Piano

A Medici workshop and a question of volume

Historians generally agree that the piano began in Florence, in the workshop of Bartolomeo Cristofori, a harpsichord maker in the service of the Medici court. A court inventory from around 1700 is usually cited as the earliest record of a keyboard that could play both soft and loud, the quality that gave it its early name, gravicembalo col piano e forte, meaning harpsichord with soft and loud. The exact year of the first finished instrument is uncertain. Three Cristofori pianos survive, made between 1720 and 1726 and now in New York, Leipzig and Rome.

The idea spread slowly, through published descriptions and imitation rather than through any single workshop. By the later eighteenth century, makers in German-speaking lands and in London were building pianos to their own designs, and the new instrument was displacing the harpsichord in homes and concert rooms. A grand piano made in London in 1796, now in Boston, was commissioned for Manuel de Godoy, a powerful Spanish minister; its veneered case and slender, clear tone show the taste of the period.

The nineteenth century changed the piano's scale and strength. Composers wanted more volume and a wider compass, and makers answered with heavier strings, cast-iron frames to resist the pull, and actions that allowed a note to be repeated quickly. Sébastien Érard's repetition mechanism of the 1820s is usually credited with the last of these. The keyboard grew from about five octaves to the seven-and-a-quarter of today, and the modern form was largely settled by 1900.

Wood, iron and some two hundred strings

Inside a full-size grand piano, roughly 230 strings are stretched across a large plate of cast iron, which carries the combined pull of many tons. Treble notes have three strings each, the tenor two, and the lowest bass notes one; the bass strings are steel wound with copper to add mass without excessive length. Beneath the strings lies the soundboard, a thin panel of spruce, and a wooden bridge passes the string vibration into it.

The action is the part that most separates a piano from any other keyboard. Each key is a lever that sets a small chain of parts in motion, throwing a felt-covered hammer toward the string. Just before contact, a mechanism called the escapement lets the hammer travel freely, so that it rebounds at once rather than resting on the wire and choking it. A felt damper then stops the string when the key is released. A modern grand holds 88 such assemblies, each made of dozens of separate pieces.

From finger to felt to string

A struck string behaves very differently from a plucked or bowed one. The hammer supplies a single impulse and then withdraws, leaving the string to vibrate freely, so the note begins with a sharp attack and then fades. Hammers that are harder strike more brightly, since they excite more high partials, the faint upper tones that sit above the fundamental pitch; softer felt gives a rounder sound. Technicians adjust this by needling or filing the felt, a process known as voicing.

Loudness in a piano is governed by how fast the hammer meets the string, which the player controls through the force of the finger and the weight of the arm. That relationship is the whole point of the instrument and explains its early name. Pitch is fixed once the piano is tuned, because no key can bend a note. Tuners use equal temperament, in which the octave is divided into twelve equal steps, usually with the A above middle C set near 440 vibrations per second.

Seven octaves and a little more

The standard compass runs from A0, at about 27.5 hertz, to C8, near 4,186 hertz. That is seven and a quarter octaves across 88 keys, 52 of them white and 36 black, and it covers nearly the span of a large symphony orchestra. Some concert grands have been built with extra bass keys reaching down to C0, but the 88-note layout remains the working standard for composers and teachers.

Timbre shifts noticeably from one end of the keyboard to the other. The lowest strings produce a dark, bell-like complexity in which the individual partials can be heard; the middle register is the most even and vocal; the top octave is brief and glassy, with very little sustain. Because the same instrument can sound a dense chord across six octaves, pianists and composers often treat it as a small orchestra rather than a single melodic voice.

Touch, pedals and the pianist’s posture

Piano technique begins with the hands but depends on the whole arm. Players sit at a height that lets the forearm run roughly level with the keys, and they learn to vary touch from a close, singing legato to a crisp staccato, and to heavy chords played with the weight of the shoulder. Both hands normally read music on two staves: treble clef for the right hand and bass clef for the left, with the staves joined by a brace.

The pedals extend the pianist's control over sound. A modern grand usually has three. The right pedal lifts all the dampers, so that strings ring on after the keys are released and sympathetic resonance fills the room. The left pedal, called una corda, shifts the action so that the hammers strike fewer strings, softening and thinning the tone. The middle pedal, the sostenuto, holds up only those dampers that were raised at the moment it was pressed; many uprights replace it with a muting device or a bass sustain.

