Sound types can be categorized into two main groups: audible sounds and inaudible sounds. Audible sounds are those that can be heard by the human ear, typically ranging from 20 Hz to 20,000 Hz. Examples include music, speech, and environmental noises. In contrast, inaudible sounds fall outside this range, such as ultrasound (above 20,000 Hz) and infrasound (below 20 Hz). Ultrasound is often used in medical imaging, while infrasound can be produced by natural events like earthquakes or by man-made sources like explosions.