message: does not require device and deviceId in gUM
diff: @@ -109,11 +109,13 @@ define(["Tone/core/Tone", "Tone/component/Volume", "Tone/core/AudioNode"], funct
  //do getUserMedia
  var constraints = {
  audio : {
  - "deviceId" : device.deviceId,
  "echoCancellation" : false,
  "sampleRate" : this.context.sampleRate
  }
  };
  + if (device){
  + constraints.audio.deviceId = device.deviceId;
  + }
  return navigator.mediaDevices.getUserMedia(constraints).then(function(stream){
  //start a new source only if the previous one is closed
  if (!this._stream){
  