[alsa-devel] amixer and mono

Jon Smirl jonsmirl at gmail.com
Fri Aug 1 23:32:00 CEST 2008

Amixer says my device is mono:

root at phyCORE-MPC5200B-tiny:~ amixer
Simple mixer control 'PCM',0
  Capabilities: pvolume pvolume-joined
  Playback channels: Mono
  Limits: Playback 0 - 1023
  Mono: Playback 942 [92%]
root at phyCORE-MPC5200B-tiny:~

That's coming from the Volume control....

                if (snd_mixer_selem_has_playback_volume(elem) ||
                    snd_mixer_selem_has_playback_switch(elem)) {
                        printf("%sPlayback channels:", space);
                        if (snd_mixer_selem_is_playback_mono(elem)) {
                                printf(" Mono");
                        } else {

The device's master volume control controls all channels through one
value. The device really is stereo. You use biquads if you want to
process the channels differently.

What do I do about this?

Jon Smirl
jonsmirl at gmail.com

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