ALSA sound problem in Linux

hi, folks!!
I've just installed the new Linux Mandrake 9.1. It's really cool but the sound on my machine doesn't seem to work properly. When I play sound (an mp3 or something) the sound qaulity is awful. :eek: It doesn't matter what program I use (xmms, xine, mplayer, karboodle etc). Though when I play music cds (usually with Kscd) the sound is really nice.
So I tried to configure ALSA once again, but now on startup (of KDE) I get a message that sounds something like this: "ALSA couldn't set process priority. This means that you won't be able to produce acceptable sound (ie without clicks and breaks). Try artswrapper or setuid as root". I've tried nearly everyrhing now, but no matter what I do the sound is horrible.:mad:
Does anyone know what's wrong??

thanx in advance...