Time Signatures: Grade Five Music Theory - Lesson 3
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(In this lesson, US note names are given in brackets).
Time Signature Numbers: What do they mean?
The time signature tells you how many main beats there are in one bar, and how long each main beat is.
A time signature is made up of 2 numbers, one written above the other.
For example, like this:
The lower number represents of a type of note to count in each bar:
For example, the lower number 4 tells you that the kind of note we must count is a crotchet (quarter note) because the number 4 (in the lower position) stands for crotchet (quarter note).
The numbers you can find in the lower position are:
2= Minim (Half note) count
4= Crotchet (quarter note) count
8= Quaver (8th note) count
16= Semiquaver (16th note) count
(You might also see a lower number 32 used in pieces that you play, but this doesn't normally come up in the Grade 5 Theory Exam.)
The upper number tells you how many of these notes you need to count. So,
means we count 2 crotchets (quarter notes) per bar
means we count 6 quavers (eighth notes) per bar, and
means we count 4 minims (half notes) per bar.
The time signature must appear at the beginning of a piece of music, after the clef and the key signature.
The order that these 3 symbols must be written is always Clef-Key-Time. This is easy to remember, as the letters CKT must be in alphabetical order!
clef - key - time
Although the clef and key signatures must be repeated on every new line of music, the time signature is not repeated:
Time signatures don't only tell you how many notes there are in a bar. They also give you some very important information:
They tell you how many main beats per bar there are.
This is a really important point to grasp, and one that is new to many students at this level. What am I talking about exactly? Take a look at this bar:
How many beats do you think there are in that bar?
If you thought "six", you'd be wrong.
In fact, without the time signature, we can't tell how many beats there are, but we can be sure there aren't six!
Regular and Irregular Time
All time signatures are either regular or irregular.
Regular time signatures have 2, 3 or 4 beats per bar. (No other number!)
Irregular time signatures have any number of beats per bar which is not divisible by 2, 3 or 4.
In the bar above, you can count six crotchets (quarter notes). Six is divisible by 2 or 3, so it will be a regular time signature. There could be either 2 or 3 beats per bar, depending on the time signature.
In this bar though, there are 5 crotchets' (quarter notes') worth. 5 is not divisible by 2, 3 or 4, so this will be be an irregular time signature.
Irregular time signatures are straightforward: here we have 5 crotchets (quarter notes), so the time signature is 5/4. Remember that the top number tells you how many to count, and the lower number tells you the type of note.
Regular time signatures are a little more tricky. Each regular time signature can be further described as duple, triple or quadruple, and as either simple or compound.
Duple, Triple and Quadruple Time
When there are 2 main beats per bar, the music is in duple time. Triple time means there are 3 main beats per bar, and quadruple time means there are 4.
The first beat of bar receives a stronger stress or accent than the other main beats. The other main beats receive a slightly stronger stress than the "off-beats". This gives us three types of beat: strong beat, weak beat, off-beat. When we talk about the "main beats", we mean the "strong and weak beats", and not the off-beats.
As you can see, this would give us two main beats per bar. This means the music is in duple time.
On the other hand, we could play it a different way, so that the 1st, 3rd and 5th notes are slightly stressed:
This would give us a total of three main beats per bar, so the music is in triple time.
Simple and Compound Time
Look again at the 6/4 bar above. What note values would you use if you wanted to write just one note for each of the two main beats?
Each main beat is equal to three crotchets (quarter notes). Three crotchets (quarter notes) written as one single note is a dotted minim (dotted half note).
Look at the 3/2 bar, and do the same thing. What note value is equal to one main beat?
Each main beat is equal to two crotchets (quarter notes). Two crotchets (quarter notes) written as one single note is a minim (half note).
Whenever the main beat splits into three, like in 6/4, the music is in compound time.
Whenever the main beat splits into two, like in 3/2, the music is in simple time.
Simple time signatures use 2, 3 and 4 as the top number.
Compound time signatures use 6, 9 and 12 as the top number.
This is how you can tell the difference between simple and compound time: the top number of the time signature tells you, and the rhythms in the bar tell you too.
The lower number depends on the top number of course. If you use "6" on the top, because the beat splits into 3, then you use "4" below, because there are six crotchets (quarter notes). If you use a "3" on top, because the beat splits into 2, then you use "2" below, because there are 3 minims (half notes).
All irregular time signatures are simple, because the main beat is always split into 2, not 3.
Clues in the Rhythm
When you need to work out a time signature, or when you are writing a melody yourself, you should understand that the way a rhythm is written is dependent on the time signature. The note values should always make it clear where the main beats are.
Look again at this 6/4 bar. The two notes fall precisely where the two main beats of 6/4 fall:
But what if we wanted to write that rhythm in a 3/2 bar? Would this be correct?
