New acoustic metasurface creates bass-heavy sound bubbles without headphones

Penn State researchers built a passive 3D-printed acoustic metasurface that bends ultrasound-based sound into a tiny focal point a few inches away.

The result is a private listening zone with strong bass and rapid sound drop-off just outside the area.

The technology could support headphones-free audio in shared spaces like kiosks, vehicles, and consumer devices.

Researchers say the low-cost approach may improve both privacy and sound quality in everyday public settings.