In C

''In C'' is a composition by Terry Riley from 1964. It is one of the most successful works by an American composer and a seminal example of minimalism. The score directs any number of musicians to repeat a series of 53 melodic fragments in a guided improvisation.

Terry Riley's 1968 recording of ''In C'' was added to the National Recording Registry in 2022. The piece inspired countless other composers, including Philip Glass, Steve Reich, John Adams, and Julius Eastman.

Composition

Alongside fellow students Loren Rush and Pauline Oliveros, Terry Riley had been involved with group improvisation since 1957–8. The immediate forerunner for the piece was the incidental music Riley wrote for Ken Dewey's play ''The Gift''. It was being performed in Paris in 1963 when Riley was asked to provide music for it. He ran into Chet Baker and recorded his quartet performing songs that included Miles Davis' "So What". Riley was familiar with the Echoplex and wanted to replicate its sound. A technician from ORTF set up a tape loop system for the composer. ''Music From The Gift'' inspired Riley to work with loops for years to come. Riley created installations using tape loops that he called "time-lag accumulators".

When he was back in San Francisco the following year, Riley was playing piano nightly at the Gold Street Saloon. On the way to work one night in March 1964, he heard ''In C'' in his head and wrote it down after the show. The score consists of short melodic fragments, which was a staple of Riley's music from that period. Soon after, Morton Subotnick asked Riley to perform solo at the San Francisco Tape Music Center. He prepared the work to be performed with an ensemble on that concert.Duckworth, William.
Talking Music
'. Schirmer Books, 1995.

Riley saw ''In C'' as way a for instrumentalists to play in the style he had developed with tape loops. Alburger, Mark. "Shri Terry: Enlightenment at Riley's Moonshine Ranch". ''Twentieth‐Century Music'' 4, no. 3. March, 1997. 1–20. His artistic goal was shamanistic. He wanted to write music that created a satori for the listener:

I was never concerned with minimalism, but I was very concerned with psychedelia and the psychedelic movement of the sixties as an opening toward consciousness. For my generation that was a first look towards the East, that is, peyote, mescaline, and the psychedelic drugs which were opening up people's attention towards higher consciousness. So I think what I was experiencing in music at that time was another world...music was also able to transport us suddenly out of one reality into another. Transport us so that we would almost be having visions as we were playing. So that's what I was thinking about before I wrote ''In C''. I believe music, shamanism, and magic are all connected, and when it's used that way it creates the most beautiful use of music.

Most of the music Terry Riley composes is not written down. ''In C'' was an early exception, and remained one of his few notated pieces until Kronos Quartet began commissioning him in the 1980s. Riley specifically scored ''In C'' so that it would be open to many interpretations. The score is so minimal it fits on a single page, and Riley felt, "if you can't do it with just that, it's not worth doing".

Performances

Terry Riley and a small group of players began trying out ''In C'' at house concerts around San Francisco in the fall of 1964. One of the issues that quickly emerged was coordinating the players. Steve Reich suggested using an 8th note pulsing rhythm to keep the ensemble together. Though Riley envisioned the piece without a prevailing rhythm, he agreed to the utility of Reich's solution. Carl, Robert. ''Terry Riley's in C''. From ''Studies in Musical Genesis, Structure, and Interpretation'', Edited by Malcolm Gillies. Oxford University Press, 2009.

The piece was premiered on November 4, 1964 during "An Evening of Music by Terry Riley" at the San Francisco Tape Music Center. ''Music from the Gift'' was played as the audience arrived. The first half included Riley's ''I'', ''Shoeshine'', ''In B or Is It A?'', and ''COULE''.

There was a break to set up ''In C''. In addition to the musicians, Tony Martin projected a light show on the ceiling. At one piano, Jeanie Brechan pulsed the top two Cs above Terry Riley who shared the instrument. Warner Jepsen and James Lowe played a second piano. The other keyboard instruments were played by Steve Reich ( Wurlitzer electronic piano), Pauline Oliveros (accordion), and Ramón Sender (Chamberlin organ, male voice setting). The Chamberlin was housed in a recording studio upstairs from the concert space. Audio was piped up to Sender in order to coordinate. The wind section included Mel Weitsman ( sopranino recorder), Morton Subotnick (clarinet), Jon Gibson (soprano saxophone), Sonny Lewis (tenor saxophone), Stan Shaff, and Phil Winsor (trumpets). Oliveros recalls that the ensemble performed at a stately tempo of 69 beats per minute.

