ANYONE who lives near an airport or nightclub knows the value of
soundproofing. Now scientists in Hong Kong have devised a new kind of sound
reflector that can cut out hard-to-block low-frequency sound.
Such a material has been elusive because sound waves are usually only
reflected by structures of a similar size to the wavelength of the sound.
Because low-frequency noise has wavelengths of several metres, shutting it out
would normally need soundproofing the size of outdoor sculptures.
But now Ping Sheng’s group at the Hong Kong University of Science and
Technology has made a sound shield just a few…
