The BBC's Tomorrow's World programme last night featured a new development which, according to its designer, is capable of transmitting sound in a straight line Sound Beam is a new device which sends sound in a straight line - working on much the same principles as a spotlight. Designed by Joe Pompei, a researcher at MIT media lab in Boston, it can be used to relay audio to just one person in a crowd. Pompei's design is based upon high frequency ultrasound waves which are beyond our hearing which act like a 'carrier' for audible sound. His design combines music with ultrasound; this then recreates the complex wave patterns of the music at a much higher frequency that can't be heard. A specially designed speaker is then used to send out this high frequency ultrasound beam. Physical properties in the air then distort the beam producing a range of frequencies, including audible sound. The sound quality isn't high enough yet to cover very long distances, but when it is, the potential applications for the product in public places such as airports, stations and cinemas are mind-boggling.
