SHE-- 環保安全健康: sound cannon,音波炮, The Long Range Acoustic Device (LRAD),

2014年9月28日星期日

sound cannon,音波炮, The Long Range Acoustic Device (LRAD),

香港專上學生聯會(學聯) 的相片。

【學聯重要呼籲】
一旦開槍或音波炮
保留實力立刻離開
我們會抗爭下去

The LRAD is the round black device on top of the New York City police Hummer.

The Long Range Acoustic Device (LRAD), also known as a sound cannon, is an acoustic hailing device and sonic weapon developed by LRAD Corporation to send messages, warnings, and harmful, pain inducing tones over longer distances than normal loudspeakers. LRAD systems have been used to counter piracy, as non-lethal crowd control weapons, and as communication devices.

According to the manufacturer's specifications, the systems weigh from 15 to 320 pounds (6.8 to 145.1 kg) and can emit sound in a 30° beam at 2.5 kHz.^[1]

LRAD systems are used by maritime, law enforcement, military and commercial security companies to send instructions and warnings over distances, and to force compliance. LRAD is also used to deter wildlife from airport runways, wind and solar farms, nuclear power facilities, mining and agricultural operations and other industrial facilities.