The concert was repeated two days later. Alfred Frankenstein reviewed the November 6th performance for the ''San Francisco Chronicle''. He raved, "'On C' was the evening's masterpiece, and I hope the same group does it again." He wrote:

At times you feel you have never done anything all your life long but listen to this music and as if that is all there is or ever will be, but it is altogether absorbing, exciting, and moving, too. One is reminded of the efforts of Carlos Chavez to reconstitute the ceremonial music of pre-Columbian Mexico. Terry Riley may have captured more of its spirit than Chavez did. Frankenstein, Alfred. "Music Like None Other on Earth", ''San Francisco Chronicle''. November 8, 1964. 28.

After the premiere, Riley headed to Mexico for three months. ''In C'' was performed again at the Center the following spring during a three day festival of Riley's music from May 25–7, 1965.

The New York City premiere took place at Carnegie Recital Hall on December 19, 1967 on a program with Igor Stravinsky's '' Octet'' and works by Harley Gaber and Dorrit Licht. The performance reminded ''New York Times'' critic Donal Henahan of Alban Berg's Invention on One Note in '' Wozzeck'', and he admired the ensemble's " gamenlanlike sonorities". He continued, "Mr. Riley's effort produced a happy din, which was at worst hypnotic and often fascinating in its multilayered rhythms and sound patterns. One observed with compassion that the woman pianist, whose duty was to pound one note throughout, wore gloves. It put one in mind of Hildegarde." Henahan, Donal.
New-Music Series Puts Toes to Test: Audience Exhorted to Walk Around—Some Don't Stop
, ''The New York Times''. December 20, 1967. 55.

The pianist was Margaret Hassell, and she wore bandages on her fingers underneath the gloves to pad them for the exertion of the part. Lukas Foss had arranged speakers throughout the venue so the music could be heard from multiple vantage points, and the audience was encouraged to circulate during the piece.

The first UK performance of ''In C'' was on 18 May 1968 at Royal Institute Galleries by the Music Now Ensemble directed by Cornelius Cardew. The performance was aggressively driven by an electric guitar playing the pulse loud and fast. ''The Musical Times'' found it "rewarding" and wrote, "whereas previous performances of Riley's work have tended to be delicate, full of barely perceptible intricacies for the relaxed mind to absorb, this one was totally uncompromising. It demanded a fight".

Alexei Lubimov organized the Soviet premiere of ''In C'' in 1969 for an audience that included Sofia Gubaidulina and Alfred Schnittke.Repetitition Orchestra, ''Terry Riley''. Liner notes. Long Arms Record CDLA 01033, 2001. The piece also received its German premiere that year at the Darmstädter Ferienkurse. Wolf-Eberhard von Lewinski was relieved when the piano strings broke under the stress of the pulse, but the neighboring B strings had been tuned up a half step and the work continued to his dismay. This scordatura had also been used at previous performances.

Oakland Symphony performed the first orchestral version of ''In C'' in 1970. Six months later, San Francisco Ballet used many of the same musicians to perform Riley's score for a production called ''Genesis 70'' choreographed by Carlos Carvajal.Hill, Sarah. ''San Francisco and the Long 60s''. Bloomsbury Academic, 2016. 277f.

A 25th anniversary concert was held on January 14, 1990 at the Fort Mason Center in San Francisco. Riley and his son Gyan performed in an eclectic group that included Jaron Lanier. Ramón Sender and Warner Jepsen also performed. The lineup included Kronos Quartet, and Riley was particularly fond of the way they slid into the notes of the musical fragments. The performance was recorded and released on CD in 1995.

Form

Score

The score of ''In C'' consists of 53 modules that fit on a single page. Each module is a short musical phrase notated in treble clef without a time signature and bracketed by repeat signs. Riley uses nine different pitches, only omitting C and E from the chromatic scale.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.

The total duration of the written score is only 521 eighth notes. The shortest module lasts one 8th note, and the longest lasts 64. The material varies widely in character, from drones to running 16th note figures. Three of the modules are repeated: Nos. 10 (as 41), 11 (as 36), and 18 (as 28). The longest figure is #35, which spans 60 pulses, ranges an octave and a half, and includes seven of the score's pitches. Its length creates a sense of figure 35 as a turning point in the piece, creating a symmetry or even hinting at a very loose ternary form.

