sound cannon/long range acoustic device (LRAD)

Article

15 June

The Long Range Acoustic Device (LRAD), or sound cannon, is a weapon that emits a painful high frequency sound to disperse crowds. It can also be used as a loudspeaker for mass notification. Police claim that the LRAD is a communication device, not a weapon (1,2,3), but the device causes extreme pain and permanent hearing damage.

The LRAD is manufactured by Genaysis Inc. formerly known as American Technology Corporation until 2010 and LRAD Corporation until 2019. The LRAD consists of an array of staggered piezoelectric transducers - devices which rapidly change shape when an electrical charge is applied, creating an extremely loud sound. Unlike a traditional loudspeaker, most LRADs focus sound in a 30° beam, but a newer vehicle-mounted model can project sound to 360° (4). The outer transducers are out of phase with the inner ones, cancelling out the outer waves to reduce sound outside of the beam (5). The LRAD is marketed as a “communication system” which has allowed it to escape US arms import bans to China (6).

LRADs come in various models which can be mounted on vehicles or carried by police officers on foot. It can emit a siren that causes pain and disorientation in its target, described by one journalist as “Your brain feels like it’s vibrating in a bowl of jelly on the table” (7). Alternatively it can be used to play recordings or voice eg. orders for a crowd to disperse. The LRAD can also be used to play music that drowns out speeches or chants at demonstrations and prevents protestors from communicating with each other. In 2015 police in the Philippines used this tactic against anti-APEC protestors though it’s not clear whether they used an LRAD device (8).

a brief history of LRAD use

In 1968, American police deployed a device called the “sound curdler” against student protestors. The curdler consisted of “amplified speakers that produced loud, shrieking noises at irregular intervals” and was mounted on helicopters or ground vehicles (9).

The LRAD was developed in response to the bombing of the USS Cole in 2000 for the US Navy and by commercial ships to defend against pirates. In February 2009 the Japanese whaling fleet deployed an LRAD against a Sea Shepherd activist helicopter and inflatable boats (10).

Police first used the LRAD in September 2009 against protestors at the G20 summit in Pittsburgh, USA. Authorities in the US have used LRADs against activists on multiple occasions. In 2014 LRADs were deployed in Ferguson and New York against Black Lives Matter protestors(11). In 2016-17 an LRAD was used against Standing Rock Sioux and allies defending water and land rights from the Dakota Access Pipeline (12). Police also used LRADs against Black Lives Matter protesters in 2020 (13).

In November 2019 an LRAD was used against protesters in Hong Kong (14).

In addition to the above uses of LRADs as weapons, several police forces have deployed LRADs to intimidate protestors or use the loudspeaker function, for example against farmer protests in India (15) and to deter asylum seekers entering Greece (16). In Sydney, Australia the police denied using an LRAD despite witness testimony and footage contradicting this (17).

The Israel Defense Forces have developed a distinct but similar sonic weapon called “The Scream” for use against Palestinians (18).

In 2019 the Chinese Academy of Sciences announced that they had developed a rifle-shaped sound weapon that contains a tube of inert gas that vibrates to create a low frequency sound, causing extreme discomfort in the target (19).

In 2021 the New York City Police Department settled a lawsuit brought by LRAD victims, agreeing to restrict the use of the siren function (20).

dangers of LRAD use

Although the weapon focuses sound, the LRAD is difficult to target and will cause pain to everyone in the general area the LRAD is aimed at, including passers-by.
The LRAD can reach 162 decibels. Sustained exposure to sounds above 90 decibels can cause permanent hearing damage and 120 decibels will cause immediate pain.
The LRAD can cause migraines, vomiting, balance issues, tinnitus, and permanent hearing loss (22, 23).

countermeasures

There are conflicting reports about the efficacy of earplugs or industrial hearing protection against LRADs (24). Most sources state that earplugs will help prevent hearing damage, but the experience will still be extremely uncomfortable and you may be forced to move.

Wearing expanding foam earplugs and over ear protection is likely the best way to mitigate the effects of the LRAD (25), as well as leaving the vicinity to regroup and re-strategise.