Many of you may have been already using isorhythms without being aware of it (I know I was doing this long before I had a fancy term for it). The basic idea is to play the same rhythmic figure while varying (or improvising) the notes. This creates a solid groove but at the same time gives you the freedom to interact with the rest of the ensemble and to vary the energy and emotion of the music (using some techniques we’ll talk about next time) while still providing a solid foundation.
Though this is a fantastic method for learning odd time signatures and various subdivisions, to start more simply we’re going to do an example in 4/4 with an eighth note feel. In this case, there are eight points in the measure to play on. We’re going to pick five, but you can do this with any amount (though if you do one it will be like last month’s exercise and if you pick zero you won’t be playing at all and eight and you’ll just be playing all the beats, so a number between two and seven is ideal). We’re going to play on 1 (it’s not a rule that you have to play on the downbeat, but it is more typical of basslines and sometimes is what’s expected) the 2, the “and of 2”, the “and of 3”, and the “and of 4” (in case you’re wondering, I picked these randomly using dice). To present this graphically, it will look like this (with underlines indicating the beats we’re playing on):
1 + 2 + 3 + 4 +
Step one is to play this rhythm just on one note, to learn what the isorhythm feels like. I’d suggest doing it with a metronome (or drum machine, or some other bass-less play-a-long), and count it out to make sure you’re playing it correctly. If you have trouble, just play the first two notes, and when you’re comfortable with that then add the next hit and so on until you’re playing the whole rhythm. When you’re grooving on it without having to count (or not having to concentrate so much on counting) then start improvising your notes within that rhythm. If you’re doing this with a drum machine, or better yet with a band, you should find it’s a lot of fun.
A final word regarding drum programming: it can make learning the isorhythm easier to put the accents into the drum part. But this can become a crutch. To really see how well you can play the rhythmic figure, try creating a drum beat that is a cross-rhythm to yours, with the drums accenting the beats you’re not playing (in the above example “+ of 1”, “3”, and “4”).