In C is a semi-aleatoric musical piece composed by Terry Riley in 1964 for any number of people, although he suggests "a group of about 35 is desired if possible but smaller or larger groups will work". It is a response to the abstract academic serialist techniques used by composers in the mid-twentieth century and is often cited as the first minimalist composition.
In C consists of 53 short, numbered musical phrases, lasting from half a beat to 32 beats; each phrase may be repeated an arbitrary number of times. Each musician has control over which phrase he or she plays: players are encouraged to play the phrases starting at different times, even if they are playing the same phrase. The performance directions state that the musical ensemble should try to stay within two to three phrases of each other. The phrases must be played in order, although some may be skipped. As detailed in some editions of the score, it is customary for one musician ("traditionally... a beautiful girl," Riley notes in the score) to play the note C in repeated eighth notes, typically on a piano or pitched-percussion instrument (e.g. marimba). This functions as a metronome and is referred to as "The Pulse".
In C has no set duration; performances can last as little as fifteen minutes or as long as several hours, although Riley indicates "performances normally average between 45 minutes and an hour and a half." The number of performers may also vary between any two performances. The original recording of the piece was created by 11 musicians (although, through overdubbing, several dozen instruments were utilized), while a performance in 2006 at the Walt Disney Concert Hall featured 124 musicians.
The piece begins on a C major chord (patterns one through seven) with a strong emphasis on the mediant E and the entrance of the note F which begins a series of slow progressions to other chords suggesting a few subtle and ambiguous changes of key, the last pattern being an alteration between B♭ and G. Though the polyphonic interplay of the various patterns against each other and themselves at different rhythmic displacements is of primary interest, the piece may be considered heterophonic.
Recordings of the piece 
The piece has been recorded a number of times:
|Artist||Instrumentation||Duration||Tempo (♩=)||Recording Information||Release Information|
|Terry Riley and Center of Creative and Performing Arts (SUNY-Buffalo)||saxophone, oboe, bassoon, trumpet, clarinet, flute, viola, trombone, vibraphone, marimbaphone||42' 03"||132||March 27–28, 1968 (many overdubs)||Columbia MS 7178 (LP); Sony SNYC 45368 (Re-mastered)|
|L'Infonie||saxophones, trumpets, percussion, piano, guitar, bass guitar, trombones||29' 20"||104||Recorded in 1970||Volume 33: Mantra (LP); Reed Streams / In C, Cortical Foundation Corti 2|
|Ensemble Percussione Ricerca||vibes, glockenspiel, marimbas, xylophone, crotales||41' 01"||116||Diamine Studio, Mestre-Venezia, Italy in 1983||In C / Djembé, Materiali Sonori|
|Shanghai Film Orchestra||traditional Chinese instruments ("various lutes, zithers, mouth organs, flute, and percussion")||28' 35"||108||Recorded in January 1989 at the Recording Studio of the Shanghai Film Industry. Mixed by Terry Riley, Jon Hassell and Brian Eno||Celestial Harmonies 13026|
|Piano Circus||concert grand piano, upright piano, Rhodes piano, harpsichords, vibraphone||20' 00"||132||Recorded in 1990||Six Pianos / In C, Argo 430380|
|Terry Riley and Friends||saxophones (sopranos, alto, tenor, and baritone), xylophone, synthesizers, voices, flute, viola, violins, trombones, cello, piano, guitars, glockenspiel, drums, marimba, clarinet, accordion, xylophone, bass clarinet||76' 16"||108||Recorded live on January 14, 1990 at the New Music Theatre and Life on the Water, San Francisco||In C - 25th Anniversary Concert, New Albion 71|
|Quebec Contemporary Music Society||flute, oboe, English horn, clarinet, bassoon, French horns, trumpets, trombone, tuba, harp, percussion, sitar, tablas, violins, viola, cello, double bass, vocal ensemble||35' 46"||116||Recorded live on June 12, 1997 at the Salle Pierre-Mercure||Atma Classique 22251|
|Ictus (with Blindman Kwartet)||percussion, double basses, harp, cello, guitar, piano, accordion, oboe, violin, clarinets, soprano saxophone, alto saxophone, tenor saxophone, baritone saxophone||65' 00"||130||Recorded live on May 31, 1997 at Chapelle des Brigitines, Brussels. Slightly overdubbed at Acoustic Recording Studio, Brussels||Cypres 5601|
|Bang on a Can||cello, glockenspiel, vibraphone, bass, mandolin, soprano saxophone, pipa, piano, violin, electric guitar, chimes, marimba, clarinet||45' 32"||120||Recorded live on November 20, 1998 at the World's Financial Center, New York||Cantaloupe 21004|
|Terry Riley Repetition Orchestra||keyboards, clarinet, trumpet, violins, cello, fretless baritone guitar, double bass, chime-bells, percussion, voices||76' 40"||108||Recorded live on April 20, 2000 in DOM, Moscow||Long Arm Records 01033|
|The Styrenes||guitars, keyboards, bass, drums, vibraphone||53' 19"||120||Recorded on September 21, 2000 at Unique Studio, NYC (many overdubs)||Enja 94352|
