"The Hum drives crazy hundreds of thousands of people worldwide.
But the cause ot the strange sound phenomenon remains unexplained. This article gives some clues of what might produce this annoying and sometimes lethal loud vibration.
What is The Hum?
The mysterious Hum phenomenon is around since the 1950s and plagues people around the world, from Bristol, England to Taos in New Mexico, USA, Bondi in Sydney, Australia and Windsor in Ontario, Canada.
Only 2-4% of people hear the noise. The low-frequency buzz is mostly heard indoors in rural and suburban locations.
The rumbling sound can get louder during the night, and is very location specific: The Bristol Hum, The Taos Hum, The Bondi Hum, The Largs Hum, The Windsor Hum."
https://strangesounds.org/the-hum