(Ubuntu 12.04 x64)
After looking at other questions (here and other sites) and trying their respective answers, I am still unable to get the hdmi audio out working.
I have downloaded the recommended hardware drivers for my card (radeon hd 4350), made sure that the card is not muted in alsamixer, and set it as the correct output device in sound settings.
I have also disabled the onboard sound devices in the bios menu. In aplay -l, it shows my hdmi card as hw:0,3
Even after doing sound tests I still cannot hear anything. Any suggestions? Not sure where to go from here, I am fairly new to linux.
Best Answer
This link solved my problem:
Go to Dashboard home. Find sound properties and change the audio output to HDMI.
http://voices.canonical.com/david.henningsson/2012/04/14/audio-over-hdmi-and-displayport-in-ubuntu-12-04/
My HDMI output audio (SPID) started to work right after the first step from the link above, by just installing the latest drivers from Nvidia. After all, the HDMI port is on the graphics card ;-)