recently bought some bass shakers. so i hooked up my old sony de-375 pro-logic receiver and hooked up the bass shakers to it. everything worked fine. and then while i was watching a movie i tured up the volume on my db-840 and fet the bass shakers start ro rumble alot more! so i get up and look and sure enough...my emote for the db-840 is turning up the volume for BOTH recivers!!! is the frequency that same? do i have any options to "change" it?