This doesn't appear to be a very common problem, but I was hoping with the combined knowledge of the crowd we might chance onto a solution.

So I've recently replaced most of the stock sound system in my '98 vette and have been happy as a clam since I've done it. But just recently, with the run of nice weather we've had in Maryland, I've been driving with the top down and the stereo cranked up. What I started to notice was that, if the stereo was at max volume for more than... lets say 20 minutes or so, the internal speakers would quiet significantly (not the subs, just the speakers). If I turned the volume down for a few songs, and turned it back up again, it would be fine, but 2 or 3 minutes after that (sometimes less) it would muffle again.

Some things that have come to mind were that the grounds around the car weren't clean, and that this was somehow bringing about these weird issues; or that the speakers (which are un-amped) just aren't getting enough power to sustain the high volume from the head unit.

As far as what I'm running, I've got the Kenwood KVT-719DVD headunit up front, 800 watts from a DDM-80 running to 2 DD1508's in a 2 cubic foot ported box, a pair of DDC6.5 components in the doors, and the stock bose speakers in the back.

I appreciate any help!