Is Police Use of Sound Cannons to Disperse Crowds Legal?

By Ephrat Livni, Esq. on March 10, 2016 | Last updated on March 21, 2019

We all have different ideas of appropriate communication based on our backgrounds, experiences, and occupations. Take the New York City Police Department, whose spokesman called sound cannons, "A safe and effective communication tool."

The police department is being sued by a group of 5 photojournalists, activists, and students who say they were injured by the sound cannons at a protest in December 2014, according to Reuters. The group is seeking unspecified damages for use of these allegedly deafening devices to disperse legal protesters, calling it unconstitutional.

Sound Waves

The plaintiffs claim that sound cannons are anything but a communications tool. Rather, the Long Range Acoustic Devices, or LRADs, give police unbridled and unconstitutional authority to suppress free speech, according to the suit.

The group complains of nausea, migraines, ringing ears, and hearing problems following the protest over the death of Eric Garner and police involvement in it. The demonstration arose in December 2014 after a grand jury declined to indict a white police officer for a chokehold that led to the unarmed black man's July death according to an autopsy.

The military grade sound cannons that police just started using regularly against protesters for dispersal in recent years are designed for multiple purposes. They can serve as loudspeakers to issue instructions in a chaotic situation. According to the manufacturer, they can easily be heard over sirens and other noises. But also, they can be used to disperse protests, apparently.

Is It Illegal?

The complaint in the lawsuit, Edrei et al v. City of New York et al, is not about sound cannons as louspeakers and communications devices, but with the LRAD for crowd dispersal. The sound cannon is obviously intentionally unpleasant when used for crowd dispersal. Is it illegal?

The NYPD stresses the fact that it's used as recommended by the manufacturer, LRAD Corporation of San Diego, which is not named in the lawsuit. Reportedly the device can reach 120 decibels and is louder than a power saw or sandblaster ... so it is an effective communication tool insofar as it communicates the desire of authorities to drown out angry crowds, like the one that followed the grand jury's decision in the Eric Garner matter.


If you or someone you know has been accused of a crime at a demonstration or in any other context, talk to a lawyer. Many criminal defense attorneys consult for free or a minimal fee and will be happy to discuss your case.

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