The Hum is the name given to a persistent, low-pitched droning sound that a small share of people hear in certain places and that most of their neighbors do not. Reports go back at least to the 1970s, and they have a familiar pattern: the sound is steady, hard to locate, often heard indoors at night, and in the best-known measurement attempt, at Taos, no instrument found a matching signal. For a site devoted to drone music the subject is irresistible, but it also invites exaggeration. This article keeps to what has been measured and published, and labels everything else as hypothesis.
Bristol, 1970s: the first investigations
British reports are among the earliest. According to a New Republic feature on the phenomenon, the Sunday Mirror asked readers in 1977 whether they had heard the Hum, and hundreds wrote in describing a low, distant rumble, usually heard indoors at night. Researchers at the University of Southampton, R. N. Vasudevan and Colin G. Gordon, investigated and judged it very probably a real phenomenon rather than an auditory hallucination.
That wording is worth reading carefully. “Real” here means that people were experiencing a consistent sound, not that investigators had located a source. The Bristol case established the template that later cases repeated: a cluster of complaints, a search, and an inconclusive result.
Taos, 1993: the measurement attempt
The best-known American case is the Taos Hum in northern New Mexico. A team from Sandia National Laboratories, Los Alamos, the Air Force Phillips Laboratory and the University of New Mexico, prompted by members of the Congressional delegation, took simultaneous acoustic, seismic, electric, magnetic and electromagnetic measurements in summer 1993. The authors, Joe Mullins and Horace Poteet, reported at an Acoustical Society of America meeting in November 1994 that hearers’ descriptions and matching tests pointed to the 30 to 100 Hz range, which the team focused on. They found no signal matching the description; the only airborne sound in that range was background noise. The authors planned new instruments and controlled tests with hearers and nonhearers.
Two features of Taos deserve emphasis. First, the null result does not prove that nothing was there; it shows that the instruments and methods used did not find a matching signal. Second, the study did not report what percentage of residents could hear the sound. The frequently quoted figure of roughly 2 percent of the population appears in later popular accounts, and the New Republic piece treats it as an estimate rather than a measurement.
Kokomo and Windsor: cases with candidate sources
Two later cases are the strongest evidence that some hums have industrial origins. In Kokomo, Indiana, the New Republic reports that an extensive study concluded two manufacturing plants were emitting specific low frequencies, and that the Hum stopped for some residents but not all.
Windsor, Ontario, is the most thoroughly documented. In 2013, Canada’s foreign affairs department contracted Colin Novak and Western University for an acoustic study, according to the University of Windsor. The team set up low-frequency monitoring stations in Windsor’s west end and used a research vessel carrying infrasound arrays on the Detroit River. Fieldwork took six months, followed by four months of analysis. The likely source was a blast furnace on Zug Island, the sound could be heard over an area larger than 10 kilometers, and the researchers concluded it was no health hazard, though it could disrupt sleep for highly affected people.
The wording of the finding matters. Novak told the New Republic that the link was highly probable but that the team could not find the decisive proof, which would have required a longer study and more cooperation from U.S. authorities. After U.S. Steel scaled back operations at the island from April 1, 2020, Novak told the Canadian Press that the hum had practically vanished. The report cited no measurement data, and an Ontario environment ministry spokeswoman disputed a councillor’s report of continuing complaints, so the end of the Windsor Hum rests on testimony and a plausible timing coincidence rather than on a published before-and-after dataset.
What the hypotheses say
The hypotheses fall into a few groups, summarized in the New Republic article. One group points to sources outside the body: factories, gas pipelines, power plants, cell towers and smart meters have all been proposed. David Deming suggested that the Hum may be a low-frequency vibration that some people perceive as sound, possibly from Navy very low frequency communications; a steel box meant to test that idea had not been tested at the time of the article. A second group points to the ear and brain, and argues that many reports are tinnitus or hallucination, an interpretation Deming disputed because of the geographic clustering of complaints.
Some cases turned out to be mundane. The New Republic reports that a Sausalito, California, hum in the 1980s was traced to the mating calls of a fish, the plainfin midshipman. That example cuts both ways: it shows that a strange sound can have an ordinary cause, and it shows how long identification can take. Claims that a single cause explains every Hum go beyond the published evidence.
The 2026 hearing study
The most recent peer-reviewed work dates from 2026. In March of that year, Bonifaz Baumann, Andrej Voss, Carlos Jurado and Markus Drexl published a study in PLOS ONE on 28 people who reported hearing a low-frequency sound that others nearby could not. They tested two explanations: unusually high sensitivity to low frequencies, and hearing one’s own spontaneous otoacoustic emissions. Participants matched the sound to a median frequency of 50 Hz. Most did not have unusually sensitive thresholds, and no low-frequency emissions were detected. The authors conclude that low-frequency subjective tinnitus is often the likely cause, while stating that external sources are not ruled out.
The limits are plain: a small sample, a conclusion phrased as “often” rather than “always”, and, as Neuroscience News notes, the authors’ own caution that conventional hearing tests can miss differences in very narrow frequency bands. The study fits the Kokomo and Windsor cases without contradicting them, since a population can contain both people reacting to a real industrial tone and people experiencing internally generated sound.
Reading the Hum as a sound culture problem
Why does the Hum matter for listening culture? A tone that never changes, never ends and never resolves is, in effect, an involuntary drone. The experience of being unable to lower its volume echoes issues explored in the article on sonic warfare and in the glossary entry on the Hum. The distinction between a sound one chooses and a sound one cannot escape also frames the psychological effects discussed in the series.
Practical listening concepts help clarify the problem. Room tone describes the low-level background every space has, and acoustic ecology studies how people relate to such soundscapes. The anechoic chamber belongs to the same vocabulary of controlled silence, although none of the studies above claims that a quiet room explains the Hum. Popular lore about killer frequencies, covered in the article on infrasound and the brown note and in the entry on the brown note, should not be mixed in either.
The honest summary is that the Hum is probably several phenomena sharing a name: some industrial, some auditory, and some not yet explained. For listeners, the useful distinction is between measurement and testimony, and between a sound that can be traced and a sound that can only be reported.
