Spectral music (or spectralism) is a musical composition practice where compositional decisions are often informed by the analysis of sound spectra. Computer based sound spectrum analysis using a Fast Fourier transform is one of the more common methods used in generating descriptive data. Using FFT analysis, features of a particular sound spectrum can be visualized using a spectrogram. Spectral composition focuses, then, on bringing out these features, interconnecting them, and transforming them. This analytical approach to spectral composition originated in France in the early 1970s and the techniques were primarily developed, and later refined, at the Institut de Recherche et Coordination Acoustique/Musique, Paris, and with the Ensemble l'Itinéraire, by composers such as Gerard Grisey and Tristan Murail.
Also can refer to music that possesses a ghostly or phantasmal quality, as found in the Hauntological genre or old blues records. .
