Taos Hum Hearers & Acoustics Experts - Experiences & Testing
The Hum: a low-frequency sound heard in dozens of cities worldwide that only 2% of people can perceive. Some cases have been traced to industrial sources. Others — including the original Taos Hum that prompted a federal investigation — remain unexplained after 30+ years.
In the early 1990s, residents of Taos, New Mexico, started complaining about a low-frequency humming sound that wouldn't stop. It was there when they went to bed and there when they woke up — a steady, throbbing drone, like a diesel engine idling somewhere over the horizon. It was louder at night, louder indoors, and impossible to locate. Not everyone could hear it. Roughly 2 percent of the Taos population reported the sound. The other 98 percent heard nothing.
The complaints were persistent enough that Congress funded an investigation. A team from Los Alamos National Laboratory, Sandia National Laboratories, and the University of New Mexico deployed specialized acoustic equipment tuned to frequencies between 8 and 80 hertz — the range where sound registers more as vibration than tone. They found that the hearers were telling the truth: something was being perceived, each person at a slightly different frequency between 32 and 80 hertz. They could not identify a source. The investigation ended inconclusively. The sound did not.
The Taos Hum was not the first and was nowhere close to the last. The case files share a strange common profile across decades and continents: a low-frequency drone, typically between 30 and 80 hertz, heard indoors more than outdoors, worse at night, worse in quiet environments, perceived by a small minority of the population while the majority hears nothing at all.
The documented cases
Bristol, England, reported a persistent thrumming in the 1970s — about 800 people heard it. It was tentatively blamed on vehicular traffic and factories running 24-hour shifts but never definitively explained, and the reports eventually faded. A 1973 university study of 50 Bristol Hum complainants found the sound always peaked between 30 and 40 hertz, was heard only during cool weather with a light breeze, and was more common in early morning. Researcher Philip Dickinson suggested at an Institute of Biology conference that year that the sound could result from the jet stream shearing against slower-moving air, possibly amplified by power line structures or by rooms with corresponding resonant frequencies. Another acoustics researcher dismissed his hypothesis as "absolute nonsense." The case was never closed.
Windsor, Ontario, erupted in late 2011 with a low droning vibration loud enough to provoke 22,000 reports to officials in a single evening in 2012. Kokomo, Indiana. Largs, Scotland. Auckland, New Zealand. Bondi, Australia. Frankfurt and Darmstadt, Germany. San Francisco's Sunset District, where residents reported it as recently as 2024. Kerry County, Ireland. The Hum has been documented on every inhabited continent.
The cases that got solved
The Windsor Hum was traced, with reasonable confidence, to Zug Island — a heavily industrialized section of River Rouge, Michigan, across the Detroit River from Windsor. Canadian officials identified the area as the likely source, but jurisdictional politics complicated the investigation: local authorities couldn't access the island, and U.S. Steel, which operated a steel mill there, said no new equipment had been installed around the time the noise became noticeable. The resolution came accidentally. When the blast furnaces were deactivated in April 2020 during the pandemic shutdowns, the Hum stopped. When operations resumed, the Hum returned.
In Darmstadt, Germany, investigators in 2022 identified multiple sources: two faulty air conditioner units, a faulty heat pump, and three structural noise protection measures on energy generation plants that were themselves producing low-frequency noise. In Kokomo, industrial fans were implicated, though some reports persisted after the fans were addressed.
These solved cases share a common mechanism. Industrial equipment generates low-frequency noise that propagates through the ground or air and is amplified by the resonant properties of certain buildings. A room with the right dimensions can amplify a faint 40-hertz signal into something perceptible — the way a wine glass vibrates when you hit the right frequency. Low-frequency sound penetrates walls more effectively than higher frequencies, which explains why the Hum is louder indoors. It's louder at night because ambient noise drops, unmasking sounds that were always present but drowned out during the day. It's louder in suburban and rural environments than in cities for the same reason: less background noise.
The cases that didn't get solved
The Taos Hum investigation found no industrial source. The full federal investigation team — Los Alamos, Sandia, University of New Mexico, with custom-built acoustic instrumentation — could not identify any external generator that explained the reports. The Bristol Hum was never definitively explained. Auckland researchers found some low-frequency sources, silenced them, and the complaints continued. The Hum in Kerry County, Ireland, was investigated and remains unexplained.
