Hello, I recently purchased a new surround sound system (Onkyo SKS-HT540) and a new receiver (Sony STR-DH720). Those items represent my first real venture into home theater assembly, and I have a few questions and concerns. I don't know if these are simple or common questions or not, but any help with them would be greatly appreciated. My questions are basically about proper sound output. I have a 7.1 surround system, which works perfectly with PS3 games and Blu-Rays that are native 7.1, but when I play something in native 5.1 or 3.0 (the Lady and the Tramp Blu-Ray being the only example I have of the latter), sound still comes out of every speaker. Shouldn't the rear speakers be inactive when I play a 5.1 DVD or Blu-Ray? (As a side note, the receiver does output stereo signals as stereo, although it does output mono signals as stereo too.) When I play 5.1 movies and games, the display on my receiver acknowledges that it's receiving no discrete channels for the rear surrounds, but also says it's outputting something and I can hear sound coming from those speakers, although I don't know exactly what that sound is (or at least, I think that's what the display's saying; in this case, the SBL and SBR symbols don't light up, but the boxes around those symbols, which seem to indicate when those speakers are active, do light up). I know it's not a case of me choosing the improper sound field because I've set the receiver to A.F.D. Auto, which according to the manual sends out the audio exactly as it is received, and not Dolby ProLogic or any other upconversion program. Is this a problem I can fix by adjusting some settings, or this just the cheap receiver being... well, cheap? As stated before, any help with this problem would be greatly appreciated. I've spent a fair amount of time, money, and effort on my home theater, and I very much want it to work properly.