I've got an SMS-1 and it has started to only partially work. Bass output is severely reduced to the point of being inaudible even though the driver appears to be somewhat vibrating. Here's the weird part, to get full, normal bass output I have to crank the bass level on the receiver to about +10, then crank the main volume to about -8 until I get a sudden shock of bass that rumbles the whole house. Once I shock the system into operation, I can turn down the volume and bass level to their pre-calibrated settings and everything works fine from then on, until I turn the system off and have to do it all over again.

At first, I blamed the sub for the issue but I've monitored the situation for some time now. When I disconnect the SMS-1 from the system and run the sub directly from the receiver the sub always operates properly, so I don't think I can blame the sub.

What could be wrong with the SMS-1 to cause this situation and what can be done to fix it????