Piano pedals are foot-operated levers at the base of a piano that change the instrument's sound in various ways. Modern pianos usually have three pedals: from left to right, the soft pedal (or una corda), the sostenuto pedal, and the sustaining pedal (or damper pedal). Some pianos omit the sostenuto pedal, or have a middle pedal with a different purpose, such as a muting function, also known as the silent piano.
The development of the piano's pedals is an evolution that began in the very earliest days of the piano and continued through the late 19th century. Throughout the years, the piano had as few as one modifying stop, and as many as six or more, before finally arriving at its current configuration of three.
Individual pedals
Damper pedal
The damper pedal, sustain pedal, or sustaining pedal is to the right of the other pedals, and is used more often than the other pedals. It raises all the dampers off the strings so that they keep vibrating after the player releases the key. In effect, the damper pedal makes every string on the piano a sympathetic string, creating a rich tonal quality. This effect may be behind the saying that the damper pedal is "...the soul of the piano." The damper pedal has the secondary function of allowing the player to connect into a legato texture notes that otherwise could not thus be played.
Soft pedal
The soft pedal, or pedal, was invented by Bartolomeo Cristofori. It was the first mechanism invented to modify the piano's sound. This function is typically operated by the left pedal on modern pianos. Neither of its common names—soft pedal or pedal—completely describe the pedal's function. The primarily modifies the timbre, not just the volume, of the piano.Siepmann, J. (1996). The Piano: The Complete Illustrated Guide to the World's Most Popular Musical Instrument, Hal Leonard & Carlton Books, 17. Soon after its invention, virtually all makers integrated the as a standard fixture.Banowetz, J. (1985). The Pianist's Guide to Pedaling, Bloomington: Indiana University Press, p. 5. On Cristofori's pianos, the una corda mechanism was operated by a hand stop, not a pedal. The stop was a knob on the side of the keyboard. When the una corda was activated, the entire action shifted to the right so that the hammers hit one string () instead of two strings (due corde).Parakilas, J., et al. (1999). Piano Roles: Three Hundred Years of Life with the Piano, New Haven and London: Yale University Press, 48. Dominic Gill says that when the hammers strike only one string, the piano "produces a softer, more ethereal tone".Gill, D., ed. (1981). The Book of the Piano, Ithaca: Cornell University Press, 27.
By the late 18th century, piano builders had begun triple stringing the notes on the piano. This change, affecting the 's function, is described by Joseph Banowetz:
The sound of the on early pianos created a larger difference in color and timbre than it does on the modern piano. On the modern piano, the pedal makes the hammers of the treble section hit two strings instead of three. In the case of the bass strings, the hammer normally strikes either one or two strings per note. The lowest bass notes on the piano are a single thicker string. For these notes, the action shifts the hammer so that it strikes the string on a different, lesser-used part of the hammer nose.Williams, J. (2002). The Piano: An Inspirational Guide to the Piano and Its Place in History, New York: Billboard Books, 45.
Edwin Good states,
Beethoven took advantage of the ability of his piano to create a wide range of tone color in two of his piano works. In his Piano Concerto No. 4, Beethoven specifies the use of , , and . He calls for , then , gradually two and then all strings, in Sonata Op. 106.
Half-blow pedal On the modern upright piano, the left pedal is not truly an , because it does not shift the action sideways. The strings run at such an oblique angle to the hammers that if the action moved sideways, the hammer might strike one string of the wrong note.Good 1982:22. A more accurate term for the left pedal on an upright piano is the half-blow pedal. When the pedal is activated, the hammers move closer to the strings, so that there is less distance for the hammer to swing.
Sostenuto pedal
The last pedal added to the modern grand was the middle pedal, the sostenuto. Using this pedal, a pianist can sustain selected notes, while other notes remain unaffected. The sostenuto was first shown at the French Industrial Exposition of 1844 in Paris, by Boisselot & Fils, a Marseille company. French piano builders Alexandre François Debain and Claude Montal built sostenuto mechanisms in 1860 and 1862, respectively. These innovative efforts did not immediately catch on with other piano builders. In 1874, Albert Steinway perfected and patented the sostenuto pedal.Williams 2002:26. He began to advertise it publicly in 1876, and soon the Steinway company was including it on all of their grands and their high-end uprights. Other American piano builders quickly adopted the sostenuto pedal into their piano design. The adoption by European manufacturers went far more slowly and was essentially completed only in recent times.For a reference describing the lack of sostenuto pedals on European pianos as of 1982, see Good 1982:22. The websites of Bechstein, Bösendorfer, Petrof, and Fazioli as of 2015 all describe their top-of-the-line instruments as including the sostenuto, and for Grotrian it is an available option.
