From Wikipedia

The string section is the largest body of the standard orchestra and consists of bowed string instruments of the violin family. It normally comprises five sections: the first violins, the second violins, the violas, the cellos, and the double basses (or basses). The abbreviation "and strings" is understood thus in descriptions of instrumentation.

In music of the classical period, the cellos and double basses often play from the same music, their parts being usually notated on a single staff, with the bassist's written notes sounding one octave lower than written.^[1]

An orchestra consisting solely of a string section is called a string orchestra.

Seating arrangement

The most common seating arrangement is with first violins, second violins, violas and cellos clockwise around the conductor, with basses behind the cellos on the right.^[2] In the 19th century it was standard^[3] to have the first and second violins on opposite sides (violin I, cello, viola, violin II), rendering obvious the crossing of their parts in, for example, the opening of the finale to Tchaikovsky's Sixth Symphony.

If space or numbers are limited, cellos and basses can be put in the middle, violins and violas on the left (thus facing the audience) and winds to the right; this is the usual arrangement in orchestra pits.^[4] The seating may also be specified by the composer, as in Béla Bartók's Music for Strings, Percussion and Celesta which uses antiphonal string sections, one on each side of the stage.

Numbers

The size of a string section may be expressed with a formula of the type (for example) 10-10-8-10-6, designating the number of first violins, second violins, violas, cellos, and basses. The numbers can vary widely; thus in a large orchestra they might be 14-14-12-12-10; the band orchestra in Darius Milhaud's La création du monde is 1-1-0-1-1. Mozart's masses and offertories written for the Salzburg cathedral routinely dispensed with violas, while famous works without violins include the Serenades of Brahms and Stravinsky's Symphony of Psalms. György Ligeti, besides writing some of the densest string divisi in history in Atmospheres and the Requiem, has also led the fashion of substituting solo string quintets for larger sections, as in the Cello Concerto and Le Grand Macabre.

References

1. ↑ Grove Dictionary of Music and Musicians, online edition, article "Orchestra", section 6.
2. ↑ Stanley Sadie's Music Guide, p. 56 (Prentice-Hall 1986). Nicolas Slonimsky described the cellos-on-the-right arrangement as part of a 20th century "sea change" (Lectionary of Music, p. 342 (McGraw-Hill 1989).
3. ↑ "Orchestra" in Encyclopedia Americana (1948).
4. ↑ Gassner, "Dirigent und Ripienist" (Karlsruhe 1844). Rousseau's Dictionnaire de musique (1768), however, has a figure showing second violins facing the audience and firsts facing the singers, reflecting the concertmaster's former role as conductor.