Originally Posted by MWRecords
Ok I found the audio mixer. I don't see an option for "hdmi". The only thing that is muted is "mic". But still no audio. I'm assuming I should have an option for hdmi. I wonder if I had to add it some how.
Audio Mixer should show all the audio devices the underlying Linux can see. In Settings > System > Audio Output what is selected in "Audio output device" and what other options are available? one of these devices should be the HDMI connection and should match what you see in Audio Mixer.
Are you connecting your HDMI to a AV Amp or to a TV? if connecting to a TV ensure the Dolby Digital capable receiver and DTS capable receiver options are not selected.