General term for instruments that produce vibrations that must be passed through a loudspeaker before they are heard as sound. It is applied to instruments in which vibrations are created by acoustic means but which require amplification to make them audible (incorporating pickups, special microphones or other transducers) and to instruments in which the sound-generating system is based on electro-mechanical or electronic oscillators. It is not applied to those instruments in which electricity is employed in an auxiliary capacity to power part of the action (as, for example, a pipe organ with electro-pneumatic action). Electrophones form a fifth class of instruments, in addition to the four (aerophones, chordophones, idiophones and membranophones) devised by Erich M. von Hornbostel and Curt Sachs in their system of classification (published in the Zeitschrift für Ethnologie, 1914; Eng. trans. in GSJ, xiv, 1961, pp.3–29; repr. in Ethnomusicology: an Introduction, ed. H. Myers, London, 1992, pp.444–61). By 1914 only a handful of electromechanical instruments had been devised, and, with one exception (William DuBois Duddell’s ‘singing arc’), none that was fully electronic, so that no term for such a group was included. By the end of the 20th century the classification system had still not been formally extended.
With the rapid development of electrophones from the late 1920s it was not long before organologists, musicologists and critics coined generic terms for them, in particular ‘electrophonic’ and ‘electrotonic’. Sachs appears to have been the first to introduce the term ‘electrophone’ into the classification system; in The History of Musical Instruments (1940), he subdivided the group into ‘electromechanical’ and ‘radioelectric’ instruments. A more detailed and accurate subdivision of ‘electrophonic’ instruments, into three categories, was proposed by F.W. Galpin in A Textbook of European Musical Instruments (1937): ‘autophonic’ (a word derived in the same way as ‘idiophonic’ and applied to instruments that produce sound by means of electronic oscillators); ‘electro-magnetic’; and ‘electro-static’. Galpin modified this system in a lecture given to the Musical Association in the following year, in which he put forward ‘autophonic’, ‘mechanical’ (combining his earlier ‘electro-magnetic’ and ‘electro-static’, and adding ‘photo-electric’) and ‘acoustical’ categories.
Galpin’s three categories of 1938 remain the most appropriate ones (though his names for them are no longer used), and they can be further subdivided to advantage. Since some of the basic principles of sound-generation were not employed, at least in commercially manufactured instruments, until the late 1930s, the first useful subdivisions of Galpin’s categories were not proposed until after World War II (Dräger, 1948; Lewer, 1948; Douglas, 1949; and Meyer-Eppler, 1949).
(1) Electronic instruments may be subdivided according to the type of oscillator circuit they employ; or according to the waveforms produced by the oscillators; or according to the relationship between the frequency of the signal generated and that of the sound heard (the frequency of the sound heard may be the same as that of the signal generated; or it may be the difference between the frequencies produced by two VHF oscillators; or it may be the result of dividing the frequency produced by a VHF oscillator by means of one or more frequency dividers). It is also possible to base subcategories on combinations of these three basic factors.
(2) Electromechanical instruments produce sound by means of rotating ‘tone-wheels’ (either with a profiled rim or an inscribed face) or an equivalent device such as moving lengths of prerecorded tape or film, which themselves generate no acoustic sound but form part of an oscillator circuit. They may be subdivided according to whether the electrical circuit contains an electromagnetic, electrostatic or photoelectric component.
(3) Electroacoustic instruments are those in which vibrating strings, reeds, plates, rods, tuning-forks or other components function exactly as in an acoustic instrument, but the vibrations are converted into voltage variations in an electrical circuit. In these instruments the acoustic sound is normally deliberately reduced, for example by removing the energy-absorbing soundboard of string instruments (as in the electric guitar and electric piano), or by enclosing the sound source in a virtually soundproof chamber (as in some electric organs using reeds). Electroacoustic instruments may be subdivided according to whether the electrical circuit contains an electromagnetic, electrostatic, photoelectric or piezoelectric component.
In each of these categories further levels of subdivision can be introduced, just as with acoustic instruments, according to whether an instrument is monophonic, partially polyphonic or fully polyphonic, whether the pitch control is continuous (as with a string) or discrete (as with a keyboard), how the sound is shaped and resonated, and so on.
In certain cases, especially in commercial instruments based on traditional models, there is such a close physical resemblance between an electroacoustic instrument and its acoustic ancestor that some have argued that these instruments could also be classified as a subcategory of the acoustic form (e.g. an electric guitar could be classified as a subcategory of Chordophone – necked lutes). This, however, ignores both the substantial reduction of the acoustic sound and the electrical components that have been integrally incorporated or are externally essential (such as an amplifier and loudspeaker). Since the pickups are an integral part of the instrument’s design, their functioning cannot be considered as electronic processing of an acoustic sound source, the argument used in most objections to this category. Furthermore an instrument, such as a reed organ, furnished with electrostatic transducers (that are not true pickups) cannot be described as ‘amplified’; the sounding objects – such as strings or reeds – actually carry a voltage (thus functioning as half of a variable capacitor) and their vibrations in the vicinity of small ‘plates’ create an electrical oscillation. Certain electroacoustic instruments are capable of producing additional variations in timbre or other parameters that would not be possible on an equivalent acoustic instrument, and this is more pronounced in those instruments which bear only a distant relationship to traditional instruments.
