In the 1950s the comp. of elec. works was a slow and laborious business, chiefly because of the comparatively primitive equipment in the early studios. A comp. consisting of hundreds of predetermined and separately recorded sounds which would last a few minutes could take weeks to assemble on the final tape. The equipment in the early studios generally comprised: (a) sine-tone generators. Sine-tones are pure sounds which have no harmonics and are on a single frequency of even dynamic level. To build a complex tone at least 8 generators were needed. (b) white sound generator. White sound comprises all audible frequencies sounding together. (c) square wave generator. Square waves are richly harmonic and produce contrasts to sine-tones. (d) filters. Devices which, as their name implies, can ‘filter’ sound, or extract a single sine-tone from the white sound. Filters are classified according to their frequency-response characteristics, i.e. low-pass, high-pass, band-pass, and band-stop. For example, the band-pass filter passes only the sound-waves within a specified band of frequencies grouped round a centre frequency. (e) ring modulator. Used to combine several sound signals so that the sound output comprises the sums and differences of all the input-frequency components. (f) variable speed tape recorders. Varying speeds of playing the tape are used to speed up or slow down specific effects. (g) dynamic suppressor. A device which allows signals to be cut out below a selected level of dynamics, thus introducing a ‘chance’ element.
Among the most celebrated elec. pieces composed in the 1950s were Eimert's Fünf Stücke, Stockhausen's Gesang der Jünglinge (which incl. a boy's v., fragmented and superimposed upon itself, thereby creating a bridge with musique concrète), Krenek's Spiritus Intelligentiae Sanctus, Berio's Mutazioni, and Maderna's Notturno. But it should be remembered that in 1939–42 John Cage's first 3 Imaginary Landscapes incl. the use of records played at different speeds, audio oscillators, and an amplified wire coil. The first public concert of elec. mus. was given by Ussachevsky and Luening in Museum of Modern Art, NY, on 28 Oct. 1953.
Elec. mus. was revolutionized in the 1960s by the invention of voltage-controlled sound synthesizers, especially the model developed in 1964–5 by the American Robert A. Moog. This instr. dispensed with the drudgery of tape-splicing and cutting. It not only presented composers with a complete spectrum of new sounds, but could be made to play itself in a remarkable variety of sounds which could be recurrent or otherwise, as required. By the fitting of a control device known as a sequencer, the synthesizer can be used by a composer to memorize a long and complicated mus. compilation and play it ‘live’ without recording or tape-editing. Because of the synthesizer's astonishing imitative qualities, its use has been commercialized and vulgarized, but its potentiality as a serious instr. is still being explored and awaits a Wagner to exploit it to the full. Its main working principle, greatly over-simplified, is that the oscillators used as sound sources are also used to ‘control’ each other. Some synthesizers have a kbd., often with its own tuned oscillator, or set to act as a voltage control.
The sequencer is a small variety of the other revolutionary device also introduced in the 1960s, digital computer synthesis. Control by digital computer means that the equipment the composer uses is supplied with a ‘memory’. For example, a work comp., or ‘programmed’, for voltage-controlled equipment by means of punched paper tape has an intrinsic major problem in that the system has no way of storing information until it is needed; everything must be supplied in detail each time it is required. The computer memorizes all this information. The disadvantages of a computer are those inherent in ‘programming’, and it remains to be seen whether a supreme work of art will evolve by this system. The advantages of elec. mus. for th., radio, and film incidental mus. are obvious, and so far it is in these fields that the best results have been achieved.
Notation of elec. mus. obviously bears no relation to conventional mus. notation, and since the principal feature of an elec. work is that it is predetermined and mechanically produced, notation as a guide to performers is unnecessary. But ‘live’ elec. mus. is a developing art-form, and graphic directions in pitch (frequency) etc. are provided in ‘realization’ scores which provide all the technical data necessary to reproduce the piece. ‘Representational’ scores, for the score reader, are slightly less fearsome. An illustration of a typical elec. score or graph will give the reader a better idea of what is involved (see p. 224).
