Real-time Compression/limiting On Os X Options

Hi everyone,

I like to use my older 500MHz iBook to do some real-time audio processing (compression/limiting) for my home theater (instead of buying a stand-alone audio compressor.)

I'd like to achieve the same effect that I might get from an Aphex Compellor or the like. Anyone know of any good software for OS X that can do something like this?

Thanks!

-Mike