Editing Piano (section)

===Modern piano===
{{details|Innovations in the piano}}

{{listen
| type         = music
| header       = '''Comparison of piano sound'''
| filename     = Frederic Chopin - Opus 25 - Twelve Grand Etudes - c minor.ogg
| title        = 19th century piano sound
| description  = [[Frédéric Chopin]]'s [[Étude Op. 25, No. 12 (Chopin)|Étude Op. 25, No. 12]], on an [[Sébastien Érard|Erard]] piano made in 1851
| format       = [[Ogg]]
| filename2    = Frederic Chopin - etude no. 12 in c minor, op. 25.ogg
| title2       = Modern piano sound
| description2 = The same piece, on a modern piano
| format2      = [[Ogg]]
}}

In the period from about 1790 to 1860, the Mozart-era piano underwent significant 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,{{sfn|Hamilton|1998|p=62}} which was made possible by the ongoing [[Industrial Revolution]] with resources such as high-quality [[piano wire]] for strings and precision [[Metal casting|casting]] for the production of massive [[Cast iron|iron frames]] that could withstand the tremendous tension of the strings.<ref>{{Cite journal|last=Petersen|first=Sonja|date=2013|title=Craftsmen-Turned-Scientists? The Circulation of Explicit and Working Knowledge in Musical-Instrument Making, 1880–1960 |journal=Osiris |volume=28|issue=1|pages=212–231|doi=10.1086/671378|issn=0369-7827|jstor=10.1086/671378|s2cid=143443333}}</ref> Over time, the tonal range of the piano was also increased from the five [[octave]]s of Mozart's day to the seven octave (or more) range found on today's pianos.{{sfn|Giordano|2010|p=118}}

Early technological progress in the late 18th century owed much to the firm of [[Broadwood and Sons|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".{{sfn|Cole|2001|loc=¶8}} 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 [[Perfect fifth|fifth]] during the 1790s, six octaves by 1810 (Beethoven used the extra notes in his later works), and seven octaves by 1820. The [[Vienna|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.

By the 1820s, the center of piano innovation had shifted to Paris, where the [[Pleyel et Cie|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 return to its resting position.{{Sfn|Rowland|1998c|p=45}} 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 [[Jean-Henri Pape]] was the first to use in pianos in 1826, was a more consistent material, permitting wider dynamic ranges as hammer weights and string tension increased.{{sfn|Rowland|1998c|p=44}} The [[Sostenuto|sostenuto pedal]] ([[#Pedals|see below]]), invented in 1844 by [[Jean-Louis Boisselot]] and copied by the [[Steinway & Sons|Steinway]] firm in 1874,{{Sfn|Rowland|1998c|p=47}} allowed for a wider range of effects.<gallery mode="packed" heights="200">
File:Broadwood grand square action.svg|Broadwood square action
File:Erard double pilot action.svg|Erard square action
</gallery>One innovation that helped create the powerful sound of the modern piano was the use of a massive, strong, cast iron frame.{{Sfn|Richardson|1998|p=99}} Also called the "plate", the iron frame sits atop the [[Sound board (music)|soundboard]], and serves as the primary bulwark against the force of string [[Tension (physics)|tension]] that can exceed 20 tons ({{convert|40000|lbf|kN|disp=out|abbr=off}}) in total for a modern grand piano.{{sfn|Fletcher|Rossing|1998|p=353}} The single piece cast iron frame for square piano was patented in 1825 in [[Boston]] by [[Alpheus Babcock]],{{sfn|Isacoff|2012|p=74}}{{sfn|Rowland|1998c|p=43}} 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 and Sons|Chickering & Mackays]] firm who patented the first full iron frame for grand pianos in 1843.{{sfn|Rowland|1998c|p=43}} 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."{{sfn|Dolge|1911|p=124}} A better steel wire was developed in 1840 by the Viennese firm Martin Miller,{{sfn|Dolge|1911|p=124}} 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.{{sfn|Dolge|1911|pp = 125–126}}

Several important advances included changes to the way the piano was strung. There is one string for each note in the bass, two for each note in the tenor, and three for each note in the treble.{{sfn|Ripin|Pollens|2001a|loc = ¶4}} 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,{{sfn|Rowland|1998c|p=44}} 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.{{sfn|Rowland|1998c|p=44}}

[[File:DuplexScale.JPG|thumb|Duplex scaling of an 1883 [[Steinway & Sons|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),<ref>{{cite web |url=http://mediatheque.cite-musique.fr/masc/?INSTANCE=CITEMUSIQUE&URL=/ClientBookLineCIMU/recherche/NoticeDetailleByID.asp |title=Piano à queue |publisher=Médiathèque de la Cité de la musique |language=fr |url-status=live |archive-url=https://web.archive.org/web/20140419124012/http://mediatheque.cite-musique.fr/masc/?INSTANCE=CITEMUSIQUE&URL=%2Fclientbooklinecimu%2Frecherche%2FNoticeDetailleByID.asp |archive-date=19 April 2014 |access-date=5 April 2014}}</ref> [[Collard & Collard]] (1821), and [[Julius Blüthner]], who developed [[Aliquot stringing]] in 1893.{{Sfn|Ehrlich|Good|2001|loc=¶4}} These systems were used to strengthen the tone of the highest register of notes on the piano, which up until 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.{{Sfn|Ehrlich|Good|2001|loc=¶4}} 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 the upper 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.{{sfn|Giordano|2010|p=143–144}}