FAQ about audio
Why is there no sound when playing an audio file?
A: The sound controlling devices are muted by default. You need to unmute them explicitly.
Using alsamixer graphical ncurses interface
Adjust sound output using the audio mixer with the alsamixer command:
- for AT73 DAC (at91sam9260ek, at91sam9xeek & at91sam9261ek boards)
- _Master_ to control volume (un-mute)
- _PCM_ to control digital source volume (un-mute)
- for WM8731 DAC (at91sam9g20ek board)
- _Master_ to control volume (un-mute)
- toggle _Output Mixer HiFi Playback Switch_ to ON (un-mute)
- for AC97 (at91sam9263ek & at91sam9rlek boards)
- _Headphone_ to control headphone volume (un-mute)
- _Headphone Jack Sense_ to Off (mute)
- toggle _Line Jack Sense_ to switch headphone on/off
- _Master Mono_ controls volume on board soldered speaker (if present) (un-mute)
Exit alsamixer with the _Escape_ key (eventually reset the terminal with the reset command).
Using amixer command line interface
- for AT91SAM9260EK, AT91SAM9261EK and AT91SAM9G10EK which use AT73 DAC:
amixer set 'PCM' 70 unmute
- For AT91SAM9G20EK which uses WM8731 DAC:
amixer set 'Output Mixer HiFi Playback Swit' unmute
- For AT91SAM9263EK and AT91SAM9RLEK which use AC97:
amixer set 'PCM' 70 unmute
amixer set 'Master Mono' 70 unmute
amixer set 'Headphone' 70 unmute
Save configuration with alsactl
You can store this sound configuration using the alsactl store command (as long as your filesystem is read/write capable).
After a reboot you can retrieve this configuration running alsactl restore.
Why is there no sound when recording an audio file?
A: As for playing sound, ALSA Linux audio subsystem keeps the devices muted by default. You need to unmute them explicitly.
Using alsamixer graphical ncurses interface
For instance the line-in and mic-in are muted by default. The user must run alsamixer and go to the capture options (F4) screen. There, the user must press the space bar on the Capture option to unmute those channels.
Why mplayer does not change volume?
A: On some platforms the volume control name is not the one expected by default by mplayer. You should change it to the one understood by the alsa control in charge of the main hardware volume control of the mixer interface.
Other helpful references
For details regarding how to connect the I2S controller (found on SAMA5D2 and SAM9X60) to a codec, please see I2S Multi Channel.
For details regarding the usage of PDMIC (found on SAMA5D2), please see PDMIC .
Related Topics
Boards
Components
Summary
Audio with ALSA