I am having issues with the rear speakers. The sound will come out of the rear speakers and then cut out. It then will only come out of the center/front/sub after that for voice. Intermittently, the rear speakers will start working again, but they cut out. Changing between Logic 7/Dolby/neo has no affect. Front/Center/Sub are Cerwin Vega. Rears are Klipsch. Setup is 5.1. I have checked the speaker wire/connections and there does not seem to be an issue. Could this be the receiver?