Grand piano by Louis Bas of Villeneuve-lès-Avignon, France, 1781. Earliest French grand piano known to survive; includes an inverted wrestplank and action derived from the work of Bartolomeo Cristofori (ca. 1700) with ornately decorated soundboard.
Early piano replica by the modern builder Paul McNulty, after Walter & Sohn, 1805
The piano is founded on earlier technological innovations. The first string instruments with struck strings were the hammered dulcimers.  During the Middle Ages, there were several attempts at creating stringed keyboard instruments with struck strings, the earliest being the hurdy gurdy, which has uncertain origins. By the 17th century, the mechanisms of keyboard instruments such as the clavichord and the harpsichord were well known. In a clavichord the strings are struck by tangents, while in a harpsichord they are plucked by quills. Centuries of work on the mechanism of the harpsichord in particular had shown the most effective ways to construct the case, soundboard, bridge, and keyboard.
The invention of the modern piano is credited to Bartolomeo Cristofori (1655-1731) of Padua, Italy, who was employed by Prince Ferdinand de Medici as the Keeper of the Instruments. He was an expert harpsichord maker and was well acquainted with the previous body of knowledge on stringed keyboard instruments. It is not known exactly when Cristofori first built a piano. An inventory made by his employers, the Medici family, indicates the existence of a piano by the year 1700; another document of doubtful authenticity indicates a date of 1698. The three Cristofori pianos that survive today date from the 1720s.
While the clavichord allowed expressive control of volume and sustain, it was too quiet for large performances. The harpsichord produced a sufficiently-loud sound, but had little expressive control over each note. The piano was likely formed as an attempt to combine loudness with control, avoiding the trade-offs of available instruments.
Cristofori’s great success was in solving, without any prior example, the fundamental mechanical problem of piano design: the hammer must strike the string, but not remain in contact with it (as a tangent remains in contact with a clavichord string) because this would damp the sound. Moreover, the hammer must return to its rest position without bouncing violently, and it must be possible to repeat a note rapidly. Cristofori’s piano action served as a model for the many different approaches to piano actions that followed. While Cristofori’s early instruments were made with thin strings and were much quieter than the modern piano, compared to the clavichord (the only previous keyboard instrument capable of minutely controlled dynamic nuance through the keyboard) they were considerably louder and had more sustaining power.
Cristofori’s new instrument remained relatively unknown until an Italian writer, Scipione Maffei, wrote an enthusiastic article about it (1711), including a diagram of the mechanism. This article was widely distributed, and most of the next generation of piano builders started their work because of reading it. One of these builders was Gottfried Silbermann, better known as an organ builder. Silbermann’s pianos were virtually direct copies of Cristofori’s, with one important addition: Silbermann invented the forerunner of the modern damper pedal, which lifts all the dampers from the strings at once.
Silbermann showed Johann Sebastian Bach one of his early instruments in the 1730s, but Bach did not like it at that time, claiming that the higher notes were too soft to allow a full dynamic range. Although this earned him some animosity from Silbermann, the criticism was apparently heeded. Bach did approve of a later instrument he saw in 1747, and even served as an agent in selling Silbermann’s pianos.
Piano making flourished during the late 18th century in the Viennese school, which included Johann Andreas Stein (who worked in Augsburg, Germany) and the Viennese makers Nannette Streicher (daughter of Stein) and Anton Walter. Viennese-style pianos were built with wood frames, two strings per note, and had leather-covered hammers. Some of these Viennese pianos had the opposite coloring of modern-day pianos; the natural keys were black and the accidental keys white. It was for such instruments that Wolfgang Amadeus Mozart composed his concertos and sonatas, and replicas of them are built today for use in authentic-instrument performance of his music. The pianos of Mozart’s day had a softer, clearer tone than today’s pianos or English pianos, with less sustaining power. The term fortepiano is nowadays often used to distinguish the 18th-century instrument from later pianos.
