Ubuntu – How to change the default audio device from command line


Ubuntu's desktop gui is great for changing audio settings (System->Preferences->Sound), like the default input/output device and setting the volume.

However, I would like to be able to do these things from the command-line. What tool is the gui using behind the scenes?

Best Answer

You can control PulseAudio thoroughly through the command line using pacmd and pactl commands. For options see man pages or the wiki at PulseAudio:

pacmd list-sinks (or pactl list short sinks) for name or index number of possible sinks

pacmd set-default-sink "SINKNAME" to set the default output sink

pacmd set-default-source "SOURCENAME" to set the default input

pacmd set-sink-volume index volume

pacmd set-source-volume index volume for volume control (65536 = 100 %, 0 = mute; or a bit more intuitive 0x10000 = 100 %, 0x7500 = 75 %, 0x0 = 0 %)

and many many more CLI options.

Note: Changing the output sink through the command line interface can only take effect if stream target device reading is disabled. This can be done by editing the corresponding line in /etc/pulse/default.pa to:

load-module module-stream-restore restore_device=false

Restart PulseAudio for changes to take effect:

pulseaudio -k

For a more elaborate tutorial on how to do this, and for instructions on how to change the sink during playback see this answer.