Getting sound out of CD players

I have a relatively simple question: My sound system
appears to work fine.  I get all sorts of sounds (real
and test.) But none of the CD players that comes with
Suse 9.1 can produce any sound, such as KsCD and xmcd.  These
players actually start playing, and the display indicates
that the CD is being played: time and tracks advance
normally.  But there is no sound.  I must be missing
one simple but vital setting.

Can anyone help?

Thanks in advance,

-sinan