Imagine a world where you can have private conversations in public spaces without headphones! Researchers at Penn State have developed a way to use ultrasonic beams and 3D-printed metasurfaces to create pockets of sound that are inaudible to others.
Being able to listen to a podcast or private conversation in a crowded room—without anyone else hearing a sound. That’s the vision behind a new audio technology that creates “audible enclaves” using ultrasonic beams.
Here’s how it works: Traditional sound waves, especially low-frequency ones, tend to spread out and can’t be easily directed to a specific listener without disturbing others. But this new method uses two special ultrasonic beams that can bend around obstacles (like people’s heads) and meet at a chosen spot. While the beams themselves are silent, when they cross paths, they interact in a way that creates a small, focused zone of audible sound—an enclave—where only the intended listener can hear it.
This isn’t just a neat trick. The technology covers a wide range of sounds, from deep bass tones (125 Hz) to higher frequencies (up to 4 kHz), ensuring clear audio across six octave bands. It’s also compact and effective, even in rooms with echoes and other noise distractions.
The potential? Think private conversations in open spaces, immersive sound experiences where only you hear certain audio layers, or creating zones where sound can be precisely controlled—like playing music for one person while keeping it silent for another. It’s a futuristic approach to making sound personal, targeted, and unobtrusive.
