It's been compared to a subwoofer blasting Barry White's greatest hits or an idling diesel truck.

Others say the low, rumbling noise that has stalked residents in the Canadian city of Windsor for years sounds like Star Trek's Enterprise gearing up for warp speed.

"Very destructive," is how Mike Provost, a 62-year-old retired insurance salesman describes the so-called Windsor Hum. "If you think of thunder, and you take that thunder and constantly repeat it for hours and days, weeks, that's all it is."

Residents on the west and south side of Windsor – a city of 210,000 people that sits just across the river from Detroit – began complaining of a mysterious noise some six years ago, blaming it for rattling windows and trembling wall hangings.

"You can't get away from it," says Provost. "You go outside to work in your garden, you go outside to enjoy the sun, the noise is there."

Part noise and part vibration, the hum varies in intensity and comes and goes at random intervals, sometimes lasting hours and other times droning on for days. Sometimes it quiets down. But in recent months, residents say the Windsor hum has intensified to unprecedented – and unbearable – levels.