Ok guys, I have the JBL S setup with a PB12 and Poineer reciever. All eqipment new. Good cables going to it The JBL PB12 is starting to emit a low hum to it. You can hear it when all sound goes away or right before the sub turns of automatically. What is the deal with that? Would it be related to the power connections? Should I give the sub it's own power outlet?