Creator: Norwegian College of Science and Expertise
Revealed: 2026/06/02
Publication Particulars: Peer-Reviewed, Analysis, Examine, Evaluation
Contents: Synopsis – Introduction – Essential – Insights, Updates
Synopsis: This analysis, peer reviewed and revealed in PLOS One, examines The Hum – a persistent low-frequency sound that some individuals hear whereas others close by discover nothing in any respect. A group led by NTNU professor Markus Drexl examined 28 individuals in Germany who report an unexplained buzzing, checking whether or not they had unusually delicate low-frequency listening to or whether or not their ears produced measurable sounds of their very own. The work is helpful as a result of it fastidiously separates the few instances that will stem from actual, measurable sound waves from the extra widespread clarification of low-frequency tinnitus, providing reassurance and a clearer framework for clinicians, audiologists, and anybody – together with seniors and other people with listening to sensitivities – who has been troubled by a noise they can not hint or show to others.
At a Look
- 1 – The Hum was first documented in Bristol, England within the mid-Nineteen Seventies, when the native newspaper started receiving letters from readers describing an inexplicable sound, and it has since been reported in cities throughout Canada, Australia, New Zealand, South Africa, and the USA.
- 2 – A Canadian instructor named Glen MacPherson was so intrigued after listening to the sound that he launched the interactive World Hum Map and Database Mission in 2012 to assemble reviews from world wide.
- 3 – The wholesome inside ear naturally generates faint sounds of its personal, often called oto-acoustic emissions, sometimes between roughly 500 and 5000 Hertz, and a small variety of individuals can really understand them.
- Subject Definition: The Hum
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The Hum is the favored identify for a persistent, low-frequency droning or buzzing sound {that a} minority of individuals report listening to, sometimes indoors and most frequently at evening, though others in the identical place understand nothing and no apparent exterior supply will be discovered. First documented in Bristol, England within the mid-Nineteen Seventies and later reported in coastal cities and densely populated areas throughout the UK, North America, and past, it’s typically felt as a vibration and may vary from a gentle annoyance to a genuinely distressing expertise. Present analysis suggests it arises from a couple of trigger, with a small variety of instances linked to unusually delicate low-frequency listening to and the bulk higher defined as a type of low-frequency tinnitus originating throughout the listener’s personal auditory system.
Introduction
A wierd buzzing phenomenon
Some individuals discover the sound annoying however can stay with it. Others can get sick from this low-frequency sound, which is usually additionally skilled as a vibration.
The buzzing sound is not straightforward to listen to open air, but it surely usually seems indoors – and is most noticeable once you’ve gone to sleep at evening. When you look out the window to see if there’s something with a motor within the neighborhood, there’s nothing to see. And others who’re in the identical place hear nothing.
Essential Content material
First found in coastal cities
The phenomenon was first recorded and mentioned within the metropolis of Bristol, England within the mid-Nineteen Seventies. Instantly, the Bristol Night Put up started receiving letter after letter from individuals who heard an inexplicable sound, and puzzled the place it got here from.
One principle was that the buzzing sound got here from giant, industrial followers that had been positioned contained in the warehouse of a big division retailer. Nevertheless, when the warehouse was closed down just a few years later, individuals continued to listen to the sound.
Since then, the sound has been recorded in a number of locations in the UK, primarily in coastal cities corresponding to Hythe, Plymouth, Southampton, and Swansea, but additionally in London. The sound is named The Hum phenomenon, or just The Hum.
Within the Nineties, it cropped up in the USA, first within the metropolis of Taos, New Mexico and within the metropolis of Kokomo, Indiana. The phenomenon has since been recorded worldwide: in Canada, Australia, New Zealand, South Africa, and several other European cities. The sound is often reported in comparatively densely populated areas.
A few years in the past, individuals within the Oslo space additionally reported an unexplained buzzing sound, in keeping with the Norwegian Broadcasting Company.
Canadian Glen MacPherson started listening to the buzzing sound when he lived and labored as a instructor on Canada’s west coast. When he moved to a different metropolis in the identical space, the sound disappeared. He turned so within the sound phenomenon that he began the interactive World Hum Map and Database Mission in 2012, which collects knowledge from locations and other people the place the sound has been famous.
Many various theories
Many various theories have been provided to elucidate the reason for the phenomenon; every little thing from acoustic air pollution from human-made sources to sounds that nature itself makes – in addition to conspiracy theories that the sound is produced by the CIA and even aliens.
There are a lot of human sources of low-frequency sound. These can embrace air flow techniques, warmth pumps, visitors noise, windmills, and extra. Examples of pure sources embrace the sounds of waves crashing alongside the coast and wind sweeping via the panorama.
