Time Signatures and Polyrhythms
I got an assload of emails asking me what time signature my last column was in, and a few asking how time signatures work so I figured since we’re on the subject of rhythm guitar here at IG.net we might as well explain how to make sense of it all.
You’re probably all seen time signatures before. There is a number on top of another number and it looks like a fraction. You might have seen a “C” across the B line on some manuscript paper before – thats also a time signature it stands for “Common Time” – 4/4
Now lets take a look at the fraction bit for a while. The top number is how many beats are in one measure or bar. Thats the “length” of the bar. If we’re in Common Time, that means there are 4 beats per measure.
Now lets take a look at the bottom number. This number is the duration of each beat. In other words, how long each beat is sounded.So in Common Time that’ll be a quater note – 1 fourth of a whole note.
So if our time signature reads “4/4″ that means 4 beats per measure, and 4 beats per measure.
The question you’re going to ask now is “So I can only make a song using quarter notes if I’m in 4/4 time?” The answer boys and girls is no, far from it. You can have alot of fun with 4/4 time using -much- more than just quarter notes.
Now how do we do this? Simple, we use our knowledge of math, specifically relating to fractions. Yes, those dreaded fractions from third grade. Heres how.
If you want to hold a note longer that 1/4 a whole measure, simply make a fraction that is larger than one fourth. Just so we’re moving in equal pieces and lengths. What if I only want 1 note per measure. I use a whole note. If I want something half as long, I use a half note. What if I need something smaller than a quarter note? Break that in half, an 1/8 note, smaller still? 1/16th note. Easy beans right? Moving on.
So we know we can make longer and short notes, and fill a measure with the appropriate amount of them to fill the measure. But is that all there is to rhythm? No. Not by a long shot – ask any drummer (and for the drummers reading this I appologise, I’m a guitarist, but I’m trying ^_^). So how to make all those cool rhythmic things? Simple, mix it up. You can put a half note, a quarter note, and 4 sixteenth notes all in one measure and make it fit, because it all equates out to 4 beats per measure. Groovy eh?
So what else is there? Other time signatures!!!
Ever seen 6/8? This time there are 6 beats per measure, and an 1/8th note gets one beat. Same as 4/4 – but different…?
So what about triplets and such? All you do there, is pick a note, in your measure, or the entire measure, and break it up over the course of the duration you selected.
So if I see a triplet in the space of a 1/4 note, than means play three notes evenly in the space of one 1/4th note.
What if it’s got a 4 or 5 or anyhting else in place of the 3 on a triplet? Then you play however many notes are there in the space of the note that’s being divided.
So if I have a half note, thats divided into 5 equal peices, I have a quintuplet over the space of two beats – thats 2.5 notes per beat. Trippy huh?
Well, that’ll cover the “‘tuplets” – what else? Polyrhythms… hehe I’m gonna make it short and sweet – a poly rhythm is a “‘tuplet” inside a “‘tuplet” – you divide your divisions.
With me? Say you have a triplet on a half note, – now take the first note of that triplet, and give it a triplet through that duration. Lets just assume we’re playing rediculously slow say 40 bpm. It’s gonna sound – very – fast compared to the rest of the notes played inside the triplet on the half not. It’ll be the quick notes, and then two faster notes, and then back to regular rhythm, say one quarter note and two 1/8ths.
To ilistrate this, see below.
H - half note, Q - quarter note, E - eighth note, X - "'tuplet note" . - polyrhythm note H Q E / | \ | /\ 4/4 -...-x--x----Q---E--E-
Three rapid notes by two quick ones completes the poly rhythm and the triplet and the quarternote and two eighth notes complete the measure giving us 4 beats per measure with a quarternote standing for one beat. Our polyrhythm is complete, and now that your brains are racked, so is this lesson. Good luck and see you next month!