We have been using Sox, a Mac, and a Focusrite Scarlett 2i2 (configured to be the default audio input) to capture samples from an electret microphone. We often capture data for several hours and will use the command below to do so. Is it possible to only capture one channel of the device to keep the file sizes smaller?

Thanks.

$ ./rec test.raw


Input File     : 'default' (coreaudio)

Channels       : 2

Sample Rate    : 96000

Precision      : 32-bit

Sample Encoding: 32-bit Signed Integer PCM