The answer is "no", because we cannot see where the 2nd or 3rd beats are supposed to be, and the 2nd G falls on an off beat (see the diagram above!) Writing the rhythm like this makes it more confusing for the player to understand where the beats are supposed to be.
To write this rhythm correctly in 3/2, first we need to work out where the main beats lie. Currently, the 3rd beat starts somewhere in the middle of the 2nd dotted note. We need to rewrite it, so that the 3rd beat is evident. We can do this by breaking the dotted note up, and using a tie instead.
Now it is easy to see where the 3rd beat starts.
Ties are very useful when you need to work out what a time signature is. The 2nd note of the tie will always start a new main beat.
Another very useful clue can be found in beams. Beams are those horizontal lines that join together fast notes like quavers (eighth notes) and semiquavers (16th notes).
Generally, notes are beamed together to make complete beats. How would you beam together 12 quavers (eighth notes) in 3/2 and in 6/4? Try and work it out for yourself first, then check below (hover your mouse over the image to see the answer (tap on mobile devices)).
In 3/2, the notes are beamed to the value of a minim (half note), but in 6/4 they are beamed to the value of a dotted minim (dotted half note). This also helps you to see that 3/2 is triple time, and 6/4 is duple.
Summary of Time Signatures
- Top number is 2 (duple), 3 (triple) or 4 (quadruple)
- Main beat is split into 2
- Main beat is not a dotted note
- Top number is 6 (duple), 9 (triple) or 12 (quadruple)
- Main beat is split into 3
- Main beat is a dotted note
There are 4 types of question:
- Putting bar lines in an extract with a given time signature.
- Putting a time signature in an extract with given bar lines.
- Rewriting music in a new time signature without changing the rhythmic effect.
- General knowledge questions about the technical names of time signatures.
You won’t get every type of question in your exam, but any of them can come up, so be prepared for all of them!
In this type of question, you are given a short melody with the time signature. You need to work out where the bar lines should go, and draw them in neatly. You will be told whether the melody starts on the first beat of the bar. Here's a typical question (which starts on the first beat of the bar):
1. Look at the lower number in the time signature. This tells you the kind of note to count:
= count minims (half notes)
= count crotchets (quarter notes)
= count quavers (eighth notes)
= count semiquavers (16th notes)
2. Next look at the upper number. This tells you how many of those notes there need to be in each bar.
3. Count out the required number of notes, then, using a ruler and a sharp pencil, draw a bar line. Repeat, until you get to the end.
In the above melody, the time signature is 4/8. This means each bar needs to have the equivalent of four quavers (eighth notes). Pay attention to the way the notes are beamed - you will never draw a bar line through a beamed group. Also pay attention to the triplet. Remember that a triplet means there are 3 notes in the space of 2, so the triplet here is worth the same as two semiquavers (two 16th notes). (A triplet always consists of three notes, so the quaver G (eighth note G) which is part of the beamed group is not part of the triplet).
Have a go at putting the bar lines in place in the above melody, then hover your mouse over the stave to reveal the answer (or tap if you have a mobile device).
In this type of question, you are given one or more bars and have to work out what the time signature(s) is (or are). The question could look like this:
The following melody requires a different time signature in each bar. Add the correct time signatures.
1. Work out what value of note is used for the main beat. Use clues to help you:
- Look for beamed notes. Notes are generally beamed together to add up to one main beat. A new main beat cannot begin in the middle of a beamed group.
- Look for tied notes. The 2nd tied note of a pair will show you where a new main beat falls.
- Look at where longer notes are placed in the bar. A long note (crotchet (quarter note) or longer) will always fall on the beat. (Look again at the diagram above, if you need to remember which are the off beats.)
- Look for triplets. Triplets are only used in simple time signatures.
- Look for duplets. Duplets are only used in compound time signatures.
The type of note used for the main beat will give you the lower number of the time signature. Remember, this can only be 2, 4, 8 or 16. (16 is very rare and unlikely to come up in the exam).
2. When you have worked out what the main beat is, count up how many times it is used in the bar. This will give you the top number. Remember that if the main beat is an undotted note, the time signature will be simple, so the top number can only be 2, 3 or 4, (regular time) or a number which doesn't divide into 2, 3 or 4 (irregular time). If the beat is a dotted note, the time signature will be compound, and the top number can only be 6, 9 or 12.
Use the following table to help you:
|Simple||2/4, 2/2||3/8, 3/4, 3/2||4/8, 4/4, 4/2|
|Compound||6/8, 6/4||9/8, 9/4||12/8, 12/4|
Let's work through the above question.
