Subwoofer Problem - Need help

[duckydan]

I am having a problem with my sub (a Klipsch Sub 12). Randomly it will start emiting bass at a very high level (much higher than it is set for) even if nothing is turned on. I turn the dial on the back and nothing happens. I am able to turn it off or unplug it and that obviously stops it but I can't figure out why it is happening. Sometimes it'll happen when you walk past it. It's also not constant.

I have a few ideas as to what it may be but I'm hoping someone can help me pin it down:

a) a bad subwoofer cable

b) I have a wireless router pretty close to it, could that be causing interference?

c) It's plugged directly into a grounded electrical outlet and is only about 1' away from it, could it be getting interference from that?

d) interference from another device (cable box, tv, etc)

Before I start rewiring and moving everything I'd like to get an idea as to where to start. Thanks to any and all that can help.