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What is LRAD? The ‘sound cannon’ used by police, explained

As protests in response to the police killing of George Floyd continue to roil the country, Twitter has been abuzz lately with reports that police departments are bringing LRAD (long-range acoustic device) systems with them as part of their response.

Genasys Inc. (formerly the LRAD Corporation), which produces LRAD devices, announced in a press release Thursday that “Police departments in Portland Ore., San Jose, Calif., Colorado Springs, Colo., Phoenix, Ariz, Columbus, Ohio, Charleston, S.C., Ft. Lauderdale, Fla., and other cities used LRAD systems to communicate unlawful assembly and other orders to crowds after recent protests turned violent.”

NYPD using an LRAD
The SRG (Strategic Response Group) of the NYPD using the LRAD to give announcements in 2015 Shay Horse / NurPhoto via Getty Images

We reached out to the various police departments Genasys mentioned; a representative for the Phoenix police department told us the department “utilizes the Long Range Acoustic Device to effectively communicate clear and concise messages during events.” On Friday, Portland police said that they used an LRAD device to scatter protesters, according to Willamette Week.

Those planning to attend protests may be wondering: What exactly is an LRAD, and are these devices dangerous?

What is an LRAD?

LRAD refers to a line of “acoustic hailing devices” designed to broadcast “live or recorded voice messages with exceptional clarity for any operational scenario … even above crowd, engine, and background noise.”

Acoustic device deters enemies with ear-splitting noise

The sound produced by an LRAD is highly directional. According to representatives from Genasys, an LRAD device broadcasts sound in a 30-degree beam.

LRAD devices have been in use for more than a decade. Ships often use them to hail distant vessels, and in 2005, a cruise ship used an LRAD device to help repel pirates, with Der Spiegel describing the device as a “sonic cannon … that beams hellishly loud noise that is deafening but not lethal.”

When we reached out to Genasys to ask if LRAD could be used as a weapon, the company told Digital Trends that “LRAD systems are voice communication systems, not weapons. Training for the systems is contrary to such use,” adding that “These systems enable police to clearly communicate during emergency situations.”

The company also said “The maximum voice output of the 100X [a particular LRAD model commonly used by police] is 131 decibels (dB) at just one meter from the system” and that “LRAD voice broadcasts follow the inverse square law, which teaches that for every doubling of the distance from an audio source, sound pressure levels diminish by 50% (6 dB). At the recommended distances, the audio output of the LRAD 100X and LRAD 450XL is similar to police and fire sirens at close range.”

Can an LRAD be used as a weapon?

Despite Genasys’ insistence that LRAD is not a weapon, the technology has a reputation as a “sonic cannon” capable of inflicting bodily harm. Writing for The Conversation, Professor Ian McLoughlin says that “When on high power, the effects are like a ‘punch in the guts’, ranging from nausea to involuntary evacuation of the bowels.”

An ongoing lawsuit against the City of New York involves the use of an LRAD 100X model, the kind typically used by police. After the NYPD used a 100X model LRAD during protests over the death of Eric Garner, a group of plaintiffs filed a lawsuit against the city, alleging that the use of the device caused “physical injuries, such as migraines, sinus pain, dizziness, facial pressure, ringing in ears, and sensitivity to noise.”

In an opinion on the case, Judge Robert Sweet noted that “In addition to amplifying sound, LRAD devices can possess a high-pitched, volume adjustable “deterrent tone” that is marketed to law enforcement as useful for crowd control by creating audible discomfort when used at close range … The 100X can project messages up to 600 meters away, produce a maximum continuous output of 136 dB at one meter away, and has the capacity to overcome 88 dBs of background noise at 250 meters.”

Sweet also compared the X100 to “items like stun grenade, flashbang, or concussion grenades,” which, when used with disregard for the targets, can be considered “excessive force.”

Genasys representatives told Digital Trends that the “deterrent tone” is meant to be used by police in a momentary or instantaneous manner to get people’s attention during chaotic situations before delivering instructions. They also told us that “On the 100X even the tone at three meters in front of the device is below a level that’s going to cause any hearing issues or damage to your ear,” adding that “NIOSH and OSHA both say that you need continuous exposure above 140 decibels to cause any sort of temporary or permanent hearing damage. The LRAD 100X, which is what most police forces have, is only capable of putting out 137 decibels, and that’s measured at one meter. At three meters [roughly 9.8 feet], you’re well under 130 decibels.”

According to the CDC, “Noise above 70 dB over a prolonged period of time may start to damage your hearing. Loud noise above 120 dB can cause immediate harm to your ears.”

Although Genasys maintains that proper use of the tone is to get people’s attention, Portland Police Bureau Assistant Chief Chris Davis told reporters on Friday that the device “will emit a tone that is very hard to be around,” according to Willamette Week.

Genasys points out that the LRAD allows officers to warn people about the impending use of tools like tear gas or rubber bullets, creating a chance to deescalate before using such measures.

Will Nicol
Former Digital Trends Contributor
Will Nicol is a Senior Writer at Digital Trends. He covers a variety of subjects, particularly emerging technologies, movies…
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