Anatomy of Rhythm

Okay. Before we get started, it bears mentioning that if you haven’t been exposed to this material before, there is much to cover.  You may want to return to this regularly to refresh your  awareness. It also bears mentioning that the material here is a summary of years of study of different musics from around the world. Typically in the west, there is a certain understanding of what terms we use when talking about the rhythmic aspects of music. I have borrowed liberally from these terms, but I am not presenting the strictly western concept of rhythm. Instead, here you will find a distillate of common features of virtually any (metronomic) rhythmic tradition. Finally, it is important to know that the theory of music doesn’t sound like anything. It is a map – and just as a recipe for beef stew doesn’t have any particular flavor (though the stew itself does!) a map (or more precisely, the tools for map making) does not have any particular sound. From this we can conclude that sound is the authority; the map is only good so long as it can be used to create/replicate the music it is supposed to describe. If it fails to do so, the map – or map-system may require revision.

Music, and more specifically, rhythm, assumes periodicity – repetition – a specific event or context that is predictable in a specific time period. Of all of the possible sounds that could happen in a moment (the meow of a cat, jet airplane engines, cowbells, the flow of water over stones), a subset is selected – usually sounds from musical instruments, and often a subset of the available sounds of the instrument (7 notes of the available 12 in a typical scale). The sounds selected – and the time periods in which those sounds take place – serve as the pallet we use to paint on our canvas of silence.

Predictability is a crucial component of what makes music musical. The flow of music at a microcosmic and macrocosmic scale is based on tension and resolution. Tension and resolution refer to musical content’s feeling. Resolution can be thought of as the foundation or ground of the music. Tension is the flow of musical ideas that depart from the ground.

Pulse and Meter

The foundation of musical rhythm is pulse.

Pulse is modified by tempo which refers to the number of pulses per a specific time period – for example a minute.  Tempo is usually described in beats (pulses) per minute (BPM)
[audio:RP-pulse_80bpm.mp3|loop=yes]
Listen to the audio clip of a pulse at 80 Beats per Minute
[audio:RP-pulse_100BPM-1.mp3|loop=yes]

Listen to the clip of a pulse at 100 Beats per Minute. Notice that the pulses happen more closely together.

Once a pulse is established, the structure of rhythm is of comprised of multiples of pulses and divisions of pulses.

Multiples of pulses are used to form a measure.

[audio:RP-pulse_with_one-2.mp3|loop=yes]
1 2 3 4
X X X X

(play a measure of 5)

1 2 3 4 5
X X X X X
[audio:RP-pulse_measure_of_5_beats-1.mp3|loop=yes]

Listen to the audio clip of a bass note every 5 pulses. This produces a measure of 5 beats.

Divisions of pulses are used to establish available common note density or pulse subdivision. Note density or pulse subdivision can be thought of as the smallest common or predominant unit of time. In other words, how many notes are commonly available in the music between pulses.

1 & 2 & 3 & 4 & 5 &
X . X . X . X . X .
[audio:RP-pulse_measure_of_5_beats_2_pulse_subdiv-2.mp3|loop=yes]

Listen to the clip of a 5 beat measure with a pulse subdivision of 2.

1 e & a 2 e & a 3 e & a 4 e & a
X . . . X . . . X . . . X . . .
[audio:RP-pulse_with_one_and_up_and_2nd-4.mp3|loop=yes]

Listen to the clip of a 4 beat measure with a pulse subdivision of 4

The most common pulse subdivisions in most cultures are 2 3 and 4, though 5, 6, 7, 8, 9 and more can be found (usually in western or Indian classical music). In western terms, pulse subdivisions of any number that is not divisible by 2 are considered tuplets.

[audio:RP-pulse_with_one_and_up_and_2nd-4.mp3|loop=yes]
1 e & a 2 e & a 3 e & a 4 e & a
t t t t t t t t
T T T T
X X X X

Again, listen to the clip of a 4 beat measure with a pulse subdivision of 4.

