The frequency content of a sound or audio signal often displayed as a graphic representation of amplitude against frequency. Three-dimensional displays of a spectrum add the time variation on the third axis. The spectrum of a sound is a primary determinant of its perceived timbre.

A partial spectrum consists of discrete frequencies known as overtones, harmonics or inharmonics. A continuous spectrum consists of noise components. The spectrum of a sound may be determined by a number of sound analysers or by Fourier analysis and is distributed over the audible range (20 to 20,000 Hz). A partial spectrum is also known as a line spectrum, where discrete frequencies are present. A continuous spectrum, on the other hand, shows frequencies continuously distributed over the audible range. (Source: Barry Truax - Handbook for Acoustic Ecology CD-ROM Edition. Cambridge Street Publishing, 1999 - CSR-CDR 9901)

See also:

Frequency, Harmonic, Inharmonic, Noise, Spectral Fusion, Spectral Shaping, Spectral Space, Spectralisme, Spectromorphology, TimbreBibliography: Piszczalski, Martin (1979a). Spectral Surfaces from Performed Music: Part 1

Piszczalski, Martin (1979b). Spectral Surfaces from Performed Music: Part 2

ROEDERER, Juan G. (1979). Introduction to the Physics and Psychophysics of Music

Verma, Tony S., Meng, Teresa H. Y. (2000). Extending Spectral Modeling Synthesis with Transient Modeling Synthesis