The term "sostenuto" ("sustained") can be confusing in light of the pre-existing sustain (or "damper") pedal on modern pianos. The sostenuto pedal was originally called the "tone-sustaining" pedal, reflecting its role in sustaining a single tone or group of tones.
The sostenuto pedal holds up only dampers that were already raised at the moment that it was depressed. The effect, therefore, is that when the player plays one or more keys, depresses the pedal, and subsequently releases those keys, the played notes are sustained until the pedal is lifted. Any subsequently played notes played whilst the pedal is already depressed are damped normally when released.
Uses for the sostenuto pedal include playing transcriptions of organ music, where selective sustaining of notes can substitute for the organ's held notes in its pedals; or in contemporary music, especially spectral music. The sostenuto pedal is typically played with the right foot.
Other common uses for the middle pedal
It is common to find uprights and even grand pianos that lack a middle pedal. Even if a piano has a middle pedal, one cannot assume it is a true sostenuto, for there are many other functions a middle pedal can have other than that of sostenuto. Often an upright's middle pedal is another half-blow pedal, like the one on the left, except that the middle pedal slides into a groove to stay engaged. Sometimes, the middle pedal may only operate the bass dampers.Good, E. (1982). Giraffes, Black Dragons, and Other Pianos: A Technological History From Cristofori to the Modern Concert Grand, Stanford: Stanford University Press, 22. The middle pedal may sometimes lower a muffler rail of felt between the hammers and the strings to mute and significantly soften the sound, so that one can practice quietly (also known as a "Practice Rail").Crombie 1995:94. True sostenuto is rare on uprights, except for more expensive models such as those from Steinway and Bechstein. They are more common on digital pianos as the effect is straightforward to mimic in software.
Other pedals Among other pedals sometimes found on early pianos are the lute stop, moderator or celeste, bassoon, buff, cembalo, and swell. The lute pedal created a pizzicato-type sound.Good 1982:74. The moderator, or celeste mechanism used a layer of soft cloth or leather between hammers and strings to provide a sweet, muted quality. According to Good, "[The piece of leather or cloth was] graduated in thickness across its short dimension. The farther down one pushed the pedal, the farther the rail lowered and the thicker the material through which the hammer struck the strings. With the thicker material, the sound was softer and more muffled. Such a stop was sometimes called a pianissimo stop."Good 1982:110.
The moderator stop was popular on Viennese pianos, and a similar mechanism is still sometimes fitted on upright pianos today in the form of the practice rail (see Sostenuto pedal, above). Joseph Banowetz states that for the bassoon pedal, paper or silk was placed over the bass strings to create "...a buzzing noise that listeners of the day felt resembled the sound of the bassoon."Banowetz 1985:5-6. The buff stop and cembalo stops seem similar to each other in method of manipulation and sound produced. The buff ("leather") stop used "...a narrow strip of soft leather ... pressed against the strings to give a dry, soft tone of little sustaining power." The cembalo stop pressed leather weights on the strings and modified the sound to make it resemble that of the harpsichord.Banowetz 1985:6 Johannes Pohlmann used a swell pedal on his pianos to raise and lower the lid of the piano to control the overall volume.Crombie 1995:18-19. Instead of raising and lowering the lid, the swell was sometimes operated by opening and closing slots in the sides of the piano case.
Famous for his pianos, Muzio Clementi was a composer and musician who founded a piano-building company, and was active in the designing of the pianos that his company built. The Clementi piano firm was later renamed Collard and Collard in 1830, two years before Clementi's death. Clementi added a feature called a harmonic swell. "[This pedal] introduced a kind of reverberation effect to give the instrument a fuller, richer sound. The effect uses the sympathetic vibrations set up in the untuned non-speaking length of the strings. Here the soundboard is bigger than usual to accommodate a second bridge (the 'bridge of reverberation')."Crombie 1995:31.
The Dolce Campana pedal pianoforte c. 1850, built by Boardman and Gray, New York, demonstrated yet another creative way of modifying the piano's sound. A pedal controlled a series of hammers or weights attached to the soundboard that would fall onto an equal number of screws, and created the sound of bells or the harp.Gill 1981:248. The Fazioli concert grand piano model F308 includes a fourth pedal to the left of the traditional three pedals. This pedal acts similarly to the "half-blow" pedal on an upright piano, in that it collectively moves the hammers somewhat closer to the strings to reduce the volume without changing the tone quality, as the una-corda does. The F308 is the first modern concert grand to offer such a feature.
Novelty pedals In the early years of piano development, many novelty pedals and stops were experimented with before finally settling on the three that are now used on the modern piano. Some of these pedals were meant to modify levels of volume, color, or timbre, while others were used for special effects, meant to imitate other instruments. Banowetz speaks of these novelty pedals: "At their worst, these modifications threatened to make the piano into a vulgar musical toy"; professional musicians did not like them.
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