Polyrhythms: What they are and how to use them

Illustration: Michael Haddad

We took a deep dive into the functionality, history, and use cases of polyrhythms for those interested in learning more, or incorporating the technique, into their music.

Let us begin.

What is a polyrhythm?

Polyrhythm is the simultaneous use of more than one subdivision within a measure of music. This applies to both short bursts contained to one measure as well as entire songs, where it can serve as the musical backbone we rely on as listeners.

Subdivisions vs. phrases

Let’s first orient ourselves with what subdivisions are doing. When playing in a standard 4/4 time signature, each measure experiences subdivisions, where notes shorter than a full note are used to break a single beat into equally-sized segments. For example, a quarter note can be subdivided into two eighth notes.

Therefore, an important distinction here is that performing a measure like the left (below) is not a subdivision, but rather a phrase. On the other hand, the image on the right is what a subdivision of two half notes would look like.

Sheet music showcasing a phrase vs. subdivision, in effort of answering the question, "What is a polyrhythm?"

In the case of this example, the numeric value of the subdivision is baked directly into the note name itself, as it is for a triplet (three), quarter note (four), eighth note (eight), sixteenth note (sixteen), and so on. That number can go as high as one would like, only limited by the ability of the player, or particularly in the case of synthesis, the perception of one’s ear.

What a polyrhythm sounds like

But what if you’re a piano player writing a piece in 3/4, and want to play bass notes in triplets with your right hand, and brighter chords in quarter notes with the left? Rather than deciding between one or the other, potentially changing the time signature itself to best serve your core idea, you instead decide you’d like both of them. You decide to superimpose one over the other, allowing their transients to eclipse in and out of unison at different points per beat. This would sound something like this:

60 BPM, with virtual instruments native to Ableton Live (all subscription levels)

This is an example of a common polyrhythm referred to as “four over three,” or 4:3.

Sure, your version of this would be far more playful, potentially varying the notes or toying around with sustain more than this. That said, more complex polyrhythms usually don’t come naturally, even to players who deeply know their instrument—so it’s important to feel and understand the most basic pulses before embellishing.

You may also notice with this example that the time signature and polyrhythm end up notated in reverse—3/4 time experiencing a 4:3 polyrhythm. Understandably, this can be a bit confusing depending on one’s skill at music notation.

For comparison, listen to the examples below of three over four. You’ll first find two audio files in 4/4, with the instruments switching places to provide you with some variance. We’ve also included a video to visualize a MIDI pattern with a bit more complexity in Ableton Live.

140 BPM, using the software synth Astra, available with the Splice Creator and Creator+ plans

Courtesy of Nick Chen—find more from him and others on the Splice YouTube channel

When in doubt, remember that the second number in the polyrhythm’s shorthand will always reflect the beats per measure, or the first number in a provided time signature. Were we to explore a more complex polyrhythm like 7:8, we could derive from that alone that the time signature delineates eight beats per measure. While the number of measures isn’t made clear, the number that’s “over” indicates what’s considered in conflict with what we expect.

It’s the resisting force which will likely perk up the listener’s ears at some point, at times in a more disorienting fashion than others, depending on if the polyrhythm is used as an accent or a core element of the song.

Examples of polyrhythms in music

There are a number of excellent YouTube videos which dive deep into the use of polyrhythms in contexts spanning modern hits to classical music—no doubt a tempting technique to experiment with when the main instrument for composition was the acoustic piano. Polyrhythms can present themselves in many ways; they might not want you to notice them, though sometimes they give the listener no choice. The level of tension and rhythmic dissonance is in many ways one of the primary decisions in composing with this expression.

The general consensus is that the use of polyrhythms originally derived from African music, in particular throughout performances with extensive layers of percussion. As this music has inspired—and been appropriated by—the world, we now find the use of polyrhythms in a far more expansive range of genres that include, jazz, progressive rock, metal, math rock, and a range of Afro-Caribbean and Afro-Latino/a forms of expression. We’ve put together a few recommendations here:

As you apply polyrhythms in your productions, you may ask yourself: Is this polyrhythm creating a groove that I intend to hook the listener on, and get them so used to that they may not realize what I’m doing? Or, is it meant as a smaller element of my track’s vision—improvisation perhaps? Or, is the polyrhythm just meant to cause brief disorientation that catches the listener’s attention?

