OK, so I have an out-of-box Sony home theater system hooked up in my room. I know it isn't very good, but for my tiny room, it gets the job done. Lately, the sound has started acting up while watching DVDs. The sound will be set at a certain volume, and periodically, the sound will fade slightly for a few seconds, then go back up to the normal volume. This happens at inappropriate times during the movie. I have tried several DVDs since I've discovered this, and it happened during each one. I have no idea what could be causing this since it has never done this before and I haven't messed around with the set-up for quite some time. It seems to happen just in the center channel, but I could be wrong. I don't know if it's a problem with my speakers, receiver, or DVD player. Any suggestions?