Time Signatures

Topics covered on this page: Simple/compound time signatures – Relation of time signatures to time classification – Common time – Cut time – Alla breve – The tie – Rhythmic patterns – Syncopation

Musical compositions are metrically organized by a time signature. A time signature has two numbers placed on the staff with one above the other at the beginning of the composition.

A 4/4 or “common time” signature:
four four time signature

 

A 4/4 time signature abbreviated:
4-4 time abbreviated

The two types of time signatures that exist are ones for simple time and ones for compound time. Here is how to distinguish between simple and compound time:

If the upper number is 6, 9, 12, or 15, the time signature represents compound time. Any number other than these means that the signature represents simple time, including the number 3.

Some examples of compound time:
1c

1d

1e

 

Some examples of simple time:
1f

1g

2a

The top number in a simple time signature indicate the number of beats per measure. It also indicates if the meter is duple, triple, quadruple, or quintuple.

4 beats per measure, quadruple meter:

2a

or abbreviated:

2b

 

2 beats per measure, duple meter:
2c

or abbreviated:
2d

 

3 beats per measure, quadruple meter:
1f

 

The upper number in a compound time signature does not indicate the number of beats per measure as in simple time. To find the number of beats per measure in this case, the upper number of a compound time signature is divided by three.

Examples:

2 beats per measure:
3a

3 beats per measure:
3b
4 beats per measure:
3c

5 beats per measure:
3d

In both simple and compound time, the upper number indicates meter while the lower number indicates unit. In simple time, the lower number directly indicates the unit. In compound time, the lower number indicates the division of the unit.

Here we have a measure of 4/4, or common time. By looking at the time signature we see the meter is 4 and the unit is 4 (a quarter note):
4a

A measure of 3/4. The meter is 3 and the unit is 4 (a quarter note):
4b

A measure of 6/8. The meter is 2 (6 divided by 3) and the unit is 8 (an 8th note). If we group the 8th notes into two beats we have two dotted quarter notes for the unit:
4c

In compound time, the upper number in a time signature is divided by 3 to give the meter, or beats per measure. In this example below there are 2 beats per measure. The lower number indicates the unit. So in 6/8, the unit is the 8th note:
5a

And three tied 8th notes equals a dotted quarter note:
5b

Remember that in all compound time, a dotted note is used for the beats per measure.

A dotted note is always the unit in compound time. An un-dotted note is always the unit in simple time.

Compound time:
6a6b6c

Simple time:
6d6e6f

For the sake of better understanding, it may be helpful to visualize the compound time examples as 8th notes with ties:
6g6h6i

 

Time classification is expressed in terms like duple-simple, duple-compound, triple-simple, quadruple-simple, and quintuple-simple. The first portion of the classification refers to the number of beats per measure. The second portion refers to the classification being simple or compound time.

Duple = 2
Triple = 3
Quadruple = 4
Quintuple = 5

The simple chart below recaps all the common time signatures and how they are expressed using time classification:

4/4 = quadruple-simple
2/2 = duple-simple
2/4 = duple-simple
3/4 = triple-simple

6/8 = duple-compound
9/8 = triple-compound
12/8 = quadruple-compound
15/8 = quintuple-compound

Next section is Intervals