|Irregular Meters in Music|
Irregular meters (also called asymmetrical meters) establish a regular metric pattern from an asymmetrical sequence of two or more time signatures. A 5/8 time signature, for example, is usually understood as the sum of two simple meters 3/8 + 2/8 or 2/8 + 3/8. Beat hierarchy in irregular meters, just like in regular meters, is either simple (diving in two equal parts) or compound (diving in three equal parts). The time signature of 15/16, however, corresponds to the compound meter relative of 5/8. Compound meters include only those time signatures whose numerator is a multiple of three (figure 6).
Used frequently by different folk traditions across the globe, the use of asymmetrical meters is often associated as a stylistic trait of Balkan music, in Southeast Europe. In classical music asymmetrical meters are used sporadically before the twentieth century. The second movement of Tchaikovsky's Sixth Symphony (1891-93) is commonly referenced as one of the first examples of orchestral music written entirely in an asymmetrical meter (5/4).
Irregular meter can be seen represented in different ways. Hungarian composer Bela Bartok (1841-1945), for instance, wrote Six Dances in Bulgarian Rhythm using time signatures, exposing the respective addends, such as, 4+2+3/8, 2+2+3/8, 3+2+3/8 (also called a 4/4 unevenly grouped), 2+2+2+3/8.