This lesson, we’ll move a toward some more advanced rhythm. Poly-rhythms occur when you superimpose two different rhythms. You’ve probably seen and heard them often in the music you listen to everyday. Of course, the most common example of a poly-rhythm is the triplet. Triplets occur when you place a grouping of three over a grouping of two. This concept holds water for all poly-rhythms. With poly-rhythms you want to place evenly a certain number of beats over a different number of beats; for example, 3 over 2, 4 over 3, 5 over 4, 7 over 4, 5 over 3, and so on.
To start to explain this, let’s break down precisely how a triplet works:
As you know, this is a quarter note triplet. We can break this down even further:
The two above rhythms are mathematically equal. Usually 12/8 (or 6/8) is used to feel triple meter, but when written like this, it shows clearly the correlation between duple and triple meter, in other words, the 3 over 2 correlation.
We can use these correlations to show how the core concept of a poly-rhythm functions. However, in such a mathematically charged rhythmic environment, poly-rhythms prove to be the most difficult to map out. Perhaps that’s why there is a blanket way to write a polyrhythmic idea. For example, if you wanted to fit 5 quarter notes into a normal 4/4 measure, it would look like this:
5 over 4.mp3 5 over 4
(In the audio example, the 5 quarter notes are in the left ear as a cowbell, and the 4 poly rhythm are in the right as a rim shot)
That brace is a “cure-all” for poly-rhythms. Yet, it takes a lot of practice to master the actual feeling of poly-rhythms. Ask some of the best drummers, who are the ones who practice poly-rhythms most, and they will tell you it’s all about hearing the patterns (listen to the audio example carefully). I think that’s true to some extent. At first, its best to hear the pattern, but once you can hear it, it’s time to start hearing each subdivision (the two different halves) independently. The feeling of poly-rhythms is important. They are very prevalent in world music; many cultures who do not have written music use lots of poly-rhythms, which they learn through doing, not intellectualizing.
However, as we’re trying to be theorists, onto the intellectualization! 5 over 4 can also be broken down this way:
Here, we have groups of 5 sixteenth notes to evenly break down the groups of 5 quarter notes. (If you want to listen to an awesome, if surprising, example of 5 over 4, check out what Dr. Dre did to the chorus of the beat in “Underground” on Eminem’s album Reapse). You can break down anything over 4 fairly simply. As 16th notes are grouped in 4s, there is always going to be a multiple if you use the time signature of the rhythm you wish to place over it. For another example, lets look at 7 over 4:
7 over 4.mp3 7 Over 4
Same concept. Attached to this lesson is a poly-rhythm reference, and an audio file which plays the described poly-rhythms. This is a good place to start listening to the patterns created by the different, more difficult, poly-rhythms.
No worksheet for this weeks lesson, but there is a bit of homework. Listen to the poly-rhythm examples and use the reference (located below!). Try to get the 3 over 4 poly rhythm under your fingers. If you succeed in doing that, move onto the 5 over 4. These will take time to master, but through practice you’ll get it. Some of the best times to practice tapping out poly-rhythms are during work or class when you have nothing else to do or are falling asleep due to boredom.