1720 fortepiano by Italian maker Bartolomeo Cristofori
, the world's oldest surviving piano, Metropolitan Museum of Art, New York City
Early piano replica by the modern builder Paul McNulty, after Walter & Sohn, 1805
The piano was founded on earlier technological innovations in keyboard instruments. Pipe organs have been used since Antiquity, and as such, the development of pipe organs enabled instrument builders to learn about creating keyboard mechanisms for sounding pitches. The first string instruments with struck strings were the hammered dulcimers, which were used since the Middle Ages in Europe. During the Middle Ages, there were several attempts at creating stringed keyboard instruments with struck strings. By the 17th century, the mechanisms of keyboard instruments such as the clavichord and the harpsichord were well developed. In a clavichord, the strings are struck by tangents, while in a harpsichord, they are mechanically plucked by quills when the performer depresses the key. Centuries of work on the mechanism of the harpsichord in particular had shown instrument builders the most effective ways to construct the case, soundboard, bridge, and mechanical action for a keyboard intended to sound strings.
The invention of the piano is credited to Bartolomeo Cristofori (1655–1731) of Padua, Italy, who was employed by Ferdinando de' Medici, Grand Prince of Tuscany, as the Keeper of the Instruments. Cristofori was an expert harpsichord maker, and was well acquainted with the body of knowledge on stringed keyboard instruments; this knowledge of keyboard mechanisms and actions helped him to develop the first pianos. 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. The three Cristofori pianos that survive today date from the 1720s. Cristofori named the instrument un cimbalo di cipresso di piano e forte ("a keyboard of cypress with soft and loud"), abbreviated over time as pianoforte, fortepiano, and later, simply, piano.
Cristofori's great success was designing a stringed keyboard instrument in which the notes are struck by a hammer. The hammer must strike the string, but not remain in contact with it, because this would damp the sound and stop the string from vibrating and making sound. This means that after striking the string, the hammer must be lifted or raised off the strings. Moreover, the hammer must return to its rest position without bouncing violently, and it must return to a position in which it is ready to play almost immediately after its key is depressed so the player can repeat the same note rapidly. Cristofori's piano action was a model for the many approaches to piano actions that followed in the next century.
Cristofori's early instruments were made with thin strings, and were much quieter than the modern piano, but they were much louder and with more sustain in comparison to the clavichord—the only previous keyboard instrument capable of dynamic nuance via the weight or force with which the keyboard is played. While the clavichord allows expressive control of volume and sustain, it is relatively quiet. The harpsichord produces a sufficiently loud sound, especially when a coupler joins each key to both manuals of a two-manual harpsichord, but it offers no dynamic or expressive control over each note. The piano offers the best of both instruments, combining the ability to play loudly and perform sharp accents.
Cristofori's new instrument remained relatively unknown until an Italian writer, Scipione Maffei, wrote an enthusiastic article about it in 1711, including a diagram of the mechanism, that was translated into German and widely distributed. Most of the next generation of piano builders started their work based on reading this article. 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 sustain pedal, which lifts all the dampers from the strings simultaneously. This innovation allows the pianist to sustain the notes that they have depressed even after their fingers are no longer pressing down the keys. As such, by holding a chord with the sustain pedal, pianists can relocate their hands to a different register of the keyboard in preparation for a subsequent section.
Grand piano by Louis Bas of Villeneuve-lès-Avignon
, 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.
Silbermann showed Johann Sebastian Bach one of his early instruments in the 1730s, but Bach did not like the instrument at that time, saying 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. "Instrument: piano et forte genandt"—a reference to the instrument's ability to play soft and loud—was an expression that Bach used to help sell the instrument when he was acting as Silbermann's agent in 1749.
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 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 in the 21st century for use in authentic-instrument performance of his music. The pianos of Mozart's day had a softer tone than 21st century pianos or English pianos, with less sustaining power. The term fortepiano now distinguishes these early instruments (and modern re-creations) from later pianos.
In the period from about 1790 to 1860, the Mozart-era piano underwent tremendous changes that led to the modern structure of the instrument. This revolution was in response to a preference by composers and pianists for a more powerful, sustained piano sound, and made possible by the ongoing Industrial Revolution with resources such as high-quality piano wire for strings, and precision casting for the production of massive iron frames that could withstand the tremendous tension of the strings. Over time, the tonal range of the piano was also increased from the five octaves of Mozart's day to the seven octave (or more) range found on today's pianos.
