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Weapon Sends Message That's Loud and Clear

San Diego tech firm's 'sonic bullets' could be the latest device in the Pentagon's nonlethal arsenal

June 23, 2002|PETER PAE | TIMES STAFF WRITER

SAN DIEGO — The shrill cry of a baby can be one of the most annoying sounds of daily life, but it is music to Pentagon strategists.

An electronics company, American Technology Corp., has turned the wail of a baby into a weapon that fires "sonic bullets," narrow beams of noise that exceed the human threshold of pain. It can incapacitate people or compel them to flee.

"It gives you the equivalent of an intense migraine headache," said Elwood G. Norris, the company's chairman and inventor of the device. "It's just totally disabling."

Norris uses 50 different sound tracks, or sonic bullets, in his new weapon. For instance, it plays backward the sound of a baby crying at 140 decibels, or 20 decibels above the threshold of pain. The noise-level is similar to that of a passenger jet taking off. Pentagon officials see many uses for Norris' invention, such as controlling unruly crowds, foiling hijackers and keeping potential suicide bombers at bay. A commercial variant also may have applications in movie theaters, vending machines and retail stores.

The sound technology is not the first time that Norris, has made waves. A prolific inventor, he developed and patented a Doppler system that is a key component of ultrasonic imaging technology. He also invented the first digital sound-recording device, as well as a microwave radar that can detect plastic land mines.

The acoustic weapon is categorized by the Pentagon as nonlethal, but it could damage hearing or cause psychological harm. It is one of the more innovative devices among the nonlethal weapons the military is developing, analysts said.

"They're very intrigued by these nonlethal weapons," said Loren Thompson, a defense analyst with the Lexington Institute think tank in Arlington, Va. "Some acoustic weapons are so powerful that they can knock you out."

Acoustic Technology

Weapons makers have been developing a nonlethal arsenal for decades, but new advances in microwave and acoustic technology as well as post-Sept. 11 security concerns have raised interest in such weapons.

The signal emitted by the acoustic weapon can penetrate any opening and bounce off surfaces before reaching the intended targets. In Afghanistan, it could have been used to drive out enemy soldiers holed up in caves and buildings.

It could help an airline pilot fend off hijackers without harming the aircraft or bystanders. And it could help military ships protect their perimeters in port.

"Sailors protecting Navy ships don't have anything between giving a verbal warning and shooting a potential threat," said Terry Conrad, American Technology's president. "Now you have something else you can use before taking lethal action."

Despite years of research on sound-harassment weapons, Pentagon officials say this is the first time soldiers will be able to direct the harassing sound at a particular individual or target.

A significant feature of the device is the fact that the person standing behind or next to the emitter can't hear the sound. It is heard only by the person who is in the sound emitter's line of fire.

In previous efforts to use sound as a weapon, soldiers could not shield themselves from the irritating noise they were directing at a target. When the Army tried to get Panama's former dictator, Manuel Noriega, to surrender by blaring harassing music and sounds outside his retreat, U.S. soldiers also complained.

American Technology's weapon is based on a beaming technology that Norris has been trying to perfect for more than seven years. Known as the hypersonic sound system, it also is creating a major buzz within the commercial acoustics industry.

Unlike a traditional speaker, which produces sound by vibrating the membranes of a woofer or a tweeter, small crystal wafers project a beam of sound across a room like a spotlight. The emitters are semiconductors used by Norris in a configuration that produces focused sound waves.

The device sends out two ultrasonic signals that produce sound only when they hit an object or a person.

An emitter pointed at a wall will produce a sound that seems to be coming from the wall, not the emitter. However, a person who is not in the line of the beam will not hear anything unless the beam has been bounced off the wall.

In a recent test of the device in the company's parking lot, a reporter stood about 100 feet from the emitter and could hear a radio broadcast as though it were coming from within the ear. Norris then pointed the emitter at a nearby window and it seemed as though the sound were coming from within the building.

Giant retailers are swarming to buy the product, Norris said. The company is negotiating with an unidentified beverage company for a one-year exclusive right to use the device in soda vending machines. The company envisions a potential soda buyer standing in front of a vending machine or a passerby hearing the sound of a can opening and the soda fizzing as it is poured into a glass. The sound wouldn't be heard by anyone else.

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