I have had problems with my Sub since I have had it. I just upgraded my reciever to a Yamaha 1400 and changed cable to the sub which made no difference. Mostly happens when playing at louder volumes the sub will start huming like it does when you don't have the coax plug all the way in. I can move the plug around and it goes away. I can turn the reciever off and back on and it goes away. It seems to have a good fit. I took the panel on the back of the sub off to look at the conector and you can't really tell anything. It is solder directly to the board and you can not see inside it. Any suggestions on what to do. It is driving me crazy.