Sound of the police: how US law enforcement uses noise as a weapon

In Silver Spring, Maryland, fireworks can still be heard months after they first began and well past the Fourth of July holiday. “When it comes to the theory of cops being involved, I wouldn’t put it past them,” says Ira, who participates in protests and activism there. Ira, who prefers to use only a first name because of fear of police reprisal, is referring to a theory that became especially popular on Twitter which posited police were supplying or abetting the recent onslaught of fireworks in major cities in an effort to exhaust and agitate protesters during the peak of the response to George Floyd’s murder.

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The use of sound as a form of control is in the spotlight due to potentially harmful military-grade weapons such as flash-bangs and long-range acoustic devices (LRADs) being utilized with accelerating regularity at protests across the United States. Luna, an activist who is only using her first name out of fear of doxxing, has been on the frontlines of direct actions against police brutality in Portland, Oregon, for nearly two months. She says the Portland police’s use of flash-bangs, which can produce sounds as loud as 170 decibels – a jet taking off is 150 decibels, for comparison – has left her with symptoms of post-traumatic stress disorder.

“If I’m in public and I hear a loud bang, I’ll stop and duck and look around,” she says. Luna says the fireworks set off in Portland trigger the same response for her and the other protesters who rally each night. “It’s very exhausting, not just physically but mentally.”

Sound studies experts say that while LRADs and flash-bangs are worrisome tactical escalations that can permanently injure people by rupturing eardrums, they are rooted in the long, uncontested tradition of the state utilizing sound as a means of social, cultural and political control.

Even sounds heard since childhood can be used to send signals in certain communities. Briana Thompson, who has been participating in protests in Phoenix, Arizona, says, “As a Black person in America, I always have a heightened and triggered response to police sirens.”

Originally from Brazil, the sound researcher Pedro Oliveira has studied the Brazilian military police’s use of sound bombs, or stun grenades, against communities of color in São Paulo as a “material articulation of racialized sonic violence”. He says a police siren in a white neighborhood can mean protection and in a non-white neighborhood can mean threat. “Sirens and whistles function more as devices for crowd control and establishing social order,” says Oliveira. “[LRAD] performs similar functions, like organization and control, but the step ahead is that it is meant to hurt.”

This “step ahead” troubles Marisa Ewing-Moody, an audio engineer based in Washington DC. After seeing the LRAD deployed at protests, she detailed its history and specs on Twitter. She especially takes issue with its designation as a non-violent form of crowd control. “You can cause permanent damage to people that are exposed to this,” she tells me. “I wouldn’t say that’s non-violent.”

Ewing-Moody tells me that Genasys, the company that creates LRADs, brags about the LRAD reaching 30 decibels higher than typical vehicle PA systems. “The context of 30 dB being the difference between those two points is astronomically huge,” she says. A typical concert, she explains, sits in the range of 85 to 88 decibels. LRADs are capable of almost doubling that. Besides the implied hearing damage, Ewing-Moody notes that our ears mediate other bodily functions such as balance. “If you’re in a scenario where your ears are being damaged, that can cause dizziness and nausea because your body is getting confused by the way your inner ear is moving,” she says.

Besides these ramifications, Oliveira says sound is useful as a tool of social control because it isn’t just perceived by the ears, but by the whole body. “It’s difficult to describe in physical terms what sound can do,” he says. A siren’s warble, for example, is not intrinsically connected to fear, but given its use over time as a sound that often precedes violence, it causes a fear reaction.

Thompson gives another example: the roar of police helicopters flying overhead. She and others chose to observe eight minutes of silence while lying in the street in downtown Phoenix, a solemn tribute to the length of time during which Minneapolis police officers killed George Floyd.

“It was a beautiful sight, but that silence wasn’t actually silent,” she says. Police helicopters overhead filled their ears, while police in riot gear marshalled nearby. “We [were] outside in the middle of our city, but it was claustrophobic and terrifying lying there listening to police hover above us and close in around us.”

James Parker, a senior lecturer at Melbourne Law School, says examples like Thompson’s show that the weaponization of sound is problematic beyond just the possible physical harm to our ears. He says these sounds are understood as effective or necessary because they are predicated on constructions of criminality and deviance which must be policed. “[It’s] a context in which we understand a protester as the aggressor who needs to be managed en masse,” he says, despite the fact that “time and time and time again, we see that it’s police action which produces the violence [or] antagonism that they claim to be policing.

“I think the LRAD gets an undue amount of attention in some ways,” says Parker. “The thing about the LRAD is that it asserts a physical force over you. You’re literally compelled to run away. That’s a very new, strange thing in some ways, but it’s much more continuous with a siren or a whistle than it is with a gun.”

Parker explains that the LRAD, which emits sounds in the mid- to high-frequency range, is designed to target the most vulnerable parts of the human ear. “That’s fairly similar to a siren,” he says. “The only reason a siren doesn’t inflict pain is because you’re not close enough to it.”

Sound is used, according to Parker, to compete over control of public space. But it’s also deeper than that. “It competes for control over what you do, how you think of yourself,” he says, “whether you feel included or excluded when you move through the world.”