20th-century classical music

20th century classical music was extremely varied and thus there was no dominant style. However, a salient feature in classical music during this period was the increased use of dissonance. Because of this, the 20th century is sometimes called the "Dissonant Period" of classical music, because much of its music was a reaction to, or against, the common practice period, which emphasized consonance (Schwartz and Godfrey 1993, 9–43). The International Paris Exposition celebrating the centennial of the French Revolution in 1889 is referred to by one writer as the watershed transitional moment from consonance to dissonance (Fauser 2005).

 

Introduction
At the turn of the century, music was characteristically late Romantic in style. Composers such as Gustav Mahler and Jean Sibelius were pushing the bounds of Post-Romantic Symphonic writing. At the same time, the Impressionist movement, spearheaded by Claude Debussy, was being developed in France. The term was actually rejected by Debussy: "I am trying to do 'something different—in a way realities—what the imbeciles call `impressionism' is a term which is as poorly used as possible, particularly by art critics" (Politoske 1988, 419)—and Maurice Ravel's music, also often labelled with this term, explores music in many styles not always related to it (see the discussion on Neoclassicism, below).

Many composers reacted to the Post-Romantic and Impressionist styles and moved in quite different directions. In Vienna, Arnold Schoenberg developed atonality, out of the expressionism that arose in the early part of the 20th century. He later developed the twelve-tone technique which was developed further by his disciples Alban Berg and Anton Webern; later composers (including Luciano Berio and Pierre Boulez) developed it further still (Ross 2008, 194–96 and 363–64). Stravinsky (in his last works) explored twelve-tone technique, too, as did many other composers; indeed, even Scott Bradley used the technique in his scores for the Tom and Jerry cartoons (Ross 2008, 296).

After the First World War, many composers started returning to previous centuries for their inspiration and wrote works that draw elements (form, harmony, melody, structure) from this music. This type of music thus became labelled neoclassicism. Igor Stravinsky (Pulcinella and Symphony of Psalms), Sergei Prokofiev (Classical Symphony), Ravel (Le Tombeau de Couperin) and Hindemith (Mathis der Maler) all produced neoclassical works.

Italian composers such as Francesco Balilla Pratella and Luigi Russolo developed musical Futurism. This style often tried to recreate everyday sounds and place them in a "Futurist" context. The "Machine Music" of George Antheil (starting with his Second Sonata, "The Airplane") and Alexander Mosolov (most notoriously his Iron Foundry) developed out of this. The process of extending musical vocabulary by exploring all available tones was pushed further by the use of Microtones in works by Charles Ives, Julián Carrillo, Alois Hába, John Foulds, Ivan Wyschnegradsky and Mildred Couper among many others. Microtones are those intervals that are smaller that a semitone; human voices and unfretted strings can easily produce them by going in between the "normal" notes, but other instruments will have more difficulty—the piano and organ have no way of producing them at all, aside from retuning and/or major reconstruction.

In the 1940s and '50s composers, notably Pierre Schaeffer, started to explore the application of technology to music in musique concrète. (Dack 2002) The term Electroacoustic music was later coined to include all forms of music involving magnetic tape, computers, synthesizers, multimedia and other electronic devices and techniques. Live electronic music uses live electronic sounds within a performance (as opposed to preprocessed sounds that are overdubbed during a performance), Cage's Cartridge Music being an early example. Spectral music (Gerard Grisey and Tristan Murail) is a further development of electroacoustic music that uses analyses of sound spectra to create music. (Dufourt 1981; Dufourt 1991) Cage, Berio, Boulez, Milton Babbitt, Luigi Nono and Edgard Varèse all wrote Electroacoustic music, often promoted in "happenings".

From the early 1950s onwards, Cage introduced elements of chance into his music. This has resulted in various musical techniques such as indeterminacy, aleatoric music, stochastic music, intuitive music, and free improvisation. Process music (Karlheinz Stockhausen Prozession, Aus den sieben Tagen; and Steve Reich Piano Phase, Clapping Music) explores a particular process which is essentially laid bare in the work. The term Experimental music seems to have been coined by Cage who was interested in writing complete works that performed an unpredictable action (Mauceri 1997, 197) according to the definition "an experimental action is one the outcome of which is not foreseen" (Cage 1961, 39). The term is also used to describe music within specific genres that pushes against their boundaries or definitions, or else whose approach is a hybrid of disparate styles, or incorporates unorthodox, new, distinctly unique ingredients.

