If the capability existed to project voices into people's heads, there would be a startup using it for advertising by now. Oh, right, that's been done.[1] "In

If the capability existed to project voices into people's heads, there would be a startup using it for advertising by now. Oh, right, that's been done.[1] "In 2007, the advertising and marketing campaign for A&E's Paranormal State broke the mold using Audio Spotlight directional sound technology. A seven-story billboard was erected in Lower Manhattan, New York City, visually reminding the public of the channel's popular new programming. A pair of AS-24i focused sound speakers mounted above the billboard projected directional audio onto a targeted area of the sidewalk – all the way from the rooftop." "The projected sound produced by the Audio Spotlight speakers was a woman's whispering voice that startled and entertained passersby with spooky and suggestive messages such as "Who's that?," "Who's there?," and "It's not your imagination." To those within the narrow coverage area, the sounds seemed as though they were being whispered right next to their heads, while others standing right next to them heard nothing, thanks to the focused sound beam of the Audio Spotlight." [1] https://www.holosonics.com/applications/creative-marketing https://www.holosonics.com/applications/creative-marketing