[Editorial] Tired of headphone listening? Get ready for the "Audible Enclaves"!

April 2025 Editorial

Are “Audible Enclaves” the future of private listening?

Author: Lucio Cadeddu - TNT-Audio Italy
Published: April, 2025

Tired of listening with headphones? Researchers at Penn State University, led by Yun Jing, professor of acoustics at Penn State College of Engineering, have just published an article, titled Audible enclaves crafted by nonlinear self-bending ultrasonic beams in the prestigious scientific journal Proceedings of the National Academy of Sciences of the USA, where they describe a system for recreating sound bubbles, called audible enclaves, inside which a single listener can hear sounds in a private way, without wearing any audio device and without disturbing those around them.

The idea, explained in the words of the researchers, is the following:

“We use two ultrasound transducers paired with an acoustic metasurface, which emit self-bending beams that intersect at a certain point. The person standing at that point can hear sound, while anyone standing nearby would not. This creates a privacy barrier between people for private listening.”

In practice, by placing metasurfaces in front of two ultrasonic transducers, dual ultrasonic waves travel at two slightly different frequencies along a crescent-shaped trajectory until they intersect, forming an audible enclave where sound can be heard. At other points along the trajectory, sound is not heard - meaning private listening is possible.

Because they use ultrasonic beams, they cannot be heard individually; it is their local, nonlinear interaction that generates audio-band sound. The beams can bypass obstacles, such as human heads, to reach a designated intersection point.

So far, this technology allows the sound to be remotely transmitted about a meter away from the intended target, and the volume of the sound is about 60dB, equivalent to the volume of a conversation. However, both the distance and the perceived volume could increase with the intensity of the ultrasound.

This is very recent research (the article was published on March 17, 2025!) and any commercial applications are far from being realized, also because for now the useful band seems to be confined between 125 Hz and 4 kHz, but the potential is extremely interesting.

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