(image: Vladimir Gavreau)

Infrasound is low frequency audio beneath the human range of hearing. Infrasound constantly surrounds us, generated naturally; wind, waves, earthquakes and by man; building activity, traffic, air conditioners and so-on. Low frequency sound is used by marine mammals to communicate over vast distances and by birds to determine migration patterns.

At higher volumes infrasound of around 7-20hz can directly affect the human central nervous system causing disorientation, anxiety, panic, bowel spasms, nausea, vomiting and eventually unconsciousness (supposedly 7-8hz is the most effective being the same frequency as the average brain alpha wave). The effect is unintentionally (or not?) generated by the extreme low frequencies in church pipe organ music, instilling religous feelings and causing sensations of “extreme sense sorrow, coldness, anxiety, and even shivers down the spine.”(1) in the unsuspecting congregation. Low frequency sound generated naturally or by building work and traffic is said to be the cause of reported apparitions and hauntings (2) – blamed on the ghostly 19hz frequency which matches the resonating frequency of the human eyeball:

Frequency & effects:

7 Hz: Supposedly the most dangerous frequency corresponding with the median alpha-rhythm frequencies of the brain. It has also been alleged that this is the resonant frequency of the body’s organs therefore organ rupture and even death can occur at prolonged exposure.

1-10hz: “Intellectual activity is first inhibited, blocked, and then destroyed. As the amplitude is increased, several disconcerting responses have been noted. These responses begin a complete neurological interference. The action of the medulla is physiologically blocked, its autonomic functions cease.” (Gavreau )

43-73hz: ” lack of visual acuity, IQ scores fall to 77% of normal, distortion of spatial orientation, poor muscular coordination, loss of equilibrium, slurred speech, and blackout”.(Gavreau )

50-100hz: “intolerable sensations in the chest and thoracic region can be produced – even with the ears protected. Other physiological changes that can occur include chest all vibration and some respiratory rhythm changes in human subjects, together with hypopharyngeal fullness (gagging). The frequency range between 50 and 100 Hz also produces mild nausea and giddiness at levels of 150 – 155 dB, at which point subjective tolerance is reached. At 150 to 155 dB (0.63 to 1.1 kPA), respiration-related effects include substernal discomfort, coughing, severe substernal pressure, choking respiration, and hypopharyngeal discomfort.” (Davies)

100hz – At this level, a person experiences irritation, “mild nausea, giddiness, skin flushing, and body tingling.” Following this, a person undergoes “vertigo, anxiety, extreme fatigue, throat pressure, and respiratory dysfunction.”(Gavreau )



(images: tables from “Acoustic Weapons—A Prospective Assessment: Sources, Propagation, and Effects of Strong Sound” Jürgen Altmann)

The first documented attempt to reproduce the infrasound effects was by the much mythologised Russian/French physicist Vladimir Gavreau in 1957. Gavreau became interested in infrasound when he was asked to cure a case of ‘Sick Building Syndrome’; Staff at a research plant in Marseilles were mysteriously falling ill. Chemical or pathogen poisoning was suspected but Gavreau eventually traced the origin of the illnesses to an air conditioning units rotating fans that were generating low frequency sound waves. Gavreau began to experiment with low frequency acoustics with the intention of creating a viable audio weapon for the French military. Several prototype designs of various sizes were produced christened ‘canon sonique’ consisting of piston driven tubes and smaller compressed air horns and whistles. Gavreau and his team tested the instruments on themselves at the Marseilles plant with unexpected success as apparently one of the team died instantly “his internal organs… mashed into an amorphous jelly by the vibrations”:

“Luckily, we were able to turn it off quickly. All of us were sick for hours. Everything in us was vibrating: stomach, heart, lungs. All the people in the other laboratories were sick too. They were very angry with us.

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Part 1: ‘Long Range Audio Device’

Baghdad, Fallujah, New York, Tbilisi

Designed and built by the American technology Corporation in 2005 and originally designed as a ship to ship hailing device to protect US naval shipping, LRAD is now used by the Illegal American occupation forces in Iraq as an assault weapon, by the US government on their own people as part of their ‘non lethal’ arsenal for crowd control and more recently by the (US sponsored) Georgian state to repress internal dissent.

LRAD emits a high pitched warning tone “similar to a fire alarm” or a series of ‘verbal challenges’ (translatable through an inbuilt ‘phrase-olator’ or online via TCP/IP connection “immediately retrieve thousands of messages recorded by the Defense Language Institute”) over a maximum effective land distance of 300metres at a volume of120-150db(1.). Used at medium range and beyond the manufactures specified duration the device is capable of delivering sounds well beyond the human pain theshold (120 – 140 dB); at a distance of 90m the LRAD will cause intense pain and permanent hearing loss(2.)


(image: back of the LRAD)

The LRAD is basically a series of in-phase speakers (not a infra-sound generator as commonly supposed). The phasing of the sound (combined amplitude giving louder sound) gives the device the ability to project high frequency sounds over a long distance at high volume.To focus the sound the LRAD uses a set of out of phase speakers around the perimeter of the device to phase-cancel the sound giving a directional arc of 30 degrees. Fifteen degrees outside the beam, the volume drops about 20 dB which although still loud means that the operator can focus the LRAD to a specific target without being themselves affected.


  • Range: 300 meters over land or 500 meters (1640 feet) over water.
  • Beam width: About 30 degrees
  • Size: 33-inch diameter by 5-inch thickness
  • Weight: 45 lbs
  • Input: Microphone, laptop, MP3 player, CD player, ‘Phraselator’ translation device
  • Maximum Volume: 120 dB at 1 meter in normal operation, 146 dB sustained or 151 dB burst at 1 meter with override

(1.) The American Technology Corporation (ATCO)
(2.)Carl Gruenler, (former) vice president of military and government operations for American Technology Corp