The Fear Frequency: How Sonic Weapons and Infrasound Affect Human Biology | Havana Syndrome Explained
The quest to understand unexplained phenomena has led scientists to fascinating discoveries about sound and its effects on the human body. In the early 1980s, a British engineer named Vic Tandy had a ghostly encounter while working late in his lab at Warwick. After experiencing intense fear, seeing a gray figure, and noticing his fencing foil vibrating without being touched, Tandy investigated the cause. His research revealed that a newly installed fan was creating infrasound waves at approximately 19 hertz—just below human hearing range but capable of causing physical and psychological effects.
This discovery opened doors to understanding how sound affects us beyond our awareness. Infrasound at certain frequencies can resonate with human organs and eyes, creating visual distortions and triggering fear responses. Similar frequencies appear in nature, such as in tiger roars before attacks. More extreme low-frequency sounds have been studied for their potential physiological impacts, from the infamous "brown note" to the documented health complaints from people living near wind farms. Research continues to explore both the accidental and intentional applications of sound's powerful effects on human biology.
Key Takeaways
Infrasound below 20 hertz can cause physical symptoms, visual distortions, and feelings of fear without being audible to humans.
Low-frequency sound waves can resonate with human organs and tissues, potentially causing effects ranging from discomfort to severe health impacts.
Sound has been researched extensively for its capacity to affect human physiology, leading to applications in various fields including military development.
Vic Tandy and the Haunted Lab
Vic Tandy, a medical equipment designer at Warwick Labs in the UK during the early 1980s, experienced something extraordinary that led to a scientific discovery. While working late one night, he suddenly felt a sense of dread wash over him. The hairs on his neck stood up, he broke into a cold sweat, and he had the distinct feeling of being watched.
To his horror, he glimpsed a gray figure drifting across the room that vanished when he turned to look directly at it. Terrified, Tandy fled the building. Rather than accepting supernatural explanations, he returned the next day determined to find a scientific reason for his experience.
The breakthrough came when Tandy noticed his fencing foil, locked in a vice, was vibrating without being touched. Further investigation revealed that a recently installed fan was creating a standing wave in the room at approximately 19 hertz - just below the threshold of human hearing. This infrasound was concentrated precisely where Tandy had been standing during his ghostly encounter.
At 19 hertz, the human eye naturally resonates, causing visual distortions that might appear as spectral figures. This frequency also triggers physical responses in humans including anxiety and fear. When the fan was switched off, staff reported feeling as if a weight had been lifted from them.
This "fear frequency" appears elsewhere in nature. Tigers produce roars containing 18 hertz frequencies right before attacking, potentially disorienting prey. Filmmakers have also incorporated these near-infrasonic sounds to create underlying unease in horror movies.
Lower frequencies can cause even more pronounced effects on the human body. The infamous "brown note," theoretically between 5-9 hertz, was once thought to cause involuntary bowel movements, though this remains unproven despite testing on shows like Mythbusters.
More serious effects occur at specific frequencies. At around 7 hertz - the median alpha rhythm of the brain and resonant frequency of many organs - high volume exposure can cause panic, convulsions, and with sufficient duration, organ damage or death. This understanding has led to research into infrasonic weapons.
French scientist Vladimir Gavrow pioneered such weapons after discovering that low-frequency sounds from air conditioning units were causing illness in a Marseille research facility. His military prototypes reportedly produced devastating effects, with test subjects experiencing violent internal organ vibrations.
Ultrasound (above human hearing range) presents different dangers, capable of heating human cells and causing tissue cavitation - the formation of bubbles in tissue similar to decompression sickness in divers. These properties have made sonic technologies effective for military and security applications.
Exploring Infrasonic Phenomena
Vic Tandy's Laboratory Experience
In the early 1980s, Vic Tandy was working at Warwick Labs in the UK designing medical equipment when he encountered something unusual. While working late one night, he experienced a series of disturbing physical sensations—the hair on his neck stood up, he broke into a cold sweat, and felt an overwhelming sense of dread. Most alarmingly, he glimpsed a gray figure drifting across the room that disappeared when he turned to look directly at it. Rather than accepting supernatural explanations, Tandy was determined to find a scientific explanation for his experience.