|Acid Mothers Temple & the Melting Paraiso U.F.O||voices, monster bass, electric guitars, synthesizers, drums, violin, zuruna, tambura, sruthi box, vibraphone, glockenspiel||20' 31"||92||Recorded at FTF Studio, Indo-yo and Acid Mothers Temple, 2002||Squealer 37|
|European Music Project, zignorii++||violin, viola, violoncello, marimba, electric piano, English horn, clarinets, alto saxophone, electronic arrangements||60' 48"||120||Recorded April 19–22, 2001 at Sendesaal des Funkhauses Köln||Wergo 66502|
|re-sound||flute, clarinet, soprano saxophone, alto saxophone, voice, electric guitar, electric bass, percussion, keyboards, violin, cello||57' 00"||Recorded in Australia||Move Records MD 3262 (2002)|
|DésAccordes / d-zAkord||classical guitars, electric guitars, electric basses, harp, cellos, percussion, drums, bass||48' 54"||120||Recorded on November 23, 2003 at Espace Culturel du Bois Fleuri, Lormont, France||MUSEA/GAZUL GA8681.AR|
|Ut Gret||synthesizer, alto saxophone, vibes, marimba, flute, bass clarinet||64' 11"||120||Recorded live at Tewligans in 2002||Recent Fossils, Ear-X-tacy Records|
|Ars Nova Copenhagen, Percurama Percussion Ensemble||vocals, marimbas, bass marimba, vibraphone, Bali gong||55' 16"||116||Recorded on January 17, 2005 at Focus Recording, Copenhagen||Dacapo 8.226049|
|American Festival of Microtonal Music||just-fretted guitars, viola, harpsichord, kanon, guitar "pulse"||23' 11"||112||Recorded live as "In C in Just Intonation," Terry Riley’s reworking commissioned by the AFMM in 1988||Ear Gardens, Pitch P-200209|
|Oxford Minimalist Ensemble||45' 09"||Recorded live at Sheldonian Theatre Oxford UK on 11 May 2006||www.minimalistensemble.co.uk|
|The New Audience Ensemble||16' 36"||Live at the Edge, Odessa Mama (2006)|
|Jeroen van Veen||Piano and other keyboards||57' 56"||120||Recorded at Barbara Church, Culemborg on October 23–28, 2006 (many overdubs)||Minimal Piano Collection, Brilliant Classics 8551|
|GVSU New Music Ensemble||piano, percussion, xylophone, bassoon, accordion, flute, bass flute, clarinet, bass clarinet, cello, English horn, soprano and tenor saxophones, marimba, vibraphone, guitar, trumpet, violin||20' 43"||In C Remixed, Innova 758 (2009)|
|Orkest de Volharding||51' 36"||108||The Minimalists, Mode 214/215 (2009)|
|Hans Balmer||Flutes (overdubbed)||40' 04"||124||Minimal Flute, Fontastix (2009)|
|Salt Lake Electric Ensemble||Laptop orchestra with percussion||65' 56"||85||Laptops recorded live Feb. 3, 2010 in Salt Lake City, acoustic instruments overdubbed Feb/Mar 2010||sleearts.com (2010)|
|GVSU New Music Ensemble||Piano, Percussion, Flute, Cello, Accordion, Violin, Clarinet, Bass, Saxophone, Acoustic Guitar, Electric Guitar, Trumpet. Featured Guest Dennis DeSantis on laptop and effects.||61' 28"||124||Recorded live on November 8, 2009, at Le Poisson Rouge, New York City||Terry Riley: In C
Ghostly International GI-108 (2010)
Limited Edition CD + Digital Download
|Invisible Polytechnic||Analogue modular synth 'pulse', organ, piano, marimba, percussion, violin, viola, hurdy gurdy, harp, bass guitar, oboe, daegeum, bassoon, voices||45' 40"||115||Recorded at Hatchlands Park, Surrey, and Them Usem, London||Junior Aspirin Records (ASP020, 2011)|
|Anton Glushkin and friends||Piano 'pulse', guitar, electric guitar, 2 violins, viola, cello, balalayka, balalayka-contrabass, flute, clarinet, bassoon, French horn, bayan, harp, harpsichord, synthesizer, percussion||51'||110||Recorded live on March 17, 2012, at museum of contemporary arts "Erarta", St. Petersburg, Russia||Hands For Friends studio|
|Sensorium Saxophone Orchestra||Saxophones, snare drum||Recorded Decemember 2010, Brooklyn, New York||Living Records (2012)|
Impact on other music 
Probably more than any other single work, In C established and influenced subsequent developments in musical minimalism, particularly the work of Steve Reich and Philip Glass. In his composition The Dharma at Big Sur, John Adams paid homage to Terry Riley in the second movement with a musical pulse and figures similar to those found in In C, jokingly referred to by the composer as "In B." The movement is also titled Sri Moonshine, the name of Riley's ranch in California.
Grand Valley State University New Music Ensemble produced an album of remixed versions of In C with guest remixers including Jad Abumrad of Radio Lab. A discussion of the In C remixing project including music played from three of the remixed versions can be heard in Radio Lab's podcast on In C from December 14, 2009.
- Riley, Terry, "'In C': Performing Directions", from the score for "In C", 1989, Celestial Harmonies
- This direction seems to be in the original score, but is not in the OtherMinds CC-licensed score.
- Move Records MD 3262 re-sound: In C
- Radio Lab, "In C," December 14, 2009, Online: http://www.radiolab.org/blogs/radiolab-blog/2009/dec/14/in-c/
Further reading 
- Reed, S. Alexander. 2011. "In C on Its Own Terms: A Statistical and Historical View". Perspectives of New Music 49, no. 1 (Winter):47–78.
- MIDI realization by Jeffrey C. Hall