The Hum has attracted the curiosity of listening to and audiology researchers worldwide. Markus Drexl, a professor on the Norwegian College of Science and Expertise, is amongst this self-selected group. He and two PhD analysis fellows and a postdoc have carried out a research of 28 individuals in Germany who expertise listening to an unexplained buzzing or buzzing.
Sounds that may be measured
The researchers examined two hypotheses. One was that The Hum will be measured, each from human-made infrastructure and business and likewise from nature itself, which creates low-frequency sounds.
“We all know that there are individuals who hear low-frequency sounds that may really be measured, even when different individuals do not hear them. Nevertheless it’s not really easy to seek out the supply of those sound waves, as a result of it is a battle to localize low-frequency sounds,” Drexl mentioned. These sounds have lengthy wavelengths that may journey over nice distances.
Additional good listening to?
The very first thing the researchers did was check whether or not the contributors had notably good listening to for low-frequency sounds which might be really recognized to exist. Most didn’t, besides for 2 contributors who had higher listening to than common at sure low frequencies.
“Regardless that the group we examined was small, it nonetheless signifies that the speculation of getting particularly good listening to for low-frequency sounds doesn’t maintain for most individuals,” Drexl mentioned.
He provides a small caveat: There are variations in listening to thresholds (microstructures) that make it attainable for some individuals to listen to sensitively in a really slender frequency vary, for instance between 50 and 51 Hertz. These nuances aren’t captured by typical listening to assessments.
The ear can produce sounds itself
The cochlea within the inside ear itself produces weak sounds with totally different frequencies, sometimes between about 500 and 5000 Hertz. These sounds don’t have any perform of their very own, however are a by-product of a physiological sound amplification course of.
“Most of us do not hear these sounds. Nevertheless, just a few individuals can really hear the sounds that the ear itself produces. And these sounds will be measured objectively,” Drexl mentioned.
These specific sounds are known as oto-acoustic emissions and will be detected by inserting a delicate microphone within the ear canal. In some individuals, these spontaneous oto-acoustic emissions will be skilled as troublesome tinnitus.
“One speculation was that the contributors in our group might hear oto-acoustic emissions at low frequencies. That is why we examined whether or not they had them,” says Drexl. However the reply was no.
Sounds that can not be measured
“Then there are individuals who hear one thing that can not be measured objectively. We consider individuals on this class have a type of low-frequency tinnitus,” Drexl mentioned.
Tinnitus or ringing within the ears is once you hear a sound within the ear or within the head, which isn’t attributable to an exterior sound supply. Many individuals expertise tinnitus, both completely or for shorter intervals. These people first expertise the sounds of their ears as a sound coming from exterior. However because the sound persists, even once they transfer to different locations, they step by step change into conscious that the supply of the sound just isn’t exterior.
Drexl says that based mostly on what is understood about listening to and the assessments they carried out on research contributors, the most effective clarification is twofold. Just a few individuals who hear The Hum even have notably good low-frequency listening to. Nevertheless, for most individuals, it might be a type of tinnitus, which means a sound that originates from contained in the auditory system.
“Based mostly on our outcomes, though we have not dominated out instances of bodily exterior sound sources, we recommend that subjective tinnitus within the low-frequency vary is usually the reason for listening to pulsations of low-frequency sound perceptions,” he mentioned.
Should perceive the complete auditory system
Markus Drexl turned thinking about The Hum phenomenon as a result of he research low-frequency sounds.
“What we all know in regards to the listening to system is especially based mostly on how we seize and course of sound with increased frequencies. We all know much less about how the auditory system handles and processes low-frequency sound, or infrasound,” he mentioned.
Drexl says that over the previous decade there was a rising concern about noise from technical sources within the low-frequency vary (between about 20 and 250 Hz) and the infrasound vary (beneath 20 Hz).
“If we need to conduct a radical evaluation of low-frequency sounds and infrasound, we first want a greater understanding of how sensory techniques course of low-frequency sound and infrasound,” he mentioned.
Reference:
On the potential sources of a low-frequency sound percept that only some can understand, Plos One, March 2026.
Editorial Notice: What makes this research value sitting with is its humility – quite than chasing a single dramatic trigger for a sound that has fueled many years of hypothesis about business, nature, and even conspiracy, the researchers acknowledge how little is genuinely understood about how the ear handles the low finish of the spectrum, they usually make the case that answering questions on The Hum first requires a greater grasp of how our sensory techniques course of low-frequency sound and infrasound in any respect.
Attribution/Supply(s): This peer reviewed publication was chosen for publishing by the editors of Disabled World (DW) on account of its relevance to the incapacity neighborhood. Initially authored by Norwegian College of Science and Expertise and revealed on 2026/06/02, this content material could have been edited for type, readability, or brevity.