Tetrad (music)

In music theory, a tetrad is a set of four notes. When these four notes form a tertian chord they are more specifically called a seventh chord, after the diatonic interval from the root of the chord to its fourth note (in root position close voicing). Four-note chords are often formed of intervals other than thirds in twentieth- and twenty-first-century music, however, where they are more generally referred to as tetrads (see, for example, Hanson 1960, , and Gamer 1967, 37 & 52). A four-note segment of a scale or twelve-tone row is more particularly known as a tetrachord, although Allen Forte in his The Structure of Atonal Music uses the term tetrachord synonymously with tetrad.

See also

• Tetrachord
• Hexachord

References

• Forte, Allen (1973). The Structure of Atonal Music. New Haven and London: Yale University Press. ISBN 0-300-01610-7 (cloth) ISBN 0-300-02120-8 (pbk).
• Forte, Allen (1985). "Pitch-Class Set Analysis Today". Music Analysis 4, nos. 1 & 2 ( (March–July: Special Issue: King's College London Music Analysis Conference 1984): 29–58.
• Gamer, Carlton (1967). "Some Combinational Resources of Equal-Tempered Systems". Journal of Music Theory 11, no. 1:32–59.
• Hanson, Howard (1960). Harmonic Materials of Modern Music: Resources of the Tempered Scale. New York: Appleton-Century-Crofts.