I wanted to be able to fall asleep with audio/music coming from my Mac, but not have the sound continue all night or turn off abruptly. I wanted a smooth transition fade out to silence. 'Hush' simply waits a user specified amount of time and then fades the system volume to silence over another user specified period of time. Optionally, wait another period of time before fading back to the original system volume. Fade out while falling asleep, and back up while waking.