I'm new at home theater and just set up this system. Everything works fine except for the sound in concert DVDs. I am not getting sound from rear and back surround speakers when playing these concert DVDs even though they indicate Dolby 5.1 surround. I'm playing the David Gilmour in Concert DVD in a Bravo D1 with optical audio out to a Denon 2803. I have 6.1 Omnisat Micro speakers. On the Gilmour DVD audio set up, I have a choice of stereo or Dolby 5.1 so I select the Dolby. Even tried the 5.1 sound tester on the DVD and all speakers respond. But when I play the DVD sound only comes from front, center and sub, not rear or back speakers. If I select stereo on the DVD set up, then all speakers work. The AVR indicates a digital signal is being received. The Bravo D1 DVD player audio out is set for encoded digital. Can someone tell me where am I going wrong in the set up?