Sunday, January 2, 2011

Introduction to Polyrhythms

Polyrhythm is a very misunderstood musical phrase for the Indian film music listener. Lots of things do get passed on as polyrhythms during discussion. Here is a text book definition:

"Polyrhythm is the systematic exploitation of different rhythms performed simultaneously"

Doesn’t help much isn’t it? Two sets of phrases are worth noting from this text book defition: “Different rhythms” and “simultaneously”. Just throw a whole bunch of rhythms simultaneously in a track and you have polyrhythms – very convenient definition. The trouble is with the other phrase: “systematic exploitation”. Everything gets complicated when you start defining rules for systematic exploitation. These rules help one tell whether a particular track has true polyrhythm designed into it or not. Before we get a little deeper into the rules, let’s get a little bit more historic perspective.

Polyrhythm is a non-Western concept, originating from Africa and Latin America. Other musical systems have taken advantage of this wonderful innovation in many situations.  Polyrhythms got imported into the Western world through Jazz music. Jazz music originated in New Orleans, US, and was pioneered by Afro Americans, who brought with them century old traditions passed on by generations. One such contribution was the introduction of polyrhythms into Jazz music, which later got adopted into Rock and Roll and mainstream pop culture.

Most Indian music composers have been quick in taking advantage of simple polyrhythms. Most Bollywood music today (2010) take advantage of electronic drum machines, synth pads and so on and they are characterized by simple polyrhythms where one of the rhythm pattern is an unmistakable bhangra beat emerging out of a synthpad. But for a few exceptions, most dance music from Bollywood can be categorized this way. Technically, most of these tracks may not meet the academic criteria for polyrhythms. However, the difficulty is that the academic definition of polyrhythms can be complicated to understand as well as apply.

As mentioned, there are very strict theoretical definitions for poly rhythms from a musicology standpoint which we will not dive too deep. There is no universally accepted definition on what defines a polyrhythm. We have to unfortunately settle with the least common denominator. However, in order to appreciate polyrhythms and Raja, let’s focus on the simplicity of this musical idea. A polyrhythm is, simply, more than one rhythm happening at once. For example…

  1. When you get together with your friends to jam, each playing what you feel like, you create a polyrhythm.
  2. When you tap your foot while you play your drum, you create a polyrhythm.
  3. When you play along to a CD with drumming on it, you create a polyrhythm (unless you play the exact same rhythm as the drummer on the CD). When you count out loud as you play, you create a polyrhythm.
(Courtesy: Drums for Dummies)

There is a perception that African drumming (the origin of polyrhythms) is highly complex and that it takes years of study and practice to play such intricate rhythms. Not true. African drumming sounds difficult because, taken as a whole, a lot is going on, but taken individually, the parts are often very simple. The difficulty lies in being able to keep your rhythm steady while the other instruments around you play opposing rhythms.

The meter is the standard unit of time that divides Western music. In most symphonies or ensembles, all instruments basically follow the same meter; the shared rhythm is counted evenly and stressed on every main beat. We thus call Western rhythm divisive because it is divided into standard units of time. But the traditional rhythms of African music are considered additive, a term which already gives us an indication of their fundamental multiplicity. The music's complex percussive patterns bubble up from the shifting and open-ended interaction between many different individual drum patterns and pitches.

Time for an example: Fanga, a West African rhythm, uses four instruments: the bell, a set of two djun djuns (one person can play both the bell and the djun djuns), and two djembes. The djun djuns (also spelled jun jun or doun doun and pronounced either way) are natives of West Africa and consist of three drums. The djembe (also spelled jembe — either way it’s pronounced jem-bay) is a goblet-shaped African drum that is the staple of every drum circle. With its unabashedly tribal look, loud expressive sound, and ease of playing, the djembe has become one of the most popular drums around. Let’s hear the Fanga poly rhythm where the djembe plays the lead or the ‘call’. The Djun Djun and the bell play the ‘response’ and does it on a different time.

As mentioned before, the polyrhythm tradition is quite prevalent in the Latin American world. Examples include Cuban Bolero, with ballad style of music, or the fast paced Mambo. Further South, Brazilian Bossa Nova or the fast paced Samba music.

