I have had ringing in my ears for years, but now I have it in my system. All tweeters, all speakers. I have determined that the ringing can be stopped by changing the surround mode (Denon 3805) from auto to direct. I can run through the different settings and any dolby or dts setting produces the ringing on vcr or sat. I have tried disconnecting the sub and changing inputs. The volume of the ringing increases with volume change. Any ideas?