Subsonic may refer to:
Motion through a medium Any speed lower than the speed of sound within a sound-propagating medium Subsonic aircraft, a flying machine that flies at air speeds lower than the speed of sound Subsonic ammunition, a type of bullet designed to avoid creating a loud shockwave when fired Subsonic flight, an aircraft flight at air speeds lower than the speed of sound in air Subsonic and transonic wind tunnels
Music Subsonic (album), a 2002 album by Vigleik Storaas Trio Subsonic (EP), a 2013 EP by Younha Subsonic album series: Subsonic 2: Bass Terror, a 1995 album by Bill Laswell and Nicholas Bullen Subsonic 3: Skinner's Black Laboratories, a 1995 album by Andy Hawkins and Justin Broadrick Subsonic Music Festival, an annual electronic music festival in Monkerai, Australia "Subsonic", a song by Com Truise on the EP Wave 1 (2014)
See also Infrasound, sound at frequencies below the normal threshold of human hearing