Spectral music (or spectralism) is a musical practice where compositional decisions are often informed by sonographic representations and mathematical analysis of sound spectra. The spectral approach focuses on manipulating the features identified through this analysis, interconnecting them, and transforming them. In this formulation, computer-based sound analysis and representations of audio signals are treated as being analogous to a timbral representation of sound.
The spectral approach originated in France in the early 1970s, and techniques were developed, and later refined, primarily at IRCAM, Paris, with the Ensemble l'Itinéraire, by composers such as Gerard Grisey and Tristan Murail. Murail has described spectral music as an aesthetic rather than a style, not so much a set of techniques as an attitude – that "music is ultimately sound evolving in time". Julian Anderson indicates that a number of major composers associated with spectralism consider the term inappropriate, misleading, and reductive. The Istanbul Spectral Music Conference of 2003 suggested a redefinition of the term "spectral music" to encompass any music that foregrounds timbre as an important element of structure or language.
The term "spectral music" was coined by Hugues Dufourt in an article written in 1979 and first published two years later. Dufourt, a trained philosopher and composer, was the author of several important articles on spectral music.
The term was initially associated with composers of the French Ensemble l'Itinéraire, including Dufourt, Gérard Grisey, Tristan Murail, and Michael Levinas, and the German Feedback group, principally Johannes Fritsch, Mesias Maiguashca, Peter Eötvös, Claude Vivier, and Clarence Barlow. Features of spectralism are also seen independently in the contemporary work of Romanian composers Ştefan Niculescu, Horațiu Rădulescu, and Iancu Dumitrescu.
Notable composers building on the spectral idea today include Julian Anderson, Ana-Maria Avram, Joshua Fineberg, Jonathan Harvey, Fabien Lévy, Magnus Lindberg, and Kaija Saariaho. Jazz saxophonist and composer Steve Lehman has introduced spectral techniques into the domain of improvised music.
Proto-spectral composers include Claude Debussy, Edgard Varèse, Giacinto Scelsi, Olivier Messiaen, György Ligeti, Iannis Xenakis, and Karlheinz Stockhausen. Theoretical predecessors include some of the composers mentioned and Harry Partch, Henry Cowell, and Paul Hindemith.
Romanian folk music, as collected by Béla Bartók (1904–1918), with its acoustic scales derived directly from resonance and natural wind instruments like "buciume", "tulnice", and "cimpoi" inspired several spectral composers: Vieru, Stroe, Niculescu, Dumitrescu and Nemescu.
This music began to emerge in the 1970s both in France amongst the composers of the Groupe de l'Itinéraire, influenced by work of composers such as Maurice Ravel and Olivier Messiaen, in Germany amongst the members of the Feedback group in Cologne, and in Romania, with composers around Hyperion Ensemble, all of whom created harmonies and orchestrations based on the harmonic and inharmonic partials contained in complex sounds, such as multiple-stop organ tones, bell sounds, and bird song.
Compositional technique 
The "panoply of methods and techniques" used are secondary, being only "the means of achieving a sonic end". The composition of spectral music is concerned with timbral structures, especially when decisions about timbre are mathematically informed by Fourier analysis using the computer-efficient fast Fourier transform (FFT). FFTs can be run to provide graphs that illustrate details about the timbral structure of a sound which might not be initially apparent to the ear. Also, when creating sounds with computers, FFTs can be used to transform the timbre of a sound in various ways, such as by generating hybrid timbres through a collection of processes known as cross-synthesis, or applying a room reverberation to a sound by means of convolution. If the music is to be performed by live musicians (as opposed to being played electronically via computer through speakers), then these novel effects must be translated into an extended traditional notation that can be read and executed by a human being with some additional training. The fine gradations of pitch are usually rounded off to the nearest quarter-tone or even eighth-tone—dividing the octave into 24 or 48 discrete pitches, instead of the usual twelve of Western music. Temporal aspects and dynamics are subject to similarly fine controls, creating additional notational hurdles.[original research?]
Formal concepts important in spectral music include process, though "significantly different from those of minimalist music" in that all musical parameters may be affected. These processes most often achieve a smooth transition through interpolation.
The Romanian spectral tradition focuses more on the study of how sound itself behaves in a "live" environment. Sound work is not restricted to harmonic spectra but includes transitory aspects of timbre and non-harmonic musical components (e.g., rhythm, tempo, dynamics). Furthermore, sound is treated phenomenologically as a dynamic presence to be encountered in listening (rather than as an object of scientific study). This approach results in a transformational musical language in which continuous change of the material displaces the central role accorded to structure in spectralism of the "French school".
