In musical composition, a sound mass (also sound collective, sound complex, tone shower, sound crowd, or cloud) is the result of compositional techniques, in which, "the importance of individual pitches," is minimized, "in preference for texture, timbre, and dynamics as primary shapers of gesture and impact," obscuring, "the boundary between sound and noise" (Edwards 2001, pp. 326–27).
Techniques which may create or be used with sound mass include extended techniques such as muted brass or strings, flutter tonguing, wide vibrato, extreme ranges, and glissandos as the continuum for "sound mass" moves from simultaneously sounding notes – clusters etc., towards stochastic cloud textures, and 'mass structure' compositional textures which evolve over time (Edwards 2001, pp. 326–27). In a sound mass, "the traditional concept of 'chord' or vertical 'event' [is] replaced by a shifting, iridescent fabric of sound" (Kostka, Payne, and Schindler 1995, 546).
The use of "chords approaching timbres" begins with Debussy and Edgard Varèse often carefully scored individual instrumental parts so that they would fuse into one ensemble timbre or sound mass (Erickson 1975, pp. 18 and 21). Explored by Charles Ives and Henry Cowell in the early part of the twentieth century, this technique also developed from the modernist tone clusters and spread to orchestral writing by the mid 1950s and 1960s (Edwards 2001, pp. 326–27). "Unlike most tonal and non-tonal linear dissonances, tone clusters are essentially static. The individual pitches are of secondary importance; it is the sound mass that is foremost" (Reisberg 1975, p. 355). One French composer active in this period whose music takes a sound-mass approach directly influenced by both Debussy and Varèse is Maurice Ohana (Rae 2001).