The first electric pianos from the late 1920s used metal strings with a magnetic pickup, an amplifier and a loudspeaker. The electric pianos that became most popular in pop and rock music in the 1960s and 1970s, such as the Fender Rhodes use metal tines in place of strings and use electromagnetic pickups similar to those on an electric guitar. The resulting electrical, analogue signal can then be amplified with a keyboard amplifier or electronically manipulated with effects units. Electric pianos are rarely used in classical music, where the main usage of them is as inexpensive rehearsal or practice instruments in music schools. However, electric pianos, particularly the Fender Rhodes, became important instruments in funk, jazz fusion and some rock music genres.
Electronic pianos are non-acoustic; they do not have strings, tines or hammers, but are a type of synthesizer that simulates or imitates piano sounds using oscillators and filters that synthesize the sound of an acoustic piano. They need to be connected to a keyboard amplifier and speaker to produce sound (however, some electronic keyboards have a built-in amp and speaker). Alternatively, a person can practice an electronic piano with headphones to avoid disturbing others.
Digital pianos are also non-acoustic and do not have strings or hammers. They use digital sampling technology to accurately reproduce the acoustic sound of each piano note. They also need to be connected to a keyboard amplifier and speaker to produce sound (however, most digital pianos have a built-in amp and speaker). Alternatively, a person can practice with headphones to avoid disturbing others. Digital pianos can include sustain pedals, weighted keys, multiple voice options (e.g., sampled or synthesized imitations of electric piano, Hammond organ, violin, etc.), and MIDI interfaces. MIDI inputs and outputs allow a digital piano to be connected to other electronic instruments or musical devices. For example, a digital piano's MIDI out signal could be connected by a patch cord to a synth module, which would allow the performer to use the keyboard of the digital piano to play modern synthesizer sounds. Early digital pianos tended to lack a full set of pedals but the synthesis software of later models such as the Yamaha Clavinova series synthesised the sympathetic vibration of the other strings (such as when the sustain pedal is depressed) and full pedal sets can now be replicated. The processing power of digital pianos has enabled highly realistic pianos using multi-gigabyte piano sample sets with as many as ninety recordings, each lasting many seconds, for each key under different conditions (e.g., there are samples of each note being struck softly, loudly, with a sharp attack, etc.). Additional samples emulate sympathetic resonance of the strings when the sustain pedal is depressed, key release, the drop of the dampers, and simulations of techniques such as re-pedalling.
Digital, MIDI-equipped, pianos can output a stream of MIDI data, or record and play via a CD ROM or USB flash drive using MIDI format files, similar in concept to a pianola. The MIDI file records the physics of a note rather than its resulting sound and recreates the sounds from its physical properties (e.g., which note was struck and with what velocity). Computer based software, such as Modartt's 2006 Pianoteq, can be used to manipulate the MIDI stream in real time or subsequently to edit it. This type of software may use no samples but synthesize a sound based on aspects of the physics that went into the creation of a played note.
The piano is a crucial instrument in Western classical music, jazz, blues, rock, folk music, film and television scoring, and many other Western musical genres. A large number of composers and songwriters are proficient pianists because the piano keyboard offers an effective means of experimenting with complex melodic and harmonic interplay and trying out multiple, independent melody lines that are played at the same time. Bandleaders often learn the piano, as it is an excellent instrument upon which to learn new pieces and songs which one will be leading during a performance. The piano is an essential tool in music education in elementary and secondary schools and universities and colleges. Most music classrooms and practice rooms have a piano. Pianos are used to help teach music theory, music history and music appreciation classes. Many conductors are trained in piano, because it allows them to play parts of the symphonies they are conducting (using a piano reduction or doing a reduction from the full score), so that they can develop their interpretation.