The defining feature of modern music (and modern art generally) is the breaking-down of all traditional aesthetic conventions, thereby unleashing complete freedom in all aesthetic dimensions, including melody, rhythm, and chord progression. The convention of major-minor tonality (already heavily strained by Wagner and his successors) was completely abandoned by many composers (see Tonality). Even the very notion of what constitutes "music" was redefined.
The development of audio recording technology, along with the ability to quickly and cheaply distribute recordings and scores, were central to the revolutions of modern music. The vast catalogue of Western art music became much more accessible. Moreover, non-Western music was suddenly open to exploration (via notated and recorded works), thus exposing Western composers to countless exotic musical ideas.I484-86
Recording technology also provided composers with a new "instrument": recorded sounds, which could be manipulated in endless ways. Further advances in audio technology gave rise to electronically-produced sounds. Ultimately, many composers agreed that all sounds, even "noise", can be considered forms of music.I530,I568
Some modern music features indeterminacy, in which the composer deliberately abstains from clearly defining certain aspects of a composition (e.g. instrumentation, melody, dynamics), such that they are realized in different ways for each performance. For instance, a composition might ask a player to generate a melody by interpreting something (e.g. curving lines that suggest the shape of a melody), or to choose from a selection of melodies by rolling a die.I516,I538
New Music Families
Music (and art generally) of the pre-modern world can be broadly divided into two kinds. Folk music emerged naturally among cultures throughout the world, while art music was deliberately cultivated by small numbers of professional composers. Folk music generally features relatively simple structure/theory and has a relaxed, informal quality, whereas art music generally features relatively complex structure/theory has an elevated, formal quality.
With the development of modern mass media (communication technologies that quickly reach large numbers of people, e.g. radio, television, audio recordings), a new family of music was born: popular music, which has the simple structure/theory and informal quality of folk music. Instead of developing gradually among a given culture, however, popular music develops at a swift pace (due to its rapid dissemination via mass media) in the hands of professional composers (like art music).
Popular music emerged in the United States from the fusion of two folk traditions. One was American folk music, which consisted of various traditions descended chiefly from British folk music (which, naturally, had been imported to colonial America); the other was African music, carried to America by thousands of slaves. Most genres of popular music can be traced back to the merging of these traditions, in which Western major-minor tonality was combined with the rhythms of Africa.I541-47
Mass media also gave rise to film music, a special branch of Western art music. Film music generally employs major-minor tonality, given that this system allows emotion to be conveyed in such a clear, powerful manner (see Tonality). Film music is the only form of art music in history to be regularly experienced by a large proportion of society; all other art music (especially that of the modern age, which is generally quite inaccessible) is enjoyed by a much more limited audience.
The style of Western music known as impressionism is considered to embody the transition from Romantic to modern music. Romantic music (like Baroque and Classical music before it) tends to feature a strong sense of forward motion, in which a well-defined melody is supported by chord progressions that provide tension and release (see Tonality). Impressionist music, on the other hand, tends to feature static harmony; chords are not arranged to provide tension and release, and thus the sense of forward motion is mild or absent.I473-77,5
Impressionist composers often select chords for their individual sounds rather than arranging them in progressions. Impressionist music can thus be described as series of harmonic textures, as opposed to a melody supported by a harmonic foundation. This makes impressionism superb for conveying atmosphere (rather than forceful emotion).I473-77,5
The two foremost impressionist composers are Claude Debussy (who founded the style during the early modern period of music, ca. 1850-1900) and Maurice Ravel (who led impressionism during the late modern period, ca. 1900-60). Both excelled in works for piano and orchestra. Debussy's most famous composition is the piano work Clair de Lune, while Ravel's is the orchestral work Bolero.
A revolutionary development of the late modern period (ca. 1900-60) was atonal music, which lacks a tonal centre. This was an extraordinarily novel concept; all pre-modern musical traditions throughout the world are tonal. In Western art music, major-minor tonality had prevailed throughout the Baroque, Classical, and Romantic periods (see Tonality).