Notable works 
Characteristic spectral pieces include Gérard Grisey's Partiels, Tristan Murail's Gondwana. Jonathan Harvey's Mortuos Plango Vivos Voco (1980) is an example of electronic music that embraces spectral techniques.
- Fineberg 2000a, 2.
- Anderson 2000, 7.
- Reigle 2008
- Dufourt 1981; Dufourt 1991, 289–93.
- Anderson 2001.
- Anon. 2009.
- Rose 1996, 6; Moscovich 1997, 21–22
- Anderson 2000, 8-13.
- Halbreich 1992, 13-14
- "... the question of timbre, though it is rigorously tackled by Schönberg (in his theory of the "melody of timbres") and above all by Webern, nevertheless has pre-serial origins, especially in Debussy—in this regard a "founding father" of the same rank as Schönberg. [...] Later, it also provided the grounds for the break with Boulez's "structural" orientations and the contestation of the legacy of serialism which was carried out by the French group L'Itinéraire (Gérard Grisey, Michaël Levinas, Tristan Murail ...)" (Badiou 2009, 82).
- Anderson 2000, 14.
- Halbreich 1992, 50
- Teodorescu-Ciocanea 2004, 144
- Fineberg 2000a, 107.
- Reigle 2008, 16.
- Fineberg 2000a, 128.
- Joos 2002; Sykes 2003.
See also 
- Anderson, Julian. 2000. "A Provisional History of Spectral Music". Contemporary Music Review 19, no. 2 ("Spectral Music: History and Techniques"): 7–22.
- Anderson, Julian. 2001. "Spectral Music". The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell. London: Macmillan Publishers.
- Anon. 2009. "Doctoral Student Continues Legacy of Professor's Spectral Music". Research: Breakthroughs in Knowledge and Ideas at Columbia website (Accessed 7 May 2012).
- Badiou, Alain. 2009. Logics of Worlds: The Sequel to Being and Event, translated by Alberto Toscano. London, New York: Continuum. ISBN 978-0-8264-9470-2
- Arrell, Chris. 2002. "Pushing the Envelope: Art and Science in the Music of Gérard Grisey". Doctoral Dissertation, Cornell University.
- Arrell, Chris. 2008. "The Music of Sound: An Analysis of Gérard Grisey's Partiels". In Spectral World Musics: Proceedings of the Istanbul Spectral Music Conference, edited by Robert Reigle and Paul Whitehead. Istanbul: Pan Yayincilik. ISBN 9944-396-27-3.
- Busoni, Ferruccio. 1907. "Entwurf einer neuen Ästhetik der Tonkunst". In Der mächtige Zauberer & Die Brautwahl: zwei Theaterdichtungen fur Musik; Entwurf einer neuen Aesthetik der Tonkunst, by Ferruccio Busoni, Arthur, comte de Gobineau, and E. T. A. Hoffmann. Triest: C. Schmidt. English edition as Sketch of a New Esthetic of Music, translated from the German by Th. Baker. New York: G. Schirmer, 1911.
- Cohen-Lévinas, Danielle. 1996. Création musicale et analyse aujourd'hui. Paris: Eska, 1996. ISBN 2-86911-510-5
- Cornicello, Anthony. 2000 "Timbral Organization in Tristan Murail's "Désintégrations. Ph.D. Dissertation, Brandeis University.
- Cowell, Henry. 1930. New Musical Resources. New York & London: A. A. Knopf. Reprinted, with notes and an accompanying essay by David Nicholls. Cambridge [England] & New York: Cambridge University Press, 1996. ISBN 0-521-49651-9 (cloth) ISBN 0-521-49974-7 (pbk.)
- Dufourt, Hugues. 1981. "Musique spectrale: pour une pratique des formes de l'énergie". Bicéphale, no.3:85–89.
- Dufourt, Hugues. 1991. Musique, pouvoir, écriture. Collection Musique/Passé/Présent. Paris: Christian Bourgois. ISBN 2-267-01023-2
- Fineberg, Joshua (ed.). 2000a. Spectral Music: History and Techniques. Amsterdam: Overseas Publishers Association, published by license under the Harwood Academic Publishers imprint, ©2000. ISBN ISBN 90-5755-131-4. Constituting Contemporary Music Review 19, no. 2.
