Number of cycles per second, in audio commonly used in reference to sound waves. Human hearing ranges roughly from 20 Hz (20 cycles per second of a sound wave) to 20,000 Hz (20 kHz – kilohertz). he lower the frequency in hertz, the greater the size of the wave form. A 20 Hz signal is produced by subwoofers or speakers with large bass drivers. The drivers of these speakers are large in order to create the large sound waves necessary to reproduce a 20 Hz or similar low bass signal. On the other end of the human hearing spectrum (topping out at around 20 kHz and less for many people) the sound waves are very small. Small tweeters, normally around 1 to 2 inches in diameter, are used to reproduce these high frequencies’ small waves. ach cycle can be thought of as a wave, with a 20 Hz signal pushing out 20 large waves per second while a 20,000 Hz signal produces 20,000 very small waves per second. The lower frequency range (around 20 Hz) can be felt as well as heard adding visceral impact to movies and music.