Ring modulation using the web audio api

ringmodulation.js

var wac = new webkitAudioContext();

var ringGain = wac.createGainNode();
ringGain.gain.setValueAtTime(0, 0);

var ringCarrier = wac.createOscillator();
ringCarrier.type = ringCarrier.SINE;
ringCarrier.frequency.setValueAtTime(2500, 0);

var url = "Ring_Modulation-Original_sample.ogg";

var mediaElement = document.createElement("audio");
mediaElement.setAttribute("id", "audioElement");
// mediaElement.setAttribute("src", url);                                                                                                                                                 
mediaElement.setAttribute("src", "Ring_Modulation-Original_sample.ogg");

var sourceNode = wac.createMediaElementSource(mediaElement);

ringCarrier.connect(ringGain.gain);
sourceNode.connect(ringGain);
ringGain.connect(wac.destination);

ringCarrier.noteOn(0);

var request = new XMLHttpRequest();
request.open('GET', url, true);
request.responseType = 'arraybuffer';

request.onload = function() {
    wac.decodeAudioData(request.response, function(pianoBuffer) {
                            var source = wac.createBufferSource();
                            source.buffer = pianoBuffer;
                            source.connect(ringGain);
                            source.noteOn(0);
                        }, function (e) {});
}
request.send();