Daniel J SaitNew sound-suppressing silk can create quiet spaces even in large areas, researchers say.
Unwanted noise is a problem across many sectors in the AV world, affecting both domestic and commercial spaces. A potential solution may be on the horizon, thanks to new technology developed by an interdisciplinary team of researchers from MIT and other institutions. They have created a sound-suppressing silk fabric that is just slightly thicker than a human hair.
The fabric contains a fibre that vibrates when a voltage is applied to it. The researchers have utilised these vibrations to suppress sound in two distinct ways.
In the first approach, the vibrating fabric generates sound waves that cancel out unwanted noise, similar to the technology behind noise-cancelling headphones.
In the second approach, the fabric is held still and suppresses the types of vibrations that are crucial to the transmission of sound, preventing audio from being transmitted through the fabric. This technique allows for noise reduction in much larger spaces.
The researchers used common materials like silk, canvas, and muslin, suggesting that this type of approach could be cost-effective and relatively easy to implement in a wide range of scenarios.
Yoel Fink, a professor in the Departments of Materials Science and Engineering and Electrical Engineering and Computer Science, a principal investigator at the Research Laboratory of Electronics, and the senior author of a paper on the fabric, told MIT News, “Noise is a lot easier to create than quiet. In fact, to keep noise out we dedicate a lot of space to thick walls. Grace’s work provides a new mechanism for creating quiet spaces with a thin sheet of fabric.”
As reported in MIT News, the study’s lead author is Grace (Noel) Yang SM ’21, PhD ’24. Co-authors include MIT graduate students Taigyu Joo, Hyunhee Lee, Henry Cheung, and Yongyi Zhao; Zachary Smith, Robert N. Noyce Career Development Professor of Chemical Engineering at MIT; graduate student Guanchun Rui and Professor Lei Zhu of Case Western University; graduate student Jinuan Lin and Assistant Professor Chu Ma of the University of Wisconsin at Madison; and Latika Balachander, a graduate student at the Rhode Island School of Design.
The Sound of Silence
The sound-suppressing silk builds on the group’s previous work to create fabric microphones. This earlier work involved sewing a single strand of piezoelectric fibre into fabric, a material that produces an electrical signal when squeezed or bent. When a noise causes the fabric to vibrate, the piezoelectric fibre converts the vibrations into an electrical signal, capturing the sound. The new technique reverses this concept to produce the opposite effect.
Speaking to MIT News, Grace said, “While we can use fabric to create sound, there is already so much noise in our world. We thought creating silence could be even more valuable.”
To enable sound suppression, the researchers used a silk fabric ‘loudspeaker’ to emit sound waves that interfere and cancel out unwanted sound waves. This technique is effective over a small area, so the researchers developed the second approach to address larger spaces.
While it is still early days, the implications and applications in the smart home and luxury AV worlds could be significant.