Keyboard expression

Keyboard expression—often shortened to expression—is the ability of a keyboard musical instrument to respond to change tone or other qualities of the sound in response to velocity, pressure or other variations in how the performer depresses the keys of the musical keyboard. Expression types include:

Keyboard instruments offer a range of expression types. Acoustic pianos, such as upright and grand pianos, are velocity-sensitive—the faster the key strike, the harder the hammer hits the strings. Baroque-style clavichords and professional-level modern electronic keyboards are after-touch-sensitive—applied force on the key after the initial strike produces effects such as vibrato or swells in volume. Tracker pipe organs and electronic organs are displacement-sensitive—partly depressing a key produces a quieter tone.