It's also capable of working out if you've shared your sounds with a friend and will push out a mono mix to both headphones -- so neither of you miss out on the other half.

ENGADGET: Self-aware headphones switch channels depending on which ear they're in (video)

By turning the stereo mix into a mono mix having the same audio information come out of both speakers the vocal would come up two decibels.

WSJ: Anatomy of a Song: Otis Redding's '(Sittin' on) the Dock of the Bay'