CONTROL SONORO

Technology which uses ultrasonic energy to focus sound to the intended listener and nowhere else.

From Wikipedia, the free encyclopedia

Sound from ultrasound is the name given here to situations when modulated ultrasound can make its carried signal audible without needing a receiver set. This happens when the modulated ultrasound passes through anything which behaves nonlinearly and thus acts intentionally or unintentionally as a demodulator.

Scuba divers and naval submarines have been using modulated ultrasound underwater communicators for many years, but to hear the sound signal needed a receiver set to demodulate the received ultrasound signal, much as a radio receiver is needed for RF demodulation.

Researchers since the early 1960s have been experimenting with creating directive low-frequency sound from nonlinear interaction of an aimed beam of ultrasound waves produced by a parametric array. Ultrasound has wavelengths much smaller than audible sound and thus can be aimed in a much tighter narrow beam than any traditional audible loudspeaker system.

The first modern device was created in 1998 (105th AES Conv, Preprint 4853, 1998), and is now known by the trademark name “Audio Spotlight”, a term first coined in 1983 by the Japanese researchers who abandoned the technology as unfeasible in the mid 1980s.

A transducer can be made to project a narrow beam of modulated ultrasound that is powerful enough (100 to 110 dBSPL) to change the speed of sound in the air that it passes through. The air within the beam behaves nonlinearly and extracts the modulation signal from the ultrasound, resulting in sound that can be heard only along the path of the beam, or that appears to radiate from any surface that the beam strikes. The practical effect of this technology is that a beam of sound can be projected over a long distance to be heard only in a small well-defined area[citation needed]. A listener outside the beam hears nothing. This effect cannot be achieved with conventional loudspeakers, because sound at audible frequencies cannot be focused into such a narrow beam.

There are some criticisms of this approach. Anyone or anything that disrupts the path of the beam will interrupt the progression of the beam, not unlike lighting.

HyperSonic Sound

Elwood “Woody” Norris, founder and Chairman of American Technology Corporation (ATC), announced he had successfully created a device which achieved ultrasound transmission of sound in 2002. ATC named and trademarked their device as “HyperSonic Sound” (HSS). In December 2002, Popular Science named HyperSonic Sound the best invention of 2002.[citation needed] Norris was also the winner of the 2005 Lemelson-MIT Prize in part for his invention of a “hypersonic sound”. However, commercial adaptation of the device has not yet occurred as of February 2008.

LINKS
http://www.silentsound.co.za/technology.htm
http://www.woodynorris.com/mit1.htm
http://www.atcsd.com/site/content/view/34/47/

VIDEO DEMOSTRATION