This week I read that the LRDA – or Long Range Acoustic Device – will be used by the British Ministry of Defense during the London Olympics of 2012. According to the official release, the device would be used, if necessary, to give instructions to large crowds and not as a weapon.
The company website states that, when used as a super loudspeaker, the LRDA can reach distances of up to 3km. The quality of the message would be highly intelligible. I doubt that considering that the it is hard to find highly intelligible people working in public defense. The LRDA can also be used as a sound weapon. In this case, the noise produced can reach 150db within 100 meters, which is enough to cause permanent hearing damage in seconds. The range of headache inducing sound can reach up to 300 meters.
In 2001, it was published in the New Scientist magazine that the US Department of Defense was considering to provide air marshals with sonic guns that could be fired at terrorists in order to incapacitate them without causing any damages to the airplane. The guns would be made of a number of piezoelectric discs that would act as mini speakers. The series of these mini speakers would be able to generate a targeted sound of 140db for a few seconds.
Sometime ago I watched a Mythbusters episode about the brown note. According to the show, there is a specific frequency that when played at a volume high enough would make individuals lose their bowel movement. They tried to reproduce the effects using different frequencies hooked on gigantic speakers but did not achieve any success besides the subjects of the test complaining about anxiety, shortness of breath and nausea.
In Belgium, recently, a sound device called Mosquito was forbidden to be used. The Mosquito emits a very high frequency sound that can only be heard by young people. The newest models generate 108db at 17.5 KHz frequency which most people over 25 years old cannot hear, but is extremely unpleasant for anyone under that age. The prohibition of the Mosquito is being discussed by the European Commission as some claim that it breaches the human rights of young people and generate age discrimination, even though it reduced vandalism and youth problem when used.
The use of sound weapons will be more common as it seems to be an efficient device to control the masses. The LRDA potential is a bit worrying considering that it can cause real and permanent damage when used on full power. I don´t know how easy it would be for someone with bad intentions to steal one and ask Mr. Chong to copy it – good thing I use intro-auricular headphones.