title: Merge 2 audio files in sox
body: <p>I am trying to merge 2 wave files into one file. The 2 files should start playing at the beginning of the new file. Independently of sound length. Running the following command does not give me this result.</p>
  
  <pre><code>  sox -M new_input.wav myrecording.wav output_test.aiff
  </code></pre>
  
  <p>Are there other ways of achieving this through sox or other command line libraries?</p>