A body of singers who perform together as a group is called a choir or chorus. The former term is very often applied to groups affiliated with a church (whether or not they actually occupy the choir) and the second to groups that perform in theatres or concert halls, but this distinction is far from rigid.
The term “Choir” has the secondary definition of a subset of an ensemble; thus one speaks of the “woodwind choir” of an orchestra, or different “choirs” of voices and/or instruments in a polychoral composition. In typical 18th- to 21st-century oratorios and masses, chorus or choir is usually understood to imply more than one singer per part, in contrast to the quartet of soloists also featured in these works.
Structure of choirs
Choirs are often led by a conductor or choirmaster. Most often choirs consist of four sections intended to sing in four part harmony, but there is no limit to the number of possible parts as long as there is a singer available to sing the part: Thomas Tallis wrote a 40-part motet entitled Spem in alium, for eight choirs of five parts each; Krzysztof Penderecki’s Stabat Mater is for three choirs of 16 voices each, a total of 48 parts. Other than four, the most common number of parts are three, five, six, and eight.
Choirs can sing with or without instrumental accompaniment. Singing without accompaniment is called a cappella singing (although the American Choral Directors Association discourages this usage in favor of “unaccompanied,” since a cappella denotes singing “as in the chapel” and much unaccompanied music today is secular). Accompanying instruments vary widely, from only one to a full orchestra; for rehearsals a piano or organ accompaniment is often used, even if a different instrumentation is planned for performance, or if the choir is rehearsing unaccompanied music.
Many choirs perform in one or many locations such as a church, opera house, or school hall. In some cases choirs join up to become one “mass” choir that performs for a special reason. In this case they provide a series of songs or musical works to celebrate and provide entertainment to others.
- Mixed choirs (with male and female voices). This is perhaps the most common type, usually consisting of soprano, alto, tenor and bass voices, often abbreviated as SATB. Often one or more voices is divided into two, e.g., SSAATTBB, where each voice is divided into two parts, and SATBSATB, where the choir is divided into two semi-independent four-part choirs. Occasionally baritone voice is also used (e.g., SATBarB), often sung by the higher basses. In smaller choirs with fewer men, SAB, or Soprano, Alto, and Baritone arrangements allow the few men to share the role of both the tenor and bass in a single part.
- Male choirs, with the same SATB voicing as mixed choirs, but with boys singing the upper part (often called trebles or boy sopranos) and men singing alto (in falsetto), also known as countertenors. This format is typical of the British cathedral choir.
- Female choirs, usually consisting of soprano and alto voices, two parts in each, often abbreviated as SSAA, or as soprano I, soprano II, and alto, abbreviated SSA.
- Men’s choirs, or Male Chorale, usually consisting of two tenors, baritone, and bass, often abbreviated as TTBB (or ATBB if the upper part sings falsetto in alto range). ATBB may be seen in some barbershop quartet music.
- Children’s choirs, often two-part SA or three-part SSA, sometimes more voices. This includes boy choirs.
- Indian music choral group, takes the elements of western music in Indian music. Madras Youth choir is a pioneer in this.
Choirs are also categorized by the institutions in which they operate:
- Church and cathedral choirs
- Collegiate and university choirs
- Community choirs (of children or adults)
- Professional choirs, either independent (e.g. Anúna) or state-supported (e.g., BBC Singers, National Chamber Choir of Ireland, Canadian Chamber Choir, Swedish Radio Choir).
- School choirs
- Signing choirs (of Deaf or Hearing individuals), using Sign Language rather than voices
- Integrated Signing and Singing Choirs, using both Sign Language and Voices and led by both a Signductor and a Musical Director.
Some choirs are categorized by the type of music they perform, such as
- Bach choirs
- Barbershop music
- Gospel choirs
- Show choirs, in which the members sing and dance, often in performances somewhat like musicals
- Symphonic choirs
- Vocal jazz choirs
- Modern and Contemporary choirs