Ive checked..it is coming from the subwoofer. FRom what I told Debbie..she thinks its getting over-driven. From the adjustments I've tried..it helped, but still rattles when a movie is playing explosions...thunder...anything on the really low end. I've never had a subwoofer before so I'm unsure if it "sounds" like it should when playing music, but it doesn't rattle at all when doing so.