I installed Gentoo clean on my system, except my /home but I deleted all hidden folders that might have an impact on sound (.mplayer .pulse* .config .esd_auth and more) and with a fresh user
adduser mistertest -m -G audio,video,users the result is the same, no sound when I play a file in mplayer.
Its a Z68 Chipset and I am using the Intel IGP H2000 inside my CPU, so this should not be an issue of the spdif connector on my mainboard and I think i have installed all the correct modules in the kernel. I have no aditional hardware to check if my sound is working at all (no headset or external speakers), but I suppose the problem is either some bad config or the internal spdif (if there is such).
dronemother ~ # lsmod | grep snd snd_hda_codec_hdmi 22705 1 snd_hda_codec_realtek 190506 1 snd_hda_intel 21727 3 snd_hda_codec 63422 3 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel snd_hwdep 5726 1 snd_hda_codec snd_pcm 69969 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec snd_timer 17697 1 snd_pcm snd 53814 13 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_ timer soundcore 5009 1 snd snd_page_alloc 6641 2 snd_hda_intel,snd_pcm dronemother ~ # lspci -v # cut other stuff away here 00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05) Subsystem: ASRock Incorporation Device 1892 Flags: bus master, fast devsel, latency 0, IRQ 46 Memory at fe600000 (64-bit, non-prefetchable) [size=16K] Capabilities:  Power Management version 2 Capabilities:  MSI: Enable+ Count=1/1 Maskable- 64bit+ Capabilities:  Express Root Complex Integrated Endpoint, MSI 00 Capabilities:  Virtual Channel Capabilities:  Root Complex Link Kernel driver in use: snd_hda_intel Kernel modules: snd-hda-intel
I have pulseaudio, alsa-plugins, mplayer, mixer and pavucontrol installed. I get no errors when playing a file in mplayer just no sound.
So how can I examine where exactly my problem is located?
Edit: I just booted the PC from a Ubuntu Live USB stick, sound did not work, too. (took a bit longer, cannot restart the server every day, some people rely on its services.)