Polyrhythm and Polymeter
Two words that get swapped constantly. A polyrhythm divides the same span of time two different ways at once. A polymeter runs two different bar lengths side by side. Mute each layer on its own here and it becomes obvious which one you are listening to.
- two layers
- same time or same beat
- mute to hear it
which styles use it
- Afro-Cuban
- Prog
- Jazz
- Electronic
In short
In a three against two polyrhythm, one part fits three even notes into the same space where another fits two. Neither part changes speed and they line up again at the start of each cycle. In a polymeter, both parts share the same beat but group it differently, so a bar of four against a bar of three only agrees every twelve beats. The first is about subdivision, the second is about bar length.
Each layer on its own is easy. The difficulty and the whole effect come from holding both in your head at once, which is a skill that arrives suddenly rather than gradually.
How to count it
- Count the faster layer
Three against two is easiest counted in three, with the other part landing on one and on the halfway point.
- Use a phrase
Saying a short phrase with the right stress pattern beats counting numbers for most people.
- Find the meeting point
Both layers agree somewhere. Locating that moment is what turns chaos into a pattern.
Where you run into this
- In West African and Afro-Cuban music, where layered rhythms are the foundation rather than an effect.
- In prog and math rock, where polymeter is used to make a riff feel like it is turning over.
- In electronic music, where a delay set to the wrong division accidentally produces one.
Our own examples
Three against two, with each layer soloed first and then combined. Then a polymeter of four against three at the same tempo, running until the two line up again.
Keep going
Everything in rhythm
- Swing, Shuffle and Groove
- Syncopation and the Offbeat
- Polyrhythm and Polymeter
- Metric Modulation