The Hum
Partially explainedSummary
In certain places, a small proportion of people hear a low, persistent droning noise. It is usually worse indoors, and worse at night. Most people in the same room hear nothing.
It is not imaginary, and it is not one thing, and treating it as one thing is the reason it has resisted explanation for fifty years.
The Windsor Hum was traced to a specific blast furnace on a specific island, and when the furnace shut down, the hum went with it. That is the most important fact in this record, and it cuts both ways.
What is documented
The experience. A low-frequency sound, commonly likened to a distant diesel engine idling. It is typically heard indoors, is worse at night, and can be maddening. Sufferers report sleeplessness, headache, nausea and severe distress. Some have moved house.
The minority. Only a small fraction of the population in an affected area can hear it, on the order of a few per cent. Two people in the same room will disagree about whether there is a sound at all.
Instruments often find nothing. In many investigated cases, microphones placed where hearers report the sound have not recorded it, which is one of the reasons the phenomenon was for a long time dismissed.
Windsor, and this is the case that matters. From 2011, residents of Windsor, Ontario reported a persistent low-frequency hum. It was investigated properly: a study funded by the Canadian government and carried out by researchers at the University of Windsor and Western University.
They found it. It was coming from Zug Island, an industrial site on the American side of the Detroit River, and it was associated with steelmaking operations there.
When the blast furnaces on Zug Island ceased operating, the hum largely ceased with them.
Taos. Investigated in 1993 by a team from the University of New Mexico, Sandia National Laboratories, Los Alamos and the Phillips Air Force Laboratory. No acoustic source was identified. No unusual electromagnetic activity was found. Hearers did not agree with one another about the frequency.
Leading explanations
It is not one phenomenon. This is the registry's principal finding on this record, and everything else follows from it.
"The Hum" is a name, and it has been applied to reports from Bristol, Taos, Windsor, Auckland, Largs and dozens of other places, and there is no reason at all to think they share a cause. Grouping them under one heading created an entity that has to be explained, and there may be no such entity.
Industrial sources. Confirmed in at least one case. Windsor was traced to a blast furnace. Low-frequency sound travels very long distances, is poorly attenuated by walls and by terrain, and is extremely difficult to localise by ear. A source many kilometres away can be inescapable indoors and undetectable outdoors, which is exactly what hearers describe.
Internal auditory phenomena. Some cases are likely to be otoacoustic: the ear generating its own sound, or a form of tinnitus.
Hearers generally reject this, and their objection is a reasonable one: they report that the sound stops when they leave the area and returns when they come back, which an internal sound should not do. That objection is strong, and it does not apply to every case.
Microseisms. Ocean waves interacting with the seabed generate continuous low-frequency ground motion, worldwide. It is a real phenomenon and it is a proposed contributor.
Psychogenic amplification. Not a claim that hearers are inventing it. Once a person becomes aware of a faint sound and becomes distressed by it, attention makes it louder, and distress makes it worse, and it becomes very hard to stop hearing. This mechanism is well understood in tinnitus and it does not require anybody to be imagining anything.
What the popular version gets wrong
"It's all in their heads." In Windsor it was a blast furnace on an island in a river, and it went away when the furnace did. Anyone dismissing the Hum as psychological has to explain that, and cannot.
"There is a single unexplained global Hum." There is not. There is a name that has been applied to a large number of separate reports from separate places, some of which have separate causes, and at least one of which has been found.
"Nobody has ever tracked one down." Somebody tracked one down. This is the most under-reported fact about the Hum, and it is the one that ought to give hope to the people who are still living with it.
"It's secret military infrasound." No.
Current status
Partially explained. At least one Hum has been identified, located, and subsequently ended. Others have been investigated and no source found. Some cases are probably internal to the hearer, and some are probably industrial and simply have not been found yet.
The registry keeps this record with a note that is not usually part of an archive's business.
People who hear the Hum are frequently told they are imagining it. Windsor establishes that at least some of them are hearing a blast furnace twenty kilometres away, through a wall, at three in the morning, while everybody else in the house sleeps.
That is worth saying, because the default assumption in this field has been wrong at least once, in a case where somebody bothered to look.
Sources
- Novak, C. and colleagues, University of Windsor and Western University: investigation of the Windsor Hum, funded by the Government of Canada, identifying Zug Island as the source.
- Investigation of the Taos Hum (1993) by the University of New Mexico, Sandia National Laboratories, Los Alamos National Laboratory and the Phillips Air Force Laboratory.
- Published literature on low-frequency noise propagation, otoacoustic emissions, and microseisms.
- Deming, D. (2004). "The Hum: An Anomalous Sound Heard Around the World." Journal of Scientific Exploration.
Last reviewed: July 2026. Records are provisional. Where the evidence changes, the entry changes. Found an error? Tell us.