Important cultural trends often informed music of this period, romantic, modernist, neoclassical, postmodernist or otherwise. Igor Stravinsky and Sergei Prokofiev were particularly drawn to primitivism in their early careers, as explored in works such as The Rite of Spring and Chout. Other Russians, notably Dmitri Shostakovich, reflected the social impact of communism and subsequently had to work within the strictures of socialist realism in their music (McBurney 2004,). Other composers, such as Benjamin Britten (War Requiem), explored political themes in their works, albeit entirely at their own volition (Evans 1979, 450). Nationalism was also an important means of expression in the early part of the century. The culture of the United States of America, especially, began informing an American vernacular style of classical music, notably in the works of Charles Ives, John Alden Carpenter, and (later) George Gershwin. Folk music (Vaughan Williams' Variants on Dives and Lazarus, Gustav Holst's A Somerset Rhapsody) and Jazz (Gershwin, Leonard Bernstein, Darius Milhaud's La création du monde) were also influential.

In the latter quarter of the century, eclecticism and polystylism became important. These, as well as minimalism, New Complexity and New Simplicity, are more fully explored in their respective articles. Indeed, the music of the 20th century saw a large cross-over of styles: the more commercial of the 20th-century art-music styles are evident in popular music, film scores and video game music, and many elements from these latter are found in 20th-century classical music. The term postmodern music is often applied to music that "reacts" to Modernism, though it is not always clear what the "reaction" precisely is. 

 
Romantic style

At the end of the 19th century (often called the Fin de siècle), the Romantic style was starting to break apart, moving along various parallel courses, such as Impressionism and Post-romanticism. In the 20th century, the different styles that emerged from the music of the previous century influenced composers to follow new trends, sometimes as a reaction to that music, sometimes as an extension of it, and both trends co-existed well into the 20th century. The former trends, such as Expressionism are discussed later. In the early part of the 20th century, many composers wrote music which was an extension of 19th-century Romantic music, and traditional instrumental groupings such as the orchestra and string quartet remained the most typical. Traditional forms such as the symphony and concerto remained in use. Gustav Mahler and Jean Sibelius are examples of composers who took the traditional symphonic forms and reworked them. (See Romantic Music) While some writers hold that Debussy's Prélude à l'après-midi- d'un faune and Schoenberg's Verklärte Nacht are dramatic departures from Romanticism and have strong modernist traits, others hold that the Schoenberg work is squarely within the late-Romantic tradition of Wagner and Brahms (Neighbour 2001, 582) and, more generally, that "the composer who most directly and completely connects late Wagner and the 20th century is Arnold Schoenberg" (Salzman 1988, 10).

Impressionism

Impressionism started in France as a reaction, led by Claude Debussy, against the emotional exuberance and epic themes of German Romanticism exemplified by Wagner. In Debussy's view, art was a sensuous experience, rather than an intellectual or ethical one. He urged his countrymen to rediscover the French masters of the 18th century, for whom music was meant to charm, to entertain, and to serve as a "fantasy of the senses" (Machlis 1979, 86–87). Other composers associated with impressionism include Maurice Ravel, Albert Roussel, Isaac Albéniz, Paul Dukas, Manuel de Falla, Charles Martin Loeffler, Charles Griffes, Frederick Delius, Ottorino Respighi, and Karol Szymanowski (Machlis 1979, 115–18). Although impressionism is generally held to have been superseded in the 1920s by neoclassicism, many French composers continued its language, including Albert Roussel, Charles Koechlin, André Caplet, and, later, Olivier Messiaen. Composers from non-Western cultures, such as Tōru Takemitsu, and jazz musicians such as Duke Ellington, Gil Evans, Art Tatum, and Cecil Taylor, also have been strongly influenced by the impressionist musical language (Pasler 2001).

Modernism 

Modernism started as a reaction to late 19th-century Romanticism and was characterized by a desire for or belief in progress (especially in science and politics) and was often accompanied by a complete break with the past and, most particularly, a rejection of the common practice. Surrealism was an important early manifestation of this. Modernism covers most of the movements that are described below. Postmodernism was the reaction to Modernism.

