to surround 'back' speakers with a 5.1 channel input and output. Then there's no side surround speaker output at all. This is for straight 5.1 DD, DD+, DTHD modes. I was wondering if there is a new Spec from Dolby to push out surround channel info through the surround 'back' channels with only a 5.1 channel input and output in a 7.1 speaker setup?\n\nTechnically this could be better as a 5.1 only setup should have the surround speakers at 120 degrees from listening position compared to a 7.1 setup at 90 degrees. The 7.1 setup surround back speakers are setup at 135 degrees. That being a 7.1 setup 135 degree surround back speaker position being more correct for a 5.1 input\/output than the 7.1 setup 90 degree surround speaker.\n\nI never seen this before. Yamaha seems to just send the same surround channel info to both surround speakers and surround back speakers with a 5.1 input and output mode.\n\nDenon follows the 5.1 input with the 5.1 output speakers. No surround back channels at all for a 5.1 input and output, in a 7.1 speaker setup (unless using Dolby Surround Mode with a 5.1 input). Onkyo's previous models, XT-NR595, NR696, NR797 follows what Denon does.\n\nOf course using Dolby Surround Mode with a 5.1 input will upmix to use all 7.1 speakers with their correct channel information.