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'Polyrhythm' is the simultaneous sounding of two or more independent rhythms. 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, at least one of which is typically an irrational rhythm.
A simple example of a polyrhythm is 3 evenly-spaced notes against 2, with the 3-beat pattern being faster than the 2-beat pattern, so that they both take the same amount of time. Other simple polyrhythms are 3:4, 5:4, 7:4, etc. Where one of the parts involves an irrational rhythm, the resulting rhythm could be said to be an "irrational polyrhythm"
Another form of polyrhythm, which might also be termed polymeter, would be phrasing to suggest a different meter than the one being played by the rest of the ensemble. A common example of this in jazz would be phrasing quarter notes in groupings of 3 to suggest 3/4 time while the ensemble plays in 4/4. Compare with hemiola (not a polyrhythm).

Contents

Usage and history

Examples

See also

External links

Usage and history

Traditional African music, particularly that of West Africa, is known for its highly complex polyrhythms and, unlike the examples given below, the downbeats do not usually coincide. Rhythms and counter rhythms evidence the common African cultural tradition of call and response, with different drum lines, other musical instruments, bodies and voices contributing rhythmic elements that complement and communicate with one another. This element of instrumental, as well as vocalized, call and response is also evident in the polyrhythmic quality of jazz, a musical form with its origins in the African American community.
Nigerian percussion master Babatunde Olatunji exploded on the American music scene in 1959 with his album ''Drums of Passion'', which was a collection of traditional Nigerian music for percussion and chanting. The album stayed on the charts for two years and had a profound impact on jazz and American popular music. Trained in the Yoruba sakara style of drumming, Olatunji would go on to teach, collaborate and record with numerous jazz and rock artists, including Airto Moreira, Carlos Santana and Mickey Hart of the Grateful Dead. He reached his greatest popularity during the height of the Black Arts Movement of the 1960s and '70s.
Afro-Cuban music makes extensive use of polyrhythms. Cuban Rumba uses 3-based and 2-based rhythms at the same time, for example, the lead drummer (playing the quinto) might play in 6/8, while the rest of the ensemble keeps playing 2/2. Afro-Cuban ''conguero'', or conga player, Mongo Santamaria was another percussionist whose polyrhythmic virtuosity helped transform both jazz and popular music. Santamaria fused Afro-Latin rhythms with R&B and jazz as a bandleader in the 1950s, and was featured in the 1994 album ''Buena Vista Social Club'', which was the inspiration for the like-titled documentary released five years later.
Common polyrhythms found in jazz are 3:2, which manifests as the quarter-note triplet; 2:3, usually in the form of dotted-quarter notes against quarter notes; 4:3, played as dotted-eight notes against quarter notes (this one demands some technical proficiency to perform accurately, and was not at all common in jazz before Tony Williams used it when playing with Miles Davis); and finally 3/4 time against 4/4, which along with 2:3 was used famously by Elvin Jones and McCoy Tyner playing with John Coltrane. DJ Shadow Mongrel...Meets his Maker features a 3/4 guitar sample over a 4/4 hip-hop drum beat.
Frank Zappa, especially towards the end of his career, experimented with complex polyrhythms, such as 11:17, and even nested polyrhythms. The metal band Meshuggah also uses polyrhythms in their music. Contemporary progressive metal bands such as Tool and Portal also incorporate polyrhythms in their music. Much minimalist and totalist music makes extensive use of polyrhythms. Henry Cowell and Conlon Nancarrow created music with yet more complex polytempo and using irrational numbers like pi:e.
The band Queen used polyrhythm in their 1974 song The March of the Black Queen with 8/8 and 12/8 time signatures.[1]
Polyrhythm is also called "measure preserving polymeter," because there exists more than one meter, but the measure stays constant. "Tactus preserving polymeter" is used to describe what is most commonly referred to as polymeter. These terms are found in the writings of Keith Waters and Steve Larson. Waters' 1996 article "Blurring the Barline: Metric Displacement in the Piano Solos of Herbie Hancock" from the Annual Review of Jazz Studies" and Larson's 2006 "Rhythmic Displacement in the Music of Bill Evans" are two examples.

Examples

The following is an example of a 2 against 3 polyrhythm, given in time unit box system (TUBS) notation; each box represents a fixed unit of time; time progresses from the left of the diagram to the right, although this is irrelevant since the pattern is symmetric. Beats are indicated with an X; rests are indicated with a blank.

2 against 3 polyrhythm

3-beat rhythm

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X

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2-beat rhythm

X

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X

A common memory aid to help with the 2 against 3 polyrhythm is that it has the same rhythm as the phrase "not difficult"; the simultaneous beats occur on the word "not"; the second and third of the triple beat land on "dif" and "cult", respectively. The second 2-beat lands on the "fi" in "difficult." Try saying "not difficult" over and over in time with the sound file below. Another phrase with the same rhythm is "cold cup of tea":

Similar phrases for the 3 against 4 polyrhythm are "pass the gold-en but-ter" and "what atrocious weather"; The 3 against 4 polyrhythm is shown below.

3 against 4 polyrhythm

4-beat rhythm

X

X

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3-beat rhythm

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As can be seen from above, the counting for polyrhythms is determined by the lowest common multiple, so if one wishes to count 2 against 3, one needs to count a total of 6 beats, as lcm(2,3) = 6 ('''1'''2'''3'''4'''5'''6 and '''1'''23'''4'''56). However this is only useful for very simple polyrhythms, or for getting a feel for more complex ones, as the total number of beats rises quickly. To count 4 against 5, for example, requires a total of 20 beats, and counting thus slows the tempo considerably. However some players, such as classical Indian musicians, can intuitively play high polyrhythms such as 7 against 8.
Polyrhythms are quite common in late Romantic Music and 20th Century Classical Music. Works for keyboard often set odd rhythms against one another in separate hands. A good example is in the soloist's cadenza in Grieg's Concerto in A Minor; the left hand plays arpeggios of seven notes to a beat; the right hand plays an ostinato of eight notes per beat while also playing the melody in octaves, which uses whole notes, dotted eighth notes, and triplets.
Other instances occur often in Rachmaninoff's Piano Concerto No. 2. The piano arpeggios that constitute much of the soloist's material in the first movement often have anywhere from four to eleven notes per beat. In the last movement, the piano's opening run, marked 'quasi glissando', fits 52 notes into the space of one measure, making for a glissando-like effect while keeping the mood of the music. Other instances in this movement include a scale that juxtaposes ten notes in the right hand against four in the left, and one of the main themes in the piano, which imposes an eighth-note melody on a triplet harmony.
Below are some example polyrhythms in MIDI format:

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See also

★ Ewe music

★ multiphonics

External links

★ C.K. Ladzekpo's Foundation Course in African Dance-Drumming

★ African Music Encyclopedia: Babatunde Olatunji

★ "Africano, the mother of groove," an article on polyrhythms and the African drumming tradition

★ Tempo Mental- Article by Steve Vai on Polyrhythms

★ Drums Database- More Polyrhythms

★ polyPulse An athenaCL netTool for on-line, web-based MIDI polyrhythm generation

★ polymath Another on-line, web-based MIDI polyrhythm generation tool which uses symbolic input

★ Polyrhythm Lessons- Information on applying polyrhyhthms on the guitar