Aftertouch

Pressure sensitivity or aftertouch

Aftertouch sensors detect whether the musician is continuing to exert pressure after the initial strike of the key. Some aftertouch sensors also measure that pressure's intensity. The aftertouch feature allows keyboard players to change the tone or sound of a note after it is struck, the way that singers, wind players, or bowed instrument players can do. On some keyboards, sounds or synth voices have a preset pressure sensitivity effect, such as a swell in volume (mimicking a popular idiomatic style of vocal performance with melodies) or the addition of vibrato.