Pros & Cons of LRAD

Photo courtesy American Technology Corp

American Technology Corporation developed the LRAD after the attack on the USS Cole in 2000. Its original purpose was to help enforce the safe zones around United States military vessels. Using the LRAD's default settings, a ship's crew can warn a craft that it is approaching a military ship and must change course. This message can be up to 120 dB, so it's loud and clear but not usually painful. But if the craft doesn't change course, the ship's crew can override the LRAD's default settings. It can then produce a loud, irritating, potentially painful noise of up to 151 dB. Ideally, the craft would then leave the area without the ship having to use lethal force.

Police and land-based military units have found uses for the LRAD. Using the same principles, authorities can give warnings and instructions that are audible to a large group of people up to 300 meters away. Some police and other non-military personnel also use a smaller version of the LRAD, called the MRAD or the LRAD500.

However, human rights groups and hearing specialists alike have raised concerns about the LRAD. According to the National Institute on Deafness and Other Communication Disorders, any sound over 90 dB can damage a person's hearing [ref]. So the LRAD can threaten the hearing of anyone in its path, regardless of whether there is any wrongdoing, even when used only for communication.

Like stun guns, tear gas and less-lethal ammunition, LRAD can be used in crowd control and other situations as a non-lethal weapon. Non-lethal weapons are somewhat controversial. Human rights groups stress that even though they are less lethal, they are still weapons and have caused deaths in some circumstances. The LRAD in particular has drawn criticism since its effects can be permanent, and non-lethal weapons' effects are supposed to be temporary.

Finally, some people have questioned the LRAD's effectiveness, since wearing simple ear protection can render it useless.

Check out the next page for links with information about sound, the LRAD and other related topics.

Other Uses for Sound Sound is useful for lots of things besides communication and music. Here are some examples: The "Mosquito": Younger people can hear higher-pitched noises than older people. The Mosquito takes advantage of this, creating a high-pitched sound to drive away loitering teen-agers, leaving most adults unaffected. Ultrasound: Used to make medical diagnoses, ultrasound emitters let doctors examine internal organs and developing fetuses. SONAR: Sound waves bounce off of objects, and SONAR uses this property for underwater object location and navigation. Extracorporeal Shock Wave Lithotripsy (ESWL): This is a fancy term for using powerful sound waves to break up kidney stones. Sonic Screwdriver: In the BBC television series "Doctor Who," the Doctor uses a screwdriver that emits sonic impulses to do just about anything.