Friday, December 02, 2011

"simulating a jetliner on takeoff"

Sound has long been used as a weapon. The Germans put sirens on Stuka dive bombers in World War II to amplify the terror to unlucky souls below. Jamaican maroons — fugitive slaves — used the abeng horn to unnerve British colonial soldiers.

The U.S. Army blasted rock music to torment former Panamanian dictator Manuel Noriega. And according to the Bible, Joshua brought down the walls of Jericho by having his priests blow rams' horns.

Now, the power of loud noise is being harnessed by police departments.

A device known as the sound cannon is joining Tasers, rubber bullets and pepper spray in law enforcement's expanding arsenal of nonlethal weapons.

It's officially called the Long Range Acoustical Device, or LRAD, and it has two primary uses. One is as a high-tech megaphone that generates a beam of sound that can cut through the din of a noisy protest far better than conventional public-address systems.

It also functions as a tactical weapon — projecting a high-pitch chirping sound that makes people cover their ears and run away. And with a maximum volume of 149 decibels, the LRAD can get about as loud as a jetliner on takeoff.

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