By Dr. Joel Ramsey, The Paranormal Professor

For centuries, people have described feelings of unease in certain locations. A chilling sensation. The sense of a presence nearby. Shadows moving at the edge of vision, or a strange ripple effect, as if the air itself is vibrating. These experiences are real. The people who report them are not imagining things, and they are not foolish for taking them seriously.

What I've learned over fifteen years of evidence-based paranormal investigation is that understanding why these experiences happen doesn't diminish them. It deepens them. And one of the most fascinating explanations I've encountered in the field has nothing to do with spirits at all.

It has to do with sound we can't hear.

What Is Infrasound?

Infrasound refers to sound waves with frequencies below 20 Hz, lower than the threshold of human hearing. We can't consciously detect these vibrations, but our bodies respond to them in ways that are measurable, documented, and deeply relevant to paranormal investigation.

Infrasound is generated by both natural and human-made sources. On the natural side: wind moving through valleys or around buildings, seismic activity, ocean waves, and even large animal vocalizations like those of elephants and whales. On the human-made side: HVAC systems and ventilation ducts, heavy traffic, industrial machinery, building resonance, and plumbing and drainage systems.

That last one matters more than most people realize. I'll come back to it.

The Vic Tandy Discovery

The scientific link between infrasound and reported hauntings was established in 1998 by British engineer Vic Tandy, and his story is worth telling in full because it illustrates exactly how rigorous investigation works.

Tandy was working late one night in a laboratory that had developed a reputation for being haunted. Staff reported feelings of unease, cold sensations, and visual apparitions, a gray, shadowy figure appearing at the edge of vision. That night, Tandy experienced it himself. He felt a sudden, oppressive dread. His chest tightened. And in his peripheral vision, he saw a gray, translucent figure slowly materializing beside him.

He turned to face it directly. It vanished.

Most people would have left the building. Tandy, being an engineer, decided to investigate.

The following day, he brought a fencing foil into the laboratory and left it clamped in a vice. When he returned, the foil was vibrating wildly, oscillating back and forth with no visible force acting on it. Using scientific instruments, he discovered a 19 Hz standing wave in the room. The source was a newly installed ventilation fan creating low-frequency sound waves that bounced off the walls and created a resonance pattern.

19 Hz is significant because it falls close to the resonant frequency of the human eyeball. When the eyeball vibrates at this frequency, it produces visual distortions: shadows moving in peripheral vision, translucent shapes, the unsettling sense that something is present but not quite visible.

Tandy had the fan modified. The infrasound stopped. And so did the experiences.

How Infrasound Affects the Human Body

Research since Tandy's discovery has confirmed what paranormal investigators had long observed: certain locations consistently produce unease, anxiety, or the sense of being watched, and those locations often have elevated infrasound levels.

At frequencies between 18 and 20 Hz, infrasound causes eyeball vibration, producing peripheral shadows, ripple effects in vision, and the appearance of translucent figures. Below 20 Hz more broadly, it activates the body's fight-or-flight response, creating unexplained fear, chest pressure, and difficulty breathing. In the 5 to 10 Hz range, it disrupts inner ear balance, causing dizziness and the feeling that a space is simply wrong. And at various low frequencies, vibrations affect the vestibular system in ways that produce the perception of a nearby presence, the sense of being watched by something that isn't visible.

These are not supernatural effects. They are physiological responses to environmental stimuli we cannot consciously perceive. And they feel absolutely real to the people experiencing them, because they are.

Phase 2 of RCIP: Testing for Infrasound in the Field

In my Ramsey Communication-Based Investigation Protocol, Phase 2 requires systematically establishing an environmental baseline before drawing any conclusions about a reported experience. Infrasound testing is a critical part of that baseline.

I use a professional-grade condenser microphone capable of capturing frequencies below 20 Hz, connected to audio recording software with spectral analysis capability. Most consumer-grade equipment filters out low frequencies automatically, which means standard ghost hunting tools will never detect this particular variable. During investigations, I set up the microphone in locations where phenomena are reported, record continuously for extended periods, analyze the recordings for frequency patterns, and correlate any infrasound spikes with the experiences witnesses have described.

If consistent infrasound is present, the next step is identifying its source.

Case Study: The War History Museum Basement

A group of paranormal investigators contacted me about a local war history museum. They had been conducting regular investigations there and were convinced the basement was haunted.

What they reported was consistent and compelling. A pervasive feeling of unease whenever they entered the space. One investigator repeatedly experienced a ripple effect in their vision, almost as if the air itself was vibrating. The sensations intensified near specific areas of the basement. Traditional equipment, EMF detectors and spirit boxes, produced no significant results.

