The Long Range Acoustic Device (LRAD), or sound cannon, is a weapon that can emit a painful high frequency sound to disperse crowds. It can also be used as a loudspeaker for mass notification. The device can cause 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, the LRAD focuses sound in a 30° beam.[1] The outer transducers are out of phase with the inner ones, cancelling out the outer waves to reduce sound outside of the beam.[2]

The LRAD can emit a siren that causes extreme 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.”[3] Alternatively it can be used to play recordings or voice eg. orders for a crowd to disperse.

The LRAD can be used to play music that drown out speeches or chants at demonstrations and prevent 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.[4]

LRADs come in various models which can be mounted on vehicles or carried by police officers on foot.

The LRAD is marketed as a “communication system” which has allowed it to escape US arms import bans to China.


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[6]. 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.[7][8]


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.[9]

The LRAD was first used by police on 24-25 September 2009 when LRAD was used against protestors at the G20 summit in Pittsburgh, USA.

In 2014 LRADs were deployed in Ferguson and New York against Black Lives Matter protestors.[10]

In 2016-17 an LRAD was used against Standing Rock Sioux and allies defending water and land rights from the Dakota Access Pipeline.[11]

The Israeli Defence Force has developed a distinct but similar sonic weapon called “The Scream” for use against Palestinians.[12]

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.[13]

In November 2019 an LRAD was used against protesters in Hong Kong.[14]

Police have used LRADs across the United States against Black Lives Matter protesters in 2020.[15][16]

Use in Australia

In 2016 the ABC confirmed that Victoria Police, Western Australia Police, South Australia Police, Queensland Police, the Australian Federal Police possess LRADs.[17] Queensland Police have 15 LRADs.[18] The Northern Territory and NSW refused to confirm whether they had LRADs but then-NSW Police Commissioner Andrew Scipione confirmed in budget estimates that the NSW Police Force has at least one device, which cost $11,000.[19]

It’s unknown if LRADs have ever been used on protestors in Australia. Queensland Police have used LRADs for communication but refused to say whether the siren had been used.[20] During the 2016 inquest into the Lindt Cafe Siege information emerged that on 15 December 2014 NSW Police deployed an LRAD but did not use it.[21]


There are conflicting reports about the efficacy of earplugs or industrial hearing protection against LRADs.[22] 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.[23]

Written by Tom Raue