title: Recording from multiple channels through sox
body: <p>I am trying to record 2 different microphones through Sox for one of my application. I am currently just testing on Mac terminal for the audio recording. However, I am only able to get audio through one microphone.</p>
  
  <p>The sox command I am using is:</p>
  
  <p><code>sox -b 32 -e unsigned-integer -r 96k -c 2 -d --clobber --buffer $((96000*2*10)) /tmp/soxrecording.wav trim 0 10</code></p>
  
  <p>Which give me a good .wav file.</p>
  
  <p>I have two different usb microphones which show up as 2 channel I/p each in Sound/System Preferences. I tried to do <code>-c 4</code> with the sox command to record from both microphones.</p>
  
  <p><code>sox -b 32 -e unsigned-integer -r 96k -c 4 -d --clobber --buffer $((96000*2*10)) /tmp/soxrecording.wav trim 0 10</code></p>
  
  <p>However, I get a warning saying; 
  <code>sox WARN formats: can't set 4 channels; using 2</code></p>
  
  <p>And I can just get audio in from only one usb microphone. I have been trying to fiddle and understand what’s wrong but any hints would be really helpful.</p>