A Survey of Music Theory for the College Classroom: Chromatic Harmony 2 and 20th Century Music

Other 20th Century Techniques


Entire volumes can be written about many of the topics covered in this text, and this is equally true when examining the new paths that composers have forged since the end of the 19th century. The increasing influence of global resources on western art music have been profound, the advance in electronics and computer-generated music has been astounding, and new popular styles and genres have germinated and grown to maturity over in a strikingly brief period of time. It is therefore impossible to do more than provide a short overview of composers, influences, styles, and techniques, which will hopefully provide some sort of framework for the understanding of the rich diversity of practice and thought that has grown during this period.

We will confine our brief overview to the following areas, which have proven to be some of the more fertile ground in which music has grown:

  • Indeterminacy
  • Graphic Notation
  • Minimalism

Indeterminacy / Aleatory / Chance Music

Indeterminacy and aleatory both refer to the inclusion of chance in music. In the mid-20th century, composers began to assign major creative roles to the performer and to random chance in the compositional process, in part as a reaction to the total organization of integral serialism. Composers can introduce aleatoric elements into a piece by leaving some or all musical parameters to random generation. Randomization of musical parameters can be accomplished by rolling dice, using an app, or in other ways determined by the composer. Composers also inject chance into music by allowing the performer(s) to determine some or all musical parameters. When doing so, composers often abandon traditional musical notation and instead utilize some sort of graphic notation to convey the ideas, which allows great freedom to be achieved. When chance is left to the performer(s), different performances of the same work may vary greatly, and the receptiveness, musical sensitivity, and improvisational imagination of the performer(s) becomes of far greater consequence than in traditionally notated music.

John Cage

John Cage is one of the most influential music thinkers in the last of 20th century. Cage studied with Cowell and Schoenberg and was influenced by Varese and Zen Buddhism. He was a prolific writer and champion of Avant Garde music who believed that music could include all types of noise. He thought that standard methods of composition were limiting because they did not use what he termed the “entire field of sound,” and gradually evolved the idea that music was a “purposeless play.”  His development and use of indeterminacy continue to resonate into the 21st century. While indeterminacy was used by earlier 20th century composers including Charles Ives and Henry Cowell, Cage’s efforts helped to legitimize indeterminate procedures in music and lead to its broader acceptance in the 1950s. 

During the period of the 1930s-50s, Cage wrote experimental music using unconventional instruments such as brake drums, flowerpots, electrical buzzers, microphones, and generator noise. It was during this time in the 1940s that he composed the Sonatas and Interludes for solo piano (1948) for “prepared piano,” which is simply a piano with screws, pieces of wood, and rubber wedges inserted on and between the strings. 

His best-known work is 4’33’’, in which he brought the ideals of indeterminacy to their ultimate conclusion. The score consists of three roman numerals followed by the word “tacit.” The performer(s) are to remain silent during the entire work. The piece features an absence of musical materials and musical sounds, allowing silence to be as important as traditionally notated music. The focus is on the happenings in the concert hall such as audience and environmental noises. Cage considered this piece to be his most significant work.

Graphic Notation

Graphic notation (a.k.a. graphic score) began in the mid-20th century when composers interested in the infusion of aleatoric elements in music began to use a variety of visual symbols in place of traditional music notation. The imagination of the composer is the only limit as to what can be used, and the interpretation and realization of these scores can vary widely. Good introductions can be found on YouTube, and the ensuing list features a variety of websites and YouTube videos.

Further resources include:

Minimalism’s origins are in the music of Cage, Eastern music and philosophy, and the visual arts of the 1950s. Minimalist composers desired to reduce music to a much simpler style, in contrast to the highly organized and complex sounding music of twelve-tone serialism. Early minimalist music shows a great economy in musical resources, but the term minimalism imperfectly fits the music of the 1970s and later because of its increasing complexity and inclusion of varied musical resources, including more traditional harmonic progression.

Features of minimalist music include use of the following:

  • Limited pitches
  • Consonant sonorities
  • Additive process
  • Simple rhythms and steady pulse
  • Diatonic tonal and modal resources and scales
  • Repetition
  • Phase shifting
  • Drones and ostinatos

The most significant composers who were at the forefront of developing this style were La Monte Young, Terry Riley, Steve Reich, and Philip Glass.

La Monte Young

La Monte Young was influenced by Indian music, studying with the Indian singer Pandit Pran Nath. He is interested in non-equal temperament tunings like just intonation. His early work Composition 1960 No. 7 consists of a single event – a P5 (B-F♯) that is “to be held for a very long time,” as he writes in the score.

Terry Riley

Terry Riley, like Young, studied Indian music with Pran Nath. Riley adopted the use of repetitive interlocking melodic patterns in his music, was interested in electronic music, and experimented with tape loops in the early 1960s. His influential work In C (1964) consists of melodic patterns quoted from 18thcentury music and is scored for any number of any kind of instruments and performers. Instrumentalists are directed to play through the 53 fragments at any tempo and repeating individual fragments as often as desired before moving to next fragment. During this, steady 8th note C’s are played in upper register of the piano.

Steve Reich

Steve Reich studied African and Balinese music. He discovered phase shifting – in which two identical recordings gradually go out of synchronization – while working with tape loops in the mid-1960s. Two pieces from this period are It’s Gonna Rain (1965) and Come Out (1966). He began applying phase shifting to live performance with his 1967 piece for two pianos, Piano Phase (1967). Reich’s style consists of diatonic melodic figures, steady rhythmic pulsation, and percussive attacks. Other significant pieces include Music for Eighteen Musicians (1976), Vermont Counterpoint (1982), and The Desert Music (1982).

Philip Glass
Philip Glass became interested in the additive rhythm approach from his studies of Indian Music. For example, Music in Fifths (1969) contains an eight-note figure that is expanded through this additive process to include 200 notes. Glass’s music gradually moved away from earlier efforts to a style that contains more complexity and harmonic progression. In Another Look at Harmony (1975) he began to use tonal harmonic progressions. His operas Einstein on the Beach (1975) and Akhnaten (1983) have gained wide acclaim.

John Adams

John Adams is a Harvard educated clarinetist, conductor and composer who writes in a post-minimalist and neoromantic style. He has written in a variety of genres but is best known for his operas and orchestral music. An early and important work for string orchestra, Shaker Loops (1978) shows his strong minimalist influences. Grand Pianola Music (1982), for small orchestra, percussion and three sopranos, showcases the V – I progression in its finale “On the Dominant Divide.” Harmonielehre (1985) remains one of his best-known works, with grand, romantic qualities and a bold, brassy, heroic ending. The 1996 piano concerto Century Rolls is inspired by player piano music.

Adams’ operas are usually based on real people and real events. Nixon in China (1987) is about
Nixon’s 1970s visit to China, 
The Death of Klinghofer (1989) is about the Palestinian hijacking of
the cruise liner Achille Lauro, and 
Doctor Atomic (2005) focuses on the events surrounding the creation of the first atomic bomb.

Michael Torke

Michael Torke is a post-minimalist composer whose music features colorful and brilliant orchestration, an essentially tonal outlook, driving rhythms, and influences that range from jazz and pop to Debussy and Stravinsky. Representative works include Bright Blue Music (1985), Javelin (for the 1996 Olympics), Adjustable Wrench (1987), Blue Pacific (2006), and Unconquered (2016).

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