Researchers at Boston University have created a groundbreaking new form of ‘acoustic metamaterial’ capable of cancelling up to 94% of sound energy. Professor Xin Zhang and Ph.D student Reza Ghaffarivardavagh released a paper in Boston University’s Physical Review B outlining the precise creation of their open ring structure.
The design not only deadens sound but is also lightweight and enables air flow, two factors that will provide great benefit to industries from audio tech to manufacturing.
Researchers at Boston University have created a new acoustic metamaterial capable of blocking up to 94% of sound energy while preserving air flow.
“Today’s sound barriers are literally thick heavy walls,” stated Ghaffarivardavagh. The pair noted that current sound barriers are typically just thick walls. They work in some circumstances but aren’t always applicable in situations where airflow and lightness are needed. Take the example of a jet plane’s engine, if sound insulation was used in the design, it would never take flight.
Ghaffarivardavagh and Zhang used their shared passion for mathematics to calculate specific dimensions and specifications that the acoustic metamaterial would need to interfere with soundwaves effectively, while still preserving space for open airflow through the structure. The premise of the design was that the metamaterial would have to be able to redirect sounds back in the direction of their origin.
Using computer modelling based on their calculations, they tested models that would be most suited to the task, before using 3-D printing to create the perfect design. The ensuing test saw a loudspeaker sealed into one end of a PVC pipe with the acoustic metamaterial at the open end.
The test subject was a very irritating high pitched note, but with the metamaterial in place, you’d barely even know it was there. Just take a look at the video of the experiment below.
Zhang highlights the endless possibilities that this technology brings to the world of sound insulation:
“The idea is that we can now mathematically design an object that can block the sounds of anything.”
Pretty exciting stuff for anyone in the world of sound and I don’t imagine it will be long before audio technicians start snapping these up for the studio.