title: How to record mono with arecord?
body: <p>I'm using the <a href="https://pypi.python.org/pypi/SpeechRecognition/" rel="nofollow">SpeechRecognition</a> package for text to speech. Its input for WAV files, however has to be mono. When I use <code>arecord -D plughw:0 --duration=5 -f cd -vv ~/test.wav</code> and I play it using <code>aplay test.wav</code> I get (it plays back):</p>
  
  <pre><code>Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
  </code></pre>
  
  <p>How do I get <code>arecord</code> to record in mono? I have tried adding in <code>--channels=1</code> also but when it starts recording and displays information about its (<code>Plug PCM: Route conversion PCM</code>) setup, it always shows:</p>
  
  <pre><code>...
  channels    : 2
  ...
  </code></pre>
  
  <p>My <code>USB PnP Sound Device</code>'s setup shows the channel is 1 though.
  Even though I've set it to 1, it plays back as stereo too. What's wrong?</p>