Information: - A cappella (Italian for "in the manner of the chapel") music is specifically group or solo singing without instrumental accompaniment, or a piece intended to be performed in this way. It contrasts with cantata, which is accompanied singing. The term "a cappella" was originally intended to differentiate between Renaissance polyphony and Baroque concertato style. In the 19th century a renewed interest in Renaissance polyphony coupled with an ignorance of the fact that vocal parts were often doubled by instrumentalists led to the term coming to mean unaccompanied vocal music. The term is also used, albeit rarely, as a synonym for alla breve. - Alla breve is a musical meter notated by the time signature symbol (a C with a line through it), which is the equivalent of . The term is Italian for "in the style of the breve". - A cantata (literally "sung", past participle feminine singular of the Italian verb "cantare", "to sing") is a vocal composition with an instrumental accompaniment, typically in several movements, often involving a choir. - Accompaniment is the musical parts which provide the rhythmic and/or harmonic support for the melody or main themes of a song or instrumental piece. There are many different styles and types of accompaniment in different genres and styles of music. In homophonic music, the main accompaniment approach used in popular music, a clear vocal melody is supported by subordinate chords. In popular music and traditional music, the accompaniment parts typically provide the "beat" for the music and outline the chord progression of the song or instrumental piece. The accompaniment for a vocal melody or instrumental solo can be played by a single musician playing an instrument such as piano, pipe organ, or guitar. While any instrument can in theory be used as an accompaniment instrument, keyboard and guitar-family instruments tend to be used if there is only a single instrument, as these instruments can play chords and basslines simultaneously (chords and a bassline are easier to play simultaneously on keyboard instruments, but a fingerpicking guitarist can play chords and a bassline simultaneously on guitar). A solo singer can accompany herself by playing guitar or piano while she sings, and in some rare cases, a solo singer can even accompany himself or herself just using his or her voice and body (e.g., Bobby McFerrin). - The Saint Louis Chamber Chorus is a 40 voice a cappella mixed men 's and women 's chorus performing six concerts per season in St. Louis , Missouri . Under the direction of Philip Barnes , the Artistic Director from 1989 to the present , singers perform a varied repertoire of 50 or more choral works per season in multiple languages . The chorus , founded in 1956 , is respected regionally and selects historical public buildings for its venue . - Concertato is a term in early Baroque music referring to either a "genre" or a "style" of music in which groups of instruments or voices share a melody, usually in alternation, and almost always over a basso continuo. The term derives from Italian "concerto" which means "playing together" hence "concertato" means "in the style of a concerto." In contemporary usage, the term is almost always used as an adjective, for example "three pieces from the set are in "concertato" style." - In music, polyphony is one type of musical texture, where a texture is, generally speaking, the way that melodic, rhythmic, and harmonic aspects of a musical composition are combined to shape the overall sound and quality of the work. In particular, polyphony consists of two or more simultaneous lines of independent melody, as opposed to a musical texture with just one voice, monophony, or a texture with one dominant melodic voice accompanied by chords, which is called homophony. Given the paragraphs above, decide what entity has the relation 'instance of' with 'choir'.
The answer to this question is:
saint louis chamber chorus