I've just finished installing a 10 in sub in my Santa Fe. I've got all wires wired correctly (Triple checked), with 8 ga wires for power and ground. as soon as i turn on the car and the deck turns on, the humming comes on. Bass and everything sounds good, but high pitch humming is annoying the crap outta me.

 

check RCAs. The connectors on my RCAs were loose from the wires being pull to the side and it caused humming.

 

Also check that you're properly grounded to solid metal.

 

Worse when you increase rpm?

 

Yeah, you could be getting engine noise. Does it hum when the car is turned to acc, or just when it's running?