Updated: Apr 27
In 2003 a group of researchers from the UK held an experiment with 700 people. They held two concerts. One concert was untouched and the other had a 17Hz infrasound wave generated throughout the concert.
The first group praised the musicians while the second group, exposed to the 17Hz infrasound, reported feeling uneasy, fearful, and sorrowful. Similar experiments have been done with similar results. It has been concluded that infrasound does affect our biology.
Infrasound is any sound below 20Hz, below human hearing. It is believed animals can hear infrasound and react to it. Natural disasters cause infrasound as an early warning system. Often animals will flee an area hours before the actual disaster strikes.
Alpha predators can generate infrasound to disorient their prey. A tiger’s roar contains frequencies around 18Hz. A Grizzly bear is another example of a roar that generates infrasound.
Professor Richard Wiseman of the University of Hertfordshire said “These results (concert) suggest that low-frequency sound can cause people to have unusual experiences even though they cannot consciously detect infrasound. Some scientists have suggested that this level of sound may be present at some allegedly haunted sites and so cause people to have odd sensations they attribute to a ghost, our findings support these ideas.”
Vic Tandy wrote a paper in 1998 called “Ghost in the Machine” for the Journal of the Society for Psychical Research & Paranormal Investigation. The research states that an infrasonic signal of 19Hz might be responsible for some ghost sightings. He experienced anxiety and seeing a dark grey blob in his laboratory. Later he was working with a foil held tight by a vice. The foil began to vibrate, while nothing around it could be attributed to the vibration. Diving into this phenomena Tandy discovered the exhaust fan in the lab was emitting a frequency of 18.98 Hz. This is remarkably close to the resonant frequency of the eye (American Air Force, 19 Hz). Tandy speculated the grey blob was an optical illusion caused by his eyeballs resonating to the frequency from the exhaust fan. The foil vibrated due to a standing wave in the room.
NASA did a lot of research on infrasound. They found at a high intensity (160dB) .5 Hz to 20 Hz would cause several physiological effects, ranging from nausea, impeded communication to visual hallucinations.
Infrasound may be a contributing factor to ghost sightings, but it does not explain all sightings or ghostly happenings. Disembodied voices, objects moving, and strange electrical phenomena are just a few items not explained by infrasound.