Mysterious Hum Heard Around the World May Finally Have an Answer

Topic: Health

Researchers have found a possible explanation for the mysterious hum heard by some people worldwide. The study suggests that the low-frequency sound is often caused by subjective tinnitus, not external sources.

Do you ever notice a deep buzzing or humming noise with no clear source? You're not alone. An estimated 2-4 percent of people worldwide experience this unusual sound. Some find it annoying but manageable, while others feel physical discomfort or illness.

The hum is harder to detect outside and is often heard inside buildings, especially at night when people are trying to sleep. People might look for a nearby engine or machine, only to find nothing that could explain the noise. Even more puzzling, some people in the same room may not hear anything.

Reports of The Hum began in England in the mid-1970s, with letters pouring into the Bristol Evening Post from residents describing an unexplained sound. Similar accounts emerged in other parts of the UK and later in the US, Canada, Australia, New Zealand, South Africa, and several European cities. Most reports come from densely populated areas.

Researchers have proposed many explanations for The Hum, including acoustic pollution, natural environmental sounds, and even conspiracy theories involving secret agencies or aliens. One possible source is low-frequency noise generated by machines like ventilation systems, heat pumps, road traffic, and windmills. Nature also produces similar sounds through ocean waves striking the shore and wind moving across the landscape.

Markus Drexl, a professor at the Norwegian University of Science and Technology (NTNU), led a study to investigate The Hum. He and his team tested 28 people in Germany who reported hearing an unexplained hum or buzz. They examined two main hypotheses: that The Hum is an externally produced sound or that it's related to internal bodily sounds.

The researchers found that most participants did not have unusually sensitive low-frequency hearing thresholds. They also measured spontaneous otoacoustic emissions (SOAEs), which are normal, physiological sounds produced by the inner ear. However, no SOAEs in the low-frequency range were detected in the complainants.

Why It Matters

Understanding The Hum can help us better address the health concerns of those affected and improve our ability to detect and measure low-frequency sound waves.

Key Facts

• 2-4 percent of people worldwide experience The Hum, a mysterious low-frequency sound.
• Reports of The Hum began in England in the mid-1970s and have since been reported in many countries around the world.
• Researchers propose that The Hum is often caused by subjective tinnitus, not external sources.
• Low-frequency noise generated by machines and natural environmental sounds are possible sources of The Hum.
• Markus Drexl led a study to investigate The Hum, testing 28 people in Germany who reported hearing an unexplained hum or buzz.

Key Terms

Tinnitus

A condition where people hear ringing, buzzing, or other sounds that are not caused by external sources.

Implications

Understanding The Hum can help us better address the health concerns of those affected and improve our ability to detect and measure low-frequency sound waves.