Does subsonic sound cause acute anxiety?
Dear Cecil:
I read once, in some dusty and dimly remembered mystery, that subsonic sound (or sound that is much lower in pitch than can be heard) will cause acute anxiety to those within its range. It made an intriguing story. Is there any factual basis for this?
Cecil replies:
Infrasonic sound, to call it by its right name, has some effect on human "hearers," although it falls a little short of "acute anxiety." The frequency range of normal human hearing is 10-24,000 hertz. Researchers have found that frequences as low as one hertz (one cycle per second) have a definite effect on the inner ear, somehow short-circuiting its equilibrium and causing dizziness.
Infrasonically-induced dizziness may not be the stuff of paranoid fantasies, but it may yet turn out to be a serious problem. In nature, infrasonic waves are produced only by earthquakes--in which event dizziness would probably be the least of your worries. But scientists have discovered that the waves can also be produced by forcing air into an enclosed space--an experiment you can duplicate with frightening accuracy by driving at high speeds with your car windows open. This should give you something to think about as you zip down the highway next summer.