Indian music, both Carnatic and Hindustani are rich in rhythms. The timing examples from deep classical rhythms from both these systems put 'math rock' to shame. However, polyrhythm as an idea is rarely associated with Indian classical or folk music.

If you find this description very technical, do not worry. Most Indians already know polyrhythms without really knowing any such definition. I am sure you are familiar with the Dandiya dance that is very popular in Gujarat (in Western India) and this has now become a fashion in many urban parts of India during the autumn festival of Navarathri. If you carefully observe the pattern of how the dancers pat their sticks to their foot pattern, you have polyrhythm!

Here is a great and elaborate example of polyrhythm and other related topics provided by Jerry Leake on youtube. It is interesting that Jerry uses the Indian jathi to explain the concept:

Here is Jerry's video...

Jerry Leake continues...

Jerry continues...

Jerry’s explanation is a result of a huge research effort and I am sure you would get the idea of how polyrhythm works in general.

A shorter version is available in another video where you are given a summary of how poly rhythm works.

While not all experiments qualify as polyrhythms, let’s explore Raja’s rhythmic experiments – wherever they are polyrhythmic, we will highlight them. As this is a relatively new topic in Indian film music, some of our current views may change in the future. Based on a systematic application of these principles and other rhythmic work that Raja has done, we will try and grade the tracks in increasing order of complexity from a polyrhythmic viewpoint. It is unclear if Indian music composers have composed music with polyrhythms in mind. That’s a question only composers such as Raja can answer. These categorizations are entirely based on my perception of the rhythms used – it could be deliberate or accidental or entirely wrong. Some of the advances with drumming machines and synthpads have made polyrhythm creation very simple as the machines take care of the timing when one sets them on these machines or use the pre-built patches.

One thing that must be clear is what is not a polyrhythm. Just because, a composer uses a drum kit and a tabla in a track, it does not qualify to be a polyrhythm. Nor does tracks such as 'Ghanashyama' from Kochu Kochu Sandhoshangal, where Raja uses alternating rhythms.

Our journey with Raja’s rhythm innovation continues from the mono rhythm stages… We left off at rhythm innovation stage 14...

PS: For those who are interested in an academic definition of what a polyrhythm strictly is:

In order to identify polyrhythmic patterns, three rules are very helpful:

First rule:

To qualify as a poly rhythm, the contributing rhythms should be chosen such that the numbers denoting their rhythmic relation, are relatively prime to each other.

Second rule:

If the sum of two (or more) simultaneously sounding rhythms results in a subdivision of the beat that is not present in either of the constituting rhythms, we call this resultant rhythm poly rhythmic.

Third rule:

Two different rhythmic patterns do not result in a poly rhythm (when played simultaneously), when one of those rhythms can be contained in the subdivision of the beat that is implied by the other rhythm.

One major point to think about is that to qualify as a poly rhythm, the two constituting rhythms should be clearly heard and felt as separate rhythms, each with their own properties!

To be a poly rhythm, two rhythms (at least!) are needed to form this poly rhythm, and these two rhythms:

1. should be based on relatively prime subdivisions

2. should be clearly distinct from one another

Both conditions have to be met at the same time! Let’s look at prime numbers within 12 for example purposes: 2 3 5 7 11. In other words, if you have the following combinations being played simultaneously, you have polyrhythmic arrangement:

• A 2/4 simultaneously with a 3/4 (need to look at March songs).

• A 3/4 arrangement simulataneously with a 5/8 arrangement – Waltz with Kanda chapu.

• A 5/8 (kanda chapu) arrangement simulataneously with a 7/8 (misra chapu) arrangement – misra chapu with kanda chapu.

• A 3/4 arrangement simulataneously with a 7/8 arrangement – Waltz with Misra chapu.

I have no plans of doing a PhD on this. Let's enjoy Raja's music in simple terms. I am sure, you can appreciate, why I chose to stick to a simple least common denominator approach for identifying polyrhythms. Two rhythms being played simultaneously. Forget all those prime number constraints!