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Hum

Hum is a reported low-frequency humming or droning sound that some people can hear in a particular area while others cannot.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated September 11, 2026|2 min read| Fact-checked

Hum is a reported low-frequency humming or droning sound that some people can hear in a particular area while others cannot. In acoustics and auditory science, the term often refers to a poorly understood phenomenon sometimes called “The Hum,” which has been linked to both external noise sources and internal auditory causes such as low-frequency tinnitus. No single explanation has been accepted for all cases.

Description

The Hum is usually described as a persistent, low-pitched hum, rumble, or drone. It is often reported as being easier to notice in quiet settings and at night.

Scientific explanations

Proposed causes include external mechanical or environmental sources, such as industrial equipment or other low-frequency noise, as well as internal auditory causes. Recent research supports low-frequency tinnitus as a common explanation, while acknowledging that some cases may have external sources.

Geographic reports

Hum reports have been documented in several countries, including Canada, the United Kingdom, the United States, and Australia. The phenomenon is therefore treated as global rather than being limited to one location.

Research status

Studies have not identified a single cause for all cases. Current evidence suggests the Hum may be a mixture of different phenomena rather than one unified acoustic source.

Key facts

  • The Hum is a low-frequency sound reported by some listeners but not others in the same area.
  • Reports of the phenomenon have appeared internationally since at least the 1970s.
  • Researchers have proposed multiple explanations, including machinery, environmental vibrations, and auditory causes.
  • Recent studies indicate that low-frequency tinnitus may account for many reported cases.
  • There is no universal scientific consensus on a single cause for all Hum reports.
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Canadian context

Reports of the Hum have been documented in Canada, making it relevant to Canadian readers as both a local and international acoustics phenomenon.

Frequently asked questions

What is the Hum?
The Hum is a reported low-frequency humming or droning sound that some people perceive in an area, often without an obvious source.
Is the Hum a real sound?
In some cases, yes: external low-frequency noise sources may be involved. In many other cases, researchers think the perception comes from inside the auditory system.
What causes the Hum?
Possible causes include industrial machinery, environmental vibrations, and low-frequency tinnitus. Research suggests there is not one single cause for all reports.
How common is hearing the Hum?
Estimates in the sources suggest only a small minority of people, often around 2–4%, report hearing it.
Has the cause of the Hum been solved?
No. Recent studies have improved understanding, but they have not established one cause that explains every reported case.

References

  1. American Academy of Audiology — https://www.audiology.org/the-hum/
    Supports: Describes The Hum as a low-frequency phenomenon, notes reported prevalence, and discusses likely causes including low-frequency tinnitus and sensitive hearing.
  2. ScienceDaily — https://www.sciencedaily.com/releases/2026/07/260719040002.htm
    Supports: Summarizes recent research suggesting low-frequency tinnitus often explains perceived hums while not ruling out external sources.
  3. Wikipedia — https://www.wikiwand.com/en/articles/The_Hum
    Supports: Provides an overview of the phenomenon, including international reports and the view that it does not appear to have a single cause.
  4. The Guardian — https://www.theguardian.com/books/2021/jul/07/the-hum-mystery-noise-says-a-lot-about-modern-life
    Supports: States that there is unlikely to be a singular explanation and notes the phenomenon is frequently reported yet poorly understood.
  5. NBC News — https://www.nbcnews.com/sciencemain/mysterious-hum-driving-people-crazy-around-world-6c10760872
    Supports: Discusses proposed environmental and medical explanations, including tinnitus and microseisms, and notes repeated testing has not produced one agreed cause.