The next day, Tandy noticed something peculiar in his laboratory. His fencing foil, which was secured in a vice, was vibrating rapidly despite nothing touching it. This unexpected observation became the first clue in solving the mystery.
Acoustic Wave Analysis
Tandy's investigation revealed that a recently installed fan was creating sound waves that bounced between the walls of the laboratory. These waves concentrated their intensity in the center of the room—precisely where Tandy had been standing when he saw the "ghost." Through careful calculation, he determined the sound frequency was approximately 19 hertz.
This finding was significant because 19 hertz falls just below the threshold of human hearing, which begins at 20 hertz. Such sounds, called infrasound, cannot be heard but can produce physical effects. The principle of sympathetic resonance explains how objects vibrate when exposed to their natural resonant frequency, similar to how:
A piano key struck in one room can cause the same note to vibrate on a piano in another room
Running a finger around a glass rim at the right speed produces sound
The 19 Hz Effect
The most remarkable aspect of Tandy's discovery involved the human eye's natural resonance at approximately 19 hertz. When exposed to this frequency, his eyes physically vibrated, creating the illusion of a ghostly figure in his peripheral vision. Additionally, this frequency triggered physiological responses including:
Feelings of fear and anxiety
Sense of being watched
Physical discomfort
When the fan was switched off, staff reported feeling as if "a huge weight was lifted." This frequency has since been nicknamed the "fear frequency" due to its effects on mammals. Interestingly, researchers have discovered that tiger roars contain frequencies around 18 hertz, potentially disorienting prey before an attack.
The film industry has utilized this knowledge by incorporating sounds at or just above this frequency range to enhance the psychological impact of horror movies.
Physical Impact of Sound Waves Below Hearing Threshold
Human Responses to Low-Frequency Vibrations
The human body can react strongly to vibrations around 19 Hz, even though these frequencies fall just below our hearing threshold. In the early 1980s, a fascinating case occurred at Warwick Labs in the UK where staff reported ghostly experiences. Medical equipment designer Vic Tandy investigated after his own terrifying encounter—feeling watched, experiencing dread, and seeing a gray figure. He discovered these phenomena were caused by a newly installed fan generating vibrations at approximately 19 Hz.
This frequency is significant because it causes human eyeballs to vibrate through sympathetic resonance. When our eyes vibrate, peripheral vision distortions can create the impression of shadowy figures. The human body experiences other effects at this frequency:
Physical symptoms: Cold sweats, racing heart
Emotional responses: Anxiety, dread, fear
Sensory disturbances: Visual anomalies, feeling of being watched
Research shows exposure to these frequencies can induce significant discomfort. When the source is removed, people typically report immediate relief, as Tandy described it: "like a huge weight was lifted."
Animal Use of Infrasound
Animals have evolved to utilize infrasound for various purposes, with some predators weaponizing these frequencies. Tigers, for example, incorporate 18 Hz frequencies into their roars just before attacking prey. These low frequencies can temporarily disorient potential victims, creating a crucial advantage for the predator.
Many animals use infrasound for:
Animal Infrasound Purpose Elephants Long-distance communication Whales Ocean navigation and communication Tigers Prey disorientation Pigeons Navigation during migration
The effectiveness of these frequencies in the animal kingdom helps explain why humans find them so disturbing. Our nervous systems may retain ancient warning mechanisms that trigger fear responses when exposed to these sounds, explaining why 18 Hz has earned the nickname "the fear frequency" among researchers.
Infrasound in Cinema
Filmmakers have discovered the power of infrasound to enhance audience fear responses. Many horror films incorporate frequencies at or slightly above the "fear frequency" (18-20 Hz) to create a sense of dread and anxiety in viewers. These sounds work subconsciously, making scenes feel more threatening without audiences understanding why.
