A duplet is a tuplet that permit to divide the beat (or more than 1 beat) by 2 in compound meters.
The rule is: A duplet can put 2 notes in the equivalent of 3. Or more exactly, A duplet can put 2 notes of equal length in the equivalent of the duration of 3 notes of equal length.
The most famous duplet: The eighth note duplet (quaver duplet )
Below is an eighth note duplet (quaver duplet ):
With an eighth note duplet (quaver duplet ), you can performed 2 in the equivalent of the duration of 3 , so you can divide a beat by 2 in a compound meter time signature.
Example with the famous Clair de Lune from Claude Debussy:
Quarter note duplet (Crotchet duplet )
Example of quarter note duplet (crotchet duplet ):
Sixteenth note duplet (Semiquaver duplet )
Example of sixteenth note duplet (semiquaver duplet ):
