Free rhythm

Audio: free rhythm (0:06)

free rhythm plays free rhythm. There are three parts to the rhythm and the free rhythm figure shows the composite waveform:

1. Twenty beats played as a double stroke open roll on a snare drum.
2. Twelve beats played at random on the cowbell, short guiro and high wood block.
3. Four beats played on the crash cymbal, high floor tom, ride cymbal and bass drum respectively.

Free rhythm has no discernible rhythm, it is unmetered rhythm with a variable tempo.

It is an interesting task, to put it mildly, to write about writing free rhythm. First, there is the practical issue of trying to notate something which is intrinsically free and has no structure. Second, there is a profusion of words used to describe freedom in music, such as indeterminacy, aleatory, stochastic, and agogic. Third, there is a distinction between freedom in composition and freedom in performance. Fourth, it little matters what a music writer may or may not plan to do in free rhythm, some listeners are apophenic and will discern a pattern where there is none.

The rhythms in free rhythm are a mixture of random data and structured patterns.

A computer programme was used to generate random data. This determined the instrumentation, the number of beats, the timing of a beat, and whether a beat was accented or not.

The rhythm pattern in each of the three sections is structured as follows:

1. In part one the relative duration of the twenty beats is 20, 19, 18 down to 3, 2, 1. This creates the sound of an exponential drum roll. The rhythm lasts exactly 1146ms.
2. In part two a beat was assigned a random duration in the range 50-250ms and a 25% probability of being accented. Each beat was assigned to one of four instruments chosen at random from the GM2 standard drum kit. Interestingly, the computer, in its wisdom, selected the mute cuica as one of the four instruments, but did not assign any beats to it. Consequently, only the cowbell, short guiro and high wood block appear in the output. The rhythm lasts exactly 1854ms.
3. In part three, each of the four unaccented beats is assigned to a different instrument chosen at random again from the GM2 standard drum kit. The relative duration of the four beats is in the ratio 1:2:3:4 and lasts exactly 3 seconds.

free rhythm has a pattern. A most definite one, in fact, but not one you might expect, it is based on the golden ratio.

The golden ratio or golden mean is a ratio between two quantities, a and b, such that the ratio, b/a, is the same as the ratio, (a+b)/b. The golden mean is an irrational number, approximately equal to 1.618, correct to three decimal places. This proportion is said to be pleasing and it crops up all over the place in nature, in art, in architecture and, occasionally, in music.

The golden ratio is used to determine the duration of each of the three parts in free rhythm. The first part is 1146ms long and the second is 1854ms, and the ratio 1854:1146 is 1.168, the golden ratio. Similarly, the third part, which is 3000ms long, forms the ratio 3000:1854 with the second part, which again is equal to the golden ratio. All three parts add up to a nice round figure of six seconds.

Whether the end result is pleasing or not, well, over to you.