March 24, 2016 12:33 pm Leave your thoughts
Researchers have designed coiled metasurfaces that not only completely absorb low frequency sounds, but are a tiny fraction of the size of traditional sound-absorbing systems (Credit: Assouar/CNRS).
Absorbing low frequency sound is a big job, or at least, a job for big things. Acoustic absorption systems require big resonant cavities with large amounts of heavy damping material and significant surface areas to work efficiently. Consequently, the sound-deadening systems used in music studios and anechoic chambers take up a lot of room. Now scientists have flipped this notion on its head by designing coiled metasurfaces that not only completely absorb low frequency sounds, but are a tiny fraction of the size of traditional sound-absorbing systems.
Many standard resonant acoustic absorption systems work by deadening sound energy using an inner diaphragm behind a perforated plate that effectively reduces the wave energy on the way in, then funnels it into a resonant frequency chamber where it is allowed to dissipate. The wavelength of sound at low frequencies – around 200 Hertz and below – however, is in the order of meters in size, so traditional acoustic absorbers need to be physically large to resonate and cushion noise at those frequencies.listening space, sound isolation, tuned room
This post was written by Jeffrey LeClair