Among composers who have prod. elec. works are: Cage, Berio, Stockhausen, Wuorinen, Blacher, Boulez, Babbitt, Pousseur, Badings, Varèse, Davidovsky, Ligeti, Takemitsu, Penderecki, and Xenakis.
Interested readers who wish for fuller and more technical information than can be provided here are referred to Reginald Smith Brindle's The New Music (London, 1975), to which this entry acknowledges its indebtedness, and to Tristram Carey's Illustrated Compendium of Musical Technology (London, 1992). See also computers in music.
electronic music or electro-acoustic music, term for compositions that utilize the capacities of electronic media for creating and altering sounds.
Initially, a distinction must be made between the technological development of electronic instruments and the music conceived to utilize the inherent advantages of these instruments. Experiments in electronic tone production began soon after the invention of the vacuum tube (see electron tube). The first important instrument, the theremin, invented by the Russian Leon Theremin in 1920, used interference beats of two oscillators to produce sine-wave tones. The Ondes Martinot, invented in 1928, and the Trautonium, invented in 1930, were of similar design.
The earliest pieces of electronic music used recorded sounds that were then electronically altered to create sonic collages. This style, called musique concrete, was developed in Paris in 1948 by Pierre Schaeffer. The invention of the tape recorder in the late 1940s gave composers new means for modifying recorded sounds, including splicing (cutting the tape to create new juxtapositions of sound), speed variation (which changes the pitch of the recorded sound), and mixing (which allowed two or more different recordings to be played back at the same time). In popular music, Les Paul was one of the pioneers of electronic music, inventing the first solid-body electric guitar in 1946 and recording music in the 1950s in an eight-track recording studio of his own design.
Controlling aspects of the musical sound by means of voltage regulation eventually led to the invention of synthesizers, devices that could produce and modify sound for musical applications. Among the earliest of these was the RCA synthesizer developed in the late 1950s and used extensively by composer Milton Babbitt in many of his electronic works. In the 1950s various studios that specialized in the production of electro-acoustic music were developed, including the West German Radio Studio in Cologne, associated with composer Karlheinz Stockhausen, the Italian Radio Studio in Milan, associated with Luciano Berio and Bruno Maderna, and the Columbia-Princeton Electronic Music Center, associated with Otto Luening, Vladimir Ussachevsky, Mario Davidovsky, and Babbitt.
During the 1960s synthesizers were made widely available by companies such as Moog (see Moog, Robert) and Buchla and found widespread usage in rock music. Popular groups such as the Beatles and the Beach Boys began experiments in multitrack recording, years after the innovations of Paul, that enabled several different recordings to be synchronized on the same tape. Eventually synthesizers switched from voltage control to digital control.
In 1983 the MIDI (Musical Instrument Digital Interface) standard was agreed on by synthesizer manufacturers (see computer music). This digital code enables different electronic devices to communicate a variety of information to each other and allows computer control of synthesizer output. MIDI can also be used to control a wide range of equipment in addition to synthesizers; these include mixers, lights, and signal processors (devices that modify sounds by adding reverberation, by modifying pitch, and by other means).
Today MIDI is widely used in both academic and popular musical production. In MIDI production, computers are often used as sequencers (devices that control the output of musical instruments and signal processors). Throughout the last three decades of the 20th cent. electronic music increasingly became a part of pop music compositions, eventually allowing a solo artist to compose, produce, and perform music that employs a full complement of instrumental sounds. In the 1980s MIDI was also used in the creation of the radio baton, a new instrument that allows players to control the nuances of the music played.
See P. Manning, Electronic and Computer Music (1985); C. Anderton, The Electronic Musician's Dictionary (1988); H. Russcol, The Liberation of Sound: An Introduction to Electronic Music (1990); F. Rumsey, MIDI Systems and Controls (1990); N. Collins and J. d'Escrivan, The Cambridge Companion to Electronic Music (2007).