In addition to the byte twiddling in the Mac OS X sound input manager, it
has been my experience with OS X that QuickTime is more robust (and more
flexible) than some of the old microphone data stuff.  For example,
QuickTime can be used to read sound input data directly from a digital
camera.  QuickTime recording has an added bonus that the system handles
the recording and scheduling of I/O for you, without having to mess around
too much with threads.

I have no time to look at this right now, but I have always wondered if it
is possible to replace Squeak's sound recording with QuickTimes Sequence
grabber.  It would be a more complex solution, but in the end it might be
worthwhile.

-Eric