Open your \"psclient.cfg\" file in notepad, or something. Find the lines:
;Sound renderer
System.PlugIns.iSoundRender = crystalspace.sound.render.software
Add a semiclolon to the begining of the second line and save.
As far as I know, this is the only line that needs to be disabled. (It worked fine for me) If anyone can correct me, please do.