Acoustic metamaterials for in-ear noise cancellation

1 min read

A new project led by the University of Strathclyde will seek to develop miniaturised acoustic metamaterials for personal audio devices to enhance features such as noise cancellation.

Acoustic metamaterials can be used to manipulate sound, supressing the noise emanating from certain objects or from reaching the ear. Until now, however, the geometries required of these materials have not been possible to produce at the small scale needed for personal audio. The EPSRC-funded project will use a variety of commercial and custom-made UV-curable polymer resins, employing micro-stereolithography to fabricate small acoustic systems that can be stacked together to create acoustic metamaterials that work at audio frequencies.

“Unfortunately, acoustic metamaterials, which promise a step change in the way materials interact with sound, are still very large for audio frequencies,” said Strathclyde’s Dr Joseph Jackson, a lecturer in electronic and electrical engineering at the university.

“We will try and miniaturise acoustic materials to make sound absorbing materials that are small and lightweight while retaining good acoustic function.”

Dr Jackson has been awarded £422,394 for the two-year project, which he hopes will deliver acoustic metamaterials that interact with sound at audio frequencies by 2024. According to him, the physical ability of metamaterials to improve audio experience can work in tandem with the digital features that many electronics companies are already employing on headphones and other personal audio devices.

“Companies are working on noise cancellation technologies, but these are predominantly electroacoustic techniques: acquire signal, phase shift, play it back,” said Dr Jackson.

“We are attempting to miniaturise acoustic metamaterials to enable their use in wearable devices instead of or complementary to active noise cancellation.”