We've got a new build of Basilisk II for OS X available over here:
http://www.emaculation.com/forum/viewtopic.php?t=5887
This one should fix sound problems that some people may be experiencing.
Quote:
"New version build from source 4 October 2009, but without the "SDL audio patch" change that was applied 19 February 2009. The "SDL audio patch" caused poor sound performance, apparent in all BasiliskII for MacOSX builds in the past months."
