A sustain pedal or sustaining pedal (also called damper pedal) is the most commonly used pedal

Piano pedals

Piano pedals are foot-operated levers at the base of a piano which change the instrument's sound in various ways. Modern pianos usually have three pedals, from left to right, the soft pedal , the sostenuto pedal , and the sustaining pedal...

 in a modern piano

Piano

The piano is a musical instrument played by means of a keyboard. It 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...

. It is typically the rightmost of two or three pedals. When pressed, the sustain pedal "sustain

Sustain

In music, sustain is a parameter of musical sound over time. As its name implies, it denotes the period of time during which the sound remains before it becomes inaudible, or silent.Additionally, sustain is the third of the four segments in an ADSR envelope...

s" all the damped strings on the piano by moving all the dampers away from the strings and allowing them to vibrate freely. All notes played will continue to sound until the pedal is released.

This lets the pianist sustain notes which would otherwise be out of reach, for instance in accompanying chords - and accomplish legato

Legato

In musical notation the Italian word legato indicates that musical notes are played or sung smoothly and connected. That is, in transitioning from note to note, there should be no intervening silence...

passages (smoothly connected notes) which would have no possible fingering otherwise. Raising the damper pedal also causes all the strings to vibrate sympathetically

Sympathetic resonance

Sympathetic resonance is a harmonic phenomenon wherein a formerly passive string or vibratory body responds to external vibrations to which it has a harmonic likeness. The classic example is demonstrated with two similar tuning-forks of which one is mounted on a wooden box. If the other one is...

 with whichever notes are being played, which greatly enriches the piano's tone.

History

A device similar to the damper pedal in effect was invented by the piano pioneer Gottfried Silbermann

Gottfried Silbermann

Gottfried Silbermann was an influential German constructor of keyboard instruments. He built harpsichords, clavichords, organs, and fortepianos; his modern reputation rests mainly on the latter two.-Life:...

; it was operated by the player's hands rather than a pedal. A later eminent early builder, Johann Andreas Stein

Johann Andreas Stein

Johann Andreas Stein, was an outstanding German maker of keyboard instruments, a central figure in the history of the piano...

, may have been the first to allow the player to lift the dampers while still playing; his device was controlled by a knee lever.

Until the onset of the Romantic era

Romantic music

Romantic music or music in the Romantic Period is a musicological and artistic term referring to a particular period, theory, compositional practice, and canon in Western music history, from 1810 to 1900....

 in music, the damper pedal was considered a special effect, used only in particular circumstances (see Piano history and musical performance

Piano history and musical performance

The piano has evolved technologically more than any other musical instrument, giving rise to difficult issues involving the performance of music written for earlier pianos.-Background:The earliest pianos by Cristofori The piano has evolved technologically more than any other musical instrument,...

). Only with the Romantics did a fairly constant use of the pedal come to be regarded as an essential element of piano sound.

Specifying pedaling in musical compositions

Appropriate use of the pedal is often left to the musician's discretion, but composers and music editors also use pedal marks to notate it. The most common symbol for this is a horizontal line below the grand staff, which lifts up and down with the pedal. An alternative (and older) notation is the use of indicating where the sustain pedal should be depressed, and an asterisk

Asterisk

An asterisk is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star. Computer scientists and mathematicians often pronounce it as star...

  showing where it should be lifted (see Moonlight Sonata for a famous example). Occasionally there is a general direction at the start of a movement instructing that the sustain pedal be applied continuously throughout. This may be marked with senza sordini ("without dampers"), or similar wording.

In General MIDI

General MIDI

General MIDI or GM is a standardized specification for music synthesizers that respond to MIDI messages. GM was developed by the MIDI Manufacturers Association and the Japan MIDI Standards Committee and first published in 1991...

, the sustain pedal information is controlled by Control Change number 64 (CC 64).http://emusician.com/mag/emusic_midi_2/

Sostenuto pedal

The sostenuto

Sostenuto

In music, sostenuto is a term from Italian which means "sustained." It occasionally implies a slowing of tempo, though more often it refers to a very legato style in which the notes are performed in a sustained manner beyond their normal values....

 pedal is a similar device that sustains only notes which are depressed at the time the pedal is depressed. It is the usual middle of three pedals; but in some upright pianos the middle pedal instead lowers a veil of felt between the hammers and the strings for quiet practising.

Other instruments

• Electronic keyboard
  Electronic keyboard
  An electronic keyboard is an electronic or digital keyboard instrument.The major components of a typical modern electronic keyboard are:...
  
  s often include a sustain pedal, a simple foot-operated switch which controls the electronic or digital synthesis so as to produce a sustain effect.
• Vibraphone
  Vibraphone
  The vibraphone, sometimes called the vibraharp or simply the vibes, is a musical instrument in the struck idiophone subfamily of the percussion family....
  
  s have sustain pedals that allow the metal bars to ring.
• Some tubular bell
  Tubular bell
  Tubular bells are musical instruments in the percussion family. Each bell is a metal tube, 30–38 mm in diameter, tuned by altering its length. Its standard range is from C4-F5, though many professional instruments reach G5 . Tubular bells are often replaced by studio chimes, which are a smaller...
  
  s have a sustain pedal.
• The Cimbalom has a sustain (or damper) pedal which allows its strings to ring or abruptly mutes them.