Today when i got in my car i was waiting on my friend and i turned my car to acc and i was running my sub with music like 12/62 on my HU and there was a different noise like coils were rubbing but not really that bad. It is really hard to explain but i could just tell it was different and it didnt sound good. I have gain like 3/4 on my amp i have the sub level on +4 @80hz and everything else is set flat. I cranked up my car and it seemed to disipate(sp) so i turn the sub level down to 0 and its a pretty big drop but is beautiful. Is it bad to have the sub level on my HU to +4/+6?