Imagine a sound you can hear clearly — a low, steady drone, like a diesel engine idling somewhere in the distance — while the person sitting next to you hears nothing at all. You turn off the television and unplug the refrigerator, but the sound is still there. You ask your neighbors, and some of them nod slowly. Yes, they hear it too. Others look at you as if you have lost your mind. That is the daily reality for a small number of people in Taos, New Mexico, and it has been going on for more than thirty years. Scientists from America’s top laboratories came to listen with microphones sensitive enough to hear a whisper across a field. They found nothing. The sound, whatever it is, is still there. This is the story of the Taos Hum.
What Does the Taos Hum Sound Like?
People who hear the Taos Hum describe it in remarkably similar words. It is a steady, low-frequency drone, often compared to a distant diesel engine idling, a refrigerator humming in the next room, or a truck parked far down the road with its engine running. It is not loud — a low rumble at the edge of hearing, noticed most when everything else is quiet. Hearers say it is most noticeable indoors, and most noticeable at night, when the day’s noise dies down and there is nothing left to mask it.
The reports put the sound in a very low frequency range, roughly 30 to 80 Hz, which is at the bottom end of what human beings can hear at all. A sound that low is felt almost as much as heard, and it is the kind of frequency that passes easily through walls and windows. That is part of why hearers find it so maddening: you cannot shut it out by closing a door, and earplugs help little against a sound that low. For people who hear it, sleep is the first casualty, then comes the fatigue and the headaches, and the slow erosion of patience that comes from a noise nobody else can confirm.
How It Came to Light in the Early 1990s
The Taos Hum entered public awareness in the spring of 1992, when a Taos resident named Catanya Saltzman wrote to the local newspaper, the Taos News, about a low humming sound that had bothered her since about May of the previous year. She asked whether anyone else could hear it and offered a reward to anyone who could find its source. The letter ran on March 19, 1992, and dozens of people wrote in or called to say they heard it too.
Local reporters picked up the story, then regional papers, then national ones, and within a year the Taos Hum was a national curiosity. Hearers said the sound had begun for them around 1991, that it came and went, and that it was worst at night. Some were so distressed that they left town; Saltzman herself eventually left Taos altogether.
The most puzzling feature, from the very beginning, was how few people heard it. Researcher Joe Mullins of the University of New Mexico, who would lead the scientific investigation, estimated that roughly 2 percent of the surveyed population could hear the sound — a few hundred people in a town of Taos’s size. That split between hearers and non-hearers on the same street is what has kept the Hum mysterious. If the sound were simply a loud machine somewhere, everyone would hear it.
The 1993 Investigation: America’s Top Labs Take a Listen
By 1993, New Mexico’s congressional delegation had asked for help, and a scientific team was assembled that, on paper, should have been able to find anything. It brought together researchers from the University of New Mexico, Los Alamos National Laboratory, Sandia National Laboratories, and the Air Force’s Phillips Laboratory. The team was led by Joe Mullins, then chairman of the University of New Mexico’s Mechanical Engineering Department, working with hearing scientist James Kelly.
The investigators did not just listen. They measured. They set up sensitive microphones in hearers’ homes, including a custom-built, ultra-sensitive low-frequency sound detector. They deployed geophones to look for seismic vibrations in the ground. They used magnetometers to check for electromagnetic signals. They also had hearers try to match the sound to test tones in a laboratory. The work went on through the summer of 1993, and the team’s findings were published in the Acoustical Society of America’s newsletter in the autumn of 1995.
The result was, in a word, nothing: no acoustic, seismic, or electromagnetic source matched the hum. The microphones in hearers’ homes picked up no unusual sound, the ground was not vibrating distinctively, and no electrical or magnetic signal lined up with what hearers described. Mullins and Kelly concluded that no known acoustic signals could account for the hum — a careful, honest, and deeply unsatisfying answer.