Atonality emerged from the abundant chromaticism of late Romantic music. "Chromaticism" denotes the use of notes that lie outside the scale on which a passage is based. A passage in the key of C major, for instance, is made up of the seven notes contained in the C major scale; the presence of any notes that lie outside the C major scale (e.g. F sharp) constitutes chromaticism. While a certain amount of chromaticism is standard in Baroque and Classical music, it was taken to new extremes in Romantic music.
When chromaticism becomes very abundant, the sense of a tonal centre weakens. When "total chromaticism" is reached, all twelve notes of the octave are given equal preference; no trace of a scale remains. Music that features total chromaticism is known as atonal, since it lacks a tonal centre altogether.
Branches of Modern Music
Modern Western art music can be divided into three branches.
One is radical modern music, which encompasses all types that depart extremely from traditional Western music. The primary member of this branch is atonal music; another is music comprised of non-musical sounds (i.e. noise).
The most famous and influential atonal composer is the Austrian Arnold Schoenberg. He developed a widely-used approach to atonal composition, the twelve-tone system, in which a composer arranges the twelve notes of the octave in any desired order; this sequence is then repeated continuously throughout the composition. Part of the motivation for this system was to force composers to treat all twelve notes equally, thus preventing them from unconsciously reverting to tonality.1
The second branch of modern Western music is moderate modern, which departs less severely from tradition. Moderate modern music features heavy chromaticism, yet retains a sense of tonality, as well as other traditional conventions.I507 The foremost moderate modern composer is Igor Stravinsky, often considered the greatest composer of the twentieth century.6 Stravinsky's most famous work is The Rite of Spring, a ballet.
The third and final branch of modern Western music is major-minor tonal (i.e. music that features major-minor tonality). In terms of art music, this branch encompasses most film music and musicals; additionally, it includes most popular music. Thus, in terms of sheer audience size, major-minor tonality continues to dominate Western music.
The age of Romantic opera extended several decades into the twentieth century, led by Puccini and Richard Strauss. Opera then became the domain of modern composers, the most popular of which is Benjamin Britten. His most-performed work is The Turn of the Screw.
The story of modern opera goes further, however. Just as the modern age features a new, highly-accessible branch of instrumental art music (film music), so does it feature an equivalent new branch of opera: musical theatre. Musical theatre (which has always been centered in New York) evolved from the operetta, a light form of opera that flourished in the late Romantic period.
There is no widely-accepted criterion for distinguishing musicals from operas. One view, however, is that opera is primarily music, while musicals are primarily theatre. In other words, an opera is essentially a vast musical performance with an underlying story, while a musical is essentially a play punctuated by musical numbers. (Note that by these definitions, some modern works termed "musicals" would actually be operas.)
The earliest musicals, which date to the early twentieth century, were (like operettas) light comedies replete with choruses and dancing, in which songs were sprinkled over a lightly-developed (and often ridiculous) plot.I550 The mature musical, in which songs are seamlessly woven throughout a well-developed plot, is often traced to the 1940s work Oklahoma!, by Rodgers and Hammerstein.8 Apart from Rodgers and Hammerstein, the most famous musical composers of the late modern period (ca. 1900-60) may be Irving Berlin and George Gershwin, while those of the postmodern period (ca. 1960-present) are likely Andrew Lloyd Webber and Stephen Sondheim.
2 - "Opera", Columbia Encyclopedia. Accessed September 2010.
3 - "Opera", Encarta 2004.
4 - "Western music", Encyclopedia Britannica. Accessed September 2010.
5 - "Impressionism", Encyclopedia Britannica. Accessed September 2010.
6 - "Igor Stravinsky", Columbia Encyclopedia. Accessed September 2010.
7 - "Chromaticism", Encyclopedia Britannica. Accessed September 2010.
8 - "Musicals", Columbia Encyclopedia. Accessed September 2010.