The ultrasonic training instruments are easy to use. But there’s a dark history behind their inventor—and their initial ...

This unique sliding whistle would produce high-pitched sounds at frequencies above the limit of human hearing. Galton tested his invention on the streets of London by blowing it near dogs and charting ...

Dog whistles are designed to deliver sounds that cut through environmental ... “The consistent, distinct and high-pitched tone of a whistle makes it a more reliable tool for controlling a ...