damper pedal) prevents individual key dampers from lifting when the player releases the key. All notes played with the sustain pedal ring until the player releases the sustain pedal (or until the note completely decays). With the dampers not applied, octave, fifth, and other overtones vibrate sympathetically, producing a richer sound. Most electronic keyboards also have a sustain pedal that holds notes and chords, but only high-end digital keyboards reproduce the sympathetic vibration effect. Electromechanical keyboards and electronic keyboards offer a range of other expression devices. Electromechanical keyboards such as the Hammond organ offer additional means of keyboard expression by modifying the starting, stopping, or speed of the rotating Leslie speaker or by engaging a variety of vibrato or chorus effects. Digital "clones" of Hammond organs offer recreations of these effects, along with other effects. The VK-9 digital organ, for example, offers a proximity-sensitive detector that triggers the Leslie speaker, a ring modulator, or other effects. Some effect pedals used with electromechanical keyboards such as the Fender Rhodes electric piano or digital keyboards respond to loudness and so, indirectly, to key velocity. Examples include overdrive pedals, which produce a clean sound for softer notes, and a distortion effect for louder notes—and fixed wah-wah pedals that filter the audio signal based on loudness. References Keyboard instruments eo:Frapdinamiko