They wanted me to investigate and help them understand what they were experiencing.

I brought my professional recording equipment and set it up to capture audio across multiple floors, spending extended time in the basement where the phenomena were most concentrated. I didn't tell the team what I was specifically testing for. I wanted their observations to remain uninfluenced by my hypothesis.

What the recordings revealed was striking. There were consistent infrasound spikes in the basement, and they correlated directly with bathroom use on the upper floors. Every time someone used a toilet or ran water in the sinks upstairs, the vertical drainage pipes, which converged in the basement before exiting to the municipal sewer system, produced low-frequency vibrations as water rushed through them. The basement amplified these vibrations. The older metal pipes were acting as resonance chambers, creating standing waves of infrasound at approximately 18 to 19 Hz, precisely the frequency range associated with eyeball vibration and visual distortions.

The experiences the investigators had been reporting were real. The cause was the building's plumbing system.

Presenting the Findings

When I gathered the team and walked them through the spectral analysis, showing the direct correlation between bathroom use and infrasound spikes, the responses were varied, and I want to be honest about that because it reflects something important about this work.

Some members of the team were immediately engaged. They asked thoughtful questions about frequency, resonance, and what this might mean for other locations they had investigated. They left with a new tool and a deeper understanding of how physical environments shape human experience.

Others were not ready to accept the findings. They had felt something real in that basement, something that mattered to them, and an explanation involving drainage pipes didn't feel adequate to the weight of what they had experienced.

I understand that response. I genuinely do. The experiences they had were real. The unease, the visual distortions, the sense of presence, none of that was fabricated. And when something feels that significant, it can be deeply unsatisfying to hear that pipes caused it.

What I try to communicate in those moments is this: identifying the source of an experience is not the same as dismissing it. Understanding that infrasound produced those sensations doesn't erase them. It explains them. And that explanation is actually more remarkable than a ghost, because it reveals how profoundly the physical environment shapes human perception in ways we can't consciously detect.

Why This Matters

I apply rigorous methodology in my investigations because I believe that if genuinely unexplained phenomena exist, we will only find them by ruling out everything explainable first. Every location declared haunted because of bad plumbing or a poorly ventilated HVAC system makes it harder to take seriously the cases where no environmental explanation can be found.

This isn't about proving ghosts don't exist. It's about doing the work carefully enough that when something genuinely resists explanation, we can say so with confidence.

The investigators at that museum were not wrong to trust their experiences. They were right to take them seriously and to seek out someone who would investigate with rigor. What I hope they took away was not disappointment, but a more complete picture of how human beings experience the world, and a methodology they can carry into every investigation that follows.

How to Test for Infrasound in Your Own Investigations

If you conduct paranormal investigations, incorporating infrasound testing will strengthen your work considerably.

You'll need a professional-grade condenser microphone such as the RODE NT1 or a comparable model, an audio interface like the Focusrite Scarlett series, and recording software capable of spectral analysis. Audacity is free and works well for this purpose.

Set up your microphone in locations where phenomena are reported and record continuously for thirty to sixty minutes. Analyze the recordings by examining the frequency spectrum for activity below 20 Hz. Correlate any spikes with the timestamps of reported experiences. Then identify likely sources: HVAC systems, plumbing, nearby traffic, structural resonance, or the dimensions of the room itself.

Common sources worth checking include ventilation systems, older metal plumbing and drainage pipes, buildings near busy roads or rail lines, and long hallways or rooms with specific dimensional ratios that can create standing waves.

If you find consistent infrasound, you've found a significant variable. Whether it accounts for everything reported at that location is a separate question, and one worth continuing to investigate.

The Deeper Lesson

Infrasound is real. Its effects on the human body are documented. And it is responsible for a meaningful number of experiences that get classified as paranormal without any further investigation.

That doesn't mean every reported haunting has a physical explanation. It means we owe it to the people who trust us with their experiences to look carefully before we conclude.

What I've found, over and over again, is that rigorous investigation doesn't make paranormal experiences less meaningful. It makes the genuinely unexplained ones more credible. And it gives the people who come to me something more valuable than a ghost story: an honest account of what happened to them, and why.

That is what evidence-based investigation is for.

Dr. Joel Ramsey is a paranormal research scientist and certified investigator with a Ph.D. in Communication from Regent University. He applies the Ramsey Communication-Based Investigation Protocol (RCIP) to unexplained phenomena and has been conducting evidence-based investigations since 2010. For investigation inquiries or speaking engagements, contact him at paranormalprofessor@yahoo.com.