title: Multiple Microphone Recording
body: <p>I'm trying to record from three microphones simultaneously for microphone array research. I have three USB Microphones connected to my Macbook air via a USB hub. In the Audio MIDI I have them as an aggregate device. </p>
  
  <p>Matlab isn't recognizing them, and is still just recording from the internal microphone in the computer. What do I add to: </p>
  
  <pre><code>recobj1 = audiorecorder (22500,16,2);
  disp ('recording started')
  record(recobj1,5);
  recordblocking(recobj1,5);
  
  y = getaudiodata(recobj1);
  wavwrite(y,22500,16)
  </code></pre>
  
  <p>to get Matlab to record from the USB Mic?</p>