Riley indicates no tempo, instrumentation, or dynamics. The notation is extremely uncluttered, and by implication, open to a wide range of interpretation. The first melody outlines a major third with its three quarter note Es ornamented with grace note Cs. The final melody is a minor third between G and B played in sixteenth notes. The structure of the melodic modules creates a vague sense of tonal shifts, for instance from C to E and then C to G.

All of the motifs are diatonic until #14, which introduces an F. The raised fourth scale degree prevails until module 31 when the F returns. The F makes one final appearance in module 35, shortly after a B is introduced. The seventh scale degree returns to B until #49, where it remains lowered until the end of the piece. Riley composed the modules with strong interrelations. Rarely is a module not clearly related to its predecessor.

Instructions

There are a few rules for performing ''In C'' that have remained since its first performance. They primarily define the indeterminacy of the piece:
*Instrumentation: The piece can be played by any group of musicians on any type of instrument.
*Tempo: There is no required tempo. All performers play at the same pace.
*Patterns: The 53 patterns are to be played in order.
*Repetitions: Individual players determine how often to repeat any pattern.
*Transposition: Patterns may be transposed up or down.
*Coordination: An 8th note pulse may be used to coordinate the performance. It can be played on the top two octaves of a piano or mallet percussion. Time can also be kept by improvised percussion.
*Ending: The piece ends when all players arrive at pattern 53. Performers stop playing individually.

Riley suggests a group of about three dozen performers, while acknowledging smaller and larger groups are possible.Riley, Terry
''In C''
Associated Music Publishers, 2005. Though they are governed by the same tempo, the musicians are not required to play together. Performers are encouraged to stagger their entrances, which creates a heterophonic canon. Riley diagrammed the 12th module in several alignments to demonstrate how freely the musicians can perform the score. He initially asked players to remain within 4–5 modules of each other. The current instructions reduce that bandwidth to 2–3 patterns. Riley also recommends coalescing in unison at some point.

If one of the motifs is too difficult to play, a performer is allowed to omit it. Riley even allows for the rhythms of patterns to be augmented.

''In C'' has elements of aleatoric music due to its improvisatory nature. However, much of its structure is specifically designed to reduce the scope of chance. Riley conceived of a version where each pattern lasted a week and the final pattern was played in the new year. He estimates an average run time of 45–90 minutes. His instructions avoid declarative statements and read like a series of helpful suggestions. Riley composed the piece to deliberately have "a lot of liberties".

Performance Practice

The score's instructions for performers have gone through several iterations. Originally, it had none as musicians played from Riley's ozalid copies of the score. After the 1968 release of the Columbia LP, many performances relied on the score that was printed in the album liner. The Soviet premiere, for instance, was made possible because Edison Denisov passed on his copy of the record to Alexei Lubimov. The LP includes a terse paragraph, written by David Behrman, that explains how to interpret the score. Most musicians were exposed to Behrman's instructions before Riley bothered to write any down.

Riley did eventually pen two pages of handwritten notes to explain how to perform ''In C''. In 1989, he released a shorter typed set of instructions.Riley, Terry. ''In C''. Celestial Harmonies, 1989. The most recent set of instructions from 2005 differ significantly from Riley's originals, and all three are afterthoughts, born from the experience of playing the piece with a wide range of instruments and skill levels.

The one thing the composer has stressed in every version of the instructions is listening:
::"Don't be in a hurry to move from figure to figure. Stay on your part and keep repeating it, listening for how it is relating to what the rest of the ensemble is playing."
::"It is important to think of patterns periodically so that when you are resting you are conscious of the larger periodic composite accents that are sounding, and when you re-enter you are aware of what effect your entrance will have on the music's flow." (1989)
::"It is very important that performers listen very carefully to one another and this means to occasionally drop out and listen...One of the joys of playing ''In C'' is the interaction of the players in polyrhythmic combinations that spontaneously arise among patterns. Some quite fantastic shapes will arise and disintegrate as the ensemble progresses through the piece." (2005)

Behrman's instructions for the album refer to an unwritten part, "Not included in the score is a piano part, called the Pulse, which consists entirely of even octave eighth notes to be drummed steadily on the top two C's of the keyboard throughout the duration of a performance." The prevalence of the Pulse on the recording, along with Behrman's note gave rise to the impression that it is a requirement of the piece. One set of liner notes even fetishizes it, " In the beginning was the pulse."

