The NYC police are reported to have a weapon-like acoustic device called an LRAD at the RNC protests.
Here is a picture from Indymedia.
Earlier this month, the New York Police Department showed off a machine called the Long Range Acoustic Device, developed for the military and capable of blasting at an earsplitting 150 decibels -- as loud as a firecracker, a jet engine taking off or artillery fire at 500 feet, according to the Noise Center at the League for the Hard of Hearing. The NYPD said it would use the machine to direct crowds to safety if there's a terrorist attack or remind protesters where they're allowed to march. Police said they wouldn't use the earsplitting screeching noise feature at the convention. "It's only to communicate in large crowds," Inspector Thomas Graham of the police department's crowd control unit said.
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