Sound designers achieve this effect through:
Carefully engineered soundtracks that include subsonic elements
Theater sound systems capable of reproducing these low frequencies
Strategic placement of these sounds during particularly tense moments
The technique works because these frequencies physically affect viewers. While audience members can't consciously hear these sounds, their bodies respond with the same anxiety and unease that Vic Tandy experienced in his laboratory. This physical reaction amplifies the emotional impact of frightening scenes, making the viewing experience more immersive and unsettling.
The Extraordinary Sound Phenomenon
MythBusters' Sound Experiments
Low-frequency sound has long fascinated researchers and paranormal investigators alike. When Adam Savage tackled this phenomenon on MythBusters, he famously subjected himself to an extreme test. Positioning himself amid massive speakers, he experienced direct exposure to frequencies between 5-9 Hz, the alleged "bowel-disrupting" range.
Despite wearing protective gear (including adult diapers), Savage reported discomfort but no loss of bodily control. The test demonstrated how air proves an inefficient conductor for these frequencies, potentially explaining the inconclusive results.
This experiment highlighted a crucial scientific principle: sound transmission method significantly impacts biological effects. Direct bodily contact with vibrating surfaces produces much stronger reactions than airborne sound waves alone.
Space Agency's Vibration Research
Government space programs conducted more intensive investigations using advanced methodologies. Their research involved direct vibration transfer through specialized seating at frequencies from 0.5 Hz to 40 Hz at extraordinary power levels reaching 160 decibels—far exceeding everyday noise exposures like chainsaws (130 dB) or firearms (140 dB).
Test participants experienced severe symptoms including:
Nausea and disorientation
Visual hallucinations
Respiratory difficulties
Involuntary muscle movements
These findings potentially explain the origins of certain urban legends about sound effects. The research demonstrated how frequencies around 7 Hz—which coincidentally match the brain's alpha rhythms—can particularly affect humans by resonating with internal organs.
When French scientist Vladimir Gavreau investigated mysterious illnesses at a Marseille research facility in the late 1950s, he traced the cause to air conditioning units generating low-frequency vibrations. This discovery prompted further sonic weapons research with reportedly devastating effects during testing, including severe internal damage to researchers exposed to prototype devices.
Wind Turbine Health Effects and Research
Physical Symptoms and Reported Cases
Wind farms have generated health concerns for approximately 20% of nearby residents. These individuals report a range of negative symptoms from concentration difficulties to extreme stress and debilitating migraines. In one notable case, an air traffic controller nearly caused a catastrophic plane accident due to insomnia allegedly resulting from living near wind turbines.
The physical responses can be quite serious. Some people experience sleep disturbances, heightened anxiety, and persistent headaches that significantly impact their quality of life. These symptoms often appear shortly after wind farms begin operation in their vicinity.
Research on Acoustic Impact and Well-being
Approximately 20 scientific studies have investigated wind farms and health effects, yet found no conclusive link between turbines and illness. However, questions remain about potential conflicts of interest in some research funding sources.
What we do know with certainty is that chronic noise exposure correlates with increased stress levels. People living and working in consistently noisy environments show elevated cortisol levels compared to those in quieter settings. This physiological response may explain some reported symptoms.
Sound below human hearing thresholds (infrasound) may play a role in these effects. The human eye resonates at approximately 19 hertz, potentially causing visual disturbances, while frequencies around 7 hertz can affect brain rhythms and organ function. At sufficient volumes, these sounds could theoretically trigger panic, convulsions, and even organ damage with prolonged exposure.
Human Noise Perception and Effects:
Frequency Range Classification Potential Effects Below 20 Hz Infrasound Anxiety, visual disturbances, resonance with organs 20-20,000 Hz Audible sound Stress, sleep disturbance if chronic Above 20,000 Hz Ultrasound Tissue heating, cellular cavitation
The scientific community continues to investigate these phenomena to better understand the relationship between wind turbines and human health.