However, Riley's first instructions are more playful and hint at the available leeway, "The pulse is traditionally played by a beautiful girl on the top two octaves of a grand piano. She must play loudly and keep a strict tempo for the entire ensemble to follow."Riley, Terry. ''In C'' in ''Analytical Anthology of Music''. Edited by Ralph Turek. 2nd ed, McGraw-Hill, 1992. 540. The current version of the score explicitly makes the Pulse optional, "The ensemble can be aided by the means of an eighth note pulse played on the high C's of a piano or mallet instrument."

After decades of familiarity with ''In C'', Riley recognized that the pulse had outlived its usefulness. Technique had advanced to a point where "any good musicians now could keep it together...I don't like The Pulse, as is sometimes used, 'out in front,' where it becomes very annoying. That wasn't my intention of the piece at all." At the 20th anniversary performance in Hartford, no pulse was used to revelatory effect.

Recording

In late 1965, Terry Riley moved to New York City and started performing on soprano saxophone in his apartment on Grand Street in the Bowery. He would use Revox machines to create tape delays and loop his improvisations. One of the people who loved the shows was David Behrman, the producer for Columbia Records' ''Music of Our Time'' series.

When Columbia was ready to record the piece, Riley performed it once more at Carnegie Recital Hall on March 26, 1968. The musicians then recorded the piece on the following two days, along with works by Carlos Alcina, David Rosenboom, and Yuji Takahashi. The sessions were engineered by Fred Plaut and Russ Payne. David Behrman conducted the ensemble by holding up cue cards for each module. His job was to keep the ensemble on pace for a recording that would fit on the two sides of an LP record. Margaret Hassell broke a string on the piano while playing the pulse.

Riley knew that the texture would be more captivating if it were thicker. With only eleven musicians, he decided to record the piece three times and overdub the takes.Carl, Robert.
'In C'—Terry Riley (1968)

Library of Congress
National Recording Preservation Board (2022). Columbia staff were hesitant to apply a pop music recording technique to a classical piece, but the ensemble was consciously blurring the boundaries between the two genres. When everyone listened to the initial mix of the session, David Behrman exclaimed, "I think we've just changed music."

The album's cover was designed by Billy Bryant, and it incorporates a blurb from Alfred Frankenstein's review of the premiere. The founder of ''Crawdaddy!'', Paul Williams, also wrote an enthusiastic essay for the package. He writes:

I'm not here to justify this record, or explain it...Allright, so let's say that what we have here is a ' trip', a voluntary, unpredictable, absorbing experience, one which brings together parts of one's self perhaps previously unknown to each other...Playing this record for a small group of people is like watching a web being spun. Playing it for a friend means watching a '' Pilgrim's Progress'' of reactions.Riley, Terry.
In C
'. Columbia Records (MS 7178), 1968.

Most importantly for ''In C's'' legacy, a foldout in the record liner included a copy of the score which enabled people to perform it. Whereas most of Riley's compositions are formally published in order to control the performing rights, Riley has never relied on a publisher to protect ''In C''. This decision is a marked departure from the other titans of minimalism (Young, Reich, and Glass) who zealously guard their performing rights.Sun, Cecilia J. ''Experiments in Musical Performance: Historiography, Politics, and the Post-Cagian Avant-Garde''. University of California, 2004. By giving the piece away as a kind of freeware, Riley inadvertently ensured its popularity.

Personnel

*Terry Riley – leader and saxophone
*Jon Hassell – trumpet
*Edward Burnham – vibraphone
* David Rosenboom – viola
*Darlene Reynard – bassoon
*Jerry Kirkbride – clarinet
*David Shostac – flute
* Jan Williams – marimbaphone
*Lawrence Singer – oboe
* Stuart Dempster – trombone
*Margaret Hassell – the pulse

