The casual observer may mistake the viola for the violin because of their similarity in size, closeness in pitch range (the viola is a perfect fifth below the violin), and identical playing position. However, the viola's timbre sets it apart: its rich, dark-toned sonority is more full-bodied than the violin's. The viola's mellow voice is frequently used for playing inner harmonies, and it does not enjoy the wide solo repertoire or fame of the violin. The name of the instrument is properly ("vee-oh-la") but often incorrectly pronounced "vye-oh-la" as the woman's name and plant "Violet" is spoken.
Experiments with the size of the viola have tended to increase it in the interest of improving the instrument's sound. These include Hermann Ritter's "viola alta", an instrument measuring about intended for use in Richard Wagner's operas. The Tertis model viola, which has wider bouts and deeper ribs to promote a better viola tone, is another slightly "non-standard" shape which allows the player to use a larger instrument than normal. Many experiments with the acoustics of a viola, particularly increasing the size of the body, result in a much deeper tone of the instrument, making the instrument resemble the tone of a cello. Since many composers wrote for a traditional-sized viola, changes in the tone of a viola, particularly in orchestral music, can have unintended consequences on the balance in ensembles.
More recent (and more radically-shaped) innovations address the ergonomic problems of playing the viola by making it shorter and lighter while finding ways to keep the traditional sound. These include Otto Erdesz "cutaway" viola (which has one shoulder cut out to make shifting easier); the "Oak Leaf" viola (which has two extra bouts); viol shaped violas like Joseph Curtin's "Evia" model (which also utilizes a moveable neck and a maple-veneered carbon fiber back to reduce weight): violas played in the same manner as cellos (see vertical viola); and the eye-catching "Dalí-esque" shapes of both Bernard Sabatier's violas in fractional sizes (which appear to have melted) and of David Rivinus' "Pellegrina" model violas.
Other experiments besides those dealing with the "ergonomics vs. sound" problem have appeared. American composer Harry Partch fitted a viola with a cello neck to allow the use of his 43-tone scale. Luthiers have also created five-stringed violas, which allow a greater playing range. Modern music is played on these instruments, but viol music can be played as well.
A person who plays the viola is called a violist or simply a viola player. While it is similar to the violin, the technique required for playing viola has many differences, although much of the fingering technique is comparable. The difference in size accounts for some of the technical differences, as notes are spread out farther along the fingerboard and on occasion the vibrato may be broader. The less responsive strings and heavier bow warrant a somewhat different bowing technique.
The viola's four strings are tuned in fifths: C3 (an octave below middle C) is the lowest, 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. Although the violin and viola have three strings tuned the same, the tone quality or sound color is markedly different.
Violas are tuned by turning the pegs near the scroll, around which the strings are wrapped. Tightening the string will raise the note (make it sharper) while loosening the string will lower the note (making it flatter). The A string is normally tuned first, typically to 440 Hz or 442 Hz (see pitch). The other strings are then tuned to it in intervals of perfect fifths, 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 end of the string, at the tailpiece. Such tuning is generally easier to learn than using the pegs, and adjusters are usually recommended for younger players, although they are usually used in conjunction with one another. Adjusters work best, and are most useful, on higher tension metal strings. It is common to use one on the A string even if the others are not equipped with them. The picture on the right shows normal stringing of the pegs. Some violists reverse the stringing of the C and G pegs, so 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, which is in E flat, wrote the viola part in D major and specified that the viola strings were to be raised in pitch by a semitone; his intention was probably to give the viola a brighter tone to avoid its 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.
An example of a piece written before the 20th century which features a solo viola part is Hector Berlioz's Harold in Italy, though there are also a few Baroque and Classical concerti, such as those by Telemann (one of the earliest viola concertos known), Franz Anton Hoffmeister and Carl Stamitz.
The viola plays an important role in chamber music. Mozart succeeded in liberating the viola somewhat when he wrote his six string quintets, which are widely considered to include some of his greatest works. The quintets use two violas, which frees the instrument (especially the first viola) for solo passages and increases the variety and richness of the ensemble. Mozart also wrote for the viola in his Sinfonia concertante in which the two solo instruments, viola and violin, are equally important. Another important contribution was a set of two duets for violin and viola. From his earliest works Johannes Brahms wrote music that features the viola prominently. Among his first published pieces of chamber music, the sextets for strings Op.18 and Op.36 contain what amounts to solo parts for both violas. Late in life he wrote two greatly admired sonatas for clarinet and piano, his Opus 120 (1894); later Brahms transcribed these works for the viola. Brahms also wrote Two Songs for Alto with Viola and Piano (Zwei Gesänge für eine Altstimme mit Bratsche und Pianoforte), Op. 91, "Gestillte Sehnsucht" or "Satisfied Longing" and "Geistliches Wiegenlied" or "Spiritual Lullaby," which was a present for the famous violinist Joseph Joachim and his wife, Amalie. Antonín Dvořák played the viola, and apparently said it was his favorite instrument; his chamber music is rich in important parts for the viola. Another Czech composer, Bedřich Smetana, included a significant viola part in his quartet "From My Life"; the quartet begins with an impassioned statement by the viola. It should also be noted that Bach, Mozart and Beethoven all occasionally played the viola part in chamber music.
