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


Time signature

The time signature indicates the metric, that is, the number and the value of the beats in a measure.

Position

Time signature is composed of two numbers one on the other, like a fraction, but without horizontal line to separate them. It is indicated immediately after the key signature, at the beginning of staff. If there is no key signature, it is just after the clef.

FIGURE 1 - Time signature position, with and without key signature
Time signature without key signature Time signature with key signature

Unlike key signature, time signature is not repeated at each new staff.

Time signature is valid for all measures of a song. However, it is possible to make a change of metric by indicating a new time signature at the beginning of the measure where the change must take place. In this case, the new time signature will be valid until the end of the song, unless new signature appears.

Instead of time signature, you may also find the terms meter signature or measure signature.

Time signature and meter

There are two types of meter: simple meter (or simple time), when each beat is divisible into two equal parts (binary beat), and compound meter (or compound time), when each beat is divisible into three equal parts (ternary beat). The time signature differs according to the type of meter considered.

Simple meter

In simple meter, the beat is divided into two equal parts (binary beat). We can therefore use simple note figures, such as quarter or half note as beat value, hence the simple meter name.

For example, if the beat is equal to the quarter note, it can be divided into two equal eighth notes.

When the meter is simple, the denominator (lower number) indicates the beat value. This value corresponds to the division of the whole note.

For example, the number indicates the note figure equivalent to ¼ of the whole note, that is the quarter note. The beat will be equal to the quarter.

The numerator (higher number) indicates the number of beats within a measure.

FIGURE 2 - Simple time signature
Numerator = number of beats in a bar Denominator = whole note division = beat value

Some examples of simple time signature

A  time signature indicates a 3-beat measure, the beat being equal to the quarter note ( ).  = 3

A  time signature indicates a 2-beat measure, the beat being equal to the half note ( ).  = 2

A  time signature indicates a 3-beat measure, the beat being equal to the quarter note ( ).  = 3

A  time signature indicates a 5-beat measure, the beat being equal to the quarter note ( ).  = 5

Abbreviations

There are two common abbreviations for  and  time signatures.

(common time) is equivalent to .

( cut time) is equivalent to .

Compound meter

In compound meter, the beat is divided into three equal parts (ternary beat). Unlike simple meter, you cannot use simple note figures as a beat value. Indeed, the simple figures (quarter, half note...) cannot be divided into three equal parts. The solution is to use the subdivision of beat, that is, one-third of a beat as the base value of the denominator.

Thus, to obtain the beat value, it is necessary to multiply by 3 the note figure indicated by the denominator.

For example, if the denominator equals , it means that it represents 1/8 of the whole note, that is the eighth note. The beat will be equal to three times the eighth note, i.e. the dotted quarter note.

The numerator indicates the number of subdivisions per measure. To obtain the number of beats, divide this number by three.

For example, with a  time signature, the number of beats in a measure will be equal to 3 (9 divided by 3). A  meter is therefore 3-beat measure, each beat worth a dotted quarter.

FIGURE 3 - Compound meter signature
Numerator = number of thirds of a beat per bar Denominator = whole note division = third of a beat

Some examples of compound meter signature

A  meter indicates a 2-beat measure (6 / 3 = 3), the beat being equal to the dotted quarter (   )

 = 6 x = 2  

A  meter indicates a 4-beat measure (12 / 3 = 4), the beat being equal to the dotted quarter (   )

 = 12 x = 4  

A  meter indicates a 2-beat measure (6 / 3 = 2), the beat being equal to the dotted half (   )

 = 6 x = 2  

Simple or compound meter?

Whether the meter is simple or compound, the denominator always indicates a note figure resulting from the successive divisions of the whole note. It is therefore always a power of two (1, 2, 4, 8, 16...). In case of doubt, do not hesitate to consult the paragraph Rhythm figures tree of the rhythm figures course.

To differentiate between a simple and a compound time signature, we must therefore look at the numerator.

If the time signature numerator is 6, 9 or 12 (multiples of 3 except 3), it is a compound meter. If the numerator is 2, 3 or 4, it is a simple meter.

Never use the denominator to distinguish between simple and compound meter. Look at the numerator and only the numerator, only the latter makes it possible to determine the nature of the meter.

There is some ambiguity when the numerator is equal to 3. For example, with a  time signature, it is usually a meter with three binary beats, the beat being equal to the quarter. On the other hand, when the signature is equal to , we can meet the case of a one ternary beat, the beat being equal to the dotted quarter.

Summary

Table - Some common time signatures (simple meter)
Time signatureBeat valueBeat number
2
3
4
2
3
4
5
2
3
4

Table - Some common time signatures (compound meter)
Time signatureDenominator valueBeat valueBeat number
 2
 3
 4
 2
 2

Complex meter

Until the end of the nineteenth century, classical music was written in simple or compound meter. From the twentieth century, the (re)discovery of folk music by composers, the appearance of jazz and compositional research towards unexplored lands lead to the introduction of meters mixing binary beats and ternary beats or introducing split beats. These special meters are called complex meters.

Complex time signature — Example 1

A  meter indicates a 2-beat measure, one binary beat (beat = quarter), one ternary beat (beat = dotted quarter).

This meter is equivalent to:  +  that is to say 2 x + 3 x = +  

The order of the beats can be reversed. Only the context makes it possible to say whether it is the first beat or the second beat of the measure that is binary.

In the following figure, the eighths of the same measure are beamed (grouped) first by 3 then by 2. In this first case, the measure is thus composed of a ternary time followed by a binary time.

FIGURE 4 -  as  + 
Eighths grouped by 3Ternary beat Eighths grouped by 2Binary beat

Audio of Figure 4

The clarinet plays the written theme, a string section marks the beats on the first and fourth eighth of each measure

On the other hand, in the following figure, the eighth notes are grouped differently, first by 2 then by 3. In this second case, the measure is constituted by a binary time followed by a ternary time.

FIGURE 5 -  as  + 
Eighths grouped by 2Binary beat Eighths grouped by 3Ternary beat

Audio of Figure 5

The clarinet plays the written theme, a string section marks the beats on the first and third eighth of each measure

When the numerator is equal to , it can be a true 5-beat measure or a 2-beat measure, one binary, the other ternary.
Complex time signature — Example 2

A  meter indicates a 3-beat measure, two binary beats (beat = quarter), the remaining beat is ternary (beat = dotted quarter).

This meter is equivalent to:  +  +  that is to say 2 x + 2 x + 3 x = 2 +  

Here too, the beat order can be reversed. We can have the following variants:

 +  + 

 +  + 

 +  + 

Only the context makes it possible to precisely determine the alternation between binary beat and ternary beat.

Multiple time signature

Sometimes the time signature is broken down in two, to clarify the interpretation of the metric.

The   time signature indicates a 3½-beat measure.

3 +

The   time signature, that seems to be equivalent to the previous meter, indicates a 3-beat measure. The first two are binary, the last is ternary.

2 + 3 x = 2 +  

Last update on 2018/12/21

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