Normally, half-volume is more than loud enough for me. Cruising in the 66 degree weather here today I noticed I had to turn the volume up to about three/fourths to hear the radio. When I got home I started trying to adjust the problem and found that my rear speakers were extremely tinny and weak sounding. Put the "balance" to rear speakers only, turned the "base" way up, and the rear speakers still were weak sounding and no base. The front (door) speakers seem to be okay and sound like they should. It's the 2 rear ones that seem to have "petered out". They have some volume just very weak and tinny. I'm not much of a stereo expert and wondered if this sounds like an amplifier problem or a speaker problem. I don't have a lot of faith in my local Chevrolet Service Dealer, (small country dealer who has yet to receive a SSR for sale) but guess I'll have to let them try to solve the problem. If anyone has any suggestions or ideas as to what my problem might be I'd love to hear from you. Thanks!