As for audio cues, I do know there is a system called SoundSense which does exactly what you suggest: <a href="http:&#x2F;&#x2F;df.zweistein.cz&#x2F;soundsense&#x2F;" rel="nofollow">http:&#x2F;&#x2F;df.zweistein.cz&#x2F;soundsense&#x2F;</a>