An Introduction to Polyrhythms
In most music, drummers play rhythms and patterns that adhere to a single rhythmic grid, such as combinations of 8th notes and 16th notes. 16th notes nest evenly into 8th notes, which nest evenly into quarter notes. But playing it safe and predictably gets a bit stale after a while. Drummers can create tension in music by playing within two different rhythmic grids simultaneously, such as 8th notes and 8th triplets. Doing so creates a polyrhythm.
If you have some drumming experience, you may have encountered the term “polyrhythms.” But what exactly is a polyrhythm and how can we use them in music?
The Concept
A polyrhythm is the combination of two (or more) incongruous steady pulses fitting evenly in the same space. They are the rhythmic foundation for many styles of African and Caribbean music, but can function in any musical setting. Polyrhythms create rhythmic ambiguity (in a good way), which allows listeners to feel time based around more than one underlying pulse. For example, playing 8th notes and 8th note triplets at the same time creates a polyrhythm, but playing 8th notes and quarter notes at the same time is not considered polyrhythmic since the 8th notes can evenly fit inside the space of a quarter note. There’s no musical tension created by rhythms that nest seamlessly into one another.
Polyrhythms are sometimes stigmatized as an unnecessary technical element that musicians use for the sake of showing off, and they’re definitely not the right choice for EVERY style of music. But there are many functional uses for polyrhythms that feel very organic. If used with careful consideration, polyrhythms should not create a jarring effect for listeners, but instead offer an alternate way to feel music.
3-Against-2
The most basic form of a polyrhythm is 3-against-2, which basically means there are 3 evenly-spaced pulses played against 2 evenly-spaced pulses that resolve in the same space. We can use quarter notes and dotted quarter notes as a specific example. Thinking in 3/4, we can play quarter notes with one hand, and dotted quarter notes with the other. Both hands will play at the same time at the very beginning of the pattern and won’t align again until the pattern restarts. If you play the quarter notes (the “3” element) with your right hand and the dotted quarters (the “2” element) with your left, the right hand will land on all 3 beats, but the left hand only plays beat 1 and the “&” of beat 2. In other words, the right hand plays 3 evenly-spaced hits against the left hand’s 2 evenly-spaced hits. Polyrhythms are often expressed as a ratio, so a 3-against-2 polyrhythm would be simplified to 3:2.
All polyrhythms have a common underlying beat division. With 3:2 played as quarter and dotted quarter notes, the common underlying subdivision is 8th notes. One quarter note has the same value as two 8th notes, and one dotted quarter note has the value of three 8th notes. The two rhythmic rates meet up again after six 8th notes. We’re essentially dividing those six 8th notes into two groups of three, and three groups of two at the same time.
Common Uses
3:2 polyrhythms are the basis of many styles of West African drumming, as well as Afro-Cuban music. In Afro-Cuban jazz, the 3:2 polyrhythm is often expanded into a 6/8 meter. Instead of 2 dotted quarter notes against 3 quarter notes, the rhythmic relationship is scaled down to 2 dotted 8th notes against 3 8th notes. For a specific example, we can refer to a Bembe (noted below) groove. The ride bell pattern implies a 6/8 rhythm, but the rhythm of the hihat foot implies 4/4. Listeners can feel the beat both ways since the two rhythmic patterns resolve in the same larger space. Musicians can phrase their rhythms around either the 6/8 feel or the 4/4 feel without losing the time.
Another way to shrink the pattern is to play 8th notes against steady 8th note triplets. The rhythm works out exactly the same way as before, but it’s compressed into the space of a single beat.
Mnemonic devices are useful for learning and internalizing basic polyrhythms. People often use the phrase “Nice cup of tea” (which is said rhythmically like “1, 2 &, 3”) to keep the framework of the polyrhythm in mind.
4-Against-3
The next most common polyrhythm is 4-against-3. This rhythmic pattern became popularized in modern music by jazz drummers, particularly Elvin Jones and Tony Williams. But it still has its roots in African drumming. In this case, we have 4 evenly-spaced pulses spaced against 3 beats.
One way to interpret this rhythm is to think of it as 4 dotted 8th notes played over 3 quarter notes. In this case, 16th notes are the common underlying beat division. We essentially bunch 16th notes into groupings of 4 (the quarter notes - one hit every four 16th notes) and groupings of 3 (the dotted 8th notes - one hit every three 16th notes).
Just like before, we can scale the rhythm up or down to fit into different contexts. Instead of thinking of quarter notes and dotted 8th notes, we can scale the rhythm up slightly and think of the polyrhythm with triplets as the underlying pulse. We can bunch triplets into groups of 3 (quarter notes) and then play every 4th triplet to create the same pattern. Or we can compress the rhythm into one beat of 16th notes played against one beat of 8th triplets.
A common mnemonic device used to internalize the polyrhythm is “pass the bread and butter,” said to the cadence of the pattern (like “1--a, 2-&-, 3e--”).
Musical Examples
Polyrhythms can function in any style of music, but they’re mostly prevalent in African music, jazz, metal, and progressive rock. Here are some examples that put the above concepts to use.
This demonstration primarily uses a 3:2 polyrhythm, but there are some instances of 4:3 included as well. The clapping and slapping rhythms imply a 6/8 feel, but their stepping, singing, and body movements imply more of a 4/4 feel. Even though there aren’t any drums in this clip, the same concepts are often applied to hand drums of different pitch and timbre.
In this recording of John Coltrane’s rendition of “Afro Blue,” the band explores 3:2 and 4:3 polyrhythms. While the drums, played by Elvin Jones, maintain a fast 3/4 swing feel, the melody and harmony (played by the piano) is centered around a dotted quarter note rhythm. Listeners can count the music as both 3/4 or 4/4 and everything will still line up.
This next example, Led Zeppelin’s “Kashmir,” is technically a cross rhythm, where one part essentially plays in one meter against instruments playing in another meter. But cross rhythms are a sort of extension of polyrhythms. In this case, the guitar and orchestral parts play a rhythm that takes 3 beats, but the drums maintain a straight-ahead rock feel, which only takes 2 beats. Both parts align every 6 beats, but each rhythm carries equal weight.
Meshuggah’s “Bleed” is a pretty extreme example, but still makes use of the same rhythmic concepts mentioned above. In this case, the double kick pattern, the guitar, and the bass, begin by playing a 3-beat rhythm while the cymbal and snare drum imply a 4-beat rhythm (a straight backbeat in a half-time feel, so the snare hits on beat 3). At about 0:50, the guitars and kick drum switch to playing a 5-beat rhythm, which creates a 5:4 polyrhythm against the cymbal and snare drum. The entire song is filled with polyrhythmic concepts that gradually progress in complexity as it goes on.
Taking it Further
Any two steady pulses can be combined to create polyrhythms. Beyond 3:2 and 4:3, musicians use 5:4, 5:3, 6:5, and 7:8. But those go far beyond the introductory nature of this post. It’s just a matter of finding the shared underlying subdivision and the least common multiple between two numbers.
Certain polyrhythms are more common in certain styles of music. As mentioned above, polyrhythms are a foundational component in lots of West African drumming, but more complex polyrhythms are widely prevalent in certain styles of Indian music, too. When using polyrhythms on a drum set or in a more contemporary music setting, we need to remind ourselves that just because we can do something does’t always mean we should.
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