Audio: complex rhythm (0:10)
complex rhythm plays two complex rhythms in 5/4 meter. The complex rhythm figure shows the score:
A complex rhythm is one in which the number of beats is a prime number other than 2 or 3. Complex rhythm is not duple, triple or quadruple meter.
In principle, there are as many complex rhythms as there are prime numbers. In practice, most complex rhythms contain either 5 beats, quintuple meter, or 7 beats, septuple meter. The next prime number after 7 is 11 and there is probably a rhythm somewhere with 11 beats, known as undecimal meter, but who knows where.
A true complex rhythm is one in which the beats are not grouped in twos or threes but in fives or sevens. A true complex rhythm is rare, probably because a listener has difficulty perceiving a group of five or seven beats as a single unit and is more used to perceiving beats in groups of two, three or four. The first rhythm in complex rhythm is a true complex rhythm. The beat is ONE-two-three-four-five.
In practice, a complex rhythm is often played as a composite rhythm in which the beats are grouped in twos and threes. The second rhythm in complex rhythm is a composite (2+3)/4 rhythm with the beat going something like ONE-and-two-AND-one-AND-two-AND-three-AND.
There are plenty of other complex composite rhythms and, if your brain does not hurt too much after reading this stuff, you might care to peruse this list of unusual meters at your leisure.