title: Changing the pitch of the sound of an HTML5 audio node
body: <p>I would like to change the pitch of a sound file using the HTML 5 Audio node.
  I had a suggestion to use the setVelocity property and I have found this is a function of the Panner Node
  I have the following code in which I have tried changing the call parameters, but with no discernible result. </p>
  
  <p>Does anyone have any ideas, please?</p>
  
  <p>I have the folowing code:</p>
  
  <pre><code>var gAudioContext = new AudioContext()
  var  gAudioBuffer;
  var playAudioFile = function (gAudioBuffer) {
      var panner = gAudioContext.createPanner();
      gAudioContext.listener.dopplerFactor = 1000
      source.connect(panner); 
      panner.setVelocity(0,2000,0);
      panner.connect(gainNode);
      gainNode.connect(gAudioContext.destination);
      gainNode.gain.value = 0.5
  
      source.start(0); // Play sound 
  
  };
  
  var loadAudioFile = (function (url) {
      var request = new XMLHttpRequest();
      request.open('get', 'Sounds/English.wav', true);
      request.responseType = 'arraybuffer';
      request.onload = function () {
              gAudioContext.decodeAudioData(request.response,
                   function(incomingBuffer) {
                       playAudioFile(incomingBuffer);
                   }
              );
      };
      request.send();
  }());
  </code></pre>