Craig O'Donnell passes on some notes on Macintosh audio as of Macworld Expo in San Francisco:
I verified that the IIvx, Performa 600, and Duo 210/230 do NOT reproduce the right channel of a stereo sound file, for example, a stereo System Beep or a stereo QuickTime soundtrack. Apple's engineers did not know why this might be, but promised to track things down.
I also verified that the AppleCD 300 can send audio tracks (from your favorite Elton John CD, for example) down the SCSI bus as a 16-bit audio data stream. However, Apple engineers had no idea of applications for the firmware capabilities. (Essentially there are two problems: first, stereo audio is 10 MB per stereo minute which makes for large disk files; and second, the data would have to be sucked into an application or utility and made into a file, like an AIFF file, before it could be used for much of anything). This may, however, presage some sort of CD-ROM to DSP sound chip capability in future Macintoshes.
Craig O'Donnell -- firstname.lastname@example.org