The Polyrhythm Guide
Posted in Learn | Last Updated on October 4, 2018
This guide is meant both to explain the concept of polyrhythms to those just getting familiar with it, as well as to provide information, ideas, and inspiration to those looking to further their knowledge.
I was introduced to the “poly-rhythms” (which means many rhythms) by jazz drummer Ari Hoenig. If you don’t know his playing, check it out. Be warned, however; he has a very strong sense of rhythm, and it might drive you crazy trying to follow him as he weaves in and out of the groove, the time signature, the form, and the melody.
What are these mysterious rhythms? First, we must understand what cross-rhythms are, and what the difference between the two is.
Cross rhythms occur when accents are placed in such a way that another time signature/rhythmic pattern is implied within a groove or rhythm. For example, say we’re playing in 4/4, but we want it to sound like we’re playing in 6/4. That’s what’s happening in the example below.
What makes it sound like 6/4? It’s all in how you accent it. If you were to accent beat 1 of every bar of 4/4, it would sound like 4/4. In this example, the listener would have no idea you were playing in 4/4 (unless they could read the music), because you’re playing a different set of accents. It sounds just like 6/4 because you’re playing an accent on the bass drum every 6 quarter notes (and a snare accent to round out the groove). A cross-rhythm is a sort of rhythmic trickery.
Cross rhythms create phrases that go over and beyond barlines. This particular example only takes 3 bars of 4/4 for both the imaginary rhythm in 6/4 and the bar of 4/4 to land simultaneous on beat “1″ together.
What’s A Polyrhythm?
There is a slightly blurry line between polyrhythms and cross rhythms. In my mind, the former spring out of the latter. Let’s take a 5/8 cross-rhythm for example…
This 5/8 cross-rhythm is just a bunch of eight notes grouped in 5′s throughout some bars of 4/4. It would start to become a polyrhythm if you singled out the first beat of the 5/8 grouping, then at the time of those 5 eighth notes, you played, for example, 2 eight notes. See example…
In my examples, I tend to put backbeat grooves onto lots of my polyrhythms. This is because these grooves are simple and powerful. They really pull the listener into your “new illusionary tempo”.
This gives the illusion that a backbeat groove is being played in a brand new tempo. The listener is tricked twice: they lose their relation to the new tempo, and then lose their orientation to the original 5/8 cross-rhythm. The bass drum and snare drum are still notated within the original 4/4 rhythm since they still can relate. The hi-hat 8th notes are placed approximately, but the “2:5″ written above them means 2 eighth notes are played in the time of 5 eighth notes. The original 5/8 cross-rhythm is essentially replaced with a simple backbeat groove (poly-rhythm) in the time of5 eighth notes of the original tempo.
This example is slightly advanced, but the concept can be done with simpler rhythms. I chose this example because it’s a clear example of a poly vs. cross-rhythm.
Still struggling? Here are some examples of polyrhythms, some simpler than the first example above.
#1 A very simple example is a triplet. A quarter note triplet in 4/4 time, for example, is a 3:2 rhythm. That means there are 3 quarter notes played in the time of 2 quarter notes. An advanced drummer can imply that these new, evenly spaced quarter note triplets are anything else, such as 8th notes in a slower backbeat groove, for example!
#2 The 4:3 rhythm is very common. The example below is one correct way to write it; the bottom eight notes are unaffected by the polyrhythm bracket (“4:3″ sign above top notes). They appear as they would in a normal bar of 4/4. The top notes are modified by the “4:3″ sign above them. They are 4 eighth notes in the time of 3 eight notes and are placed as such in relation to the bottom notes. There are other ways to write it out; if you use the rhythmic equation below, you can write it out using 32nd notes in 4/4, instead of the “4:3″ brackets above the top set of eight notes.
Some polyrhythms can seem difficult to execute accurately. Thankfully, there is a formula designed to tell you exactly how to play any given rhythm.
If you want to play a 6:2 (6 in the time of 2) rhythm, for example, you’d begin like this:
- the “2″ in the 6:2 is the number of beats that the rhythm will take place over.
- You then subdivide each of these (2) beats by the first number (which is 6 in this case).
- You’re left with something that looks like ONE-2-3-4-5-6 TWO-2-3-4-5-6
- Finally, you play every 2 of these 12 beats, which will (if you’re following), give you 6 beats in the time of 2.
How about a 4:7 rhythm? Sounds hard, but using this method, you can easily figure it out.
- You take your second number, 7. Again, this is the number of beats that the rhythm will take place over.
- Then you subdivide each of those 7 beats by your first number, 4.
- Then, you play every (second number) 7 of those (7×4=28) subdivided beats.
- You should end up playing 4 evenly spaced notes in the time of 7 evenly spaced notes.
The trick to this is that it’s easy to figure out polyrhythms that start with multiples of 2 or 3 because we’re already used to hearing beats divided by twos and threes.
Figuring out polyrhythms that start with 5, or 7 for example, take a lot of getting used to because we need to learn to feel a quintuplet or septuplet. It can be done though! See Single Stroke Roll for an example of a 5:6 rhythm, and how natural it can feel.