long time since i've posted on this thread. i have an issue that i can no longer stand. a while back(months) i noticed i developed an intermittent high pitch hiss. it comes and goes in 5 to 10 second intervals on and off. its coming from all speakers evenly, although i haven't checked my ceiling speakers yet. i do know this started after an update i received on my receiver but thats the only change i've noticed. prior to that i did have a small ground loop noise that easily was hidden when audio was present, so it didn't bother me. i plan to rework my wires and ground to amp ect. today to start looking for the issue. so far the only move i've made was disconnecting my hdmi output from my cable box going to the receiver with no change.
samsung un55hu9000 sek3500 Marantz av7702 Audiocontrol Savoy 7x150 4x MA500U
swope center, tmww fronts, tm surrounds and rears
polk audio OWM3 x4 atmos
4 12" t3 audio subs ep4000 amp 2x15" type r sonotubes