What is Aftertouch?

Aftertouch is a performance control feature in keyboards and MIDI instruments that responds to pressure applied to a key after it has been pressed. It is known for adding expressive control beyond the initial note trigger.

The concept typically involves detecting how much pressure is applied while holding a key and using that data to modulate parameters such as vibrato, volume, filter cutoff, or effects.

Aftertouch emphasizes real-time expression, allowing musicians to shape a sound dynamically without needing to play additional notes or use external controls.

There are different types of aftertouch, including channel aftertouch (affecting all notes equally) and polyphonic aftertouch (affecting each note independently).

Today, Aftertouch is widely used in synthesizers and MIDI controllers, valued for its ability to enhance performance, add nuance, and provide deeper interaction with sound.