The 'Ghost in the Machine': How a 19 Hz Sound Wave Explained One Lab's Haunting
In 1998 engineer Vic Tandy published how an extractor fan's inaudible 19 Hz standing wave may have produced a 'ghost' in his lab. Here's what the paper actually says.
Science: research findings and proposed natural explanations
Lots of ghost stories involve a feeling of dread, a cold presence, or a gray shape at the edge of your vision. In 1998, two Coventry University researchers published a paper suggesting one possible natural cause: sound too low to hear.
The paper
The paper, "The Ghost in the Machine" (opens in a new tab) by Vic Tandy and Tony R. Lawrence, appeared in the Journal of the Society for Psychical Research in April 1998. The authors write that they wanted to outline "an as yet undocumented natural cause for some cases of ostensible haunting." They used Tandy's own experience in a lab as the example.
What happened in the lab
According to the paper, Tandy noticed that a foil blade clamped in a drill vice was vibrating on its own. By sliding it across the floor, he found that the vibration was strongest in the middle of the room. That pattern pointed to a low-frequency standing wave: sound reflecting back and forth between the walls so its energy peaks in one place. He calculated the frequency at about 19 Hz, below what most people can hear.
The source turned out to be ordinary. The works foreman told Tandy a new fan had been installed in the extraction system for a nearby cleaning room. "We switched off the fan and the standing wave went away," the paper says. In a later article for ProSoundWeb (opens in a new tab), Tandy wrote that turning the fan off also lifted the oppressive feeling in the room and "effectively exorcised the 'ghost'." According to the paper, the problem was fixed for good by changing how the fan was mounted.
Why it matters for ghost hunters
Tandy and Lawrence don't claim that all hauntings are infrasound. They suggest researchers rule it out first in haunting or poltergeist-type cases. The paper notes that low-frequency sound is hard to detect without the right equipment. It also says that because people's bodies resonate differently, a standing wave might affect one person and not another. Their advice: be "very wary of ghosts reported to haunt long, windy corridors," because long, enclosed spaces are ideal for standing waves.
Takeaway
This is one documented case with a proposed mechanism, not proof that every haunting has the same cause. It's a useful reminder to check the building before anything else.
Sources
- The Ghost in the Machine (Tandy & Lawrence), Journal of the Society for Psychical Research, Vol. 62, No. 851, April 1998 (opens in a new tab), Journal of the Society for Psychical Research (PDF copy hosted by SGHA), published 1998-04. Accessed 2026-11-02.
- Ghost Story: Low Frequency Illusions Created By Standing Waves? (opens in a new tab), ProSoundWeb (Vic Tandy). Accessed 2026-11-02.
This article is an original summary written from the sources above. Quotes are short and attributed. Paranormal claims are reported as claims and have not been independently verified. Spotted an error? See our contact page.
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