Bar 1. Look at the beamed notes, and add them up. These notes add up to the value of one dotted crotchet (dotted quarter note). This value is likely to be the main beat. Next, see what is left: the crotchet+quaver (quarter note + eighth note) add up to the same value, so the beamed group is equal to half a bar. There are therefore two main beats per bar (duple time), and the main beat is a dotted note (compound time). In compound duple time, the top number is 6. We have a total of 6 quavers (eighth notes), so the time signature is 6/8.
Bar 2. The beamed notes add up to one crotchet (quarter note). The other notes are of the same value. The Ab, C and Bb should all fall on the beat, so there are three beats in the bar, and they are crotchet (quarter note) beats. This means the time signature is 3/4.
Bar 3. All the notes are beamed. (It is common to beam notes across a whole bar). There cannot only be one beat per bar though, because the minimum number is 2 (duple). Here we have the equivalent of three quavers (eighth notes), so it is simple triple time, with a quaver beat (eighth note beat). The time signature is 3/8. (Notice that 3/8 is simple time, not compound, even though the lower number is 8. Don't forget that it is only the top number of a time signature which can distinguish between simple and compound time.)
Bar 4. The quaver (eighth note) triplet is worth one crotchet (quarter note). There are four more beats of the same value, making five in total. Five doesn't divide into 2, 3 or 4, so this bar is irregular. The time signature is 5/4 because there are five crotchets (quarter notes) in the bar.
In this type of question, you are asked to rewrite a short excerpt using a different time signature without changing the rhythmic effect.
This is easy if both the old and new time signatures are simple time. (The grade 4 course explains this in more detail).
Notice how the note values change when 3/4 becomes 3/8:
Each note value is halved; for example, a minim (half note) becomes a crotchet (quarter note) and a dotted minim (dotted half note) becomes a dotted crotchet (dotted quarter note).
Compound to Simple (and Vice Versa)
The task is more complicated when you are moving from simple time to compound time or vice versa, and when you also have to work out what the new time signature is!
The first step is to look at the given time signature and remind yourself what kind of beat and how many beats it represents.
Let's say you have an extract in 12/8, to rewrite in simple time. What does 12/8 actually mean?
12/8= 4 dotted crotchet (dotted quarter note) beats per bar.
The equivalent simple time signature will use the same value of note without the dot. Which time signature uses four undotted crotchets (quarter notes) per bar?
Each dotted main beat in compound time should be written as an undotted note in simple:
Now think about how each main beat is divided into sub-beats:
12/8: 1 dotted crotchet (dotted quarter note) =3 quavers (eighth notes)
4/4: 1 crotchet (quarter note) =2 quavers (eighth notes)
In order to keep the rhythmic effect when re-writing the rhythm, you might need to use duplets or triplets.
- Duplets are used in compound time (3 becomes 2)
- Triplets are used in simple time (2 becomes 3)
Let’s look at an example.
Duplets are used in compound time, when you need 2 notes instead of 3.
Triplets are used in simple time, when you need 3 notes instead of 2.
Triplets can be made with any note value - not just quavers (eighth notes).
Here is a rhythm in 9/8. How would you rewrite it in a simple time signature? (Hover your mouse over the lightbulb (or tap on a mobile device) to reveal the answers, but try to answer them yourself first!)
What does the time signature 9/8 actually mean?
What is the equivalent simple time signature?
The first note F is a dotted crotchet (dotted quarter note). What should this be in the new time signature?
The second main beat is a crotchet+quaver (quarter note + 8th). How should this be written in the new time signature?
The third main beat is the same rhythm as the second main beat (minus the tie).
Here is the whole bar rewritten:
The most common mistake I find among students tackling this question, is failing to work out what the new time signature is supposed to be. Often, a student will assume that a bar in 6/8 ought to be rewritten in 3/4, because they contain the same number of quavers (eighth notes) per bar. This is a mistake! 6/8 is duple time, and 3/4 is triple time, so it is impossible to rewrite a rhythm in that way without changing the rhythmic effect. Always keep the same number of main beats per bar: duple time stays as duple time, and so on.
Rests sometimes make the exercise look more difficult, but you should think about them in exactly the same way as you think about notes.
A common mistake, (especially with compound times), is to forget that a rest sometimes makes up a whole beat with the note before it.
In this bar, the 9/8 time signature might make you think that you should group quavers (8th notes) into threes, so you might think the second beat of the bar starts with the quaver (8th) rest:
Look more closely, and you’ll see that the first complete beat, (which must be a dotted crotchet (dotted quarter note) beat), is the G plus the rest. The second beat is the duplet B - D, and the third beat is C sharp - A.
Rests can be included in duplets and triplets in the same way that notes can. Here’s an example:
For a complete table of time signatures, take a look at the chart in our reference section. It includes all time signatures, with examples of rhythms written in those time signatures.