FAQ020

From the ALSA wiki

The FAQs have been reorganized. The new location of this question is FAQ#"aplay -D rear <soundfile>" fails with "Invalid type for PCM rear definition" What does this error mean? How do you fix it?

"aplay -D rear <soundfile>" fails with "Invalid type for PCM rear definition". What does this error mean? How can you fix it?

Takashi answered:

It means that the alsa-lib doesn't support the rear output of your soundcard yet. Usually it's defined in /usr/share/alsa/cards/*.conf... ok, a bit more explanation for the common cases. This error can appear also when you try "rear" output with the AC97 chip supporting 5.1 output. This is because the AC97 doesn't support the independent rear output. That is, you cannot access only the rear speakers. The rear output is always together with the front (4.0) or the front/center/LFE (5.1). Ditto for "center_lfe" output.

BTW, the individual output is possible by setting up all 5.1 channels and splitting them via dshare plugin. An adventurous user can try that :)