I have experimented with a sigmoid and logarithmic fade out for volume over a period of about half a second to cushion pause and stop and prevent popping noises in my music applications.
However neither of these sound "natural". And by this I mean, they sound botched. Like an amateur engineer was in charge of the sound decks.
I know the ear is logarithmic when it comes to volumes, or at least, twice as much power does not mean twice as loud. Is there a magic formula for volume fading? Thanks.