Aftertouch, in the context of sound and music, refers to a feature found on some electronic musical instruments, particularly on keyboard controllers, synthesizers, and electronic pianos. Aftertouch allows a musician to apply additional pressure to a key or a keybed after it has been initially depressed. This additional pressure can trigger various effects or modulations on the sound being produced.
There are typically two types of aftertouch:
- Channel Aftertouch: Channel aftertouch, also known as mono aftertouch, affects all the notes played on the keyboard simultaneously. When a player applies pressure to one key, it will affect the modulation or control parameters for all the notes currently being played. Common uses of channel aftertouch include modulating vibrato, filter cutoff, or volume for all played notes.
- Polyphonic Aftertouch: Polyphonic aftertouch, also called polyphonic pressure, is a more advanced form of aftertouch that allows for individual pressure sensitivity on each key independently. This means a musician can apply varying amounts of pressure to different keys while playing a chord or melody, leading to expressive and nuanced control over each note’s modulation or pitch.
Aftertouch adds an expressive dimension to a musician’s performance, enabling them to infuse their music with dynamic changes and subtle nuances. It’s a feature commonly appreciated by keyboardists and synthesizer players who want to create more emotive and evolving soundscapes in their compositions.