"Subsonic" refers to speeds that are slower than the speed of sound, which is approximately 343 meters per second (1,125 feet per second) at sea level. This term is commonly used in aviation to describe aircraft that do not exceed this speed. Subsonic flight is characterized by smooth airflow around the aircraft, resulting in less turbulence and noise compared to supersonic flight. In the context of sound waves, subsonic frequencies are those below the range of human hearing, typically below 20 Hertz. These low-frequency sounds can be produced by various sources, including subwoofers and natural phenomena like earthquakes. Subsonic technology is also utilized in various fields, such as acoustics and engineering, to study and manage sound waves effectively.