Explanation of 9/8 time signature
In the article time signature, this is explained that:
- the top number indicates the number of time units in a measure (bar ).
- the bottom number determines the unit of time.
We can visually translate like this:
That is to say that there are 9 eighth notes (quavers ) per measure.
But, what is not indicated in the time signature is that can to a simple meter measure or a compound meter. In the article simple and compound meter, you learned that:
- Simple meter (or simple time) is a meter where each beat in a measure can be subdivided by two.
- Compound meter (or compound time) is a meter where each beat in a measure can be subdivided by three.
A beat with 9/8 time signature can be divided by two or three, it depends on the context.
Here are the beats for a simple meter measure:
In that case (simple meter):
- 1 eighth note (quaver ) equals 1 beat
- 2 sixteenth notes (semiquavers ) equals 1 beat
- 1 dotted quarter note (dotted crotchet ) equals 3 beats
- and so on...
Here are the beats for a compound meter measure:
- 1 dotted quarter note (dotted crotchet ) equals 1 beat
- 1 dotted half note (dotted minim ) equals 2 beats
- 3 eighth note (quaver ) equals 1 beat
- 6 sixteenth notes (semiquavers ) equals 1 beat
- and so on...
In the vast majority of cases, a 9/8 bar is a 3 beats compound measure, where each beat equals a dotted quarter note (dotted crotchet ):
Examples found in famous works
Debussy, Clair de Lune (moonlight)
The movement entitled Clair de Lune (moonlight in French) from Suite bergamasque by Claude Debussy use 9/8 time signature:
This royalty free sound sample was recorded by Caela Harrison (source, Attribution-No Derivative Works 3.0 license. You will notice the use of duplets.