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In the period lasting from about 1790 to 1860, the Mozart-era piano underwent tremendous changes that led to the modern form of the instrument. This revolution was in response to a consistent preference by composers and pianists for a more powerful, sustained piano sound, and made possible by the ongoing Industrial Revolution with technological resources such as high-quality steel, called piano wire, for strings, and precision casting for the production of iron frames. Over time, the tonal range of the piano was also increased from the five octaves of Mozart’s day to the 7¼ or more octaves found on modern pianos.
Early technological progress owed much to the firm of Broadwood. John Broadwood joined with another Scot, Robert Stodart, and a Dutchman, Americus Backers, to design a piano in the harpsichord case—the origin of the “grand”. They achieved this in about 1777. They quickly gained a reputation for the splendour and powerful tone of their instruments, with Broadwood constructing ones that were progressively larger, louder, and more robustly constructed. They sent pianos to both Joseph Haydn and Ludwig van Beethoven, and were the first firm to build pianos with a range of more than five octaves: five octaves and a fifth during the 1790s, six octaves by 1810 (Beethoven used the extra notes in his later works), and seven octaves by 1820. The Viennese makers similarly followed these trends, however the two schools used different piano actions: Broadwoods were more robust, Viennese instruments were more sensitive.
By the 1820s, the center of innovation had shifted to Paris, where the Pleyel firm manufactured pianos used by Frédéric Chopin and the Érard firm manufactured those used by Franz Liszt. In 1821, Sébastien Érard invented the double escapement action, which permitted a note to be repeated even if the key had not yet risen to its maximum vertical position. This facilitated rapid playing of repeated notes, and this musical device was pioneered by Liszt. When the invention became public, as revised by Henri Herz, the double escapement action gradually became standard in grand pianos, and is still incorporated into all grand pianos currently produced.
One of the major technical innovations that helped to create the sound of the modern piano was the use of a strong iron frame. Also called the “plate”, the iron frame sits atop the soundboard, and serves as the primary bulwark against the force of string tension. The increased structural integrity of the iron frame allowed the use of thicker, tenser, and more numerous strings. In a modern grand the total string tension can exceed 20 tons. The single piece cast iron frame was patented in 1825 in Boston by Alpheus Babcock, combining the metal hitch pin plate (1821, claimed by Broadwood on behalf of Samuel Hervé) and resisting bars (Thom and Allen, 1820, but also claimed by Broadwood and Érard). Babcock later worked for the Chickering & Mackays firm who patented the first full iron frame for grand pianos in 1843. Composite forged metal frames were preferred by many European makers until the American system was fully adopted by the early 20th century.
Other innovations for the mechanism included the use of felt hammer coverings instead of layered leather hammers. Felt hammers, which were first introduced by Henri Pape in 1826, were a more consistent material, permitting wider dynamic ranges as hammer weights and string tension increased. The sostenuto pedal (see below), invented in 1844 by Jean Louis Boisselot and improved by the Steinway firm in 1874, allowed a wider range of effects.
Other important technical innovations of this era included changes to the way the piano was strung, such as the use of a “choir” of three strings rather than two for all but the lower notes, and the use of different stringing methods. With the over strung scale, also called “cross-stringing“, the strings are placed in a vertically overlapping slanted arrangement, with two heights of bridges on the soundboard instead of just one. This permits larger, but not necessarily longer, strings to fit within the case of the piano. Over stringing was invented by Jean-Henri Pape during the 1820s, and first patented for use in grand pianos in the United States by Henry Steinway, Jr. in 1859.
Duplex scaling: Treble strings of a 182 cm. grand piano. From lower left to upper right: dampers, main sounding length of strings, treble bridge, duplex string length, duplex bridge (long bar perpendicular to strings), hitchpins
With duplexes or aliquot scales, which was patented in 1872 by Theodore Steinway, the different components of string vibrations are controlled by tuning their secondary parts in octave relationships with the sounding lengths. Similar systems developed by Blüthner (1872), as well as Taskin (1788), and Collard (1821) used more distinctly ringing undamped vibrations to modify tone.
