Razor-thin silk 'dampens noise by 75%' — could be game-changer for sound-proofing homes and offices

A new sound-suppressing silk fabric could be used to create quiet spaces in homes, offices and elsewhere, researchers say.

The fabric contains a "piezoelectric" material woven through the silk that produces an electrical signal when the material is deformed — with the fibers reacting to movements as small as the vibrations caused by sound waves.

The fabric is slightly thicker than the width of a human hair and can suppress sound in two ways, according to a statement from MIT. 

First, electric signals are converted to mechanical movements that cause the silk to vibrate and emit its own sound waves. These oscillate out of sync with undesirable sound waves and therefore cancel them out. The same principle is at play in noise-canceling headphones, which work well in tiny spaces, such as ears — but don't prevent sound from entering or transmitting through larger spaces such as a bedroom, an office or an airplane.

To suppress sound across a larger surface area, the researchers developed a separate mechanism, which immobilizes the vibrations that normally transmit sound through fabric. They stretched the silk and forced the fibers to remain still, reflecting the sound waves back toward their source, similar to how light bounces off a mirror.

The fabric could be used in one mode or the other, depending on the source of the noise.

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