Remember Maxwell Smart’s Cone of Silence?
In Japan, in a Burger King restaurant (and I use that word cautiously here), they’ve introduced exactly such a thing.
No, it’s not what you think: they’ve introduced iPod docks into some of their booths, so that you may listen to your own music while enjoying the romantic settings of the BK, but in order to isolate your music from that of the people in the next booth, they have also implemented a cone, above each booth, which restricts the music output to just those sitting within the confines of each booth.