Some early pianos had shapes and designs that are no longer in use. The square piano had horizontal strings arranged diagonally across the rectangular case above the hammers and with the keyboard set in the long side. This design is attributed to Gottfried Silbermann or Christian Ernst Friderici on the continent, and Johannes Zumpe or Harman Vietor in England and it was improved by changes first introduced by Guillaume-Lebrecht Petzold in France and Alpheus Babcock in the United States. Square pianos were built in great numbers through the 1840s in Europe and the 1890s in America, and saw the most visible changes of any type of piano: the celebrated iron framed over strung squares manufactured by Steinway & Sons were more than two and a half times the size of Zumpe’s wood framed instruments from a century before. Their overwhelming popularity was due to inexpensive construction and price, although their performance and tone were often limited by simple actions and closely spaced strings.
The mechanism in upright pianos is perpendicular to the keys.
The tall, vertically strung upright grand was arranged like a grand set on end, with the soundboard and bridges above the keys, and tuning pins below them. The term was later revived by many manufacturers for advertising purposes. Giraffe, pyramid and lyre pianos were arranged in a somewhat similar fashion in evocatively shaped cases.
The very tall cabinet piano was introduced about 1805 and was built through the 1840s. It had strings arranged vertically on a continuous frame with bridges extended nearly to the floor, behind the keyboard and very large sticker action. The short cottage upright or pianino with vertical stringing, made popular by Robert Wornum around 1815, was built into the 20th century. They are informally called birdcage pianos because of their prominent damper mechanism. Pianinos were distinguished from the oblique, or diagonally strung upright made popular in France by Roller & Blanchet during the late 1820s. The tiny spinet upright was manufactured from the mid-1930s until recent times. The low position of the hammers required the use of a “drop action” to preserve a reasonable keyboard height.
Modern upright and grand pianos attained their present forms by the end of the 19th century. Improvements have been made in manufacturing processes, and many individual details of the instrument continue to receive attention.
History and musical performance
Much of the most widely admired piano repertoire, for example, that of Haydn, Mozart, and Beethoven, was composed for a type of instrument that is rather different from the modern instruments on which this music is normally performed today. Even the music of the Romantics, including Liszt, Chopin, Robert Schumann, Felix Mendelssohn and Johannes Brahms, was written for pianos substantially different from ours. Modern piano
A schematic depiction of the construction of a pianoforte (Part names are listed in the illustration’s file)
Modern pianos come in two basic configurations (with subcategories): the grand piano and the upright piano.
In grand pianos, the frame and strings are horizontal, with the strings extending away from the keyboard. There are several sizes of grand piano. A rough generalization distinguishes the concert grand (between about 2.2 m and 3 m/9.84 feet long) from the parlor grand or boudoir grand (about 1.7 m to 2.2 m) and the smaller baby grand.
All else being equal, longer pianos with longer strings have larger, richer sound and lower inharmonicity of the strings. Inharmonicity is the degree to which the frequencies of overtones (known as partials, partial tones, or harmonics) depart from whole multiples of the fundamental frequency. Pianos with shorter and thicker strings (e.g., baby grands) have more inharmonicity. The longer strings on a concert grand can vibrate more accurately than the shorter, thicker strings on a baby grand, which means that a concert grand’s strings will have truer overtones. This allows the strings to be tuned closer to equal temperament in relation to the standard pitch with less “stretching” in the piano tuning. Full-size grands are usually used for public concerts, whereas smaller grands, introduced by Sohmer & Co. in 1884, are often chosen for domestic use where space and cost are considerations.
A grand piano action has a repetition lever for each key. If the key is pressed repeatedly and fairly quickly this repetition lever catches the hammer close to the strings, which assists the speed and control of repeated notes and trills.
Upright pianos, also called vertical pianos, are more compact because the frame and strings are vertical. The hammers move horizontally, and are returned to their resting position by springs, which are prone to wear and tear. Upright pianos with unusually tall frames and long strings are sometimes called upright grand pianos. Some authors classify modern pianos according to their height and to modifications of the action that are necessary to accommodate the height.
- Studio pianos are around 42 to 45 inches tall. This is the shortest cabinet that can accommodate a full-sized action located above the keyboard.
- Console pianos have a compact action (shorter hammers), and are a few inches shorter than studio models.
- The top of a spinet model barely rises above the keyboard. The action is located below, operated by vertical wires that are attached to the backs of the keys.
