I have the yamaha rxv 2500. want to set up 7.1. have all the speakers. Now when i play a THX certified dvd, all the speakers work and it shows on the receiver that they are all working. (this is before the movie when the THX sound somes on). Once the movie starts, the surround back no longer is showing on the receiver. why is this? i thought they should be on during the entire movie.
The surround back will only be on in movies with a Dolby Digital-EX or DTS-ES soundtrack.
Otherwise you must use a DSP on the receiver to copy the surround channels to the surround back channels. The benefits of this depend solely upon the size and layout of your room in my opinion.