Polyrhythm
Polyrhythm is the simultaneous use of two or more rhythms that are not readily perceived as deriving from one another, or as simple manifestations of the same meter.[2] The rhythmic layers may be the basis of an entire piece of music (cross-rhythm), or a momentary section. Polyrhythms can be distinguished from irrational rhythms, which can occur within the context of a single part; polyrhythms require at least two rhythms to be played concurrently, one of which is typically an irrational rhythm. Concurrently in this context means within the same rhythmic cycle. The underlying pulse, whether explicit or implicit can be considered one of the concurrent rhythms. For example, the son clave is poly-rhythmic because its 3 section suggests a different meter from the pulse of the entire pattern.[3]
For the Perfume song, see Polyrhythm (song).Jazz[edit]
3:2 cross-rhythm[edit]
Polyrhythm is a staple of modern jazz. Although not as common, use of systemic cross-rhythm is also found in jazz. In 1959, Mongo Santamaria recorded "Afro Blue", the first jazz standard built upon a typical African 6:4 cross-rhythm (two cycles of 3:2).[19] The song begins with the bass repeatedly playing 6 cross-beats per each measure of 12
8 (6:4). The following example shows the original ostinato "Afro Blue" bass line. The cross noteheads indicate the main beats.
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