Why Only Some People Hear It
The 2 percent figure is the key to the Taos Hum, and it has driven most of the thinking about it ever since. If only a small fraction of people in the same town hear the sound, then either the sound is very quiet and only the most sensitive ears can pick it up, or the sound is not really in the air at all — it is being generated somewhere in the hearer’s own auditory system.
Human hearing varies, but not usually by that much at low frequencies, and the 1993 team found nothing obviously unusual about hearers’ hearing. The second possibility — that the hum is, in some sense, inside the hearer — was long treated as a polite way of saying the sound was imaginary. That was unfair. A sound that originates in the auditory system is still a real perception: tinnitus, the ringing many people experience after a loud concert, is a genuine sound generated by the auditory system itself. The question was never whether hearers were making it up, but where the sound was coming from: the air, the ground, or the ear.
Hearers in Taos reported that the hum was more prevalent at night and persistent, though not around the clock, and about 80 percent of hearers reported hearing it at least once a week. That pattern fits both explanations: a faint external sound would be masked by daytime noise and revealed at night, and so would an internal one.
Theories: Industry, Geology, and the Inner Ear
Over three decades, three broad explanations have been offered for the Taos Hum, and none has been proven.
Low-frequency sound can travel a long way, so a pump, ventilation fan, or piece of heavy equipment miles away could, in principle, produce a low drone that reaches the town. The trouble is that the 1993 team looked for exactly that kind of source and found nothing that matched, and industrial sounds tend to be heard by everyone nearby, not by 2 percent of the population.
The second theory is geological. Taos sits near the Rio Grande Rift, a great crack in the Earth’s crust that runs through New Mexico, and some have suggested that the hum could be produced by seismic activity or by natural vibrations in the ground. The problem is the same: the 1993 team’s geophones found no seismic signal that matched the hum.
The third theory is the inner ear: that the hum is a low-frequency sound percept — a phantom sound generated inside the auditory system, similar in kind to tinnitus, but at a much lower pitch than the usual ringing. The theory has gained ground in recent years, and a new study has given it its strongest support yet — but it is still a theory, not a verdict, and different hearers may be hearing different things.
Taos Is Not Alone: Bristol, Windsor, Largs, and Beyond
The Taos Hum was not the first of its kind. In the 1970s, hundreds of residents of Bristol, England, complained to the city council about a strange low hum audible at night, that only the most sensitive ears could pick up. Experts attributed it variously to factory noise, electricity pylons, or tinnitus. In the late 1980s, the coastal Scottish town of Largs began to experience its own hum, loudest indoors and at night.
Across the Atlantic, the Windsor Hum tormented residents of Windsor, Ontario, for years, with investigators eventually pointing to industrial activity on Zug Island, across the Detroit River in the United States — though the private island’s operators were uncooperative with further study, and the case was never fully closed. Similar hums have been reported in Kokomo, Indiana, in Auckland, New Zealand, and in towns across Britain and Europe. The pattern is strikingly consistent: a low drone, heard by a minority, worst indoors at night, no clear source. Either there is a common cause nobody has identified, or the human auditory system has a common quirk — and the new research points toward the second possibility.
A New Clue in 2026: The Sound May Come From Inside the Ear
In 2026, the Taos Hum story took a significant new turn. A study published in PLOS One in March 2026, led by audiology professor Markus Drexl of the Norwegian University of Science and Technology (NTNU), examined 28 people in Germany who reported hearing a persistent, unexplained low-frequency hum. The researchers tested two ideas: that these people had unusually sensitive low-frequency hearing, or that the perceived sound originated inside the auditory system.
The results were striking. Only 2 of the 28 participants showed clearly unusual sensitivity to low-frequency sound — far too few to explain the phenomenon. The team also tested whether the participants might be hearing spontaneous otoacoustic emissions, the faint sounds the cochlea itself produces. Those emissions turned up in some participants, but all of them fell between 861 and 4,637 Hz — nowhere near the low pitch of the hum, which the participants matched to a median of about 50 Hz. With the measurable-source explanations largely ruled out for the people studied, the researchers concluded that the most plausible explanation for most hum perceivers is subjective tinnitus — a phantom sound originating within the auditory system in the low-frequency range. As one summary of the study put it, the Hum is most likely a form of tinnitus for most sufferers.
