In MIDI terms, velocity is how fast a key is moved by the player. There are actually two types: “Attack” velocity (normally referred to simply as “velocity”) is how fast the key is struck, while release velocity refers to how fast the player lets go of the key at the end of a note. Velocity is often routed to control the volume of a note, how fast of an attack a note might have, or how bright a sound might be. Release velocity is commonly used to set the amount of time a note hangs or rings on after being released.
