N.Y.P.D. to Limit Use of ‘Sound Cannon’ on Crowds

The Police Department has agreed to stop using an “alert” noise on the devices after demonstrators and photographers sued, saying it caused migraines and dizziness.

Police officers first deployed the earsplitting beeps against protesters more than a decade ago in Pittsburgh: Painfully loud noises emitted from a powerful speaker atop a police vehicle, a crowd-control device known informally as a “sound cannon.” Since then the items, called Long Range Acoustic Devices, or LRADs, have provided a soundtrack to marches and demonstrations in New York, Portland, Ore., and other cities. They have functioned as giant megaphones to give commands, but also produced shrieks that can be louder than a lawn mower or a police siren. Now, the New York City Police Department has agreed in a legal settlement to stop using the shrill beeping — referred to as the “deterrent” or “alert” tone — becoming one of the first big city departments to do so.