Rui CarmoLike Detour, Audio Hijack Pro allows you to manipulate Mac OS X audio, with an emphasis on capturing (hence the name) and post-processing (it allows for routing the captured audio through DSPs):
Like Detour, Audio Hijack Pro allows you to manipulate Mac OS X audio, with an emphasis on capturing (hence the name) and post-processing (it allows for routing the captured audio through DSPs):