Two comparatively recent additions to the first category of electrophones are the computer-controlled digital oscillator, in which a continuous waveform is not generated directly but assembled by means of a ‘sampling’ technique that normally requires a rate of at least 20,000 samples per second, and digitally ‘sampled’ recordings of sounds from any source. In practice, both approaches have frequently been inseparably combined, as with a sampled attack added to a digitally-generated sound.
It is possible to consider the various methods of storing sound information (all of which may be creatively modified, and have been used as the basis for instruments) as special cases of the three main categories:
(1) Electronic: analogue and (particularly) digital oscillators can be controlled or programmed by a plug-in card, floppy disc, hard cartridge or other information storage device.
(2) Electromechanical: variations in an electromagnetic field, similar to that produced by a tone-wheel, are caused by playing back a pre-recorded magnetic tape disc; the photoelectric principle, now common in the compact disc, is paralleled in the ‘optical’ film soundtrack (see Drawn sound).
(3) Electroacoustic: the playing back of a shellac or vinyl gramophone record produces acoustic vibrations which, in modern equipment, are nearly always electrically amplified; this is exemplified by the hand-manipulated ‘scratching’ of LP records by disc jockeys and others.
Ki Mantle Hood (1982) has proposed for ‘electronophones’ a set of organogram symbols for the various types of sound-generating, -processing and -diffusing devices found in electronic instruments; they are partly derived from the relevant electrical symbols. This appears to have had only limited application and influence, apart from the use of the term in the GAMES (Generators and Modifiers of Electronic Sound) system proposed by Bakan and others (1990), devised primarily by students of ethnomusicology, which contains inconsistencies and omissions in its subdivisions of the classification system as well as inaccuracies in the description of several earlier instruments and principles. The clarity and universality of a similar set of electrically-based symbols, adopted by some composers (notably Stockhausen) but still ignored by many others, has much to commend it in this context, since it can be applied with equal appropriateness to the items of equipment that are connected together in an electronic music studio or in a live electronic concert performance and to the elements or modules of a synthesizer or other electronic instrument. An aspect that has been comparatively neglected in existing classification systems is the complexity of even the simplest action of a performer, regarding the various combinations of the parameters of pitch, timbre, loudness and articulation, which in electrophones are frequently allocated separate controls; this is remedied in Hugh Davies’s unpublished system, which combines elements of a flowchart and those of an electrical block diagram.
See also Instruments, classification of, and Electronic instruments, esp. §I.
SachsH
P. Lertes: Elektrische Musik: eine gemeinverständliche Darstellung ihrer Grundlagen, des heutigen Standes der Technik und ihre Zukunftsmöglichkeiten (Dresden and Leipzig, 1933)
F.W. Galpin: A Textbook of European Musical Instruments (London, 1937, 3/1956/R), 245–51
F.W. Galpin: ‘The Music of Electricity: a Sketch of its Origin and Development’, PMA, lxiv (1937–8/R), 71–83
H.-H. Dräger: Prinzip einer Systematik der Musikinstrumente (Kassel, 1948)
S.K. Lewer: Electronic Musical Instruments (London, 1948), 21–4
A. Douglas: Electronic Musical Instrument Manual: a Guide to Theory and Design (London, 1949), 31–45
W. Meyer-Eppler: Elektrische Klangerzeugung: elektronische Musik und synthetische Sprache (Bonn, 1949), 37–71
M. Hood: The Ethnomusicologist (New York, 1971, 2/1982), pp.xxii–xxiii
H. Heyde: Grundlagen des näturlichen Systems der Musikinstrumente (Leipzig, 1975)
H. Davies: ‘Electrophones’, MT, cxxvi (1985), 332–3
H. Davies: ‘Storia ed evoluzione degli strumenti musicali elettronici’, Nuova Atlantide: il continente della musica elettronica 1900–1986, Palazzo Sagredo, 25 Oct – 23 Nov 1986 (Venice, 1986), 17–59 [exhibition catalogue]; rev. as ‘Elektronische instrumenten: classificatie en mechanismen’, Elektrische Muziek: drie jaar acquisitie van elektrische muziekinstrumenten, Haags Gemeentemuseum, 28 May – cNov 1988 (The Hague, 1988), [23pp] [exhibition catalogue]; rev. as ‘Instruments électroniques: classification et mécanismes’, Contrechamps, no.11 (1990), 53–69
M.B. Bakan and others: ‘Demystifying and Classifying Electronic Music Instruments’, Selected Reports in Ethnomusicology, viii (1990), 38–64
M.J. Kartomi: On Concepts and Classifications of Musical Instruments (Chicago, 1990), 162–97
HUGH DAVIES