I recently acquired a fairly decent media center computer and up until this weekend I had not really used it for much more than storing a lot of music and video files as it has a large hard drive and it isn't a computer that I plan to experiment much with once I have it set up properly.
Yesterday however I decided to install Ubuntu 12.04 and attempt to get the computer set up so that it can be used for its intended purpose which is as both a media centre and as a gaming computer (mainly retro gaming).
The computer is connected to a flat screen television via a HDMI cable and it looks and behaves quite well.
When I say quite well there was obviously one issue otherwise this article would not have been written. There was no sound.
I tried the usual hunt around Google for an answer and there are a number of possible solutions but I am going to highlight the one that worked for me and it is so simple it is unbelievable.
A number of the solutions revolved around the fact that the HDMI sound output was not available at all but in my case the HDMI output was available.
First of search for "Sound" and click on the "Sound" icon.
Look at the list of sound output devices. As you can see in the image above I have an HDMI output option.
NOTE: If you do not see an HDMI output option then you should follow one of the other methods for getting HDMI sound working because this solution relies on the HDMI output already being present
Before the fix when I clicked the test sound button on this screen nothing happened. There was no sound played.
Load up the Ubuntu Software Centre.
Now search for Gnome ALSA Mixer
Install the Gnome ALSA Mixer application.
Run the Gnome ALSA Mixer
When I first ran Gnome ALSA Mixer all of the volume bars were set to mute. By unchecking the mute boxes on this screen I was then able to play music via Rhythmbox.
The solution was so simple it is unbelievable. Bizarrely I had tried running ALSA Mixer from the terminal and there was no indication that the volume was muted.
I know this is not the solution for everyone but hopefully by posting this article I will at least aide someone else.