Broadwood square action (click for page with legend)
Early technological progress in the late 1700s 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". This was achieved by about 1777. They quickly gained a reputation for the splendour and powerful tone of their instruments, with Broadwood constructing pianos 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 used a more robust action, whereas Viennese instruments were more sensitive.
Erard square action (click for page with legend)
By the 1820s, the center of piano 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 incorporated a repetition lever (also called the balancier) that permitted repeating a note even if the key had not yet risen to its maximum vertical position. This facilitated rapid playing of repeated notes, a musical device exploited 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 in the 2000s. Other improvements of the mechanism included the use of firm felt hammer coverings instead of layered leather or cotton. Felt, which was first introduced by Jean-Henri Pape in 1826, was 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 copied by the Steinway firm in 1874, allowed a wider range of effects.
One innovation that helped create the powerful sound of the modern piano was the use of a massive, strong, cast 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 that can exceed 20 tons (180 kilonewtons) in a modern grand piano. 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. The increased structural integrity of the iron frame allowed the use of thicker, tenser, and more numerous strings. In 1834, the Webster & Horsfal firm of Birmingham brought out a form of piano wire made from cast steel; it was "so superior to the iron wire that the English firm soon had a monopoly." But a better steel wire was soon created in 1840 by the Viennese firm of Martin Miller, and a period of innovation and intense competition ensued, with rival brands of piano wire being tested against one another at international competitions, leading ultimately to the modern form of piano wire.
Several important advances included changes to the way the piano was strung. The use of a "choir" of three strings, rather than two for all but the lowest notes, enhanced the richness and complexity of the treble. The use of a Capo d’Astro bar instead of agraffes in the uppermost treble allowed the hammers to strike the strings in their optimal position, greatly increasing that area’s power. The implementation of over-stringing (also called cross-stringing), in which the strings are placed in two separate planes, each with its own bridge height, allowed greater length to the bass strings and optimized the transition from unwound tenor strings to the iron or copper-wound bass strings. Over-stringing was invented by Pape during the 1820s, and first patented for use in grand pianos in the United States by Henry Steinway Jr. in 1859.
Duplex scaling of an 1883 Steinway
Model 'A'. From lower left to upper right: main sounding length of strings, treble bridge, duplex string length, duplex bar (nickel-plated bar parallel to bridge), hitchpins, plate strut with bearing bolt, plate hole
Some piano makers added variations to enhance the tone of each note, such as Pascal Taskin (1788), Collard & Collard (1821), and Julius Blüthner, who developed Aliquot stringing in 1893. These systems were used to strengthen the tone of the highest register of notes on the piano, which up till this time were viewed as being too weak-sounding. Each used more distinctly ringing, undamped vibrations of sympathetically vibrating strings to add to the tone, except the Blüthner Aliquot stringing, which uses an additional fourth string in the upper two treble sections. While the hitchpins of these separately suspended Aliquot strings are raised slightly above the level of the usual tri-choir strings, they are not struck by the hammers but rather are damped by attachments of the usual dampers. Eager to copy these effects, Theodore Steinway invented duplex scaling, which used short lengths of non-speaking wire bridged by the "aliquot" throughout much of upper the range of the piano, always in locations that caused them to vibrate sympathetically in conformity with their respective overtones—typically in doubled octaves and twelfths.
Variations in shape and design
Some early pianos had shapes and designs that are no longer in use. The square piano (not truly square, but rectangular) was cross strung at an extremely acute angle above the hammers, with the keyboard set along the long side. This design is attributed to Christian Ernst Friderici, a pupil of Gottfried Silbermann, in Germany, and Johannes Zumpe 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 the United States, and saw the most visible change of any type of piano: the 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 tone and performance were limited by narrow soundboards, simple actions and string spacing that made proper hammer alignment difficult.
The mechanism and strings in upright pianos are 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. "Giraffe pianos", "pyramid pianos" and "lyre pianos" were arranged in a somewhat similar fashion, using 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. The oblique upright, popularized in France by Roller & Blanchet during the late 1820s, was diagonally strung throughout its compass. 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, 2000-era forms by the end of the 19th century. While improvements have been made in manufacturing processes, and many individual details of the instrument continue to receive attention, and a small number of acoustic pianos are produced with MIDI recording and sound module-triggering capabilities, the 19th century was the era of the most dramatic innovations and modifications of the instrument.