Hypersonic® sound (HSS®) is an audio technology that uses the interaction between ultrasonic waves and air to generate audible sound. Radically different from traditional speakers, HSS® devices generate sound indirectly so they don’t suffer from the many types of distortion found in other devices. Hypersonic® sound can also be used to target a very specific area, much like a spotlight concentrates light in a narrow beam. The technology was invented by Elwood “Woody” Norris of the American Technology Corporation, but has struggled to find a market.
Traditional speakers generate sound by vibrating a fixed material that creates waves of pressure that travel through the air. Hypersonic® sound takes a completely different approach and emits ultrasonic tones which cannot be heard by the human ear. These ultrasonic tones in turn generate sound in air molecules themselves. This is possible because air has a non-linear property, meaning that sound tones of both lower and higher frequencies can be produced when air interacts with sound. Ultrasonic tones can therefore generate audible frequencies when they come into contact with air molecules.
Since HSS® emitters do not directly generate sound waves, they have a few advantages over regular speakers. An HSS® emitter does not suffer from the various forms of distortion caused by the mechanical elements of a speaker. The emitter can be relatively small and lightweight yet still generate quality audio. The volume of the audio doesn’t change over a fixed distance, so HSS® emitters could be used at a concert and deliver sound at the same level from the front row to the back of the venue.
Perhaps the most important benefit of Hypersonic® sound technology is the ability to emit sound in narrow “beams” that can be directed at a particular location or individual. Anyone inside this beam can hear the sound, while those outside the beam, perhaps just a few feet away, will hear nothing. This ability has many potential applications from highly targeted advertising to surround sound channels that don’t require speakers or wires.
Though Hypersonic® sound has clear potential and has been met with praise from several media outlets, the technology has had limited commercial success. American Technology Corporation, which developed the technology and holds several related patents, initially adopted a strategy that avoided competing with major consumer electronics companies. Instead, they sought to carve out a niche where audio had historically not been used, such as in vending machines. Over time, the company shifted its focus to making ultrasonic devices for the U.S. military. In 2010, the Hypersonic® sound business was spun-off into a new corporation called Parametric Sound, with Woody Norris leading the new company.