Bars And Time Signatures

In this lesson we're going to learn all about time signatures and how to use them when reading and writing music.

We'll be covering

  • What are bars in music
  • How to use bar lines and the three different types
  • What is a time signature

Let's start with looking at bars and bar lines.


Bars And Bar Lines

To make notes easier for musicians to read we put them into groups. 

The most common way is to group them in twos, threes and fours. 

For example, let's start by looking at the twelve crotchets below:

Here, you can see they are not grouped at all.

But, if we wanted to put them into groups of two, three or four, we can draw vertical lines separating them as shown below.

Crotchets in groups of two

Crotchets in groups of three

Crotchets in groups of four

We call these groups of notes separated by vertical lines bars.

In the US they’re also referred to as measures

The vertical lines separating the notes are called bar lines.

We always emphasise the first beat of each bar.

That means we play the note after a bar line a little stronger than the other notes in the bar. 


Double Bar Lines

There are two other types of bar lines that we need to know about.

The first one is two thin lines as shown below.

A double bar line like this indicates the end of a section of music.

The other type of double bar line has a second line which is thicker than the first.

This type of double bar line indicates that this bar was the very last one of the piece of music.


What Is A Time Signature?

A time signature is how we tell musicians how to group the notes.

For example should we group them in beats of two, three or four.

A time signature also tells us what what kind of beat to count. 

I'll explain what I mean by this shortly but first, let's see what a time signature looks like.

A time signature is made up of two numbers, one on top of the other.

The three time signatures that you need to know for grade one are:

Now we're going to look at what these two numbers mean.


What Does The Top Number Represent?

The top number in a time signature represents how many beats there are per bar

So if the top number is two, then there must be two beats in a bar.

If the top number is three, there must be three beats in a bar.

If the top number is four, there must be four beats in a bar.

And so on.


What Does The Bottom Number Represent?

The bottom number tells us what kind of beat to count.

For example, we might be counting crotchet beats, or minim beats or quaver beats. 

This is best explained with some examples.


The Time Signature 2/4

If we look at the time signature 2/4 below, it means there should be two crotchet beats in each bar.

The top number tells us how many beats per bar (two in this case) and the bottom number tells us what kind of beat (crotchet beats in this case).

But why does the number four mean that we should count crotchet beats? 

Well the number four is used because four crotchet beats are equal to one semibreve.

For grade one, you only need to know about time signatures with the bottom number four so you will always be counting in crotchet beats.

Side note: It’s worth knowing that in further grades you can have numbers other than four as the bottom number in a time signature.

If the number two is the bottom number then this represents minim beats because two minims go into one semibreve. 

If it’s the number eight then it represents quaver beats because eight quavers go into one semibreve. 

We’ll cover those in a different lesson though so don’t worry for now


The Time Signature 3/4

The time signature 3/4 means there should be three crotchet beats in a bar.

Again, the top number tells us how many beats per bar (three in this case) and the bottom number tells us what kind of beat (crotchet beats as it's a number four).


The Time Signature 4/4

The time signature 4/4 means there are four crotchet beats in a bar.

The top number tells us how many beats per bar (four in this case) and the bottom number tells us what kind of beat (crotchet beats as it's a number four which represents crotchets).


Common Time

Another time signature you might see is one that looks like the letter C.

This stands for common time and is exactly the same as 4/4 and so has four crotchet beats per bar. 


Using Combinations Of Different Notes

But we don’t only have to use only crotchets if the bottom number in the time signature is a four.

We can use longer or shorter notes too. 

The only rule is that they have to equal the number of beats in the time signature.

For example any of these are correct:

Just remember that every single bar should always add up to the correct number of beats indicated in the time signature.


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