Irregular metre

What it means

Irregular or asymmetrical metres are time signatures whose beats cannot be divided into equally sized groups — for instance 5/8, 7/8, 5/4, or 11/8. The bar then falls into unequal parts: 5/8 into 2+3 or 3+2, 7/8 into 2+2+3, 3+2+2, or 2+3+2.

The grouping is the heart of the matter. The time signature alone only says how many small values a bar contains; how they are grouped results from the music and can change. Herein lies the difference from compound time signatures such as 6/8 or 9/8, whose groups are all the same size, and from simple time signatures with an even beat.

The term “irregular” therefore refers to the unequal groups, not merely to an odd number in the numerator: a three-four bar has three beats, but of equal length, and does not count as asymmetrical for that reason.

In the notation

The beaming shows the grouping by combining the eighths into the intended groups. Some editions write the division expressly above the time signature, for instance as 3+2+2, others place dashed strokes within the bar. Where the grouping changes, the beaming changes too.

Musical use

In the folk music of several regions, especially the Balkans and Turkey, such metres have long been customary and connected with particular dances. They reach art music sporadically earlier, but become widespread only in the late nineteenth and in the twentieth century, partly through engagement with folk music, partly from the wish to leave metric regularity behind. In jazz and popular music, too, they are widespread as a rhythmic device.

Performance practice

Determine the grouping first and count it in groups, not up to the total number: “one two, one two three” carries further than “one to five”. Mark the beginnings of the groups clearly; they hold the bar together. Practise slowly until the pattern sits physically, before you increase the tempo. And watch passages with changing grouping — most errors lie there.