Keyboard instruments demonstrate a combination of simplicity and complexity. Their uniform key layout underlies a systematic musical structure, yet mastering such instruments is often challenging due to the numerous techniques required to interact with the keys to produce a seemingly infinite range of sounds. Nevertheless, keyboards are prominent features of a diverse group of instruments, including the piano, which is one of the most beloved music staples in history.
A musical keyboard consists of a row of adjacent long and short keys that serve as levers when pressed and released. Each key usually corresponds to a specific note in the predominant 12-note musical scale, with the lowest note on the left and progressing to the highest on the right. Groups of keys are repeated to represent the desired number of octaves, which are pitch intervals that differ by a frequency of one half (i.e., an octave one-step down) or twice as much (i.e., an octave one step above).
The keys produce musical sounds through various methods. Pressing a key causes the lever to initiate airflow through a pipe on an organ, completes the connection of a circuit on a synthesizer, and strikes a bell on a carillon.
The piano is the most famous and widely used keyboard instrument in the world. According to the Metropolitan Museum of Art, at the turn of the 18th century, Italian instrument maker Bartolomeo Cristofori (1655–1731) was primarily responsible for inventing the earliest version of what is now known as the piano. In 1711, journalist Scipione Maffei dubbed this creation "gravicembalo col piano e forte" (i.e., harpsichord with soft and loud), giving rise to the earlier term fortepiano (i.e., "loud-soft" in Italian) for the instrument, as well as the current formal name pianoforte (i.e., "soft-loud").
The European clavichord and harpsichord, both invented in the 14th century, preceded the piano in the spectrum of keyboard instruments. All three, however, rely on similar mechanisms for manipulating strings made of metal to create vibrations, thus sound. Like pianos, a clavichord strikes the relevant string with a hammer-like device after a key on the keyboard is pressed, but clavichords use tangents, which are small metal blades.
Harpsichords don't strike strings to create musical sounds, but instead pluck them. When a key is pressed, the opposite end of the key raises a long piece of wood called a jack. The jack is attached to a pick called a plectrum that plucks the string. After the key is released to resume a resting position, the jack falls away and felt padding at the top of it dampens the string's vibrations.
There are three main categories of musical instruments that incorporate keyboards. Aerophones, which utilize vibrating air to create sound, include the accordion, harmonium, melodeon, melodica and pipe and reed organs. Chordophones. which manipulate the vibration of strings to create sounds, include the tangent piano, bowed clavier, hurdy gurdy (i.e., wheel fiddle) and various electric pianos. Pianos, clavichords and harpsichords are chordophones as well. Finally, idiophones, which produce sound predominantly through the vibration of the instrument itself, include the carillon, celesta and glasschord.