Controlling sound has long been a staple of science fiction and fantasy. In Dune, the cone of silence allows characters to converse privately, even in open spaces. The eerie billboards of Blade Runner 2049 whisper advertisements into the ears of those passing by.
In the real world, quirks of architecture, intentional or not, can direct where sound goes. In the U.S. Capitol’s hall of statues, for example, a whisper can travel silently across the room from one spot to another. The sound waves interact with curved surfaces to focus the audio. Now, scientists are looking to precisely control sound, perhaps one day resulting in a world without earbuds, but