jorgenmz Thanks for responding so quickly!
Yeah, I think I got the terms wrong, sorry! 
What I mean is, I want everything to use my digital out connection, like in my older openSuse installation (I think it was 11.0).
I use Amarok for music, Kaffeine for DVDs and (s)mplayer for mkv’s and other kind of videos.
Amarok, Kaffeine and system sounds (e.g. when login in) work fine, but for firefox I have to change to analog. PCM files through mplayer don’t work as well.
I’m currently using Kde4 on the newest openSuse 11.3 x64.
Hello jorgenmz and good morning. After positing my response to you, I realized that you did mention your openSUSE version in your title. So silly me. Your comment: “I’m currently using Kde4 on the newest openSuse 11.3 x64.” sounds fine as I know how to deal with this.
There several places where sound can be configured. Two of these places affect everything. One is in your mixer configuration. If you open the kmixer control on the icon tray, press the speaker and then the mixer button. In Mixer go to settings / Configure channels and drag everything from Available Channels to Visible channels. This puts all controls at your finger tips. Some, if not a lot of the controls you can add to the mixer may not do anything but some can effect just how your speakers will function. You can close the mixer for now.
Next lets go to KDE menu / Personnel Settings / General Tab / Computer Administration (at the bottom) / Multimedia. Next, check the “Show Advanced Options” option so all sound devices will show up. On the Device Preference Tree / Audio Output / for both the Music and Video I put my Analog PCM Standard Output at the to of the Output Device Preference listing. I put my my S/PDIF Digital Audio Output as number two in the listing. Some sound cards can have multiple outputs that say almost the same thing and you may have to play around with them to get the two that work at the top of the lists.
Depending on the sound card, most if not all of the outputs work all of the time, no matter the list setup. So, this list, along with the Mixer channel settings effect which outputs have priority and how your volume and other controls work. For instance, if you put the Digital Output at the top, even if your sound cards allows for volume adjustments for PCM audio going out a digital output, all volume level controls stop working since in the Pass Through mode, there is no level control possible. So, this listing preference does not make an output work or stop an output from working. It does effect level controls in the mixer.
In the mixer, which you can open again, your may have some controls that work with the S/PDIFF Digital outputs and which may have a mute button. The application of the mute function, can prevent a digital output from working. Most often there is no level associated with digital outputs. If you have more than one digital output, the mute control can determine which one does anything and which ones don’t work. You can remove the ones that don’t work and the one that does should be second in your listing for KDE multimedia.
Now, as for Pass Through mode for Dolby Digital 5.1 and 7.1 production, this ability is a function of the DVD player setup and not a sound setup in the mixer (except for the mute function) and when one DVD player is setup right does not make another player work right. The trick is to determine how to configure the Pass Through to work on any particle DVD player. So the question for DVD player is which one do you want to use and have you ever got pass through to work? I suggest you install Kaffeine/KDE3 version for this purpose. If you have not done so, ask how to do this if not done already.
As for your music player, I would stick with Amarok for now. It is hoped that when you go through all of the sound settings you can find one configuration that allows everything to work properly for you. I request that you tell me what channels do you have in the mixer and what are they called. I ask that when you go into KDE Multimedia sound setup, what Outputs do you have listed. With this info we should be able to get you working as required.
Thank You,