To showcase what this writer considers a well-hidden polyrhythm, have an active listen to “Fake Empire” by The National. Pay particular attention to the guitar panned to the left, which is at times strengthening the primary rhythm (3) of the track, and at other times bolstering the infringing rhythm (4) which is maintained largely throughout the piece by the piano.

How to use polyrhythms in your own music

Experimentation is the only way to start. The recorded examples provided towards the top of this piece are a perfect example of MIDI patterns that anyone can program into their DAW to begin training their ear on how these rhythmic patterns interact with one another.

As you become more familiarized with the basics, you may begin to capture these takes live, first recording individually to a metronome, or challenging yourself to record the second rhythm with the first in your headphones. Here’s an example of a simple idea I recorded on guitar, with a bit of bass underneath before an unexpected three over four:

90 BPM

You can also use platforms like Splice Sounds. While there’s much to be said about how we as producers disguise our samples, as taught by Thavius Beck in this Skills lesson, combining two samples of different time signatures is another method of reimagining the stem we first heard and downloaded.

Splice Sounds provides us with the exact BPM and key of each sample, whereas the time signature is usually indicated in the file name, should it diverge from 4/4. Some samples are polyrhythmic in their own right, yet again often indicated in the file name.

What we encourage you to try, however, is to create polyrhythms by merging individual samples. This can be achieved in two ways. The first method is identifying two loops which differ in time signature, and then using Splice Bridge to align both to the BPM of your project. Alternatively, you can download individual one-shots you’d like to combine and set up a polyrhythmic MIDI pattern, as described above.

Have a listen to another example of three over four, which solely utilizes samples that were aligned with Bridge:

120 BPM, with the following samples: 4/4 Drums, 4/4 bass, 4/4 vocals, 3/4 cajon

Do polyrhythms need to be contained to a measure?

Technically speaking, yes, and this is why we began with such an emphasis on subdividing into equal parts. Being contained to one measure holds the traditional definition together, causing the situation where different rhythms all begin playing on beat one, and eventually move out of unison to evenly fit their determined number of notes.

Polyrhythm vs. polymeter

But what if you’re interested in performing two phrases simultaneously that differ in length? Perhaps their relationship with one another changes measure-over-measure as they loop back to their “1” at a different time.

While commonly confused with polyrhythm, this is actually polymeter, an incredibly fun technique that also brings rhythmic conflict and surprise to your music. We absolutely recommend experimenting with it, as I’ll share a personal example of briefly.

An example for distinguishing polymeter

When I was first beginning to compose music, topics like this one were a shared interest of my bandmates and I, even if we didn’t know what names meant what at the time. We were in truth fascinated by anything that could surprise (confuse) the audience and elevate our entertainment (absurdity) value.

In one particular instance, we set out to compose an introduction to a track that would eventually return to a standard 4/4 time signature, but begin with four instruments playing in different time signatures. At the time, we constantly referred to it as “the polyrhythm section” despite it truly being the “polymeter section.” The goal was to compose something fun, in which each band member needed to hyper-focus on sticking to our unique time signature, even when moving far out of phase with the other players. In many ways, we were just trying to confuse each other and see who would mess up first.

The produced work we ended up with can be heard below:

Production credit: TJ Martin

Could you count along? Looking back years later, this was an incredibly silly, yet musically deepening experience that to this day feels like a formative moment for the way I look at creating, and in particular listening, to music. At the end of the day, polyrhythms as well as polymeter are incredibly fun, rewarding musical elements to experiment with, even if they don’t become a prominent piece of your next single, or a distinguishing element of your overall sonic brand.

Continue your journey with polyrhythm

If you’re looking to learn more, Andrew Huang, who shared some tips with Splice back in 2020, put together a wonderful explainer video for the distinction between polymeter and polyrhythm:

And if you have any examples of these elements in your own music, please feel free to send them to mattbrooks.beratung@gmail.com and let us know what you thought of this piece!

Dive deeper into other key topics in music theory spanning rhythm, melody, and harmony:

March 23, 2023

Matt Brooks Matt Brooks is an event producer, musician and poet based in Berlin. The grandson of jazz musicians in 1940s Chicago, music was ever-present, permeating the fondest of memories that would shape his life and career.