Mus. prod. by elec. means, the resulting sounds being recorded on tape. At first the term applied strictly to sounds synthesized electronically, to differentiate from musique concrète, which was assembled from normal mus. and everyday sounds. But by now it covers both groups. Attempts to produce elec. sounds began in the USA and Canada in the 1890s. Early in the 20th cent., experiments were made in Ger. by Fischinger; and in USSR in the 1930s elec. mus. was prod. by the use of photo‐electric techniques rather than by oscillator. In fact, the development of elec. mus. has proceeded step by step with the invention of equipment: telephone, loudspeaker, microphone, tape, film sound‐track, oscillator, gramophone recording, etc. For composers, an important milestone was reached with experiments at Bonn Univ. in 1949–50 followed by a public perf. at Darmstadt in 1951. The first elec. mus. studio was est. 1951 by W. Ger. Radio, Cologne, dir. by Herbert Eimert. Other studios were set up in Milan, Tokyo, London, Warsaw, Brussels, Munich, Eindhoven, Paris, and at Columbia Univ., NY.
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.