Where are your signal cables running? Are they near the power cables? If it is an aftermarket head unit... is it grounded well?Low hz rumble though sub only while stereo is on i have 2 0awg power and 2 0awg grounds plus aditional grounds connecting bed and cab of truck to frame. seems like a ground loop but i cant find it. i have a skar zvx15d.2 v.3 and a RP2000D
It's not Humming it sounds exactly like my exhaust Its weirdHmmm, hard to say. If it is "humming" at idle, no music playing... I would start physically touching cables and wires with your bare hand. Many times a suspect cable will either silence or amplify the hum. Then you can trace that wire or cable and correct the connection usually. Just a suggestion. It may or may not yield a result.
Disconnect RCAs from the amp. If hum reamains, amp is at fault. If hum goes away, reconnect at amp then disconnect at the stereo. If hum persists, RCA cable is at fault. If hum stops, stereo is at fault.It's not Humming it sounds exactly like my exhaust Its weird