Reception

''In C'' was well-reviewed by critics. For '' Glamour'', Janet Rotter dubbed the composition "the global village's first ritual symphonic piece" and raved, "Terry Riley has not yet reached the mass concert audience that the Beatles have, but he has written in his own way to that audience". In ''Stereo Review'', David Heckman admired the effect while disliking the result, "In C produces, over the course of its forty-three minutes, a vague hypnotic effect, that is doubtless related to the repeated C, hammering away incessantly through the musical fabric. Isolated motives, bits and snatches of themes, and a kind of '' Klangfarbenmelodie'' of individual pitches drift in and out of one's consciousness. Very nice, for a while, but ultimately wearing." Alfred Frankenstein revisited the piece with undimmed enthusiasm in his album review for ''High Fidelity'', "Terry Riley's ''In C'' is one of the definitive masterpieces of the twentieth century. It is probably the most important piece of music since Boulez' '' Marteau sans maître'', conceivably it is the most important since the '' Sacre''."

In 2022, the 1968 LP recording of ''In C'' was selected by the Library of Congress for preservation in the United States National Recording Registry as being "culturally, historically, or aesthetically significant".

Legacy

Upon hearing the premiere of ''In C'', Alfred Frankenstein remarked that Riley had developed "a style like that of no one else on earth", and the critic accurately predicted, "he is bound to make a profound impression with it." Indeed, Riley's composition is often cited as the first minimalist composition to make a significant impact on the public consciousness and inspire a new movement. Terry Riley's website advertises ''In C'' as "The composition that launched the Minimalist movement". However, he has repeatedly dismissed the idea in interviews:

People say minimalism started with Erik Satie, and it may have started with Gesualdo; I don't know who it started with. But in this group of people, which is Steve Reich, Philip Glass, La Monte Young, and me, obviously it was La Monte who was the first one. The '' Trio for Strings'' is the landmark minimalist piece.

''In C'' came at a time when experimental music in America was synonymous with atonality. The simple fact of using a key signature for a title was its own form of revolt against current trends. The modal patterns of ''In C'' proved a much more malleable device than Young's static sonorities. Steve Reich and others point to Riley's technique as a seminal influence on their work.Potter, Keith. ''Four Musical Minimalists: La Monte Young, Terry Riley, Steve Reich, Philip Glass''. Cambridge University Press, 2002. 164. Morton Subotnick recalled how ''In C'' "brought a forward movement to repetition...it blossomed in a direction, and that directionality, and the beat, was not what people were thinking at the time...it was a kind of cockamaimie Ravel ''Bolero''; people don't think about it now because it's so ordinary. Everyone's grown up with Glass and Reich, but that didn't exist at that point." One historian concluded that Riley's composition "achieved something unprecedented...It was ''In C'' that made minimalism a viable commercial force in American music, for it took minimalism out of the lofts and galleries - where Young's far more austere music was destined to remain".

A decade after it was written, ''In C'' was described as "the single most influential post-1960 composition by an American". Riley's score is one of the classics of experimental music, and it injected a physical exhilaration into the genre that was previously lacking. Because of the openness of the score, ''In C'' is attractive to presenters. It has become one of the most widely performed pieces from the twentieth century. Riley described the score as "a gift that The Universe kindly bestowed on the Terry Riley of 1964, who might possibly be a stranger if he showed up at my door today".

The foregrounding of the repeated C gave rise to the mistaken impression that the piece is about that relentlessly hammered note. One detractor mused, "A modern vision of Hell might well contain an unbroken loop of ''In C''". Another writer concluded, "''In C'' is, at root, an exercise in human relations." Riley described it as a "musical hall of mirrors". Due to its communal ethos, ''In C'' has been called "the quintessential Sixties piece".

Discography

Robert Carl published extensive analyses of several commercial recordings. He found tempi ranging 92–132 beats per minute:
;With Terry Riley's involvement:
*Terry Riley, ''In C'' ( Columbia, 1968) – Re-mastered for CD release by Sony Classical in 2009
*Shanghai Film Orchestra, ''In C'' (Celestial Harmonies, 1989) – Performed on traditional Chinese instruments. Mixed by Riley, Brian Eno, and Jon Hassell.
*Terry Riley, ''In C – 25th Anniversary Concert'' (New Albion, 1995) – With Riley singing and directing the ensemble.
*The Repetitition Orchestra, ''Terry Riley'' (Long Arms Records, 2001) – With Riley on piano

