title: How to get microphone input volume value with web audio api?
body: <p>I am using the microphone input with web audio api and need to get the volume value.</p>
  
  <p>Right now I have already got the microphone to work:
  <a href="http://updates.html5rocks.com/2012/09/Live-Web-Audio-Input-Enabled" rel="noreferrer">http://updates.html5rocks.com/2012/09/Live-Web-Audio-Input-Enabled</a></p>
  
  <p>Also, i know there's a method manipulating the volume of audio file:
  <a href="http://www.html5rocks.com/en/tutorials/webaudio/intro/" rel="noreferrer">http://www.html5rocks.com/en/tutorials/webaudio/intro/</a></p>
  
  <pre><code>    // Create a gain node.
      var gainNode = context.createGain();
      // Connect the source to the gain node.
      source.connect(gainNode);
      // Connect the gain node to the destination.
      gainNode.connect(context.destination);
     // Reduce the volume.
     gainNode.gain.value = 0.5;
  </code></pre>
  
  <p>But how to combine these two and get the input volume value?
  I just need to the value, no need to manipulate it.</p>
  
  <p>Does anybody know?</p>