A while back I released a program called Audax sound selector. The program is designed to make it easier to use sound with Alsa devices. See the original release post from here. One issue that I did not address within the release post was the case of the muted HDMI sound.
The setup of the HDMI sound with Alsa sound selector should be easy. The program itself (as seen above) is very simple. In any case, after you have completed the program and selected your HDMI sound device you still might not get any sound. The reason for the previous is this: your HDMI device (usually a display) might have its channels muted.
In order to unmute your HDMI device do the following. Open Alsamixer. For example, open a terminal client and type: alsamixer . Within Audax 0.2, open the Fluxbox menu by right clicking on an empty space of the desktop and choose System –> Alsamixer. Once Alsamixer is opened, you might see a window like this:
The MM (with the green color) just above the <S/PDIF> means that your HDMI sound device is muted. In order to unmute it click on the Alsamixer window (select it) and press the m key from your keyboard. Things should now look like this:
The above means that everything is done and you should be good to play sound with your HDMI device.