Overview of the Piano
The piano is one of the most popular instruments in the world. Widely used in classical and jazz music for solo performances, ensemble use, chamber music and accompaniment, the piano is also very popular as an aid to composing and rehearsal. The piano's versatility have made it one of the world's most familiar musical instruments.
Pressing a key on the piano's keyboard causes a felt-covered hammer to strike steel strings. The hammers rebound, allowing the strings to continue vibrating at their resonant frequency. These vibrations are transmitted through a bridge to a sound board that more efficiently couples the acoustic energy to the air. The sound would otherwise be no louder than that directly produced by the strings. When the key is released, a damper stops the string's vibration.
History of the Piano and Technological Advancement
The piano was 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. 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 Ferdinando de' Medici, as the Keeper of the Instruments. He was an expert harpsichord maker, and was well acquainted with the body of knowledge on stringed keyboard instruments.
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 solving, with no 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 dampen 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 was a model for the many different approaches to piano actions that followed. Cristofori's early instruments were made with thin strings, and were much quieter than the modern piano— but compared to the clavichord (the only previous keyboard instrument capable of dynamic nuance via the keyboard) they were much louder and had more sustain.
Cristofori's new instrument remained relatively unknown until Scipione Maffei wrote an enthusiastic article about it (1711). This article was widely distributed, and most of the next generation of piano builders started their work due to reading it. One of these builders was Gottfried Silbermann, whose 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 simultaneously.
Silbermann showed Johann Sebastian Bach one of his early instruments in the 1730s, but Bach did not like it then, claiming that the higher notes were too soft to allow a full dynamic range. The criticism was heeded, and Bach approved of a later instrument he saw in 1747, and later promoted Silbermann's pianos.
Piano-making flourished during the late 18th century in the Viennese school, which included Johann Andreas Stein . Viennese-style pianos were built with wood frames, two strings per note, and had leather-covered hammers. It was for such instruments that Wolfgang Amadeus Mozart composed his concertos and sonatas. The pianos of Mozart's day had a softer, more ethereal 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.
From 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 preference by composers and pianists for a more powerful, sustained piano sound, and made possible by the Industrial Revolution with resources such as high-quality 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 7⅓ or more octaves on modern pianos.
Technological progress was advanced by the Broadwood firm, whose principals designed a piano in the harpsichord case— the origin of the "grand" piano. They achieved this in about 1777 and gained a reputation for the powerful tone of their instruments. They sent pianos to 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.
In the 1820s, the center of innovation 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 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 pioneered by Liszt. When the invention became public, as revised by Henri Herz, the double escapement action became standard in grand pianos, and is incorporated into all grand pianos currently produced.
Other improvements of the mechanism included the use of felt hammer coverings instead of layered leather or cotton. Felt, which was first introduced by 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 Steinway in 1874, allowed a wider range of effects.
One innovation that helped 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 piano 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 important advances 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 lowest notes, and the implementation of an over-strung scale in which the strings are placed in two separate planes, each with its own bridge height. (This is also called "cross-stringing". Whereas earlier instruments' bass strings were a mere continuation of a single string plane, over-stringing placed the bass bridge behind and to the treble side of the tenor bridge area. This crossed the strings, with the bass strings in the higher plane.) This permitted a much narrower cabinet at the "nose" end of the piano, and optimized the transition from unwound tenor strings to the iron or copper-wrapped bass strings. Over-stringing was invented by Jean-Henri Pape during the 1820s, and first patented for use in grand pianos in the US by Henry Steinway, Jr. in 1859.
Some piano makers developed schemes to enhance the tone of each note. Julius Blüthner developed Aliquot stringing in 1893 as well as Pascal-Joseph Taskin (1788), and Collard & Collard (1821). Each used more distinctly ringing, undamped vibrations to modify 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. Some piano makers developed schemes to enhance the tone of each note. 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 range of the piano, always in locations that caused them to vibrate in conformity with their respective overtones— typically in doubled octaves and twelfths
The vertically strung “upright grand” piano was arranged like a grand set on its end, with the soundboard and bridges above the keys, and tuning pins below them. The very tall cabinet piano was introduced around 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.
Source: Wikipedia and company information