@Override
    public void cleanUp() {
        TrackInfo t = (TrackInfo) audio.getUserData("TrackInfo");
        t.getTracks().remove(this);
        if (!t.getTracks().isEmpty()) {
            audio.setUserData("TrackInfo", null);
        }
    }
recursive function responsible for finding the newly cloned AudioNode

@param spat
@return
jme3-core/src/main/java/com/jme3/animation/AudioTrack.java