Simple metre (or simple time) is a metre in which each beat of the bar divides naturally into two (as opposed to three) equal parts. The top number in the time signature will be 2, 3, 4, 5, etc.
Simple time signatures consist of two numerals, one stacked above the other:
- The lower numeral indicates the note value that represents one beat (the beat unit). This number is typically a power of 2.
- The upper numeral indicates how many such beats constitute a bar.
For instance, 2/4 means two quarter-note (crotchet) beats per bar, while 3/8 means three eighth-notes (quavers) per bar, which are beats at slower tempos (but at faster tempos, 3/8 becomes compound time, with one beat per bar). The most common simple time signatures are 2/4, 3/4, and 4/4.
Simple duple time
Two or four beats to a bar, each divided by two, the top number being "2" or "4" (2/4, 2/8, 2/2 ... 4/4, 4/8, 4/2 ...). When there are four beats to a bar, it is alternatively referred to as "quadruple" time.
Alla breve, cut time: Used for marches and fast orchestral music.
Used for polkas, galops, and marches.
Simple triple time
Three beats to a bar, each divided by two, the top number being "3" (3/4, 3/8, 3/2 ...)
In the time signature 3/4, each bar contains three quarter-note beats, and each of those beats divides into two eighth notes, making it a simple metre. More specifically, it is a simple triple metre because there are three beats in each measure; simple duple (two beats) or simple quadruple (four) are also common metres.
Used for waltzes, minuets, scherzi, polonaises, mazurkas, country & western ballads, R&B, sometimes used in pop
Also used for the above but usually suggests higher tempo or shorter hypermeter
Simple quadruple time
Common time: Widely used in most forms of Western popular music. Most common time signature in rock, blues, country, funk, and pop.