Music Theory of African Polyrhythms. Music Essay Example
Imagine playing two pieces of music at the same time that have nothing in common. It is a nearly impossible feat that might only be accomplished by the most experienced musicians and classically trained performers. However, in African music, there are often several contrasting rhythms that are being played at the same time. African rhythms are a complex set of interlocking and contrasting components that combine together to form a layered and musically deep piece. These pieces combine together to form a complex rhythm that is somehow with structure and a timed context, but without timing in the typical western sense.
In the western sphere of music, you will always feel a steady pulse. This pulse defines almost every part of the music: The feel, the tempo, the speed, etc.. There is a similar concept in the African sphere of music which is called the Elementary pulse. The elementary pulse is the invisible steady beat that all performers feel and base their performance and timing off of. This pulse will repeat after a set interval. That is to say, a continuous set of pulses that will always have the same timing in between each pulse.
These pulses are repeated ad infinitum. In African music, the elementary pulse is the smallest unit of time. This means that there is no measurement that holds a shorter interval. You may split this pulse into smaller units of 2 value, but it will only count as part of a pulse and not anything else. Similar to the tempo in western music, you will build all higher concepts of rhythm and timing off of this one concept. The elementary pulse creates the basic structure and outline for a song so that all performers are synced and on the same time scale.
Because each performer is keeping their timings with the music on the level of the elementary pulse, there is no way to keep time in between pulses. The space in between pulses effectively becomes a lull where no activity is taking place. While it would be possible to play in between pulses, it is not a very common feat. What would typically happen would be that a performer would speed up the elementary pulse to some multiple of what its previous value was in an effort to place the offbeat pulse onto a new faster beat. For example, if there was a pulse some distance in between the two pulses (for example 12) of the way in between two pulses, the performer would multiply the speed of the elementary pulses by the inverse (for the example’s case: (12)-1or 2) of the smaller distance to get the adjusted speed of the elementary pulses.
To restate: The elementary pulses can be split, but the speed of the pulses will typically be adjusted in order for the pulse to match. When several consecutive elementary pulses are combined, what is created is called a cycle (See image). Cycles are groupings of several pulses that are used to organize the structure and create a repeating pattern. As the name implies, there is a cyclic nature to the cycles. As such, the cycles are meant to be repeated ad infinitum to create a base layer for the higher level performers to play off of. The typical grouping of cycles uses a number that has several common factors. For example, 24 elementary pulses forming a cycle may be split into 12 groups of 2 pulses, 2 groups of 12 pulses, 6 groups of 4 pulses, 4 groups of 6 pulses, 3 groups of 8 pulses, and 8 groups of 3 pulses. This is important for a concept called polyrhythms.
Polyrhythms, according to the Merriam Webster dictionary, are “the simultaneous combination of contrasting rhythms in music”. This, when broken down, means that you have multiple rhythms going on in the same piece of music where the rhythms have a differing number of equal-spaced beats occurring within the same time frame. For example, in a non-polyrhythmic piece, during one cycle of 24 elementary pulses, you may have one beat occurring every 6 elementary pulses. This beat will occur 4 times for every one cycle giving a ratio of ¼. You may also have one pulse occurring every 3 elementary pulses. This beat will occur 8 times for every one cycle. Giving a ratio of ⅛.
The ratio ¼ is able to be reached by multiplying by a whole integer. (In this case 2). Because the first rhythm is able to be reached by multiplying the second rhythm by a whole integer, it is considered non-polyrhythmic. In a contrasting case, the rhythms occurring every 4 beats and every 6 beats are polyrhythmic. The one occurring every 4 beats will occur 6 times in a single cycle. The one occurring every 6 beats will occur every 4 times. This gives the two ratios of ¼ and ⅙. To reach ¼ from ½ you must multiply by 1614which is 1.5. Because this is not a whole integer, it is a polyrhythm. To restate, a polyrhythm is any set of at least two rhythms where one rate of beats per cycle is not divisible by the other.
All of the previously discussed elements may combine together in order to create a deep and complex song structure that will allow for a very expressive and complex polyrhythmic nature. Applying this into the real world, one can create a drum line in which the cycle contains 12 elementary pulses, and there is one line occurring every 4 pulses and one line occurring every 3 pulses. This creates the pattern shown below where x represents a beat and • represents a rest.
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This is what a polyrhythmic pattern will look like. As you can see, the two patterns only line up on the first beat, and after that, they are two separate patterns that have no point where they both meet.
A real-life example of this would the rhythm sometimes referred to as the ‘What Atrocious Weather” rhythm because the rhythm of the name follows the rhythm. This rhythm is the same as in the diagram above. It is written in standard musical notation to the right. This common rhythm is often used because of its simplicity, and its communicability.
In conclusion, the seemingly basic drum lines of African Music are more complex and deep than they appear. From the most basic elementary pulse to the most complex polyrhythms, each component serves its purpose and is used to create a beautiful piece. All of these components have been developed through thousands of years to create several meshing parts. And according to The Encyclopedia of Africa: South of the Sahara, it is still not fully deciphered and understood. Africa is the home and origin of polyrhythms and they will forever be a complex but beautiful element.
Bibliography
Arnold, Denis, and Percy A. Scholes. 2000. The New Oxford Companion to Music. Oxford: Oxford University Press.
Arom, Simha. 2004. African Polyphony and Polyrhythm: Musical Structure and Methodology. Cambridge: Cambridge University Press.
Kubik, Gerhard, and Donald Keith Robotham. “African Music.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 8 Apr. 2016, www.britannica.com/art/African-music/Musical-structure. Accessed 26 Apr. 2019.
Middleton, John. 1997. Encyclopedia of Africa South of the Sahara. New York: Scribner.
“Polyrhythm.” n.d. Merriam-Webster. Merriam-Webster. Accessed May 10, 2019. https://www.merriam-webster.com/dictionary/polyrhythm.
Tarquin. 2003. Music Cross-Rhythm, What Atrocious Weather. Wikipedia Commons. Wikipedia. https://en.wikipedia.org/wiki/File:Music_cross-rhythm,_what_atrocious_weather.PNG#filelinks.
