My NEX-8000 installation has been working perfectly for weeks - until today. I have it set to announce when I go too far over the speed limit. It quiets the audio (not full mute) says its thing, and then restores the audio level. Today it told me I was going too fast, but the audio stayed at the quiet level, and I could not get it to come back. The + and - volume button were not functional, nor could I do anything by hitting the Mute spot to the left of the volume slider. I tried changing the Mute level in Audio setting (it was set to ATT), and everything else I could think of. This stat