cluster chord
theoryKLUS-tur kord
A chord built from adjacent notes, creating a dense, dissonant mass of sound.
Tone clusters stack seconds (rather than the usual thirds) to create thick, dissonant sonorities. Henry Cowell pioneered the technique in the 1910s, playing the piano with fists, forearms, and palms. Bartok, Ligeti, and Penderecki developed clusters into a sophisticated compositional tool. In Ligeti's Atmospheres, dense chromatic clusters shift gradually, creating slowly evolving sound masses. Cluster chords also appear in jazz and rock for percussive, dissonant accents.
The terrifying music in Stanley Kubrick's 2001: A Space Odyssey features Ligeti's cluster-based compositions, which were used without the composer's permission, leading to a famous lawsuit.