I just finally switched over to 64 bit intrepid because I need the memory for photo editing. My sound is broked. Again.

I only care about SPDIF. It's the only audio connection my computer has. I simply want everything to play out of SPDIF, all the time.

mplayer -ac hwac3 *dvd* works and triggers dolby surround. There's no hardware problem. But Amarok is silent, even though it says it's playing.

Alsamixer only has one slider in it. No IEC958 slider this time. Must be that PulseAudio.

OK, so I'm not touching anything. I know there are probably at least 4 separate GUI widgets (sound countrol widget, KDE sound system, Alsamixer, pulseaudio, who knows what else by now) that must be simultaneously set to the right setting in order to get my sound to work. So I'm not touching anything without advice.

Please, what should I do? I so just want my sound to work. I wish it was a simple matter of editing a configuration file, but it's so complicated now that it's simple.

First of all, get rid of pulseaudio. I forget the command, I think it's something like "killall pulseaudio".

Then, you can set the default ALSA device for sound output to SPDIF (IEC958) in your window manager (where that is depends on which WM you're using) *OR* you can do the same thing in a ~/.asoundrc file --> http://alsa.opensrc.org/.asoundrc#Default_PCM_device (If you do it this way, you might have to log out & log back in for it to take effect)

Then, just make sure that all of your media apps are set to output to ALSA.

With pulseaudio installed, you can still get to all the sliders in alsamixer, if you do:
alsamixer -Dhw

Check to see if IEC958 is muted.

Hope that helps,

-Mark

The attached diagram ought to clear things up for you :D

(...ducks for cover)

Yes, Linux audio can be overly complicated, but easily simplified if you just use Alsa+OSS, i.e. disable/remove Pulseaudio, and don't install any other audio API unless a specific app needs it and you know why you need it, like Jack, etc.