function channelCallbacks(channel, time, value){
		if (NoteChannels.hasOwnProperty(channel)){
			var callbacks = NoteChannels[channel];
			for (var i = 0, len = callbacks.length; i < len; i++){
				var callback = callbacks[i];
				if (Array.isArray(value)){
					callback.apply(window, [time].concat(value));
				} else {
					callback(time, value);
				}
			}
		}
	}
invoke all of the callbacks on a specific channel
 @private