Sound as a Weapon
Infrasound's Destructive Potential
Infrasound – frequencies below 20 Hz that humans cannot hear – can have profound physical and psychological effects on the body. The story of Vic Tandy illustrates this perfectly. While working late at Warwick Labs in the UK during the early 1980s, Tandy experienced inexplicable dread, cold sweats, and even witnessed a ghostly figure. The culprit? A fan generating 19 Hz sound waves bouncing between walls, creating a focused wave at the center of the room.
This frequency is significant because it's just below human hearing threshold but can cause physical reactions. At 19 Hz, human eyes can vibrate through sympathetic resonance, potentially creating visual distortions. This "fear frequency" has been incorporated into horror films to heighten viewer anxiety.
Lower frequencies produce even more severe effects. Between 5-9 Hz lies the theoretical "brown note" – a frequency supposedly capable of causing involuntary bowel movements. While Mythbusters attempted to debunk this, more rigorous testing by the US space program used vibrating cockpit chairs at 160 decibels across frequencies from 0.5-40 Hz, producing symptoms including nausea, hallucinations, and breathing difficulties.
Vladimir Gavreau's Infrasound Weapon
In 1957, French scientist Vladimir Gavreau began investigating infrasonic weapons after identifying low-frequency sounds from air conditioning units as the cause of mysterious illnesses at a Marseille research facility. This discovery prompted him to develop acoustic weapons for the French military.
Gavreau's experiments with infrasound had devastating consequences. According to reports, one researcher died instantly after exposure, with internal organs reportedly reduced to "an amorphous jelly" by the vibrations. Even researchers in nearby laboratories experienced severe symptoms lasting hours, describing sensations of their entire bodies vibrating uncontrollably.
The most dangerous frequencies Gavreau identified were around 7 Hz – coinciding with the brain's median alpha rhythm and the resonant frequency of many human organs. At sufficient volume, these frequencies can:
Trigger panic attacks
Cause convulsions
Induce severe vomiting
Lead to organ rupture with extended exposure
Potentially result in death
Gavreau's work demonstrated that completely inaudible sounds could be weaponized with lethal efficiency.
Ultrasound Applications and Dangers
While infrasound involves frequencies below human hearing, ultrasound operates above our audible range and presents its own dangers. Ultrasound damages the body through two primary mechanisms:
Thermal effects: Sound waves can heat human cells, causing tissue damage
Cavitation: The rapid compression and refraction of sound waves creates tiny bubbles in tissue, similar to decompression sickness experienced by divers
Ultrasound Effects Description Comparison Thermal damage Sound waves heat cellular tissue Similar to microwave radiation effects Cavitation Creates bubbles in tissue through pressure changes Comparable to "the bends" in diving accidents Practical applications Effective deterrent against pirates Deployed by US Navy
The effectiveness of ultrasound as a deterrent has been proven in practical applications, with the US Navy employing ultrasonic devices to repel pirates from vessels in high-risk waters.
Military Use of Sonic Weapons
Both infrasound and ultrasound have been developed into military applications. The documented health effects of sonic exposure make these technologies particularly appealing for crowd control and area denial.
Studies on people living near wind turbine farms provide insight into how chronic exposure to specific sound frequencies affects human health. Approximately 20% of residents report symptoms ranging from concentration problems to debilitating migraines and insomnia. In one alarming case, an air traffic controller reportedly nearly caused a fatal accident due to sleep deprivation attributed to nearby wind turbines.
Military sonic weapons capitalize on these effects, deliberately generating frequencies that:
Disrupt cognitive function
Induce disorientation
Cause physical discomfort
Create panic in target populations
These weapons offer several tactical advantages – they're non-lethal at lower intensities, leave no physical evidence, and can affect large areas simultaneously. The invisibility of sound waves makes them particularly effective psychological weapons, as targets may not immediately understand what's causing their symptoms.
