In this lesson we will look at some uncommon time signatures and how to count them. These time signatures appear mostly in music written after 1900.

Irregular Time Signatures

Irregular time signatures can be emphasized in different ways unlike simple time or compound time signatures. In 3/4 time, the first beat gets the emphasis, but in an irregular time signature, the beats can be emphasized differently depending on the music. They will always be divided into 2 or 3. This type of meter will have the feel of alternating between different time signatures.

5/4 Time

A full measure in 5/4 will have five quarter notes:

The 5/4 time signature can be emphasized two different ways: on the first and fourth beats, or on the first and third beats:

This divides the meter into two or three.

7/4 Time

This time signature has seven beats per measure:

This time signature can be emphasized in many different ways, since there are more ways to group this rhythm into 2 and 3:

5/8 Time

One measure in 5/8 time has 5 eighth notes:

The 5/8 time signature shows us how it can be confusing when deciding which beats are emphasized:

We must group the beats by 2 or 3. This time signature, like 5/4, is emphasized on the first and fourth beats, or the first and third beats:

The music will look like alternating 3/8 and 2/8 time.

7/8 Time

This time signature has 7 eighth note beats per measure.

If we group the notes in twos we come up with an awkward rhythm:

To avoid this, one group of beats must be a group of three. This time signature is usually emphasized on the first and fifth beats, like alternating 4/8 and 3/8 time:

Alternating Time Signatures

But written like this:

Irregular Alternating Time Signatures

In this type of meter, the time signatures do not alternate every other bar. One time signature may appear after multiple bars of the other, or in select parts of the piece, as shown in the next example.

Debussy uses this in his prelude Les sons et les parfums. The first two bars are in 5/4 (dotted line showing the emphasis) and the third bar is in 3/4:

Dotted lines are used to show the beat emphasis in each measure that is in 5/4.

Mixed Meters

This time signature uses more than one time signature for each bar, but the note that gets the beat may change.

In this example, the beat goes from a quarter note to an eighth note and back to a quarter note:

The different meters may be separated with a dashed line in each measure.

Composite

This time signature is used to show emphasis of meter when all the beats are the same note value. Dashed lines may be used to show the division of the meter:

Non-Dyadic Time Signatures

So far we have looked at time signatures where the bottom number represents a note. But what if the number is a 6? There are no 6th notes.

This kind of meter is called Non-Dyadic.

In the rare chance that you come across one of these time signatures, this is a diagram you will need:

This diagram shows how many notes are in the time of a whole note, which is the bottom number on the time signature. The top number of the time signature will be how many notes occur from that group.

The bottom number tells us that each beat is 1/10 of a whole note, and the 5 tells us that there are 5 beats. This is half the length of a whole note, because the measure is 5/10 of a whole note, which would be 1/2 of a whole note.

This rhythm would have the same feel as a 5 note tuplet lasting the length of a half note.

Let’s look at another non-dyadic meter:

In this time signature, the length of each beat is 1/12 of a whole note, and there are 6 beats. Six is half of twelve, so each measure lasts the length of a half note.

This has the same feel as a 6 note tuplet (two triplets together):

Sometimes the rhythm makes an incomplete tuplet:

In this meter, each beat is 1/3 of a whole note and there are 4 beats. This leaves us with a rhythm of one and 1/3 tuplets:

Which is not easy to write another way, since we have 1/3 of a whole note. It best thought of as a tuplet plus one note of another tuplet.

Here is another meter which leaves us with an incomplete tuplet:

Each beat is 1/6 of a whole note, and there are 5 beats. It is the same as playing 5 notes of a 6 note tuplet:

Next: Nested Tuplets