String orchestra

A string orchestra is an orchestra consisting solely of a string section made up of the bowed strings used in Western Classical music. The instruments of such an orchestra are most often the following: the violin, which is divided into first and second violin players (each usually playing different parts), the viola, the cello, and usually, but not always, the double bass.
String orchestras can be of chamber orchestra size ranging from between 12 (4 first violins, 3 second violins, 2 violas, 2 cellos and 1 bass = 12) and 21 musicians (6 first violins, 5 second violins, 4 violas, 4 cellos and 2 double basses= 21) sometimes performing without a conductor. It could also consist of the entire string section of a large symphony orchestra which could have 60 musicians (16 first violins, 14 second violins, 12 violas, 10 cellos and 8 double basses = 60; "Gurre-Lieder" calls for 84: 20.20.16.16.12).
Repertoire.
The repertoire includes several works by Mozart (including "Eine kleine Nachtmusik"), William Boyce (his eight symphonies are for strings only), and Haydn which dispense with the baroque basso continuo. Some of these works are problematic when it comes to deciding whether they are for orchestra or string quartet. Particularly in Haydn's early works it is argued that the inversions of harmony from the occasional crossings of the bass and viola line imply a double bass; the question is not settled, however.
Important 20th century works have been written for string orchestra by Bartók (Divertimento for String Orchestra), Stravinsky ("Apollo"), Witold Lutosławski ("Musique funèbre"), Benjamin Britten ("Simple Symphony" and "Variations on a Theme of Frank Bridge"), Charles Wuorinen ("Grand Bamboula"), and Malcolm Williamson (Symphony No. 7). Sir Michael Tippett wrote a "Concerto for Double String Orchestra" and Ralph Vaughan Williams wrote a "Partita for Double String Orchestra". Composers who have written a Serenade for string orchestra include Tchaikovsky, Dvořák, Suk and Elgar. Mendelssohn, in his youth, also wrote thirteen symphonies for string orchestra.
Sometimes works originally written for string quartet, quintet, sextet etc. are arranged for string orchestra. Samuel Barber's "Adagio for Strings", Alban Berg's 3 Pieces from his "Lyric Suite", Arnold Schoenberg's string sextet "Verklärte Nacht" and String Quartet No. 2, Pyotr Ilyich Tchaikovsky's sextet "Souvenir de Florence", John Corigliano's Second String Quartet and Jean Sibelius's "Andante Festivo" are examples. An optional timpani part is also added in the Sibelius piece. The work "Shaker Loops" written in 1978 for septet then arranged in 1983 for string orchestra by the American composer John Adams has become a popular addition to the repertoire in recent times. Graham Waterhouse composed several works for string orchestra ("Sinfonietta"), also in combination with contrasting sounds as Great Highland Bagpipe ("Chieftain's Salute").