Free dissonance and experimentalism

In the early part of the 20th century, Charles Ives integrated American and European traditions as well as vernacular and church styles, while using innovative techniques in his rhythm, harmony, and form (Burkholder 2001). His technique included the use of polytonality, polyrhythm, tone clusters, aleatoric elements, and quarter tones. Edgard Varèse wrote highly dissonant pieces that utilized unusual sonorities and futuristic, scientific sounding names. He pioneered the use of new instruments and electronic resources (see below).

Futurism 

At its conception, Futurism was an Italian artistic movement founded in 1909 by Filippo Tommaso Marinetti; it was quickly embraced by the Russian avant garde. In 1913, the painter Luigi Russolo published a manifesto, L'arte dei rumori (The Art of Noises), calling for the incorporation of noises of every kind into music. In addition to Russolo, composers directly associated with this movement include the Italians Silvio Mix, Nuccio Fiorda, Franco Casavola, and Pannigi (whose 1922 Ballo meccanico included two motorcycles), and the Russians Artur Lourié, Mikhail Matyushin, and Nikolai Roslavets. Though few of the futurist works of these composers are performed today, the influence of futurism on the later development of 20th-century music was enormous. Sergei Prokofiev, Maurice Ravel, Igor Stravinsky, Arthur Honegger, George Antheil, Leo Ornstein, and Edgard Varèse are among the notable composers in the first half of the century who were influenced by futurism. Characteristic features of later 20th-century music with origins in futurism include the prepared piano, integral serialism, extended vocal techniques, graphic notation, improvisation, and minimalism (Dennis & Powell 2001).

Expressionism

Expressionism was a prominent artistic trend associated especially with Austria and Germany before, during, and immediately after World War I. In some measure a reaction against the perceived passive nature of impressionism, it emphasized an eruptive immediacy of expressive feeling, often based on the psychology of the unconscious. Expressionism is primarily identified with Arnold Schoenberg’s "free atonal’ period" (1908–1921), in particular the monodrama Erwartung, the Klavierstück op. 11, no. 3, and the first and last of his Five Orchestral Pieces op. 16. Certain works from this same period by his pupils Alban Berg and Anton Webern are also usually included. Although this music sets out from Wagner’s chromatic harmony (especially Kundry’s music in Parsifal), it tends to avoid cadence, repetition, sequence, balanced phrases, and any reference to traditional forms or procedures, for which reason it came to be associated with a rejection of tradition. Other composers active in approximately this period such as Gustav Mahler, Alexander Skryabin, Josef Matthias Hauer, Igor Stravinsky, Karol Szymanowski, Béla Bartók, Paul Hindemith, Charles Ives, and Ernst Krenek also exhibit expressionist traits, while important stage works of the 1920s by Kurt Weill, Hindemith, and Krenek retain expressionistic textual and visual aspects even though their musical language no longer reflects expressionism's aesthetic principles. By the late 1920s, though many composers continued to write in a vaguely expressionist manner, it was being supplanted by the more impersonal style of the German Neue Sachlichkeit and neoclassicism. Because expressionism, like any movement that had been stigmatized by the Nazis, gained a sympathetic reconsideration following World War II, expressionist music resurfaced in works by composers such as Hans Werner Henze, Pierre Boulez, Peter Maxwell Davies, Wolfgang Rihm, and Bernd Alois Zimmermann (Fanning 2001).

Second Viennese School, atonality, twelve-tone technique, and serialism 

Arnold Schoenberg is one of the most significant figures in 20th-century music. While starting off as a Late Romantic influenced by Wagner (Transfigured Night), he moved to Atonality (Drei Klavierstücke and Pierrot Lunaire). In 1921, after several years of research, he developed the twelve-tone technique of composition, which he first described privately to his associates in 1923 (Schoenberg 1975, 213) (Variations for Orchestra, Op. 31). He later returned to a more tonal style (Kammersymphonie no. 2). He taught Anton Webern and Alban Berg and these three composers are often referred to as the principle members of the Second Viennese School (Haydn, Mozart and Beethoven - and sometimes Schubert - being the First Viennese School in this context). Webern wrote works using a rigorous 12-tone method String Quartet and influenced the development of total serialism. Berg often combined the 12-tone method method with Late Romanticism and Post-romanticism (Violin Concerto, which quotes a Bach Choral and uses Classical form). He wrote two major operas (Wozzeck and Lulu).

