SL/R129: Speakers sound blown when car is cold

When the car is physically cold, the radio sounds like the speakers are blown, but once it warms up, the sound quality is fine. I'm thinking the problem must be in either the amp or the head unit, as there really isn't much else that could effect sound quality, right?
Any thoughts or how to go about narrowing this down or fixing the problem?
Thanks,
jdg



