SEEN it on tommorows world (Score 1)

I saw this last year on Tommorows World. They thought it could be used on a dancefloor, to focus the music on the couple dancing, not blast it all over the ballroom. Think of having several couples dancing to different music. Or maybe advertisers focusing the adds on just a few people. And I guess it would be better than a loudhailer, you could say whatever you like and only the listener woudl get it.