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{{use mdy dates|date=February 2022}}
{{use American English|date=February 2022}}
[[File:soundweapon1.jpg|thumb|right|An LRAD on top of a
[[File:LRAD-US-Navy.jpg|thumb|LRAD operator wearing hearing protection]]
[[File:USS Donald Cook.jpg|thumb|LRAD on a
A '''long-range acoustic device''' ('''LRAD'''), '''acoustic hailing device''' (AHD) or '''sound cannon''' is a specialized [[loudspeaker]] that produces sound at high power for communicating at a distance. It has been used as a method of [[crowd control]], which has caused permanent hearing damage, having an extremely high [[decibel]] capacity (up to 160 dB measured at one meter from the device).<ref name=g20lawsuit>{{cite web | title=CITY OF PITTSBURGH SETTLES G-20 LAWSUITS | website=ACLU Pennsylvania| date=14 November 2012 | url=https://www.aclupa.org/en/press-releases/city-pittsburgh-settles-g-20-lawsuits | access-date=11 May 2022}}</ref> Other uses have included for negotiations in [[siege]] situations; to deal with [[piracy]] at sea; for mass notification during [[natural disaster]]s or other emergencies; and by defense forces, including several [[navies]].
== Overview ==
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The focus of an AHD is typically measured at the frequency of peak directionality. This is typically in the 1–2 kHz range. Not all frequencies of sound are able to be directed equally. Lower frequencies in the bass range are difficult to form. As such, their directionality may be a 40 degree radius or more depending on the design of the AHD.
==Specifications and functionality==
LRAD devices are made by Genasys. {{as of|2022}}, the company
▲LRAD devices are made by Genasys. {{as of|2022}}, the company produces a range of LRAD products for mass notification systems. Touting its primary advantage of clarity and intelligibility of voice broadcasts over large distances, its product guide cites the following features:<ref name=genprodguide>{{ cite web| url=https://apac.genasys.com/wp-content/uploads/LRAD-Product-Guide-Final-PRINT.pdf| title=LRAD overview and product guide|publisher= Genasys}}</ref>
* 30° audible transmission ranges out to 5,000 meters
*
LRAD
The parameter "ka", which is the [[wave number]] multiplied by the speaker radius, is often used to characterize sound source directivity. For this source, ka=19 at 2.5 kHz, and according to the LRAD data sheet, the beam angle of about 30 degrees total is what is predicted for a regular loudspeaker.<ref>Beranek, Leo L. 1986. Acoustics, p.132, [[American Institute of Physics]].</ref>{{update inline|date=February 2022}}
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The device came to the attention of the wider public when it was used at the [[convoy to Canberra|2022 anti-vaccine mandate Canberra protests]] in "loud hailer" mode for voice messages to be announced to the protesters, and there was speculation among protesters regarding purported harms from its use. However, there was no evidence that it was used as a siren. In addition, some reports appeared to confuse the LRAD with other crowd control devices, such as the [[Active Denial System]];<ref name=convfeb2022/> one activist claimed that "[[supersonic]] weapons" had been used.<ref name=abcfeb2022>{{cite web | last=McCutchan | first=Ellen | title='Sonic weapons' were used by police in Canberra's protests, but only to broadcast messages rather than do harm | website=ABC News| publisher= [[Australian Broadcasting Corporation]]| series= [[RMIT]] ABC Fact Check | date=17 February 2022 | url=https://www.abc.net.au/news/2022-02-18/coronacheck-sonic-weapons-lrad-police-canberra-protests/100839612 | access-date=22 February 2022}}</ref>
===
On June 26, 2015, Czech Special Forces Police may have deployed an LRAD 500X during anti-immigration and anti-Islam protests in [[Brno]], the second largest city in the [[Czech Republic]].<ref>{{Cite web |url=http://policejnidenik.cz/wp-content/uploads/2015/06/DSC_00613-1024x702.jpg |title=Archived copy |access-date=2015-06-27 |archive-url=https://web.archive.org/web/20150629202141/http://policejnidenik.cz/wp-content/uploads/2015/06/DSC_00613-1024x702.jpg |archive-date=2015-06-29 |url-status=dead }}</ref><ref>{{cite web| url=http://policejnidenik.cz/do-brna-se-kvuli-demonstracim-sjeli-policiste-ze-specialnich-poradkovych-jednotek-z-cele-republiky/| language=cs| title=Do Brna se kvůli demonstracím sjeli policisté ze Speciálních pořádkových jednotek z celé republiky| website=Policejnidenik.cz|date=June 26, 2015}}</ref>
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===New Zealand===
During the dispersion of New Zealand's parliament protest in March 2022, LRAD were used by New Zealand police against the protesters. A document released under the Official Information Act (OIA), revealed two long range acoustic devices (LRADs) were deployed at the Parliament protest on March 2.<ref>{{cite web|url=https://www.nzherald.co.nz/nz/revealed-police-used-sound-cannons-against-parliament-protesters/PIBFZEHRIOEADS7SK4Y4SWM464/|title=Revealed: Police used sound cannons against Parliament protesters|author=New Zealand Herald|date=29 June 2022|website=
===Poland===
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* {{flag|Canada}}: Multiple police departments<ref>{{cite news|url=http://www.lapresse.ca/actualites/montreal/201405/22/01-4768807-la-police-de-montreal-se-dote-de-canons-a-son.php|title=La police de Montréal se dote de canons à son|work=La Presse|date=22 May 2014 |last1=Sioui |first1=Marie-Michèle }}</ref>
* {{flag|China}}: [[China Coast Guard]]<ref>{{cite web|url=https://news.abs-cbn.com/news/12/09/23/ph-slams-chinese-water-cannon-lrad-attacks-on-bfar-vessels|title=PH slams Chinese water cannon, LRAD attacks on BFAR vessels|date=Dec 9, 2023}}</ref>
* {{flag|
* {{flag|Georgia}}
* {{Flag|Greece}}
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