Editing Tone cluster (section)

{{Short description|Dense musical chord}}
[[File:Tone cluster.JPG|thumb|430px|right|Example of piano tone clusters. The clusters in the upper staff—C{{music|sharp}} D{{music|sharp}} F{{music|sharp}} G{{music|sharp}}—are four successive black keys. The last two bars, played with overlapping hands, are a denser cluster.]]

A '''tone cluster''' is a [[chord (music)|musical chord]] comprising at least three adjacent [[musical tone|tone]]s in a [[scale (music)|scale]]. Prototypical tone clusters are based on the [[chromatic scale]] and are separated by [[semitone]]s. For instance, three [[steps and skips|adjacent]] [[Musical keyboard|piano keys]] (such as C, C{{music|sharp}}, and D) struck simultaneously produce a tone cluster. Variants of the tone cluster include chords comprising adjacent tones separated [[Diatonic scale|diatonically]], [[Pentatonic scale|pentatonically]], or [[microtonal music|microtonally]]. On the piano, such clusters often involve the simultaneous striking of neighboring white or black keys.

The early years of the twentieth century saw tone clusters elevated to central roles in pioneering works by [[ragtime]] artists [[Jelly Roll Morton]] and [[Scott Joplin]]. In the 1910s, two classical avant-gardists, composer-pianists [[Leo Ornstein]] and [[Henry Cowell]], were recognized as making the first extensive explorations of the tone cluster. During the same period, [[Charles Ives]] employed them in several compositions that were not publicly performed until the late 1920s or 1930s, as did [[Béla Bartók]] in the latter decade. Since the mid-20th century, they have prominently featured in the work of composers such as [[Lou Harrison]], [[Giacinto Scelsi]], [[Alfred Schnittke]] and [[Karlheinz Stockhausen]], and later [[Eric Whitacre]]. Tone clusters also play a significant role in the work of [[free jazz]] musicians such as [[Cecil Taylor]], [[Matthew Shipp]], and [[Kevin Kastning]].

In most Western music, tone clusters tend to be heard as [[consonance and dissonance|dissonant]]. Clusters may be performed with almost any individual instrument on which three or more notes can be played simultaneously, as well as by most groups of instruments or voices. [[Keyboard instrument]]s are particularly suited to the performance of tone clusters because it is relatively easy to play multiple notes in unison on them.