Loop back the first two channels of a alsa device to another device
alsa_loopback playdev captdev fsamp frsize nfrags
This tool is mainly for testing whether a given soundcard works with the zita-alsa-pcmi library. It will send the 1st two channels of the given capture device to the playback device, using the specified settings.
Note, that this might give massive (ear and equipment damaging) feedback if your capture device is connected to a microphone near some speakers connected to the playback device.
ALSA playback device (e.g.: hw:0)
ALSA capture device (e.g.: hw:0)
Sample rate (e.g.: 48000)
Period size (e.g.: 256)
Number of fragments (e.g.: 2)
This will loopback the 1st two channels of hw:0 to hw:1 using 48kHz samplerate, and 10 fragments each 2048 samples.
alsa_loopback hw:0 hw:1 48000 2048 10