structural:scholar_edition
Tuning

Violins are tuned by turning the pegs in the pegbox under the scroll or by adjusting the fine tuner screws at the tailpiece. All violins have pegs; fine tuners (also called fine adjusters) are optional. Most fine tuners consist of a metal screw that moves a lever attached to the string end. They permit very small pitch adjustments much more easily than the pegs. Turning a fine tuner clockwise causes the pitch to become sharper (as the string is under more tension), and turning it counterclockwise, the pitch becomes flatter (as the string is under less tension). Fine tuners on all four of the strings are very helpful when using those with a steel core, and some players use them with synthetic strings. Since modern E strings are steel, a fine tuner is nearly always fitted for that string. Fine tuners are not used with gut strings, which are more elastic than steel or synthetic-core strings and do not respond adequately to the very small movements of fine tuners.

To tune a violin, the A string is first tuned to a standard pitch (usually A=440 Hz). (When accompanying or playing with a fixed-pitch instrument such as a piano or accordion, the violin tunes to the corresponding note on that instrument rather than to any other tuning reference. The oboe is generally the instrument used to tune orchestras where violins are present since its sound is penetrating and can be heard over the other woodwinds.) The other strings are then tuned against each other in intervals of perfect fifths by bowing them in pairs. A minutely higher tuning is sometimes employed for solo playing to give the instrument a brighter sound; conversely, Baroque music is sometimes played using lower tunings to make the violin's sound more gentle. After tuning, the instrument's bridge may be examined to ensure that it is standing straight and centered between the inner nicks of the f-holes; a crooked bridge may significantly affect the sound of an otherwise well-made violin.

After extensive playing, the tuning pegs and their holes can become worn, making the pegs more likely to slip under tension. A slipping peg leads to the pitch of the string dropping somewhat, or if the peg becomes completely loose, to the string completely losing tension. A violin in which the tuning pegs are slipping needs to be repaired by a luthier or violin repairperson. Peg dope or peg compound, used regularly, can delay the onset of such wear while allowing the pegs to turn smoothly.

The tuning G–D–A–E is used for most violin music, including Classical music, jazz, and folk music. Other tunings are occasionally employed; the G string, for example, can be tuned up to A. The use of nonstandard tunings in classical music is known as scordatura; in some folk styles, it is called cross tuning. One famous example of scordatura in classical music is Camille Saint-Saëns ' Danse Macabre, where the solo violin's E string is tuned down to E ♭ to impart an eerie dissonance to the composition. Other examples are the third movement of Contrasts, by Béla Bartók, where the E string is tuned down to E ♭ and the G tuned to a G ♯, Niccolò Paganini 's First Violin Concerto, where all four strings are designated to be tuned a semitone higher, and the Mystery Sonatas by Biber, in which each movement has different scordatura tuning.

In Indian classical music and Indian light music, the violin is likely to be tuned to D ♯ –A ♯ –D ♯ –A ♯ in the South Indian style. As there is no concept of absolute pitch in Indian classical music, musicians can use any convenient tuning to maintain these relative pitch intervals between the strings. Another prevalent tuning with these intervals is B ♭ –F–B ♭ –F, which corresponds to Sa–Pa–Sa–Pa in the Indian carnatic classical music style. In the North Indian Hindustani style, the tuning is usually Pa-Sa-Pa-Sa instead of Sa–Pa–Sa–Pa. This could correspond to F–B ♭ –F–B ♭, for instance. In Iranian classical music and Iranian light music, the violin has different tunings in each Dastgah; it is likely to be tuned (E–A–E–A) in Dastgah-h Esfahan or in Dastgāh-e Šur is (E–A–D–E) and (E–A–E–E), in Dastgāh-e Māhur is (E–A–D–A). In Arabic classical music, the A and E strings are lowered by a whole step, i.e. G–D–G–D. This is to ease playing Arabic maqams, especially those containing quarter tones.

While most violins have four strings, there are violins with additional strings, some with as many as seven. Seven is generally thought to be the maximum number of strings practical on a bowed string instrument; with more than seven strings, it would be impossible to play any particular inner string individually with the bow. Violins with seven strings are very rare. The extra strings on such violins typically are lower in pitch than the G-string; these strings are usually tuned (going from the highest added string to the lowest) to C, F, and B ♭. If the instrument's playing length, or string length from nut to bridge, is equal to that of an ordinary full-scale violin; i.e., a bit less than 13 inches (33 cm), then it may be properly termed a violin. Some such instruments are somewhat longer and should be regarded as violas. Violins with five strings or more are typically used in jazz or folk music. Some custom-made instruments have extra strings which are not bowed, but which sound sympathetically, due to the vibrations of the bowed strings.