The Hum: the Sound Only Some People Can Hear

It is usually described the same way on every continent: a low, pulsing drone, like a diesel truck idling a street away — except there is no truck, it's 3 a.m., and the neighbours hear nothing. It is louder indoors than out, worse at night, immune to earplugs (which makes it worse), and it does not stop. The famous outbreaks have place-names — the Bristol Hum, the Taos Hum (investigated by a 1990s scientific team at congressional request; the team found no source and confirmed only that around 2% of residents heard it), Windsor in Ontario, Auckland. "Hearers", as they call themselves, describe the same trajectory: bafflement, obsessive source-hunting, then quiet despair.

The suspects, external and internal

Some hums get caught: Windsor's correlated with industrial blast-furnace operations across the river; other cases have ended at pumping stations, gas compressors and factory fans — low-frequency sound propagates absurdly far, penetrates walls (hence louder indoors), and defeats casual source-hunting. When no source is found, the inquiry turns inward: tinnitus in its low-frequency form; spontaneous otoacoustic emissions (ears genuinely EMIT faint sounds some people hear); somatosounds from blood flow and muscle tone; and heightened auditory gain — a brain turning up the amplifier in silence until the machinery of the body and building becomes signal. The bitterest finding from Taos: hearers given total-isolation conditions often still heard it, pointing inward — but not for everyone, and the 2% clustering by GEOGRAPHY remains awkward for a purely internal account.

Our files collect the hearer diaries: hums that switch off when the power grid does; hums shared by exactly two houses; the hum that began the week something else began. If you hear it — log times, locations, and try a battery-powered recorder at maximum gain. Even silence on the tape is data.