;Independent of Riley:
* Piano Circus, ''Six Pianos/In C'' (Argo, 1990)
*Ensemble Percussione Ricerca, ''In C/Djembé'' (Materiali Sonori, 1995)
* SMCQ, ''In C'' (ATMA Classique, 2000) – Conducted by Walter Boudreau
* Ictus, ''In C'' (Cypres, 2000) – With Blindman Kwartet
*Bang on a Can, ''In C'' ( Cantaloupe Music, 2001)
* The Styrenes, ''In C'' (Enja Nova, 2002)
* Acid Mothers Temple & The Melting Paraiso U.F.O., ''In C'' ( Eclipse Records, 2001) – Flipside includes the band's composition "In E"
*European Music Project, zignorii++, ''In C'' ( WERGO, 2002)
*re-sound, ''In C'' ( Move Records, 2002)
*DésAccordes, ''In C'' (Gazul Records, 2005)
*Ut Gret, ''Recent Fossils'' (ear X-tacy Records, 2006) – ''In C'' is on disc 3
* Ars Nova Copenhagen, ''Terry Riley – In C'' (Ars Nova, 2006) – Conducted by Paul Hillier with Percurama
*American Festival of Microtonal Music, ''Ear Gardens'' (Pitch, 2007) – ''In C'' in just intonation
*The New Audience Ensemble, ''Live at the Edge'' (Odessa Mama Records, 2006)
* Jeroen van Veen, ''Minimal Piano Collection'' ( Brilliant Classics, 2006) – ''In C'' is on disc 9
*Grand Valley State University New Music Ensemble, ''In C Remixed'' (Innova Recordings, 2008) – ''In C'' is on disc 2
* Orkest de Volharding, ''The Minimalists'' ( Mode, 2009)
*Hans Balmer, ''Minimal Flute'' (Fontastix, 2009)
*GVSU New Music Ensemble, ''Terry Riley – In C'' ( Ghostly International, 2009)
*Invisible Polytechnic, ''Perform In C By Terry Riley'' ( Junior Aspirin Records, 2011)
*The Sensorium Saxophone Orchestra, ''Terry Riley – In C'' (Living Records, 2012)
* Adrian Utley's Guitar Orchestra, ''In C'' ( Invada Records, 2013)
*Minimalist Ensemble, ''In C'' ( Alexander Campkin, 2013)
*'' Africa Express Presents... Terry Riley's In C Mali'' ( Transgressive, 2014) – With Brian Eno and Damon Albarn
*Fighting Windmills + Sethstat, ''In C'' (PMGJazz, 2018)
*The Young Gods, ''Play Terry Riley In C'' (Two Gentlemen Records, 2022)

;Adaptations
*L’Infonie, ''Volume 33: Mantra'' (Polydor, 1970) – Incorporates ''In C'' in a larger improvisation.
*Grand Valley State University New Music Ensemble, ''In C Remixed'' (Innova Recordings, 2008) – Features remixes by Jad Abumrad, Mason Bates, Jack Dangers, Dennis DeSantis, R. Luke DuBois, Mikael Karlsson/Rob Stephenson, Zoë Keating, Phil Kline, Kleerup, Glenn Kotche, David Lang, Michael Lowenstern, Paul D. Miller (DJ Spooky), Nico Muhly, Todd Reynolds and Daniel Bernard Roumain (DBR).Radiolab
"''In C''"
December 14, 2009

References

Further reading

*Sun, Cecilia. "Journey to the East: Asian Influences in the Performance History of Terry Riley's In C." ''Intercultural Music: Creation and Interpretation''. Edited by Sally Macarthur, Bruce Crossman, and Ronald Morelos. Sydney: Australian Music Centre, 2006.
*Vosper, Richard Field. “Structure and Probably Organization of In C by Terry Riley: An Analysis of Stochastic Projection of Pattern Behavior.” MA thesis, San Jose State University. 1980.

External links

1968 ''In C'' LP
audio with the electronic swoops between each side at Internet Archive. (See Carl, p. 83f)
*, Andrew Ford, ''The Music Show'', May 6, 2012, ABC Radio National
*Kyle Gann,
Those Jangling High C's on the Piano
, ''Artsjournal.com''. July 2, 2009.
::A review of Robert Carl's ''In C'' with instructive comments from several users.

{{Authority control

Compositions by Terry Riley
Minimalistic compositions
1964 compositions
Process music pieces
Compositions in C major
United States National Recording Registry recordings
United States National Recording Registry albums