Care is needed about what this study shows. It studied 28 people in Germany, not the hearers of Taos, did not test for tinnitus directly, and did not measure sound at participants’ homes. The authors note that real outside sounds are not ruled out. But it is the most evidence-supported explanation yet offered, and it fits the Taos facts well: a sound heard by only a small fraction of people, most noticeable in quiet rooms at night, invisible to the most sensitive microphones. If the hum is, for many hearers, generated inside the ear, then the 1993 team was listening in the wrong place.
Living With a Sound Nobody Else Hears
Whatever the cause, the human cost of the Taos Hum is real. Hearers describe broken sleep, difficulty concentrating, headaches, and a creeping sense of isolation. The hardest part, many say, is not the sound itself but the disbelief. When the person next to you cannot hear what you hear, and when the scientists with their instruments cannot find it either, it is easy to begin doubting yourself. Some hearers have moved away from Taos in search of quiet. Some have tried white noise machines, earplugs, and soundproofing, with mixed results. In Taos, hearers found each other, and today hum hearers around the world connect through online groups and databases, sharing descriptions and comparing notes — a small mercy for people who have spent years being told that the sound is all in their head.
Why the Mystery Endures
More than thirty years on, the Taos Hum remains unsolved. The instruments found nothing, and the new research suggests why: for many hearers, there may be nothing in the air to find. But “many” is not “all” — some may be hearing a genuine external drone the instruments missed, or something nobody has yet thought to look for.
That is why the Taos Hum still matters: “we found nothing” is not the same as “there is nothing there.” The hum is still heard in Taos today, by about 2 percent of the people who live there, on quiet nights, indoors, when the desert is still. The scientists came, and listened, and left. The sound stayed.
Frequently Asked Questions
What is the Taos Hum?
The Taos Hum is a steady, low-frequency drone reported in and around Taos, New Mexico, since the early 1990s. Hearers describe it as sounding like a distant diesel engine idling. It is most noticeable indoors at night, and only a small fraction of residents — researcher Joe Mullins estimated roughly 2 percent of the surveyed population — can hear it.
Did scientists ever find the source of the Taos Hum?
No. In 1993, a team from the University of New Mexico, Los Alamos National Laboratory, Sandia National Laboratories, and the Air Force Phillips Laboratory searched with sensitive microphones, geophones, and magnetometers and found no acoustic, seismic, or electromagnetic source matching the hum. Their findings were published in the Acoustical Society of America’s newsletter in autumn 1995.
What frequencies are reported for the Taos Hum?
Reported frequencies are roughly 30 to 80 Hz, at the very bottom of the range of human hearing. In the 2026 PLOS One study of hum perceivers in Germany, participants matched their hum to a median of about 50 Hz.
What does the 2026 PLOS One study say about the Hum?
Led by Markus Drexl of NTNU and published in PLOS One in March 2026, it tested 28 people in Germany who hear an unexplained low-frequency hum. Only 2 of the 28 had unusually sensitive low-frequency hearing, and sounds produced by the inner ear itself were at much higher frequencies than the hum. The researchers concluded that low-frequency tinnitus is the most plausible explanation for most hum perceivers, while noting that tinnitus was not tested directly and external sounds are not ruled out. See the Medical Xpress summary.
Are there other hums like the one in Taos?
Yes. Similar low-frequency hums have been reported in Bristol in England, Windsor in Ontario, Largs in Scotland, Kokomo in Indiana, and Auckland in New Zealand, among other places. Some, like the Windsor Hum, have been linked to industrial sources; others remain unexplained. You can read more about the hums that have stumped scientists around the world.
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