What do you think of this fact?
A lab where everyone feels uneasy. Cold shivers, a heavy feeling, and then something moves at the edge of your vision. British engineer Vic Tandy lived through exactly that. And instead of a ghost, he found a fan.
A shadow in the corner of his eye
In the early 1980s, Tandy worked in the research lab of a medical equipment company. His colleagues said the place was haunted. One evening, Tandy said he saw a dark figure out of the corner of his eye. When he turned his head, it was gone.
The next day Tandy, a keen fencer, was polishing his sword. Even clamped tight in a vice, the blade started vibrating all by itself. His suspicion: a standing sound wave was bouncing around the room, too low to hear.
The culprit was in the wall
According to Tandy, the source was a newly installed extractor fan. It produced infrasound at around 19 hertz, below what human ears consciously pick up. When the fan was finally switched off, Tandy said, “it was as if a huge weight was lifted.”
In 1998, Tandy and psychologist Tony Lawrence published the case as “The Ghost in the Machine” in the Journal of the Society for Psychical Research. Their idea: vibrations around 19 hertz could trigger unease and shivers, among other things. Tandy even suspected that this frequency can make the eyeball resonate, which would explain shadows in the corner of your eye.
One catch remains: the 19 hertz were calculated, not directly measured. The Psi Encyclopedia of the Society for Psychical Research points out this gap explicitly.
The concert with the invisible note
In 2003, a British team including psychologist Richard Wiseman tested the idea at a concert in London. Around 750 people listened to four pieces of music, some of them mixed with infrasound from a 7 meter long pipe. Nobody knew which ones.
The result: about 22 percent reported more unusual feelings during the infrasound pieces, such as unease, sorrow or chills down the spine.
Tandy later turned ghost hunter himself: in 2001 he investigated a supposedly haunted cellar in Coventry and found unusually high levels of infrasound there too.
Sometimes the creepiest thing in the room is just the ventilation system.