Septuple meter
Septuple meter (British: metre) or (chiefly British) septuple time is a meter with each bar (American: measure) divided into 7 notes of equal duration, usually 7
4 or 7
8 (or in compound meter, 21
8 time). The stress pattern can be 2+2+3, 3+2+2, or occasionally 2+3+2, although a survey of certain forms of mostly American popular music suggests that 2+2+3 is the most common among these three in these styles.[1]
A time signature of 21
8, however, does not necessarily mean that the bar is a compound septuple meter with seven beats, each divided into three. This signature may, for example, be used to indicate a bar of triple meter in which each beat is subdivided into seven parts. In this case, the meter is sometimes characterized as "triple septuple time".[2] It is also possible for a 21
8 time signature to be used for an irregular, or "additive" metrical pattern, such as groupings of 3 + 3 + 3 + 2 + 3 + 2 + 3 + 2 eighth notes.
Septuple meter can also be notated by using regularly alternating bars of triple and duple or quadruple meters, for example 4
4 + 3
4, or 6
8 + 6
8 + 9
8, or through the use of compound meters, in which two or three numerals take the place of the expected numerator 7, for example, 2+2+3
8, or 5+2
8.[3]