title: Merging two audio files with sox while adjusting their volume
body: <p>Merging two audio files can be done with <code>sox</code>:</p>
  
  <pre><code>sox -m input1.wav input2.wav output.wav
  </code></pre>
  
  <p>How adjusting the volume of one the input files can be applied in this single command. It is obvious that this can be accomplished by two command like these:</p>
  
  <pre><code>sox -v 0.7 input.wav output.wav
  sox -m input1.wav output.wav output2.wav
  </code></pre>