Representatives of both companies say that within days, they will ship some units of their respective products to areas hit by Hurricane Katrina, so authorities can use the tools for crowd control, aid distribution and rescue operations.
Costa Mesa, California-based HPV showed off three
sizes of its Magnetic Acoustic Device, or
The device uses magnets approximately 6 inches tall and 9.25 inches wide to convert electrical pulses into sound waves, and is capable of aiming sound precisely for thousands of feet -- like the sonic equivalent of a laser, or spotlight.
Its path and reach can be affected by environmental factors such as nearby flat surfaces, hills, bodies of water or strong bursts of wind.
A series of test sounds beamed out by
When a subject is at close range in
The ability to broadcast instructions or alerts at great distances with minimal distortion could be useful for authorities and rescue crews in areas where other communications systems are unavailable.
American Technology is donating four devices -- three MRADs (medium-range acoustic devices) and one LRAD
(long-range acoustic device). The four devices will be shipped out Friday to a
Marine military police unit that is deploying to the
"We are donating the use of one of our most powerful prototypes, LTPMS-2, for use in Mississippi as soon as possible, because the governor of that state said that the biggest problem they have right now is the fact that they have no communications infrastructure to get information or instructions out to people," he said. "They can very easily put this on a truck and send sound out for a minimum of at least a mile in either direction."
The Los Angeles Sheriff's Department, which hosted the
event as a guest of the Air Force base, is considering using
"You don't appreciate how powerful this stuff is until you stand a mile away and can't see the transmitter -- but can hear every word in a Queen song," said Cmdr. Sid Heal, who heads the Los Angeles Sheriff's Department technology exploration program. "At a quarter mile, it sounds as clear as a car radio; at a half a mile, you have to raise your voice to talk to the guy next to you; at three quarters of a mile, laborers raking up leaves were putting in music requests."
Also on display at Edwards Air Force Base was American Technology's LRAD, a portable device that can be easily mounted on vehicles. Its smaller size and light weight comes with an accordingly smaller reach: The device is generally used for distances from 100 to 600 meters.
While both manufacturers stressed that their devices were designed primarily to hail, warn or communicate, other sonic technologies have been used by governments as a less pleasant way to disperse crowds.
Vehicle-mounted devices were used by Israeli authorities to scatter groups earlier this year, when Palestinians and Jewish supporters gathered to protest Israel's West Bank separation barrier. Dubbed "The Scream" by the Israeli Army, the device sends out streams of noise in intervals of about 10 seconds. The specific sonic frequencies chosen affect the inner ear, creating dizziness and nausea in human targets.
In a report, AP quoted an unnamed Israeli military official as saying the device emits a frequency that targets the inner ear, can cause damage with exposure for several minutes at close range, and compels humans nearby to leave the area. Exposure for minutes at close range could cause hearing damage. Information about longer-term exposure effects at long distances has not been publicly disclosed.
Devices from both companies vary in price, depending on quantity sold, size and which agency is purchasing -- but generally range from $10,000 to $75,000 per unit.