Hello, I'm trying to play an mp3 file using SoundTouch class. But I'm getting error.

Code:
var source:Sound = new Sound1();
var output:Sound = new Sound();

var soundTouch:SoundTouch = new SoundTouch();
soundTouch.pitchSemitones = -6;

var filter:SimpleFilter = new SimpleFilter(sound, soundTouch);
output.addEventListener(SampleDataEvent.SAMPLE_DATA, filter.handleSampleData);

output.play();
This gives me error:

Sahne 1, Katman ‘Katman 1’, Kare 1, Satır 18, Sütun 44 1120: sound tanımlanmamış özelliğinin erişimi.

http://sudrap.org/paste/text/335615

https://github.com/also/soundtouch-as3