I just installed a Kenwood 9980 in my 07 Nissan Maxima and now I have a weird noise. It's a high pitched noise. I don't want to say hum becuase it's not really a hum...it's kind of a piercing noise. It's not super loud but it's there when there is no music playing or if it's a quiet spot in a song. It does get louder as I increase the volume. I had a Pioneer AVH 8400 before and I didn't have this. It's all the same power and 12 volt wiring along with the same grounding point. I did read that this might be a problem with these units...any one have any ideas?

BTW here's my equipment:

Kenwood 9980
ID 1200.1
ID 450.4
JL Audio C5's
Audio Control EQS
Monster Cable RCA's