[mythtv-users] 5.1 surround sound and two mixer controls

Achim Hofmann news at achim-hofmann.com
Thu Dec 2 21:51:07 UTC 2010

In my MythBox there's a VIA Technologies, Inc. VT8233/A/8235/8237 AC97
Audio Controller (rev 60) and the sound configuration within my MythTV
frontend looks like this:

Setup -> General -> Audio System

Audio output device: ALSA:surround51
Speakers configuraion: 5.1

Setup -> General -> Audio Mixer

Use Internal Volume Controls: Yes
Mixer Device: ALSA:default
Mixer Controls: Master

alsamixer shows me two Master controls: "Master" and "Master Surround".

Using the above configuration, 5.1 sound works fine but I've a problem
with volume control:

Using alsamixer from a remote machine over ssh I discovered that...

..."Master" / "PCM" controls front left and front right speakers
..."Master Surround" controls center speaker, LFE, sub left and sub
right speakers.

So the volume control of my remote only affects the front left and front
right speakers but not the rest. Is there any way - maybe within MythTV
or over an asoundrc configuration - to control both of the Master
switches simultaneous?


Achim Hofmann

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