On Fri, 2012-06-15 at 20:13 +0200, Ralf Mardorf wrote: > OSS (obsolete) and ALSA are the instances that are needed for audio. > Pulse and Jack are "layers". Sorry for my broken English. You need one of both, the obsolete OSS or the current used ALSA. Stuff similar to PA and jackd, there were (are) others too, handle the audio streams in different ways, but usually use ALSA as backend. Firewire audio devices might be something special.