Check the settings for the back speakers. I know my Pioneer offers a "bi-amp" option, where they rears will play the same content as the fronts. It should be set to something like, "surround back, two speakers" (some offer an option to run a single rear, or none).


Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris