I was just discussing about the R3 audio driver API, when I realised every driver source I saw included its own version, each slightly different, of the audio driver headers... sound.h and another one... I think we should fix these, and choose one to stick to. I crawled the CVS but didn't find it in the current/ tree..., but maybe it's in one of the old branches... Else someone pointed me to this one: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/sis4be/sis7018/sound.h?rev=1.2&content-type=text/vnd.viewcvs-markup I'd suggest headers/os/add-ons/audio/BeOS-R3-sound.h or something There is another one describing the audio buffers structs. François.