Line In Passthrough

Normally when you connect a device to the line-in socket you cannot hear the audio being received in the speakers.

For example, I sometimes plug in a traditional audio source like a record player into line-in, so I need to do this to hear what's playing.

For Ubuntu 20.04, one way to get the line-in audio being played on the speakers as received is to load the module-loopback module with the following command:

1pactl load-module module-loopback

Audio from line-in should appear instantly.