Two of the things I enjoy experimenting with while creating music are polyrhythms and
odd time signatures. A lot of people seem to think they're extremely hard to play, and
although they are challenging, they're not out of reach of even basic drummers if you
understand how they really work. The most difficult task is really just training your brain
to think "outside the box" of 4/4 time and realize the infinite number of combinations and
groupings at your disposal.
The “catch”, if you can call it that, is that to competently learn these types of techniques
you are required to do a little bit of work. First of all you need to become comfortable
with doing a little bit of mathematics; nothing too advanced, but these methods are all
based on manipulations of numbers. Secondly, you’re going to have to really practice
them, not just rush through the exercises. It’s one thing to be able to tap out a 3:7
polyrhythm on your lap while sitting at the computer reading this. It’s an entirely different
beast to be able to instinctively call upon your rhythmic foundation while playing a song
and create polyrhythmic patterns that fit into the structure of the piece.
Time to start into the mathematics. Consider for example that you have four measures of
4/4 to play. Subdivided, that becomes 16 quarter notes, 32 eighth notes and 64 sixteenth
notes. We'll stick with eighth notes for now. Normally we're used to grouping things in
terms of 2, 4 and 8. But why be normal? If you try grouping those 32 eighth notes as
7-7-2, you still get 32 eighth notes total.
7 + 7 = 14
14 + 2 = 16
16 * 2 = 32
Putting those numbers into some kind of perspective, you’ve basically created for
yourself 4 complete measures of 4/4 time, but grouped them in an uncommon way. This
division creates two measures of 7/8, followed by one measure of 2/8. Those three
measures are then repeated to create a full phrasing of 32 notes, or 4 full measures of
4/4.
Here's a somewhat more basic example, and one that's easily applied to drumset. Lets
assume you have a single measure of 4/4 to play. Subdivided into eighth notes, it
becomes 8/8. There are several different ways to break that up. Here are a few:
2/8 + 3/8 + 3/8 = 8/8
5/8 + 3/8 = 8/8
6/8 + 2/8 = 8/8
...and so on.
Yes, it's all based on math. But that wasn’t too terribly painful, was it? Nothing more
complex that addition and subtraction. With a little bit of practice it’ll feel
second-nature.
Now lets take a look at polyrhythms. When executing polyrhythms, you're basically
playing in multiple time signatures at the same time. But it's not as bad as you think...it
just takes a little comfort with counting and maybe a little memorization. There is a
consistent system to figuring them out that works for ANY combination you might try to
put together.
When writing polyrhythms, the notation is n:n. So a 4 against 7 polyrhythm would be
written as 4:7. Let's try working with a simple polyrhythm: 2:3. When you play this, one
or more limbs will be "playing in 2" and the others will be "playing in 3." Not impossible. The key is to train your brain to "hear" one rhythm while focusing on another, which becomes easier over time as you learn to automate patterns. First we need to figure out the total number of notes in a full cycle. To do that, we
multiply the numbers together.
2 x 3 = 6
This means that after 6 notes of whatever value we designate have been played, both time
signatures will be back on beat 1. It works for any polyrhythm; for a 7:11 polyrhythm,
you have to play 7 groups of 11 or 11 groups of 7 to make one full circle. Here's the proof
from our 2:3 example.
1 2 3 1 2 3 1 <---note 7
1 2 1 2 1 2 1 <---note 7
So now the task becomes memorizing the relationship and ratio between different
numbers to create the polyrhythms you wish to perform. In this particular polyrhythm,
memorize that the beats corresponding to 1 in the smaller value correspond to 1, 3 and 2,
in that particular order. They will always fall in that order. If you can remember ratios and
corresponding notes, then all polyrhythms open themselves up to you. Let's try
another...we'll do 5:4.
Time to do our mathematics again to find out how many notes we need to make a full
circle mathematically.
5 x 4 = 20
Twenty notes are required for us to complete the polyrhythm in proper time. Let's write it
out.
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1<---note 21
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1<---note 21
Time to memorize again. In the 4 component, beat 1 falls on beats 1, 5, 4, 3 and 2 in that
order. Once you're comfortable with that, try experimenting with other time
manipulations. This system works for any polyrhythmic grouping universally and
constantly.
PLAYING A POLYRHYTHM DOES NOT MEAN 4 LIMBS DOING 4 DIFFERENT THINGS. 4 limbs doing 4 different things could be a simple 4/4 rock beat. Yes, when executing more complex structures like these your 4 limbs will all be doing totally different things. But when playing a polyrhythm, you are placing one rhythm against another to create a larger overlapping pulse. In the example of 2:3, you are placing 3 notes against 2 notes to create a pulse that happens every 6 beats. As a result, not all combinations of numbers are polyrhythms. For example, there is no such thing as a 4:8 polyrhythm, because 4:8 is nothing more than a simple common time beat. Make sure you're clear on polyrhythms before you try to create them.