- Fineberg, Joshua (ed.). 2000b. Spectral Music: Aesthetics and Music. Amsterdam, Netherlands: Overseas Publishers Association. ISBN 90-5755-132-2. Constituting Contemporary Music Review 19, no. 3.
- Fineberg, Joshua. 2006. Classical Music, Why Bother?: Hearing the World of Contemporary Culture Through a Composer's Ears. Routledge. ISBN 0-415-97174-8, ISBN 978-0-415-97174-4. [Contains much of the same text as Fineberg 2000a and 2000b.
- Grisey, Gérard. 1987. "Tempus ex machina: A Composer's Reflections on Musical Time." Contemporary Music Review 2, no. 1:238–75.
- Halbreich, Harry. 1992 Roumanie, terre du neuvième ciel. Bucharest: Axis Mundi.
- Harvey, Jonathan. 2001. "Spectralism". Contemporary Music Review 19, no. 3:11–14.
- Helmholtz, Hermann von. 1863. Die Lehre von den Tonempfindungen als physiologische Grundlage für die Theorie der Musik. Braunschweig: Friedrich Vieweg und Sohn. Second edition 1865; third edition 1870; fourth revised edition 1877; fifth edition 1896; sixth edition, edited by Richard Wachsmuth, Braunschweig: A. Vieweg & Sohn, 1913 (Facsimile reprints, Darmstadt: Wissenschaftliche Buchgesellschaft, 1968; Frankfurt am Main: Minerva, 1981; Hildesheim & New York: G. Olms, 1983, 2000 ISBN 3-487-01974-4; Hildesheim: Olms-Weidmann, 2003 ISBN 3-487-11751-7; Saarbrücken: Müller, 2007 ISBN 3-8364-0606-3).
- Translated from the third edition by Alexander John Ellis, as On the Sensations of Tone as a Physiological Basis for the Theory of Music. London: Longmans, Green and Co., 1875; second English edition, revised and corrected, conformable to the 4th German edition of 1877 (London and New York: Longmans, Green, and Co., 1885); third English edition 1895; fourth English edition 1912; reprint of the 1912 edition, with a new introduction by Henry Margenau, New York: Dover Books, 1954 ISBN 0-486-60753-4; reprint of the 1912 edition, Whitefish, Montana: Kellinger Publishing, 2005, ISBN 1-4191-7893-8
- Humbertclaude, Eric. 1999. La Transcription dans Boulez et Murail: de l’oreille à l’éveil'. Paris: Harmattan. ISBN 2-7384-8042-X.
- Joos, Maxime. 2002. "'La cloche et la vague': Introduction à la musique spectrale—Tristan Murail et Jonathan Harvey". Musica falsa: Musique, art, philosophie, no. 16 (Fall): 30–31.
- Lévy, Fabien. 2004. "Le tournant des années 70: de la perception induite par la structure aux processus déduits de la perception". In Le temps de l'écoute: Gérard Grisey ou la beauté des ombres sonores, edited by Danièle Cohen-Levinas, 103–33. Paris: L'Harmattan/L'itinéraire. [Contains many typographical errors; corrected version online at: http://www.fabienlevy.net/Documents/pdf/tournant70.pdf.]
- Moscovich, Viviana. 1997. "French Spectral Music: An Introduction". Tempo new series, no. 200 (April): 21–27.
- Reigle, Robert. 2008. "Spectral Musics Old and New". In Spectral World Musics: Proceedings of the Istanbul Spectral Music Conference, edited by Robert Reigle and Paul Whitehead. Istanbul: Pan Yayincilik. ISBN 9944-396-27-3.
- Rose, François. 1996. "Introduction to the Pitch Organization of French Spectral Music." Perspectives of New Music 34, no. 2 (Summer): 6–39.
- Surianu, Horia. 2001. "Romanian Spectral Music or Another Expression Freed", translated by Joshua Fineberg. Contemporary Music Review 19, no. 3:23–32.
- Sykes, Claire. 2003. "Spiritual Spectralism: The Music of Jonathan Harvey". Musicworks: Explorations in Sound, no. 87 (Fall): 30–37.
- Teodorescu-Ciocanea, Livia. 2004 Timbrul Muzical, Strategii de compoziţie. Bucharest: Editura Muzicală. ISBN 973-42-0344-4.
- French Wikipedia article on Spectral music (or the "Spectral school", as they tend to call it)
- IRCAM page on Dufourt
- IRCAM page on Joshua Fineberg
- IRCAM page on Philippe Hurel
- IRCAM page on Philippe Leroux
- IRCAM page on Marco Stroppa