What type of sound frequency is typically categorized above 20 kHz?

The category of sound frequencies that falls above 20 kHz is known as ultrasonic. This classification is based on the range of human hearing, which typically spans from about 20 Hz to 20 kHz. Sounds that are higher than this range are classified as ultrasonic and are often used in various applications, such as medical imaging (ultrasound) and pest control.

Infrasonic refers to frequencies that are below the range of human hearing, specifically below 20 Hz. Audible sound is the range of frequencies that humans can hear, which is from 20 Hz to 20 kHz. Subsonic is often used in contexts of speeds that are below the speed of sound, particularly in air, and is not applicable to sound frequency categorization in this instance.

Therefore, ultrasonic is the correct classification for sound frequencies above 20 kHz, as it signifies sounds that are beyond the upper limit of human auditory perception.