@SuppressWarnings("deprecation")
private void saveAudio(String text)
{
    HashMap<String, String> myHashRender = new HashMap();
    String textToConvert = text;
    String destinationFileName = "/sdcard/audio.wav";
    myHashRender.put(TextToSpeech.Engine.KEY_PARAM_UTTERANCE_ID, textToConvert);
    tts.synthesizeToFile(textToConvert, myHashRender, destinationFileName);
}