February 24, 2010

Rhythm Science

For years I’ve been interested in what makes some rhythmic patterns more compelling than others. Certain beats and certain clave patterns have the power to entrance listeners or at least sustain a rhythmic texture for minutes. These rhythms tend share a number of mathematical characteristics, and the computer scientist Godfried Toussaint has done fascinating work in investigating these characteristics. His work becomes particularly interesting when read alongside the work of musicologists and percussionists like Simha Arom and David Locke. Locke argues persuasively in his book Drum Gahu that one of the defining characteristics of the Gahu bell pattern is metrical ambiguity–specifically, the property that almost any strike in the Gahu bell pattern could function as the downbeat. The ambiguous metrical foundation laid by the bell allows other instruments to influence subtly how the listener perceives the meter. My speculative thinking is that the ambiguity of the pattern is what keeps it interesting. Players in the ensemble can flip the listener’s metrical orientation with subtle accents, and the attentive listener can even perform a Gestalt flip on his own by deliberately trying to hear a particular bell stroke as the downbeat.

A couple years ago I tried to pivot off of Toussaint’s research to quantify metrical ambiguity. The resulting paper is here. This research, believe it or not, has actually influenced how I improvise. With Jazari, I usually try to have at least one instrument play a metrically ambiguous pattern–which isn’t to say that I’m doing the equations in my head. Rather, once you’ve researched metrically ambiguous rhythms, you get a sense for how they feel, and it’s this feel that I go after.


Comments (1)


April 17th, 2010 at 1:46 am    

No matter what others say, I think it is still interesting and useful maybe necessary to improve some minor things

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