I have noticed a problem with my sub since switching to a new processor. When it receives a signal it moves out of standby and starts working. The problem is that, when the signal is shut off, the sub does not do likewise, but retains a residual hum and noticeable cone movement. Even turning off the processor does not stop this. Removing the input lead does stop the hum, but it recurs if the lead is replaced. Turning the sub off also stops the hum, and in this case it does not come back when the sub is turned back on. I have been advised that the problem may be an earthing one, and that disconnecting the earth lead on the plug may be the answer. As the plug is sealed, I would rather not interfere with it unless it is likely to be successful. The sub is a B&W ASW CM, and the processor a Proceed AVP2. Incidentally, this processor has a sub force off option for stereo CD use, but this mode does not stop the hum. Any thoughts?