Grand, upright, square and beyond

Grand pianos keep their strings horizontal and range from short instruments of about 1.5 metres to concert models of about 2.7 metres or more, where longer strings give a fuller bass. Uprights stand vertically against a wall and are categorised by height. The square piano, a rectangular horizontal design common in the eighteenth and nineteenth centuries, has largely vanished from use but survives in museums and in historical performance. Early fortepianos, with leather-covered hammers and wooden frames, sound lighter and more sharply articulated than modern pianos.

Other descendants move further from the standard model. Many electric pianos generate sound from struck metal reeds or tines picked up electronically, while digital pianos reproduce sampled or modelled piano sound through speakers. The prepared piano, associated with the composer John Cage from the late 1930s, places screws, rubber and other objects between the strings to turn the instrument into something closer to a percussion ensemble.

Soloist, accompanist, section player

Few instruments change their social role so freely. In solo repertoire, from Baroque keyboard suites through the sonatas of Beethoven and the nocturnes of Chopin to contemporary concert works, the piano can carry a complete musical argument alone. In the concerto, it stands against the orchestra as a rival or partner. In art song and instrumental sonatas, it accompanies singers and players, shaping the harmony beneath a melody line that belongs to someone else.

Chamber groups such as the piano trio and quintet rely on its harmonic weight, and jazz pianists use it as both rhythm section and lead voice. Orchestral scores call for the piano only occasionally, as a colour with a percussive bite, and the harp, Marimba and Vibraphone sometimes share that territory with it.

Keeping a large machine in tune

A piano is tuned against enormous tension, and it drifts as wood swells and shrinks with the seasons. Most technicians advise tuning at least once or twice a year, and more often for instruments in regular professional use. Stable room conditions matter more than any product: sudden shifts in humidity can crack a soundboard, loosen tuning pins, or cause keys to stick. Keep it away from radiators and direct sunlight.

Tuning is only one part of upkeep. Regulation adjusts the action so that every key responds evenly, and voicing corrects the tone of the hammers. Both are specialist tasks that are best left to a trained piano technician. Moving a piano, even across a room, is also a job for professionals.

Small facts worth knowing

• The name piano is a shortened form of pianoforte, meaning soft and loud, which was itself a shortening of Cristofori's original phrase.
• The Cristofori piano of 1720 in New York has a wooden frame and no iron plate, so its strings are under far less tension than those of a modern grand.
• Some extended-range concert grands add extra bass keys reaching C0; on some models the added keys are finished in black, so players can see where the standard keyboard ends.
• Cage's prepared piano works date from 1938 onward and are still performed with exact instructions for each object.

Terms used in this entry

action

The system of levers, hammers and dampers that turns the movement of a key into a hammer blow on the string.

damper

A felt pad that rests on a string to silence it and lifts when the key is pressed or the sustain pedal is used.

equal temperament

A tuning system that divides the octave into twelve identical semitones so music can be played in every key.

escapement

A mechanism that frees the hammer just before it strikes, so it rebounds immediately and lets the string ring.

fortepiano

An early piano of roughly the eighteenth and early nineteenth centuries, with a wooden frame and lighter construction.

partial

One of the component tones, above the fundamental, that together make up the sound of a note.

soundboard

A thin wooden panel, usually spruce, that amplifies the vibration of the strings through the bridge.

una corda

The left pedal, whose name means one string; it shifts the action so hammers strike fewer strings and the tone softens.

voicing

The adjustment of hammer felt to change the brightness or warmth of a piano's tone.

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References

1. Musical Instrument Museum (MIM), Phoenix. Exploring the History of the Piano | Musical Instrument Museum. mim.org/exploring-the-history-of-the-piano
2. Google Arts & Culture (The Metropolitan Museum of Art). Grand Piano - Bartolomeo Cristofori — Google Arts & Culture. artsandculture.google.com/asset/grand-piano-bartolomeo-cristofori/jgG9t1nNRdHEDw?hl=en
3. Museum of Fine Arts, Boston. Grand piano – Works – Museum of Fine Arts, Boston. collections.mfa.org/objects/51248/grand-piano
4. Philharmonia Orchestra. Keyboards | Philharmonia. philharmonia.co.uk/resources/instruments/keyboards

Sources were consulted for facts and context; the text is original. See Sources and Methodology.