USB Sound – Audio Device Loopback Through Speakers


I have a USB turntable which when plugged in to my Ubuntu 10.10 machine appears in the audio settings as an input device (USB PnP Audio Device Analog Stereo) like a microphone.

What I'd like to be able to do is have the sound for that audio device played back through the audio output (speaker or whatever). I'm not too worried if there's a slight delay between the audio coming in and it being played out through the speakers.

As far as I'm aware this is refereed to as software loopback. I can achieve exactly what I want if I open Audacity, enable software loopback and press record. Obvious this isn't ideal as I don't really want it recording what I'm playing all the time.

I know this is possible because of the Audacity example however I'd like to know if there's a way to do it without it recording. I've search around for a while for a piece of software that does this, however I couldn't get anything even close.

Any help would be greatly appreciated.

Best Answer

Just a warning: This answer is theoretical, because i don't own such hardware...

AFAIK you have to enable a loopback-device for pulseaudio:

pactl load-module module-loopback

After that you should see a new application under audio-settings.

If it works well, you may add a line to the pulse-audio-config to make this persistent:

sudo sh -c ' echo "load-module module-loopback" >>  /etc/pulse/ '

Good luck!

Additional info from matto1990:

You only need to do this if you want to loopback from a device other than the microphone or line in (the default ones). Go to software center and install "PulseAudio Volume Control". Open it up and go to the recording tab. In the show dropdown select "all". In the "loopback from internal audio" section (or whatever the output device you want is) select the input device you want to loopback from (in my case the USB one).