Need a tip from some audiophiles out there

I have two 12's in my car, and I have been hearing a loud hum from them intermittently. I have a feeling it is my head unit (which is being replaced with an AVIC this weekend ), but I am curious to know if anyone else has had this issue, and what was causing it?

Maybe that way while I am in there I can fix whatever else might be wrong.

Thanks!

Installed AVIC, seems to be working ok now. Just in case however, I also re-stripped the cabling going to the amp and to the speakers. All seems fine now.

Usually a hum is caused from having your wiring ran past a fuel pump or a distributor cap. Anything that will cause electrical interference will cause a hum. Invest in some shielded wire and that should fix the problem if it comes back.