I’ve read lots of forum posts on getting audio through the HDMI interface on an NVidia ION and the solution turned out to be extremely simple: The HDMI output device (labeled as S/PDIF 1) was muted but not visible in Ubuntu’s GUI!

A note about my hardware:
I have a ZOTAC ZBOX HD-ND22, which has NVidia ION chipset and I’m running the proprietary NVidia driver version 270.41.06.

Steps that I took to get HDMI audio:

  1. Open Sound Preferences
  2. Open the Hardware tab
  3. From the Profile dropbox select Digita Stereo(HDMI) Output
  4. Open up a Terminal
  5. type alsamixer
  6. Using the Left/Right arrow keys navigate to the item labeled S/PDIF 1
  7. Press M and the OO symbol on top should light up in green to denote the channel was unmuted
  8. Test the audio output via Sound PreferencesTest Speakers

In my case the setup worked between reboots.

I’m also having a problem running Ubuntu Unity via HDMI, the screen does not update and the mouse clicks seem to be off by tens of pixels. If you have an idea how to fix that – drop me a line in the comments.

UPDATE: A simple:

unity --reset

will fix unity’s display weirdness I mentioned above