message: convert the buffer to mono
  replaces the existing buffer
diff: @@ -244,6 +244,32 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
  return this;
  };
  + /**
  + * Sums muliple channels into 1 channel
  + * @param {Number=} channel Optionally only copy a single channel from the array.
  + * @return {Array}
  + */
  + Tone.Buffer.prototype.toMono = function(chanNum){
  + if (this.isNumber(chanNum)){
  + this.fromArray(this.toArray(chanNum));
  + } else {
  + var outputArray = new Float32Array(this.length);
  + var numChannels = this.numberOfChannels;
  + for (var channel = 0; channel < numChannels; channel++){
  + var channelArray = this.toArray(channel);
  + for (var i = 0; i < channelArray.length; i++){
  + outputArray[i] += channelArray[i];
  + }
  + }
  + //divide by the number of channels
  + outputArray = outputArray.map(function(sample){
  + return sample / numChannels;
  + });
  + this.fromArray(outputArray);
  + }
  + return this;
  + };
  +
  /**
  * Get the buffer as an array. Single channel buffers will return a 1-dimensional
  * Float32Array, and multichannel buffers will return multidimensional arrays.
  