I doubt your gonna get anythin back from the request cause it creates a sound file. Thats not somethin you can pull into c2. The ajax object is basically used to request pages with the intent that the page requested echos data. That echoed data will then be stored in AJAX.LastData
Its meant mainly for text. The only way you could get the sound file across it is to somehow echo the binary data of the sound file then save that to the computer receiving it and THEN play it.
Either that or someone makes a way to play streaming sound from a url similar to how you can load images from url