Polyrhythm: Two Speeds at Once
Two hands, two different speeds, at exactly the same time. A polyrhythm is two different beat divisions played together: three against two, or four against three. Hear it in our own patterns modelled on three famous places, Chopin's Fantaisie-Impromptu (4 against 3), Debussy's Arabesque No. 1 (3 against 2) and the layered 3s and 2s of West African drumming. Then see on parallel grids where the hands meet (only on the beat, on a grid of six; four against three once every twelve steps), feel it with "nice cup of tea", and tell it apart from its cousin the hemiola. Every musical example is our own pattern, not the composers' notes.
In this lesson you'll
- Hear and recognise a polyrhythm, two beat divisions at the same time: 3 against 2 (triplets over pairs, lesson 45) and 4 against 3, and know where it lives: Chopin's Fantaisie-Impromptu, Debussy's Arabesque No. 1, West African drumming.
- See on parallel grids where the two sides meet: 3 against 2 lines up only on the beat (a grid of six: the three on steps 1, 3, 5, the two on 1, 4); 4 against 3 meets only once every 12 small steps (1, 4, 7, 10 against 1, 5, 9).
- Tap 3 against 2 with both hands using "nice cup of tea", slowly then faster, play 4 against 3 slowly on two piano notes, and tell a polyrhythm (together) from a hemiola (in a row, lesson 31) by ear.
Music in this lesson
- Fantaisie-ImpromptuChopin · composed 1834, published 1855
- Arabesque No. 1Debussy · 1888–91
- West African drummingtraditional · layers in 3 and in 2
Remember
A polyrhythm is two different beat divisions at the same time: in the time of one beat, one hand plays three even notes and the other two (or four against three).
3 against 2 lines up only on the beat; in between, every note falls in its own place on a grid of six. 4 against 3 meets only once every 12 small steps. Feel 3 against 2 with "nice cup of tea": nice together, cup (3), of (2), tea (3).
The brain follows both speeds at once, so the music flows in two currents: restless, alive. Its cousin the hemiola puts 3 and 2 in a row; a polyrhythm puts them at the same time.