Tuning
The viola's four strings are normally tuned in fifths: the lowest string is C3 (an octave below middle C), with G3, D4 and A4 above it. This tuning is exactly one fifth below the violin, so that they have three strings in common—G, D, and A—and is one octave above the cello.
Each string of a viola is wrapped around a peg near the scroll and is tuned by turning the peg. Tightening the string raises the pitch; loosening the string lowers the pitch. The 'A' string is normally tuned first, typically to a pitch of 440 Hz or 442 Hz. The other strings are then tuned to it in intervals of perfect fifths, sometimes by bowing two strings simultaneously. Most violas also have adjusters, also called 'fine tuners', that are used to make finer changes. These permit the tension of the string to be adjusted by rotating a small knob at the opposite or tailpiece end of the string. Such tuning is generally easier to learn than using the pegs, and adjusters are usually recommended for younger players and put on smaller violas, although pegs and adjusters are usually used in conjunction with one another. Adjusters work best, and are most useful, on metal strings. It is common to use one on the 'A' string, even if the others are not equipped with them. Some violists reverse the stringing of the C and G pegs, so that the thicker C string does not turn so severe an angle over the nut, although this is uncommon.
Small, temporary tuning adjustments can also be made by stretching a string with the hand. A string may be tuned down by pulling it above the fingerboard, or tuned up by pressing the part of the string in the pegbox. These techniques may be useful in performance, reducing the ill effects of an out-of-tune string until an opportunity to tune properly.
The tuning C-G-D-A is used for the great majority of all viola music. However, other tunings are occasionally employed, both in classical music, where the technique is known as scordatura, and in some folk styles. Mozart, in his Sinfonia Concertante for Violin, Viola and Orchestra in E flat, wrote the viola part in D major and specified that the viola's strings were to be raised in pitch by a semitone: his intention was probably to give the viola a brighter tone so as to avoid it being overpowered by the rest of the ensemble. Lionel Tertis, in his transcription of the Elgar cello concerto, wrote the slow movement with the 'C' string tuned down to B flat, enabling the viola to play one passage an octave lower. Occasionally the 'C' string may also be tuned up to D.
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