- Anything taller than a studio piano is called an upright.
Toy pianos began to be manufactured in the 19th century.
In 1863, Henri Fourneaux invented the player piano, which plays itself from a piano roll without the need for a pianist. A performance is recorded onto rolls of paper with perforations, and the player piano replays the performance using pneumatic devices. Modern equivalents of the player piano include the Bösendorfer CEUS and the Yamaha Disklavier, using solenoids and MIDI rather than pneumatics and rolls.
A silent piano is an acoustic piano having an option to silence the strings by means of an interposing hammer bar. They are designed for private silent practice.
The transposing piano was invented in 1801 by Edward Ryley. It has a lever under the keyboard used to move the keyboard relative to the strings so that a pianist can play in a familiar key while the music sounds in a different key.
The prepared piano, encountered in some contemporary art music, is a grand piano with objects placed inside it to alter its sound, or that has had its mechanism changed in some other way. The scores for music for prepared piano specify the modifications, for example instructing the pianist to insert pieces of rubber, or paper, or metal screws or washers, in between the strings. These either mute the strings or alter their timbre.
Available since the 1980s, digital pianos use digital sampling technology to reproduce the sound of each piano note. Digital pianos can be sophisticated, with features including working pedals, weighted keys, multiple voices, and MIDI interfaces. However, when the damper pedal (see below) is depressed on such an instrument, there are no strings to vibrate sympathetically. Physical models of sympathetic vibration are incorporated into the synthesis software of some higher end digital pianos, such as the Yamaha Clavinova series, or the KAWAI MP8 series.
With the advent of powerful desktop computers, highly realistic pianos have become available as affordable software modules. Some of these modules, such as Synthogy’s Ivory released in 2004, use multi-gigabyte piano sample sets with as many as 90 recordings, each lasting many seconds, for each of the 88 (some have 81) keys under different conditions, augmented by additional samples to emulate sympathetic resonance, key release, the drop of the dampers, and simulations of piano techniques like re-pedaling. Some other software modules, such as Modartt’s Pianoteq released in 2006, use no samples whatsoever and are a pure synthesis of all aspects of the physicalities that go into the creation of a real piano’s sound.
In recent times, piano manufactures have superseded the old fashioned pianola or player piano with new innovative pianos that play themselves via a CD or MP3 Player. Similar in concept to a player piano, the PianoDisc or iQ systems installed in select pianos will ‘play themselves’ when prompted by a certain file format designed to be interpreted by software installed and connected to the piano. Such additions are quite expensive, often doubling the cost of a piano and are available in both upright and grand pianos.
Almost every modern piano has 36 black keys and 52 white keys for a total of 88 keys (seven octaves plus a minor third, from A0 to C8). Many older pianos only have 85 keys (seven octaves from A0 to A7), while some manufacturers extend the range further in one or both directions.
Some Bösendorfer pianos extend the normal range downwards to F0, with one other model going as far as a bottom C0, making a full eight octave range. These extra keys are sometimes hidden under a small hinged lid that can be flipped down to cover the keys in order to avoid visual disorientation in a pianist unfamiliar with the extended keyboard. On others, the colors of the extra white keys are reversed (black instead of white).
The extra keys are added primarily for increased resonance from the associated strings; that is, they vibrate sympathetically with other strings whenever the damper pedal is depressed and thus give a fuller tone. Only a very small number of works composed for piano actually use these notes. More recently, the Stuart and Sons company has also manufactured extended-range pianos, with the first 102 key piano. On their instruments, the frequency range extends from C0 to F8, which is the widest practical range for the acoustic piano. The extra keys are the same as the other keys in appearance.
Small studio upright acoustical pianos with only 65 keys have been manufactured for use by roving pianists. Known as gig pianos and still containing a cast iron harp, these are comparatively lightweight and can be easily transported to and from engagements by only two people. As their harp is longer than that of a spinet or console piano, they have a stronger bass sound that to some pianists is well worth the trade-off in range that a reduced key-set offers.
The toy piano manufacturer Schoenhut started manufacturing both grands and uprights with only 44 or 49 keys, and shorter distance between the keyboard and the pedals. These pianos are true pianos with action and strings. The pianos were introduced to their product line in response to numerous requests in favor of it.