The pattern — some cases explained by identifiable mechanical sources, others remaining stubbornly unresolved — suggests that "the Hum" is not a single phenomenon. It's a symptom that can have multiple causes, some of which are industrial, some of which may be biological, and some of which haven't been identified.
The biology of hearing things that aren't there (or are)
The human ear is not a passive microphone. It generates its own sounds — called spontaneous otoacoustic emissions — produced by the motion of the outer hair cells in the cochlea. Studies show that 38 to 60 percent of adults with normal hearing produce these emissions, though most people are unaware of them. In quiet environments, some individuals perceive their own otoacoustic emissions as a faint hissing, buzzing, or humming. The Taos investigation considered this as a possible explanation: the Hum might not be coming from outside the ear but from inside it.
This hypothesis explains some features of the phenomenon — why only a small percentage of people hear it, why it's worse in quiet environments, why earplugs sometimes make it louder rather than softer (blocking external noise unmasks the internal signal) — but it doesn't explain the geographic clustering. If the Hum were purely a biological artifact, it should be distributed randomly across the population, not concentrated in specific towns during specific time periods. The geographic pattern suggests an external stimulus, even if the perception of that stimulus is mediated by individual differences in auditory sensitivity.
Low-frequency tinnitus is another biological candidate. Tinnitus typically manifests as high-pitched ringing, but a subset of cases involve low-frequency perception in the range of the Hum. Some researchers have proposed that the Hum represents a form of tinnitus that is triggered or modulated by environmental low-frequency noise too faint for most people to perceive but sufficient to activate auditory responses in sensitized individuals. Under this model, the industrial source doesn't have to be loud enough for most people to hear. It just has to be present enough to trigger a disproportionate perceptual response in the 2 percent of the population whose auditory systems are tuned to those frequencies.
The cost to people who hear it
The Hum is not a curiosity for the people who hear it. It has driven at least one person in England to suicide. Others report chronic insomnia, headaches, nausea, nosebleeds, and diarrhea. In Largs, Scotland, residents moved away. In Windsor, the 22,000 reports to officials in a single night reflected a community that had been sleep-deprived and frustrated for months. The Hum is a quality-of-life crisis that hearers often can't prove to their neighbors, their doctors, or their local government — because the person standing next to them in the same room, at the same time, hears nothing.
This is what makes the Hum a genuinely interesting epistemological problem rather than just an acoustic one. It exists at the intersection of physics, biology, psychology, and infrastructure — a sound that may be real, may be internal, may be both, and whose investigation requires expertise in acoustics, otology, environmental engineering, and psychophysics, all operating simultaneously. The solved cases prove that external low-frequency sources exist and can cause the reported symptoms. The unsolved cases prove that the solved explanations don't cover everything. The biological evidence proves that the human ear can generate perceptions that have no external correlate. And the geographic clustering proves that biology alone doesn't explain the pattern.
Every proposed explanation accounts for some features of the data while failing to explain others. The researchers who study the Hum spend as much time arguing with each other as with the phenomenon.
What's still open
The Taos Hum, after 30+ years and a federal investigation, has no identified source. The Bristol Hum, after 50 years, remains unexplained. The unsolved cases share a feature that the solved ones don't: even with serious instrumentation deployed by serious researchers, no external generator could be located. Either the source exists but is too diffuse, too intermittent, or too unusual to detect with conventional equipment — or some fraction of Hum reports represent a perceptual phenomenon for which the geographic clustering itself remains the central mystery.
Longer writeup covering the full case-by-case investigation history, the otoacoustic emission research, the jet stream hypothesis, and what acoustic researchers actually argue about when they argue about the Hum:
https://unteachablecourses.com/the-hum/
Two questions I'd love to hear from people who've actually experienced this. First: anyone here a Hum hearer? What does your experience match or contradict in the documented case profile — the indoor amplification, the nighttime intensification, the way earplugs sometimes make it worse? Second, for anyone with acoustics or otology background: is there a deployed instrumentation approach that could distinguish "external low-frequency source below the perception threshold of 98% of the population" from "internal otoacoustic emission perceived as external" in an individual hearer? Because that distinction seems like the central methodological problem and I haven't seen a clean experimental design that resolves it.
unteachablecourses.com