The young Felix Mendelssohn wrote a little-known viola sonata in C minor (without opus number, but dating from 1824). Given the beauty of the melodies in this early work, it is perhaps surprising that this sonata has not been played more frequently in concert halls.
The viola occasionally has a major role in orchestral music, for example the sixth variation of the Enigma Variations by Edward Elgar, called "Ysobel". Another prominent example is the Richard Srauss "Don Quixote" for solo viola and solo cello.
While the viola repertoire is quite large, the amount written by well-known pre-twentieth century composers is relatively small. There are many transciptions of works for other instruments for the viola, and the large amount of 20th-century literature is very diverse and always increasing. See "The Viola Project" at the San Francisco Conservatory of Music, where Professor of Viola Jodi Levitz has paired a composer with each of her students, resulting in a recital of brand-new works played for the very first time.
See The viola in popular music below.
The viola is also an important accompaniment instrument in Hungarian and Romanian folk string band music, especially in Transylvania. Here the instrument has three strings tuned g — d' - a (note that the a is an octave lower than found on the standard instrument), and the bridge is flattened with the instrument playing chords in a strongly rhythmic manner. In this usage, it is called a kontra or brácsa (pronounced "bra-cha").
There are only a few well known viola virtuosi, perhaps because the bulk of virtuoso viola music was written in the twentieth century. In this category, the name of William Primrose readily comes to mind, as he brought the virtuoso aspect of viola playing to exceptional standards.
In addition to Primrose, the most important viola pioneers from the twentieth century are Lionel Tertis, Paul Hindemith, Lillian Fuchs, Walter Trampler and Emmanuel Vardi - up to now, the only violist to have ever recorded the 24 Caprices by Paganini on viola. Contemporary well-known violists include Lawrence Power, Michael Kugel, Kim Kashkashian, Nobuko Imai, Rivka Golani, Tabea Zimmermann, Paul Neubauer and Yuri Bashmet. From the younger generation, David Aaron Carpenter, Nokuthula Ngwenyama, Cathy Basrak, Jennifer Stumm, Viacheslav Dinerchtein, and Antoine Tamestit deserve a prominent mention. Composer and violist Kenji Bunch has written a number of contemporary viola solos.
Among the great composers, several preferred the viola to the violin when playing in ensembles, the most noted being Ludwig van Beethoven, J.S. Bach and Wolfgang Amadeus Mozart. Numerous other composers also chose to play the viola in ensembles, including Joseph Haydn, Franz Schubert, Felix Mendelssohn, Antonín Dvořák, and Benjamin Britten. Among those noted both as violists and as composers are Rebecca Clarke and Paul Hindemith. Many noted violinists have publicly performed and recorded on the viola as well, among them Pinchas Zukermann, David Oistrakh, Eugène Ysaÿe, Yehudi Menuhin, Maxim Vengerov, and Nigel Kennedy The term violist is not universally used in English; some players, generally British, prefer viola player, since the word "'violist" is used in the UK to mean "player of the viol".
John Cale, a classically trained violist, played the instrument to great effect (amplified and often distorted) on some Velvet Underground tracks, most notably on "Venus in Furs", "Heroin", "The Black Angel's Death Song", "Stephanie Says", and "Hey Mr. Rain". He also played viola on "We Will Fall" a track on the debut Stooges album which he also produced.
Producer and songwriter Don Kayvan is a classically trained violist and regularly uses the viola on rap, r&b, alternative and pop songs.
Singer-songwriter Patrick Wolf is a trained violinist and viola player, and regularly uses viola in his songs and onstage.
Kansas' "Dust in the Wind", as well as other tracks by the band, features a viola melody. Robby Steinhardt played violin, viola, and cello on the song, and he or David Ragsdale plays at least one of these on most Kansas songs during their membership.
Dave Swarbrick of the English Folk-Rock group Fairport Convention has been known to contribute viola among other stringed instruments to the band, most notably on the Liege & Lief album on the track "Medley..." where he plays violin with an overdubbed viola playing the same part an octave lower.
The viola has made a slight comeback in modern pop music; aided and abetted by string groups, Bond and Wild. The band Flobots makes extensive use of the viola on nearly all of their songs as bandmember Mackenzie Roberts is a violist. In her latest album, Lonely Runs Both Ways, Alison Krauss uses the viola in many of her songs. Vienna Teng, a folk/indie artist, used the viola as a solo instrument in two of her songs from her recent album Dreaming Through the Noise (2006). Norwegian noise rock band Noxagt had a viola player until very recently; this musician left the band and was replaced by a baritone guitarist. New indie pop band The Funetics, use two violas and guitar for its instrumentation. The Six Parts Seven also used a viola. Neo-new wave indie rock band The Rentals features classically trained violist Lauren Chipman.
Instruments may be built with an internal preamplifier, or may put out the unbuffered transducer signal. While such raw signals may be fed directly to an amplifier or mixing board, they often benefit from an external preamp/equalizer on the end of a short cable, before being fed to the sound system