Neoclassicism  

In neoclassicism, composers drew inspiration from music of the 18th century. The term neoclassical is applied to several movements in the arts during the 18th and 19th centuries, but the term has become the common name for music that revives earlier practices and techniques. Famous examples include Prokofiev's Classical Symphony and Stravinsky's Pulcinella. Paul Hindemith (Mathis de Maler) and Darius Milhaud also used this style. Maurice Ravel's Le Tombeau de Couperin is often seen as neobaroque (an architectural term), though the distinction between the terms is not always made.

Electronic music
Technological advances in the 20th century enabled composers to use electronic means of producing sound.

After the Second World War, magnetic tape became available for the creation of music by recording sounds and then manipulating them in some way. When the source material was acoustical sounds from the everyday world, the term musique concrète was used; when the sounds were produced by electronic generators, it was designated electronic music. After the 1950s, the term "electronic music" came to be used for both types. Sometimes such electronic music was combined with more conventional instruments, Stockhausen's Hymnen, Edgard Varèse's Déserts, and Mario Davidovsky's series of Synchronisms are three examples. 

Jazz-influenced classical composition 

A number of composers combined elements of the jazz idiom with classical compositional styles, notably Leonard Bernstein, Aaron Copland, George Gershwin, Darius Milhaud, and Maurice Ravel.

Postmodern music
Postmodernism is a reaction to Modernism, but it can also be viewed as a response to a deep-seated shift in societal attitude. According to this latter view, Postmodernism began when historic (as opposed to personal) optimism turned to pessimism, at the latest by 1930 (Meyer 1994, 331).

John Cage is a prominent figure in 20th-century postmodernism whose influence steadily grew during his lifetime. His best-known work is 4′33″ in which any instrumentalist (or combination of instrumentalists) is instructed not to play for the duration of the work. He often uses elements of chance: Imaginary Landscape No. 4 for 12 radio receivers, and Music of Changes for piano. Sonatas and Interludes (1946–8) is composed for a prepared piano, an instrument he invented in which the sound of a normal piano is altered by placing various objects between the strings.

Most of the styles and movements that follow can be classified as "postmodern".

Minimalism 

In the later 20th century, composers such as La Monte Young, Philip Glass, Terry Riley, and Steve Reich began to explore what is now called minimalism, in which the work is stripped down to its most fundamental features; the music often features repetition and iteration. An early example is Terry Riley's In C (1964), an aleatoric work in which short phrases are chosen by the musicians from a set list and played an arbitrary number of times, while the note C is repeated in eighth notes (quavers) behind them. Steve Reich's works Piano Phase (1967, for two pianos), and Drumming (1970–71, for percussion, female voices and piccolo) employ the technique called phasing in which a phrase played by one player maintaining a constant pace is played simultaneously by another but at a slightly quicker pace. This causes the players to go "out of phase" with each other and the performance may continue until they come back in phase. Philip Glass's 1 + 1 (1968) employs the additive process in which short phrases are slowly expanded. La Monte Young's Compositions 1960 employes very long tones, exceptionally high volumes and extra-musical techniques such as "draw a straight line and follow it" or "build a fire". Michael Nyman argues that minimalism was a reaction to and made possible by both serialism and indeterminism (Nyman 1999, 139).

Recording technology

The 20th century saw a change in the way in which classical music was heard. Advances in recording technologies, beginning with the rise in popularity of the phonograph in the early part of the century, and later with the inventions of magnetic tape, the cassette, DAT, and the compact disk. In addition, broadcasting technologies, such as radio and television have meant that the concert hall, opera house, salon, and domestic music-making are no longer the only means by which a performance can reach its audience.

Spectralism 

A musical composition practice where compositional decisions are often informed by the analysis of sound spectra. Prominent spectral composers include Tristan Murail and Gérard Grisey, and the 'post-spectral' composers Kaija Saariaho and Magnus Lindberg.

(source : en.wikipedia.org)