Such research led some to the belief that capturing these ultrasonic sounds could have some audible benefit.

Obviously, ultrasonic sound would be more efficient in this respect than ordinary sound.

They generally do not direct any energy, such as ultrasonic sound or infrared light waves, toward the subject.

This organ has membranes which are vibrated to produce ultrasonic sounds.

Echolocation is a perceptual system where echoes are produced by emitting ultrasonic sounds.

However, the results were mixed and ultrasonic sound had little or no effect on some pests.

Numerous studies have rejected ultrasonic sound as a practical means of rodent control.

Again, that ultrasonic whining sound, as a dozen minds radically shifted direction and then reaccelerated.

There are machines that aim ultrasonic sounds at barking dogs to quiet them.

Lead engineer Robert Adler then suggested that ultrasonic sound be used as a trigger mechanism.