Introducing polyrhythm is one way to make your productions more interesting. It doesn’t have to be overly complex to stand out and take your music to the next level!
Polyrhythm vs. Polymeter: What’s the Difference?
Both share a prefix, but beyond that, they’re quite different. Let’s have a look at what separates a polyrhythm from a polymeter.
What Is Polymeter?
Polymeter is a combination of two or more different time signatures in a composition. The two opposing meters phase in and out with each other to create an interesting, almost hypnotic effect. 4/4 and 7/8 is one common use of polymeter, where you essentially shave off an eighth note from 4/4 meter to create 7/8. So you’d have one instrument, or group of instruments, playing 4/4, while another plays 7/8. Every seven bars the meters sync back up.
What Is a Polyrhythm?
Polyrhythm is at least philosophically similar to polymeter. But instead of combining two or more time signatures, it uses a single meter, and instead plays two or more different rhythms against each other. Usually you have one main rhythm playing against a counter rhythm, and the emphasis for both is on the first beat.
The easiest way to imagine it (and also one of the simplest examples of polyrhythm) is to picture one instrument playing four quarter-note beats in a bar and another instrument playing three beats in the same bar. A major takeaway here is that the three beats must be equal value; that is, each note length has to be the same. In this example, you’d end up with a triplet playing over four quarter notes. This is also known as a “three over four” polyrhythm.
One final thought: polyrhythms are not odd meter. In fact, most of them we hear in music are usually 4/4 or 3/4. They sound like odd meter, and that’s what makes them interesting—but you can very easily make 4/4 sound a lot crazier than it is just by creating a polyrhythm.
Polyrhythm vs. Cross Rhythm: What’s the Difference?
The only real difference between a polyrhythm and cross rhythm is how they’re used in a composition. We use the term cross rhythm when a polyrhythm forms the foundation of a whole piece; in other words, when a polyrhythm occurs throughout a whole song.
Why are polyrhythms useful in the studio?
This is a common question, if not a somewhat flawed one fundamentally. It isn’t so much that polyrhythms are useful, per se, but that they’re just another musical device you can use to spice up your productions. It’s not that they serve this utilitarian purpose to somehow make your mixes and songs better; polyrhythms are simply a way to create unique grooves that are more interesting to listeners!
As a mixer, though, you might experiment with polyrhythms through creative use of delay.
Common Types of Polyrhythms
Two over three
This is also called the hemiola and is one of the most common kinds of polyrhythms. You can call it “two over three,” “three over two,” “two against three,” etc., and it all means the same thing. It’s essentially a triplet played over a duplet, and each pair of notes syncs up on the first beat.
Three over four
After two over three, the next most common polyrhythm is three over four. You’ll typically find it in 3/4 meter, where one rhythm plays three quarter notes and another plays four dotted eighth notes.
Four over five
Thinking in fives can definitely be a challenge at first, but four over five is actually another common polyrhythm. It’s certainly best to hear it, as in the video above, to fully get a grasp on it.
Euclidean Rhythms
Relatively new to music theory is the idea of Euclidean rhythms. They’re named after the ancient mathematician Euclid because they use his algorithm to devise ways of spacing out events as evenly as possible. The term “onsets” is used to describe the event, and “positions” describes the pulses or beats.
If you’re obsessed with music and math, then Euclidean rhythms are definitely worth a deep dive on your own time. We won’t get into the super nerdy bits here, as it’s only tangentially related to polyrhythm. Let’s just say Euclidean rhythm isn’t going to revolutionize the way people compose or think about music…at least not anytime soon.