tone cluster
A chord built from adjacent notes sounded simultaneously, creating a dense, dissonant mass of sound
In Depth
Tone clusters were pioneered by American composer Henry Cowell, who played them on the piano using his fists, palms, and forearms as early as 1913. Clusters can be diatonic (white keys only), chromatic (all adjacent semitones), or pentatonic. They appear in works by Bartók, Ligeti, Penderecki, and many film composers. The effect ranges from thunderous percussive impact to shimmering textural washes depending on register, dynamics, and instrumentation.
When Cowell first performed his cluster pieces in Europe, audiences were so shocked that some critics accused him of assaulting the piano.