Engineers in Boston University's Zhang Lab have unveiled a new version of a soundproofing shield capable of blocking a wide range of noise without obstructing airflow. Unlike previous developments, which were effective only within a narrow frequency range, this new technology uses a phase-gradient metamaterial to suppress noise of varying frequencies and volumes, from ventilation to office noise.
The technology is based on a PGUOM (Phase Gradient Ultra-Open Metamaterial) design, which works similarly to noise-canceling headphones. Instead of reflecting sound, the shield transforms it into "spoof waves" that are absorbed by the structure's surface. Simultaneously, air can flow freely through the material thanks to specialized cells, achieving phase displacement without the need for continuous plugs.
Composed of repeating supercells with a thin internal structure, the metamaterial can be customized to specific needs, such as ventilation systems, industrial facilities, or transportation hubs. The team emphasizes that this solution is not universal but adaptable: the frequency range of suppressed frequencies and the level of breathability can be adjusted.
According to the developers, noise pollution is a serious yet underestimated problem. It not only affects people's health, causing stress and insomnia, but also damages ecosystems. The new technology has already passed the prototype stage and is being prepared for integration into real products: from climate control devices to solutions for the "quiet" offices of the future.
