Getting 5.1 Surround sound to work

Ok, this one took a bit of research. My Mobo, like many, has a Intel HD sound chip - a ALC662 to be exact. It supports 6 channel output via SPDIF or three analogue jacks.

The inital mythbuntu install didn't support any of this, stereo sound worked fine but no joy with the extra channels. alsamixer didn't display the Front/Center etc channels. This thread revealed the solution to the problem.

We need to explicitly add the intel hda module. Add the line:

options snd-hda-intel model=3stack-6ch

to file

/etc/modprobe.d/alsa-base

than restart your PC.


The new channels will probably be muted. Also at the far right of alsamixer (it scrolls) there is a "channels" setting, it needs to be changed from 2 to 6. then use alsactrl store to save the changes.

Testing of the channels is easy with this call:

speaker-test -Dplug:surround51 -c 6 -t wav

This gets 6 channel support working with alsa, but we still need to activate it in Myth. Just got into

MythFrontend|Utilites/Setup|Setup|General - Audio Page

Set the the Audio output device to ALSA:surround51

The Mixer control may need to be set to "Master" or "PCM" - whichever works.

Note : This is all for analogue output, SPDIF is another kettle of fish ...