Researchers have concluded that the unexplained low-frequency sound known as The Hum likely stems from a form of tinnitus for most people who perceive it. The finding comes from tests on individuals reporting the noise, which has been documented globally since the 1970s.
A study led by Markus Drexl at the Norwegian University of Science and Technology examined 28 people in Germany who reported hearing the persistent hum. The team ruled out exceptional sensitivity to external low-frequency sounds and measurable oto-acoustic emissions from the inner ear as explanations for the majority of cases.
Drexl said most participants showed no unusual hearing ability in the relevant range. He added that spontaneous emissions produced by the cochlea also did not account for the perceptions.
The researchers instead point to subjective low-frequency tinnitus as the probable cause in most instances. Reports of The Hum first appeared widely in Bristol, England, in the mid-1970s and have since emerged in locations including Taos, New Mexico, and coastal areas of the United Kingdom.
