I have been listening to my 595 with my Ascend accoustics 170's. I recently hooked up a central channel speaker, and I get no sound. I went into set up and labeled front speakers small and likewise for the center, and I have a sub connected. I get no sound. I checked the speakers by wiring them to the left front, and they do work. I must be missing something. I have a dvd/cd player connnected in the opti 1 connection(Sony 670D), and when I played several cd's, again no sound. Help, please. What am I missing ?