From: Bill Kahn: "Silent Sound Kills" (Inside Sources, December 14 2017)
Infra-sound or low-frequency sound covers acoustic longitudinal waves below usual human hearing, at below 20 Hz or 20 cycles per second. Ultra-sound is usually above 20,000 Hz, although young girls and other young people can often hear at frequencies above this. Some animals can a wider range of frequencies than humans.
Each person reacts differently to the same sound waves. Only a single person may react to a given infrasound. Infra-sound has health effects similar to extremely low frequency electromagnetic radiation.
Sounds around 19 Hz matches the resonant frequency of the human eyeball, with reports of apparitions, according to the Coventry Telegraph newspaper.
The most dangerous frequency is at 7 Hz, the median alpha-rhythm frequencies of the brain. This is also the resonant frequency of the body’s organs. At high volumes, infrasound can directly affect the human central nervous system causing disorientation, anxiety, panic, bowel spasms, nausea, vomiting and eventually organ rupture, even death from prolonged exposure.
In 1957 Vladimir Gavreau was asked to cure a case of “Sick Building Syndrome.” Staff at a research plant in Marseilles were becoming ill. Gavreau traced the illnesses to fans in air-conditioning units generating low-frequency sound waves.
Gavreau experimented with low-frequency acoustic weapons for the French military. Several prototype designs, christened “canon sonique”, consisted 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 results. One of the team members died instantly, “his internal organs mashed into an amorphous jelly by the vibrations.” They turned it off quickly but, even so, others in nearby laboratories were sick for hours. Everything was vibrating: stomach, heart and lungs.
Walt Disney and his team of cartoonists slowed down a 60 Hz tone in a short cartoon to 12 Hz. They became sick for days afterwards, according to Daria Vaisman, a research editor at the New York Press.
A woman in a new condo was made sick by low-frequency sound from nearby water pumps. She moved elsewhere and the sickness left.
Pipe organs can produce low frequencies causing sensations of sorrow, coldness, anxiety and even shivers down the spine.
Typical sources of Infrasound include motors, pumps, and traffic. A tuba vibrates at 29 Hz, a bass at 27 Hz. Wind turbines and water pumps transmit infrasound miles away.
(Bill Kahn: "Silent Sound Kills" Inside Sources, December 14 2017)
NIEHS: "Infrasound Brief Review of Toxicological Literature" (2001)