What Is the Hum?
Some people hear a low, steady buzzing that seems to come from nowhere. It is called the “Hum”. The sound is soft but can feel like a vibration in the body.
How Common Is It?
Scientists estimate that about 2‑4 % of the world’s population notice the Hum. It is most often heard inside homes, especially at night when it is quiet.
Where Did the Story Start?
The first big reports came from Bristol, England, in the 1970s. Residents wrote letters about an odd noise they could not explain. The mystery spread to other towns in the UK and later to many countries, including the United States, Canada, Australia, New Zealand, South Africa and several European cities.
Possible Sources
Many ideas have been suggested. Some think the sound comes from machines such as ventilation fans, heat pumps, traffic, or wind turbines. Others point to natural sounds like ocean waves or wind. A few even mention secret projects, but there is no proof.
What Scientists Have Learned
Researchers in Norway studied 28 people who said they heard the Hum. They tested whether the participants had unusually good hearing for low tones. Most did not. Only two showed slightly better hearing, and even that was not enough to explain the Hum.
The team also checked if the inner ear might be making the sound. The ear can create faint noises called oto‑acoustic emissions, but the participants could not hear those either.
Low‑Frequency Tinnitus
The most likely explanation is a form of tinnitus – a sound that originates inside the ear or head. In this case, the tinnitus is at very low frequencies, which many people mistake for an external hum.
Why It Matters
Understanding low‑frequency hearing is still a work in progress. As more low‑frequency noise comes from technology, scientists want to learn how our ears and brains handle these sounds.
For now, most people who hear the Hum are probably experiencing low‑frequency tinnitus, while a few may truly be picking up faint sounds from the environment.