private void initAudio() {
        if (settings.getAudioRenderer() != null && context.getType() != Type.Headless) {
            audioRenderer = JmeSystem.newAudioRenderer(settings);
            audioRenderer.initialize();
            AudioContext.setAudioRenderer(audioRenderer);

            listener = new Listener();
            audioRenderer.setListener(listener);
        }
    }
Sets the Timer implementation that will be used for calculating
frame times.  By default, Application will use the Timer as returned
by the current JmeContext implementation.
jme3-core/src/main/java/com/jme3/app/LegacyApplication.java