The Sound of Spirits:
What is Infrasound and Why Should We Care About It?

“There is certainly a world beyond our normal consciousness from which neither space nor time divides us, but only the barrier of our sense-perceptions.... this threshold is not immovable.” ~William F. Barrett, 1918

That overwhelming feeling that you are being watched; the sensation that you are not alone although no one is in sight; that “6^th sense” that many of us have experienced at one point or another…It can cause the little hairs on our arms to stand up and our heart to beat just a little bit faster. The majority of people believe that there is a world unseen, a spiritual plane perhaps coexisting with our physical world. These feelings however, do not constitute evidence. That being said, they are also not to be ignored. These perceptions originate from something…some stimulus we cannot easily interpret. In a sense, if we cannot easily determine the origin, it may be considered “para normal’, that is, outside the normal experience. As a paranormal researcher, our jobs are to provide the physical evidence to validate these 6^th sense experiences. It is our responsibility to be well-informed of all the potential natural causes of haunted feelings.

Infrasound is sound frequency that is too low for the human ear to detect, falling below 20 hertz. Some natural causes of infrasound include earthquakes, avalanches, and waterfalls. Animals such as whales communicate via infrasound. Man-made producers of infrasound include explosions, diesel machinery, and wind turbines. Researchers who have studied infrasound posit that, although it is below our conscious perception, infrasound affects our bodies nonetheless. It can cause feelings of anxiety, dread, depression, and fear. At the right frequency it can impact our eyes, causing vibrations leading to distortions in vision and hallucinations or illusions.

So if we know that infrasound exists and that it is one potential cause of a haunting, why are we not measuring it? Measuring this low frequency requires highly specialized equipment, as readily-available sound sensors only measure in decibels and cannot account for the ultra-low frequency which constitutes infrasound. Instruments for measuring infrasound are few and far between and are typically quite expensive. However, TSPI is committed to providing the highest-quality investigations to our clients, and our ongoing desire to evaluate potential hauntings in a scientific manner will ensure that we search for a way to measure infrasound in the upcoming years.

Written by Laura Palmese

Investigator & Researcher

Thames Society of Paranormal Investigations (TSPI)