are there any software programs similar to audiomulch that run on macs?

MAX/MSP is the daddy of such apps, and for many years it ran only on Macs. And then there's the venerable Metasynth, much used by Richard Aphex. Of course, neither of these packages is free.

Disclaimer: I don't use Macs myself, so these suggestions are based solely on what I've happened to read on the topic.