humming-noise

The Hum is a persistent and invasive low-frequency humming, rumbling, or droning noise audible to many, but not all, people in an area. Hums have been reported in many countries, including Australia, Canada, the United Kingdom, and the United States. They are sometimes named according to the locality where the problem has been particularly publicized, such as the "Taos Hum" in New Mexico and the "Windsor Hum" in Ontario.
The Hum does not appear to be a single phenomenon. Different causes have been attributed, including local mechanical sources, often from industrial plants, as well as manifestations of tinnitus or other biological auditory effects.

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