Usually used in organs and electronic keyboards, expression pedals help musicians control various aspects of the sound being played, most commonly its volume. Modern guitar players also use expression pedals by connecting them to their digital guitar amplifiers, where these pedals behave much like control knobs that can be adjusted at their feet. If you need help, see our review on the best amp for pedals.
Besides volume, expression pedals may also give musicians control over the effects on the sound such as wah-wah, reverb, vibrato, echo and delay. These additional controls are most prominently seen when expression pedals are used in conjunction with modern digital and simulation guitar amps.
What Are Sustain Pedals?
Sustain pedals maintain the notes played on an instrument, most commonly a keyboard or a piano, until the pedal is released or until the strings on the instrument naturally stop vibrating. On a piano, the pedal works by removing all the dampers away from the strings and allow them to vibrate freely, so they will naturally stop at some point. Sustain pedals used on an electric keyboard may allow the notes to be sustained until the pedals are released.
A special technique called half pedaling can give a fine variation of the sound by pressing your foot on the pedal slightly, giving you creative control over the sustained note or chord.
Expression pedal vs sustain pedal: the similarities
Both an expression pedal and a sustain pedal are tone-shaping tools to help you achieve your personal sound or a special pre-determined sound. In modern electronic music production, both can be connected to devices with MIDI control inputs to control MIDI track parameters.
Both these pedals can, to a certain extent, give you variations of the timbre of the sound. By using half pedaling on a sustain pedal, it is possible to vary the timbre slightly. The expression pedal can substantially change the timbre when used in conjunction with other effects like wah-wah or distortion.
Both an expression pedal and a sustain pedal can help you sustain a note or chord you want to let ring even after the key or string has been released. The expression pedal does it by controlling the volume of the note, allowing it to continue ringing, while the sustain pedal lets the note play as long as the pedal is pressed.
Expression pedal vs sustain pedal: the differences
Sustain pedals only control when the sustained note or chord ends, while expression pedals can provide control over various aspects of the sound being played such as volume, timbre and effects.
Expression pedals, in general, give you more options with regards to the possibilities of the different sounds you can achieve with the same instrument. This is because expression pedals can be used together with other digital effects to control the amounts of the effects. For instance, connecting an expression pedal to a digital amplifier with built-in effects allows you to control the effects through the expression pedal.