 Standard pedals
Pianos have had pedals, or some close equivalent, since the earliest days. (In the 18th century, some pianos used levers pressed upward by the player’s knee instead of pedals.) Most grand pianos in the US have three pedals: the soft pedal (una corda), sostenuto, and sustain pedal (from left to right, respectively), while in Europe, the standard is two pedals: the soft pedal and the sustain pedal. Most modern upright pianos also have three pedals: soft pedal, practice pedal and sustain pedal, though older or cheaper models may lack the practice pedal. Again, in Europe the standard for upright pianos is two pedals: the soft and the sustain pedals.
The sustain pedal (or, damper pedal) is often simply called “the pedal”, since it is the most frequently used. It is placed as the rightmost pedal in the group. It lifts the dampers from all keys, sustaining all played notes. In addition, it alters the overall tone by allowing all strings, even the ones not directly played, to reverberate.
The soft pedal or una corda pedal is placed leftmost in the row of pedals. In grand pianos, it shifts the entire action, including the keyboard, to the right, so that the hammers hit only one of the three strings for each note (hence the name una corda, or ‘one string’). The effect is to soften the note as well as to change the tone. In uprights, this action is not possible, and so the pedal moves the hammers closer to the strings, allowing the hammers to hit the strings with less kinetic energy to produce a softer sound, but with no change in timbre.
On grand pianos, the middle pedal is a sostenuto pedal. This pedal keeps raised any damper that was already raised at the moment the pedal is depressed. This makes it possible to sustain some notes (by depressing the sostenuto pedal before notes to be sustained are released) while the player’s hands are free to play addditional notes (which will not be sustained). This can be useful for musical passages with pedal points and other otherwise tricky or impossible situations.
On many upright pianos, there is a middle pedal called the ‘practice’ or celeste pedal. This drops a piece of felt between the hammers and strings, greatly muting the sounds. Often this pedal can be shifted while depressed, into a “locking” position.
There are also non-standard variants. On some pianos (grands and verticals), the middle pedal can be a bass sustain pedal: that is, when it is depressed, the dampers lift off the strings only in the bass section. This pedal would be used only when a pianist needs to sustain a single bass note or chord over many measures, while playing the melody in the treble section. On the Stuart and Sons piano as well as the largest Fazioli piano, there is a fourth pedal to the left of the principal three. This fourth pedal works in the same way as the soft pedal of an upright piano, moving the hammers closer to the strings.
 Unusual pedals
The rare transposing piano, of which Irving Berlin possessed an example, has a middle pedal that functions as a clutch that disengages the keyboard from the mechanism, enabling the keyboard to be moved to the left or right with a lever. The entire action of the piano is thus shifted to allow the pianist to play music written in one key so that it sounds in a different key. The pedalier piano, or pedal piano, is a rare type of piano that includes a pedalboard, enabling bass register notes to be played with the feet, as is standard on the organ. There are two types of pedal piano: the pedal board may be an integral part of the instrument, using the same strings and mechanism as the manual keyboard, or, less frequently, it may consist of two independent pianos (each with its separate mechanics and strings), which are placed one above the other, a regular piano played by the hands and a bass-register piano played by the feet.
Many parts of a piano are made of materials selected for sturdiness. In quality pianos, the outer rim of the piano is made of a hardwood, normally maple or beech. According to Harold A. Conklin, the purpose of a sturdy rim is so that “the vibrational energy will stay as much as possible in the soundboard instead of dissipating uselessly in the case parts, which are inefficient radiators of sound.”
View from below of a 182-cm grand piano. In order of distance from viewer: softwood braces, tapered soundboard ribs, soundboard. The metal rod at lower right is a humidity control device.
The rim is normally made by laminating flexible strips of hardwood to the desired shape, a system that was developed by Theodore Steinway in 1880. The thick wooden braces at the bottom (grands) or back (uprights) of the piano are not as acoustically important as the rim, and are often made of a softwood, even in top-quality pianos, in order to save weight. The requirement of structural strength, fulfilled with stout hardwood and thick metal, makes a piano heavy; even a small upright can weigh 136 kg (300 lb), and the Steinway concert grand (Model D) weighs 480 kg (990 lb). The largest piano built, the Fazioli F308, weighs 691 kg (1520 lb).
