If one car horn blows at 100 decibels, would 100 horns blowing at the same time still make a sound of 100 decibels? Or would it be higher?
—Allen Ford, Lakeland, Tennessee
The sound would be much louder, but it wouldn’t be 100 x 100 (or 10,000 decibels). That’s because the decibel scale isn’t linear, it’s logarithmic—like the Richter scale for earthquakes. So 100 cars blowing 100-decibel horns would produce a sound of 120 decibels, which is huge, like a nearby thunderclap. (The average human pain threshold is about 110 decibels.) Normal conversation is about 60 decibels. Excessive exposure to noise (not simply getting older) is the most common cause of hearing loss.