A device that Silences Sound without blocking airflow

Scientists created an acoustic metamaterial and noise cancellation device capable of blocking up to 94% percent of sound.

A new device can block sound from passing through, without blocking air flow.

Xin Zhang, Boston University College is Engineering professor of ME, MSE, ECE, BME, and Reza Ghaffarivardavagh, mechanical engineering graduate researcher in Zhang’s lab, have designed an acoustic metamaterial and noise cancellation device capable of blocking up to 94% percent of the transmitted sound energy while preserving air flow.

“I’ve been working on metamaterials for more than a decade,” says Zhang, a multidisciplinary professor at the College of Engineering and the Photonics Center. “But it was Reza that gradually got me more excited about the fundamental idea of a marriage between acoustics and metamaterials. If you ask me and my colleagues, acoustic metamaterials is a relatively young direction…. It’s the future.”

A device that Silences Sound without blocking airflow

Reza Ghaffarivardavagh (ENG) (front center) holds two of the open, ringlike structures over his ears while Stephan Anderson (MED) (left), Xin Zhang (ENG) (rear center), and Jacob Nikolajczyk (ENG) (right) make a racket.

“Sound is made by very tiny disturbances in the air. So, our goal is to silence those tiny vibrations,” Ghaffarivardavagh and Zhang say. “If we want the inside of a structure to be open air, then we have to keep in mind that this will be the pathway through which sound travels.”

Photos by Cydney Scott

source Boston University