There are two methods of creating interference rhythms. Two sources of pulse are required in both methods. For example 3:2 means a pulse travelling at frequency 3 units of time (eg. seconds) synchronized with a pulse travelling at frequency 2 units of time. Notice that the numbers in the ratio are only commonly divisible by 1 and are unequal.
METHOD 1
Example of (3 2) interference rhythm.
(* 3 2) (1) (1) (1) (1) (1) (1) ; total length
2 (3) = (1 1 1) (1 1 1) ;=> (3 3)
3 (2) = (1 1) (1 1) (1 1) ;=> (2 2 2)
result = (1 1) (1) (1) (1 1) ;=> (2 1 1 2)
In the above diagram the length of the rhythm is determined by the product of the two pulses (3*2=6). The two pulses (3 2) begin and end together forming a cycle.
All rhythms generated by this method are repetitive. Each complete cycle is symmetrical around its centre (2 1 1 2). Schillinger suggests that symmetrical rhythms have important musical qualities: economy, since one half generates the other, balance due to the mirror symmetry and a quality Schillinger refers to as contrast, the difference between successive numbers. In Figure 2.2, the contrast between the numbers is 2-1=1. The greater the difference between numbers the greater the contrast.
