Infrasound arrays at monitoring station in Qaanaaq, Greenland.
Infrasound, sometimes referred to as low frequency sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz, as defined by the ANSI/ASA S1.1-2013 standard).[1] Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. Although the ear is the primary organ for sensing low sound, at higher intensities it is possible to feel infrasound vibrations in various parts of the body.
The study of such sound waves is sometimes referred to as infrasonics, covering sounds beneath 20 Hz down to 0.1 Hz (and rarely to 0.001 Hz). People use this frequency range for monitoring earthquakes and volcanoes, charting rock and petroleum formations below the earth, and also in ballistocardiography and seismocardiography to study the mechanics of the human cardiovascular system.
Infrasound is characterized by an ability to get around obstacles with little dissipation. In music, acoustic waveguide methods, such as a large pipe organ or, for reproduction, exotic loudspeaker designs such as transmission line, rotary woofer, or traditional subwoofer designs can produce low-frequency sounds, including near-infrasound. Subwoofers designed to produce infrasound are capable of sound reproduction an octave or more below that of most commercially available subwoofers, and are often about 10 times the size.[citation needed]
^"A Study of Low Frequency Noise and Infrasound from Wind Turbines" (PDF). Ia.cpuc.ca.gov. Retrieved 12 March 2022.
Infrasound, sometimes referred to as low frequency sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20...
Infrasound is sound at frequencies lower than the low frequency end of human hearing threshold at 20 Hz. It is known, however, that humans can perceive...
ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges. Sound is defined...
including animal attacks, hypothermia, an avalanche, katabatic winds, infrasound-induced panic, military involvement, or some combination of these factors...
detect a nuclear detonation, these include seismic, hydroacoustic, and infrasound detection, air sampling, and satellites. They have their own weaknesses...
increase intelligibility by condensing them and raising the frequency from infrasound to a more audible and reproducible range. The following unidentified sounds...
the pitch, as in the low-pitched roars of big cats. The production of infrasound is possible in some mammals such as the African elephant (Loxodonta spp...
a newly-installed extractor fan, found by Tandy, that was generating infrasound of 18.9 Hz, 0.3 Hz, and 9 Hz. A long-range acoustic device (LRAD) produces...
with electronic brains to help him sabotage the SST1 project by means of infrasound (sound waves with too low frequency to be detected by the human ear) which...
engineer. He was known best for his research into the relationship between infrasound and ghostly apparitions. During 2001 Tandy was asked to investigate the...
blast yield of 400–500 kilotons of TNT (about 1.4–1.8 PJ), estimated from infrasound and seismic measurements. This was 26 to 33 times as much energy as that...
call. Males move their feathers to produce a low-frequency sonation (infrasound) and sonate more frequently in response to a sonation by other males....
addition to the detection signaling circuit. The infrasound detector works by detecting infrasound, or sound waves at frequencies below 20 hertz. Sounds...
supposed sightings. Richard Lord and Richard Wiseman have concluded that infrasound can cause humans to experience bizarre feelings in a room, such as anxiety...
2014 Central Atlantic Ocean infrasound 2–4 m (6.6–13.1 ft) 2018 LA June 2, 2018 Botswana/South Africa border visual, infrasound, meteorite recovery 2 m (6...
genre conventions. In a study by Medes et al., prolonged exposure to infrasound and low-frequency noise (<500 Hz) in long durations has an effect on vocal...
can hear sounds between 20 Hz and 16000 Hz. The range of ultrasound, infrasound and other physical vibrations such as molecular and atomic vibrations...
wild. They communicate by touch, sight, smell, and sound; elephants use infrasound and seismic communication over long distances. Elephant intelligence has...
the US Geological Survey suggests that homing pigeons use low-frequency infrasound to navigate. Sound waves as low as 0.1 Hz have been observed to disrupt...
bellows of male American alligators are accompanied by powerful blasts of infrasound. Another form of male display is a loud head-slap. In 2010, on spring...
are often not audible but still subliminally detected by humans (see: Infrasound). Typical subwoofers using moving cones do not transmit energy very well...
considered. Microbaroms are a form of persistent low-level atmospheric infrasound, generally between 0.1 and 0.5 Hz, that may be detected as coherent energy...
declare territory, and locate suitable mates. Male American alligators use infrasound to attract females. Eggs are laid in a nest of vegetation, sticks, leaves...
organisms, such as elephants, can register frequencies between 0 and 20 Hz (infrasound), and others, such as bats, can recognize frequencies above 20,000 Hz...
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