This might be better off in the Audio forum, so run me off if appropriate :)
I am working on getting a Mac in my 04 Ford Escape (will be a mini, but i'm using my work supplied PB 800 as a test platform), and have run into a couple of issues trying to use it as the stereo.
I currently have an Alpine head with 3 Alpine amps (front, rear, and sub). I picked up a M-Audio Sonica USB adapter so I could run to my amps properly (by properly I mean have front-back & left-right fade support as well as timing control). The PB is an old 800 TiBook with USB 1.0.
The first issue is that at max volume on the Mac, the audio is not very loud (louder than "normal" people would like probably, but would be too quiet doing 70+ with the windows open). And on the flip side, when I bring the Mac's volume down below 25% I get no sound output.
The second issue is that on some songs, my right front speaker sounds blown (distorted/scratchy/etc..). When I hook my HU back up it is fine though.
I tried asking the shop that install the audio gear for me, and the rattled off something about home audio vs car audio using different power levels. It sounded good until I started reading these boards and don't see many others having sound issues.
Any one have any ideas what might be going on?