Using Audio in Linux

Play Sound

To play a sound (i.e. test.wav) to the current audio output:

See options with 'aplay -h'

Record Sound

To record sound from the current audio-input source to test.wav:

Stop recording by pressing 'CTRL-C'.
See options with 'arecord -h'.

Configure Audio Device

Before using audio you might need to do some configuration; i.e. un-mute audio-output or select the audio input source.
In Linux, this can be done by the Advanced Linux Sound Architecture (ALSA): https://www.alsa-project.org

AlsaMixer

The AlsaMixer utility provides an easy way to modify audio-settings using a graphical interface.

Press 'F1' for details on how to use it.
Usually, you will use:

1. the left and right arrow keys to move between the controls

2. up and down keys change the volume setting of a control

3. 'm'-key to toggle 'mute' setting or enable/disable a switch setting.

AMixer

AMixer is a command-line utility to view and modify audio settings.
Use

to view available options.

View Available Controls

To have a look at available controls use:

Get Value of Control

I.e. to get the current headphone volume use:

Set Value of Control

Mute/Unmute Control

Unmute Headphone output:

Mute Headphone output:

Setup ALSA

ALSA can be configured through /etc/asound.conf.
Below is an excerpt of the asound.conf of Trizeps VIII Yocto image:

'pcm.!default' is the standard entry, which is used by all programs to route their audio-data – unless otherwise told.
'slave.pcm' tells to route audio to pcm.asymed, which will use dmix_48000 configuration for playback and dsnoop_48000 for capture.