Assuming openSUSE-11.4 with no messing around with pulse audio, I recommend you install the pulse audio volume control application ‘pavucontrol’ and then run ‘pavucontrol’ the first time you try to play a multimedia file in EACH multimedia application. Ensure in pavucontrol that you have SHOW ‘all output devices’ selected in the OUTPUT-DEVICE tab and ensure that you have SHOW ‘all streams’ selected in the PLAYBACK tab.
Some KDE users are frustrated with kmix and have taken to install the xfce-mixer.