An audio looping/echo problem is affecting every PowerBook G4 (Double-Layer SD), 15" and 17". The problem causes audio to intermittently stutter, echo, or skip backwards. Apple has posted a Knowledge ...

So in my car I think i have a ground loop problem, but im not positive. Its sort of a cyclical noise, so its quiet, then buzzes, quiet, then buzzes, etc. Its not terribly bad, I really dont notice it ...