ultrasonic projects mounted fore and aft on a submarine, being able to project a false sound image some distance away from actual location.

Can imagine similar military uses on land; misguiding motar/gunshot locators and such.

In a civilian use, can imagine it'd be a marketable gimmick to be able to project these sound pockets round a convention hall or such.

The novelist Ian M. Banks loved the idea of sounds pockets - used them throughout his sci fi novels.