Sooner or later, when playing and listening to lots of different music, you’re likely to run into time signatures that don’t sound like others. They’re hard to dance to or count and they seem to jump or skip a beat and feel unusual. These are most likely a type of odd time signature.
This post will cover everything you need to know about them and how to group the notes contained within.
What is an Odd Time Signature?
An odd time signature, sometimes known as an irregular, complex, asymmetric, or unusual time signature, is any time signature that doesn’t fit into the three categories of regular time signatures:
- Duple time
- Triple time
- Quadruple time
These categories of regular time signatures all have equal beats in a bar.
For instance, the simple time signature 4/4 is made up of four groups of two quavers with each group adding up to a crotchet beat.
Or the compound time signature 9/8 which is made up of three groups of three quavers, with each group adding up to a dotted crotchet beat.
But, odd time signatures don’t have equal beats in bar.
They use a combination of simple time and compound time in each bar.
An example of this would be the time signature 5/8 which is a crotchet and a dotted crotchet beat in a bar which we’ll cover in more detail shortly.
Common Types of Irregular Time Signature
The most common irregular time signatures that you’ll come across in music theory are:
You’ll also need to know about these if you’re sitting an ABRSM grade five music theory exam.
We’ll take a look at each of them in a bit more detail now.
The Time Signature 5/8
As with all time signatures the first thing to do is look at what the two numbers are telling us.
5/8 tells us that there will be five quavers (eighth notes) in a bar.
However, although the time signature indicates that that there are five quavers in each bar, there aren’t five beats in a bar.
If you were to watch a conductor conducting a piece of music written in 5/8, you might see them conducting in what seems like two beats per bar.
But these two beats are not equal in length.
That’s because we group the quavers into a crotchet beat followed by a dotted crotchet beat, or vice versa, a dotted crotchet beat followed by a crotchet beat.
The difference between the two is where we place emphasis in the bar.
In the first example, we emphasise the 1st and 3rd quaver beats.
But, in the second example, we emphasise the 1st and 4th quaver beats.
This gives us a simple beat and a compound beat in each bar.
The crotchet beat can be divided by two and so is a simple beat, and the dotted crotchet beat can be divided by three and so is a compound beat.
You can see how 5/8 is an irregular time signature as it doesn’t fit into either time.
It’s a combination of both simple and compound time.
This is the case for all odd time signatures.
The Time Signature 5/4
The time signature 5/4 is very similar to 5/8.
It’s telling us that there are five crotchet beats in a bar.
But, like 5/8, there aren’t five beats in a bar.
There are two beats in a bar.
We group the crotchets into a minim beat and a dotted minim beat, or a dotted minim beat and a minim beat.
Again, the difference is which crotchets we place emphasis on.
In the first example, it’s on the 1st and 3rd crotchet beats, and in the second example, it’s on the 1st and 4th crotchet beats.
This gives us either a minim beat followed by a dotted minim beat or, a dotted minim beat followed by a minim beat.
Again, this is and odd time signature as it contains both a simple beat (the minim) and a compound beat (the dotted minim).
Side note: Even though time signatures with a five as their top number have two beats in a bar, they are not duple time. That’s because the two beats are not equal in length. Duple time signatures must have two equal beats in a bar. Time signatures with a five as their top number are in quintuple time.
One of the most famous songs in an odd time signature is probably Take Five by the Dave Brubeck Quartet.
If you listen to the double bass you’ll hear it play a dotted minim followed by two crotchet beats in every bar.
The Time Signature 7/8
Next, we have 7/8 which tells us there are seven quavers in a bar.
But, like in quintuple time, just because the top number is a seven it doesn’t mean there are seven beats in a bar.
In time signatures with a number seven as their top number (septuple time), there is usually three beats in a bar.
In 7/8 we’d group the quavers in to one dotted crotchet beat and two crotchet beats, or two crotchet beats and one dotted crotchet beat.
This means that we put emphasis on the 1st, 4th and 6th quavers or the 1st, 3rd and 5th quavers.
If you have the two groups of quavers next to each other in the bar, then you can beam them all together in a group of four.
You might also see it as the dotted crotchet beat in the middle of the like this which is also okay.
The Time Signature 7/4
Lastly, we’ll take a look at the time signature 7/4.
We do the same thing as we did for the others by working out what the time signature tells us which is that there should be seven crotchets in a bar.
We can group them in a few different ways.
We can group them in two minim beats and a dotted minim beat or vice versa.
A great example of a piece of music in seven is Unsquare Dance by Dave Brubeck.
If you listen to the double bass you’ll here it playing two minims followed by a dotted minim.
These four odd time signatures are the most common types that come up in music but you can also get lots of others.
I’ll update this post soon with some more examples of less common time signatures.