The pinblock, which holds the tuning pins in place, is another area of the piano where toughness is important. It is made of hardwood, (often maple) and generally is laminated (built of multiple layers) for additional strength and gripping power. Piano strings (also called piano wire), which must endure years of extreme tension and hard blows, are made of high quality steel. They are manufactured to vary as little as possible in diameter, since all deviations from uniformity introduce tonal distortion. The bass strings of a piano are made of a steel core wrapped with copper wire, to increase their mass whilst retaining flexibility. If the strings in the treble section were only single, they would be quiet compared with the bass strings because of their smaller diameter, so they are doubled in higher and tripled in the highest octaves.
The plate, or metal frame, of a piano is usually made of cast iron. It is advantageous for the plate to be quite massive. Since the strings are attached to the plate at one end, any vibrations transmitted to the plate will result in loss of energy to the desired (efficient) channel of sound transmission, namely the bridge and the soundboard. Some manufacturers now use cast steel in their plates, for greater strength. The casting of the plate is a delicate art, since the dimensions are crucial and the iron shrinks by about one percent during cooling.
The inclusion in a piano of an extremely large piece of metal is potentially an aesthetic handicap, which piano makers overcome by polishing, painting and decorating the plate. Plates often include the manufacturer’s ornamental medallion and can be strikingly attractive. In an effort to make pianos lighter, Alcoa worked with Winter and Company piano manufacturers to make pianos using an aluminum plate during the 1940s. The use of aluminum for piano plates, however, did not become widely accepted and was discontinued.
The numerous grand parts and upright parts of a piano action are generally hardwood (e.g. maple, beech. hornbeam). However, since World War II, plastics have become available. Early plastics were incorporated into some pianos in the late 1940s and 1950s, but proved disastrous because they crystallized and lost their strength after only a few decades of use. The Steinway firm once incorporated Teflon, a synthetic material developed by DuPont, for some grand action parts in place of cloth, but ultimately abandoned the experiment due to an inherent “clicking” that invariably developed over time. (Also Teflon is “humidity stable” whereas the wood adjacent to the Teflon will swell and shrink with humidity changes, causing problems.) More recently, the Kawai firm has built pianos with action parts made of more modern and effective plastics such as carbon fiber; these parts have held up better and have generally received the respect of piano technicians.
The part of the piano where materials probably matter more than anywhere else is the soundboard. In quality pianos, this is made of solid spruce (that is, spruce boards glued together at their edges). Spruce is chosen for its high ratio of strength to weight. The best piano makers use close-grained, quarter-sawn, defect-free spruce, and make sure that it has been carefully dried over a long period of time before making it into soundboards. In cheap pianos, the soundboard is often made of plywood.
Piano keys are generally made of spruce or basswood, for lightness. Spruce is normally used in high-quality pianos. Traditionally, the black keys were made from ebony and the white keys were covered with strips of ivory, but since ivory-yielding species are now endangered and protected by treaty, plastics are now almost exclusively used. Also, ivory tends to chip more easily than plastic. Legal ivory can still be obtained in limited quantities. The Yamaha firm invented a plastic called “Ivorine” or “Ivorite” that mimics the look and feel of ivory; it has since been imitated by other makers.
 Care and maintenance
Pianos need regular tuning to keep them up to pitch, which is usually the internationally recognized standard concert pitch of A4 = 440 Hz. The hammers of pianos are voiced to compensate for gradual hardening, and other parts also need periodic regulation. Aged and worn pianos can be rebuilt or reconditioned. Often, by replacing a great number of their parts, they can be made to perform as well as new pianos. Older pianos are often more settled and produce a warmer tone.
Piano moving should be done by trained piano movers using adequate manpower and the correct equipment for any particular piano’s size and weight. Pianos are heavy yet delicate instruments. Over the years, professional piano movers have developed special techniques for transporting both grands and uprights, which prevent damage to the case and to the piano’s mechanics.