Odd Time Signatures and Polyrhythms
You're going to discover what happens when you step outside four beats: bars of three beats, the compound feel of 6/8 and 12/8, bars of five and seven, and then polyrhythms, which spin patterns of three over a grid of four.
Almost everything you produce is in 4/4, and that's not about to change: it's the time signature of club dancing and of pop. But knowing the other time signatures has two benefits. First, you'll recognize a waltz, a song in 6/8 or a ballad in 12/8 the day you want to sample one. Second, and above all, you'll discover that ideas in three can live inside 4/4, to create rhythms that spin and hypnotize.
Three beats per bar
A bar of 3/4, said “three-four”, holds three beats instead of four, each one a quarter note. You count “one, two, three, one, two, three”, with the weight on the one. It's the time signature of the waltz, and it gives a swaying motion, rounder than the march of 4/4.
Listen to two bars of 3/4. In this figure, each grid cell is an eighth note, so there are six cells per bar. The kick marks the one of each bar, the rim marks the other two beats, and the hi-hat is a little louder on each beat.
6/8 and 12/8: the compound feel
6/8 also holds six eighth notes per bar, exactly like 3/4. The difference is in the grouping: in 3/4, the eighth notes are grouped in twos, which gives three beats; in 6/8, they're grouped in threes, which gives two big beats, each divided into three. You count “one, two, three, four, five, six”, with the weight on the one and a lighter one on four.
Compare it with the previous figure: same number of cells, same eighth-note speed, and yet the motion is completely different. 3/4 sways in three beats; 6/8 rolls in two big beats. This division of each beat into three is called a compound feel (producers often say triplet feel), as opposed to a simple feel, where each beat divides in two.
12/8 simply doubles 6/8: four big beats per bar, each divided into three eighth notes, so twelve eighth notes. It's a bit like a 4/4 where every beat is played in triplets. You hear it in slow blues, soul, some ballads and many African rhythms. Listen to this 12/8 with a snare on the second and fourth big beats, like a backbeat in compound feel.
Listen closely to the hi-hat: it plays the first and third eighth notes of each group of three. This rhythm is called a shuffle, and it's what swing imitates when you push it hard. That's why a heavily swung 4/4 gets close to 12/8: the line between the two is thin.
Five and seven: asymmetric time signatures
A bar of 5/4 holds five beats. The ear has trouble perceiving five equal beats, so it naturally groups them into two unequal pieces: three plus two, or two plus three. A bar of 7/8 holds seven eighth notes, most often grouped as two, two, three, or three, two, two. These unequal groups give the feeling of a bar that limps, or that stumbles just before landing back on the one.
Listen to these two examples, played on a single sound and repeated three times. The high note marks the start of each group; the low note fills in the rest. Count out loud with them: “one two three, one two” for 5/4, “one two, one two, one two three” for 7/8.
These time signatures are rare in clubs, because they make dancing harder. You're more likely to come across them in jazz, progressive rock, some music from the Balkans and the Middle East, and in experimental electronic tracks or film scores. If you want to try one, change the project's time signature in your software: the ruler at the top and the metronome will reset to the new bar.
Polyrhythm: three against two, three against four
A polyrhythm is two different pulses layered on top of each other, sharing the same start and the same end. The simplest case is three against two: while one part plays two even hits, another plays three, in the same span of time, and the two meet again at the start of the next cycle. In the figure, the kick hits every beat, and the percussion plays three even hits every two beats.
Here the percussion plays quarter-note triplets, which we saw in the lesson on dotted notes and triplets. Three against four works the same way, with four hits on one side and three on the other over a whole bar. The tension is stronger, because the two pulses only meet once per bar, on the one.
These polyrhythms are at the heart of much West African and Afro-Cuban music, where several percussion parts layer pulses in two and in three. In production, they're often used more subtly: a triplet arpeggio over a straight kick, or a percussion part in quarter-note triplets during a build-up, the rise that prepares a drop, and the whole thing starts to spin.
Three-step patterns on a sixteen-step grid
Now here's the most useful idea in this lesson for a producer. Stay in 4/4, on the ordinary sixteen-step grid, and program a percussion part that hits every three steps, without ever starting over at the beginning of the bar. Since sixteen isn't divisible by three, the pattern doesn't land in the same place from one bar to the next.
Listen to how the rim seems to slide against the kick. In the first bar, it lands on the one; in the second, it starts on the and of one; in the third, on the e of one. It only gets back to its starting place after three bars, after forty-eight steps. The accents rotate: in each bar, different beats line up with the rim. This is called displacement, and it's one of the secrets behind the hypnotic patterns of techno and house: the loop is short, but it never sounds quite the same.
You can apply the same idea to a melody. In the next figure, a pluck repeats a three-note pattern in sixteenth notes, over a kick on every beat. The highest note moves to a different spot on every beat, and the phrase seems to shift endlessly, even though it contains only three notes.
Musicians sometimes call this polymeter, because it isn't two pulses working against each other, but two pattern lengths: three steps on one side, sixteen on the other. You can do the same thing with patterns of five or seven steps, or simply with a clip that's shorter than the others and loops on its own. If, on the other hand, you want the pattern to start over every bar, use the three, three, three, three, four split: four groups of three steps, then a group of four to make up the sixteen.
Here's a two-bar four-on-the-floor. Program a rim in groups of three steps that starts over at the beginning of each bar, using the three, three, three, three, four split. Which steps does it land on? Then, in your software, compare it with the version that never starts over, the one in the previous figure.
You now have the whole time grid in hand, from BPM all the way to polyrhythms. In the next part, we go back to pitch to build the first scale: the major scale.