Microphone input plus delay and reverb

HTML

<h1>Analysis of Sounds from Microphone</h1>
<canvas class="visualizer";id="myCanvas";width="640" height="100"></canvas>

JavaScript

var audioContext = new AudioContext()
var input = audioContext.createGain()
var feedback = audioContext.createGain()
var delay = audioContext.createDelay()
var leftDelay = audioContext.createDelay()
var rightDelay = audioContext.createDelay()
var outputmix = audioContext.createGain()
var convolver = audioContext.createConvolver()
var buffer = audioContext.createBufferSource()
var analyser = audioContext.createAnalyser();
var WIDTH = 300;
var HEIGHT = 300;

// Check if there is microphone input.
try {
  navigator.getUserMedia = navigator.getUserMedia ||
                           navigator.webkitGetUserMedia ||
                           navigator.mozGetUserMedia ||
                           navigator.msGetUserMedia;
  var hasMicrophoneInput = (navigator.getUserMedia || navigator.webkitGetUserMedia ||
      navigator.mozGetUserMedia || navigator.msGetUserMedia);
} catch(e) {
  alert("getUserMedia() is not supported in your browser");
}

// Create a pcm processing "node" for the filter graph.
var bufferSize = 4096;
var myPCMProcessingNode = audioContext.createScriptProcessor(bufferSize, 1, 1);
myPCMProcessingNode.onaudioprocess = function(e) {
  var input = e.inputBuffer.getChannelData(0);
  var output = e.outputBuffer.getChannelData(0);
  for (var i = 0; i < bufferSize; i++) {
     // Modify the input and send it to the output.
     output[i] = myPCMFilterFunction(input[i]);
  }
}


var errorCallback = function(e) {
  alert("Error in getUserMedia: " + e);
};  

// Get access to the microphone and start pumping data through the  graph.
navigator.getUserMedia({audio: true}, function(stream) {
 // microphone -> myPCMProcessingNode -> destination.
  var microphone = audioContext.createMediaStreamSource(stream);
  
leftDelay.delayTime.value = 0.4
rightDelay.delayTime.value = 0.4

leftDelay.connect(rightDelay)

var merger = audioContext.createChannelMerger(2)
leftDelay.connect(merger, 0, 0)
rightDelay.connect(merger, 0,...