For awhile now researchers have thought that infrasonic sound could be the thing to explain the “feelings” of danger or fear that people get in random places.

Especially if many people experience the same feeling in a similar spot – like in places folks assume must be “haunted.”

This experiment proves that infrasonic sound – sound that is too low to be heart with the ear and is instead “felt” by our bodies – can induce those collective feelings in human beings.

It took place in 2003 and involved 750 volunteers who attended a fear and anxiety-inducing concert. Scientists from the National Physical Laboratory concocted concert where infrasound would be played beneath regular music, intent on gauging their responses.

Sarah Angliss is a composer and sound designer who worked on the project.

“For our experiment we wanted to establish if infrasound in music generated unusual psychological effects, even in listeners unaware of its presence.”

The were mostly focused on learning how the sound made people feel.

“Of particular interest were its reputed emotional effects. Infrasound is used in sacred music, for instance during cathedral organ recitals, and there is debate about why it’s used. Some people say it adds a sense of awe to the music – it puts a shiver down your spine. Others say that giant infrasonic organ pipes are nothing more than ‘an expensive way to make a draught.”

If you’re someone who believes in ghosts and haunted places, well, infrasound might explain those, too.

“Stranger still, infrasound has also been detected at some ostensibly haunted sites…where it may also be making people feel very uneasy.”

One example occurred when scientists working at a laboratory in Coventry, England started feeling depressed and uneasy, and even spotted “figures” on the periphery of their vision.

The problem was resolved when they switched off a new extractor fan that was creating infrasound.

For the concert experiment, the team played sound at 17.5 Hertz (Hz), which is just beyond human hearing. They used a 23-foot pipe at a London concert hall.

The infrasound was only played during some of the pieces and the audience wasn’t privvy to which ones. Twenty-two percent of participants reported strange effects during pieces that employed infrasound – feelings of sorrow, chills, unease, and feelings of revulsion and fear.

“These results suggest that low frequency sound can cause people to have unusual experiences even though they cannot consciously detect infrasound.”

It’s worth noting that not all hauntings can be explained by infrasound, and people can get that uneasy feeling of fear for other reasons, too.

But the effects of infrasound on humans is interesting, for sure.

I’m ready to learn more about it.

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