This is still a work in progress (although I haven't worked on it in over a month).

stepmania/src/arch/Sound/Selector_RageSoundDriver.h

@@ -11,6 +11,7 @@
 
 #if defined(MACOSX)
 #include "RageSoundDriver_CA.h"
+#include "RageSoundDriver_AU.h"
 #endif
 
 #ifdef HAVE_DIRECTX

stepmania/src/arch/arch.cpp

@@ -262,6 +262,9 @@ RageSoundDriver *MakeRageSoundDriver( const RString &drivers )
 #ifdef USE_RAGE_SOUND_CA
 		if( !DriversToTry[i].CompareNoCase("CoreAudio") )	ret = new RageSound_CA;
 #endif
+#ifdef USE_RAGE_SOUND_AU
+		if( !DriversToTry[i].CompareNoCase("AudioUnit") )	ret = new RageSound_AU;
+#endif
 #ifdef USE_RAGE_SOUND_DSOUND
 		if( !DriversToTry[i].CompareNoCase("DirectSound") )	ret = new RageSound_DSound;
 #endif