Easily Confused Time Signatures
Some time signatures can look very similar, so it is not always easy to tell them apart.
Three time signatures which often cause problems are 3/2, 6/4 and 12/8, because they all have the same overall number of notes per bar.
The difference between these time signatures is in the number of beats per bar.
- 3/2 is simple triple time, with three beats per bar (the beat is a minim (half note).
- 6/4 is compound duple time, with two beats per bar (the beat is a dotted minim (dotted half note).
- 12/8 is compound quadruple time, with four beats per bar (the beat is a dotted crotchet (dotted quarter note).
If we write a melody only using fast notes like quavers (8th notes), the number of beats per bar is made clear by the way the notes are grouped together with beams. These bars have exactly the same notes in them, but they are grouped in different ways, according to the time signature. They will each sound slightly different, because different notes are emphasised in each case (i.e. the notes that fall directly on the beat each time).
When longer note values are used, the type of note value used should also reflect the number of beats per bar clearly.
Usually this means writing note values in the places where new beats begin, and using tied notes to achieve this.
To work out a time signature, you need to look at how the notes are grouped, and also match any tied notes to beats.
When two notes are tied, the second note shows where the new beat begins.