The term "electric piano" can refer to several different instruments which vary in their sound-producing mechanisms and consequent timbral characters.
Struck strings Yamaha,
Baldwin,
Helpinstill and
Kawai's electric pianos are actual grand or upright pianos with strings and hammers. The Helpinstill models have a traditional soundboard; the others have none, and are more akin to a solid-body
electric guitar. On Yamaha's pianos, such as the
CP-70, the vibration of the strings is converted to an
electrical signal by
piezoelectric pickups under the bridge. Helpinstill's instruments use a set of
electromagnetic pickups attached to the instrument's frame. All these instruments have a tonal character similar to that of an acoustic piano.
Struck reeds Wurlitzer electronic pianos (sometimes called "Wurli" as a nickname) use flat steel reeds struck by felt hammers. The reeds fit within a comb-like metal plate, and the reeds and plate together form an electrostatic or capacitive
pickup system. The reeds are tuned by adding or removing mass from a lump of solder at the free end of the reed. Replacement reeds are furnished with a slight excess of solder, and thus tuned "flat"; the user is required – by repeated trial and error – to gradually file off the excess solder until the correct tuning is achieved. In 2015, Brazilian inventor Tiago Valente created the first prototype of the Valente Electric Piano, an electromechanical instrument where the hammers strike reeds, similar to the ones used in a Wurlitzer. In 2020, the Valente Electric Piano was launched commercially; at the time of launch, Valente said that he took inspiration from the Suette Piano, another reed electric piano that was made in Brazil in the 1980s.
Struck tuning-forks The
tuning fork here refers to the struck element having two vibrating parts. In
Fender Rhodes instruments, the struck portion of the "fork" is a
tine of stiff steel wire. The other part of the fork, parallel and adjacent to the tine, is the tonebar, a sturdy steel bar which acts as a resonator and adds sustain to the sound. The tine is fitted with a spring which can be moved along its length to allow the pitch to be varied for
fine-tuning.
Plucked reeds The
Hohner Pianet uses adhesive pads made from an undressed leather surface cushioned by a
foam rubber backing. Hohner's later "Pianet T" uses
silicone rubber suction pads rather than adhesive pads and replaces the electrostatic system with passive electromagnetic pickups similar to those of the Rhodes.
Other electric keyboard instruments Hohner's "
Clavinet" is essentially an electric
clavichord. A rubber pad under each key presses the string onto a metal anvil, causing the "fretted" portion of the string to vibrate. This is detected by a series of pickups, which convert them into an electrical signal. == Digital pianos ==