(play a measure of 4 with a 3 note density)

1 & a 2 & a 3 & a 4 & a
X . . X . . X . . X . .
[audio:RP-4_with_3_pulse_subdiv-5.mp3|loop=yes]

Listen to the clip of a 4 beat measure with a pulse subdivision of 3. Notice that the tempo is still 100BPM but the feeling of the sound is slightly slower

Moments in a measure (Structure)

The moments in a measure, corresponding with the placement of notes and rests, hold different values in relation to tension and resolution. While each pulse subdivision is of equal length, its place in relation to the pulse and meter gives it a different tension value.

Because a 4 beat pulse subdivision is used most commonly, we will use it as a means to further describe significant moments in time.

The One: This is the beginning of the measure. Whether notes are played or rested, the One holds significance in most rhythmic systems. It usually signifies the moment when a change would occur; it is also the most common moment of resolution.

The pulse or downbeat – described above

1 e & a 2 e & a 3 e & a 4 e & a
O . . . X . . . X . . . X . . .

The upbeat: this is the pulse subdivision that bisects the pulse – notice that it produces a higher level of tension. When only the upbeat is present alongside the downbeat, sonically it sounds identical to a 2 beat subdivision.

1 e & a 2 e & a 3 e & a 4 e & a
O . T . X . T . X . T . X . T .
[audio:RP-pulse_with_one_and_up-3.mp3|loop=yes]

The secondary upbeat: These are the second and fourth pulse subdivisions – in terms of tension they typically hold similar value.

1 e & a 2 e & a 3 e & a 4 e & a
O t . t X t . t X t . t X t . t

Note that for every downbeat there is one upbeat and two secondary upbeats.

Notes

Upon this structure (which has no sound by default, it’s just a map), we place notes and rests of different lengths.  Typically those notes and rests correspond to multiples of the pulse subdivision of the measure. We think of these notes and rests as having a value of a certain length – typically a multiple of the pulse subdivision.
So in this example:

1 e & a 2 e & a
X . . T . . T .

Western Notation Values

At the foundation of western notation is the concept of the “whole note” which, rather arbitrarily is the length of 4 pulses in a measure of 4 with a 4 beat pulse subdivision (4×4 or in western notation 4/4). Most other notes are divisions of this.

200px-Whole_note_and_restWhole note = 4 pulses = 16 pulse subdivisions

200px-Half_notes_and_rest Half note = 2 pulses = 8 pulse subdivisions

200px-Quarter_notes_and_restQuarter note: = 1 pulse = 4 pulse subdivisions

200px-Eighth_notes_and_rest Eighth note: = half of a pulse = 2 pulse subdivisions

200px-Eighth_note_run Eighth note run – notice how the notes are tied together by a bar.

Sixteenth_notes_and_rest Sixteenth note = one quarter of a pulse = 1 pulse subdivision

Sixteenth_note_run

Sixteenth note run – again notice the bars tying the notes together

200px-Dotted_notes3

Dotted notes: A . represents half again the length of the note preceding it, so a dotted eighth note would equal an eighth note plus a Sixteenth note, or three Sixteenth notes.

Tuplets Tuple: This is a common way of describing something other than multiples of 2 as note valuations. The first example would be triplet quarter notes. The second would be triplet eighth notes or a 3 or 6 beat pulse subdivision and the third example would be quintuplet notes or a 5 beat pulse subdivision.

For more on the western European musical notation, especially as it pertains to drums, check out this site.

Because the notes of percussion instruments typically have a short duration, and the control of that duration is usually limited (compared to say a trumpet, or a flute), we can think of the value of notes in percussion a couple of different ways. One way to think about it is that each note holds the value of one pulse subdivision. Any pulse subdivision where a note is not expressed would be considered a rest. Like so:

Bass, rest, rest, tone, rest, rest, tone, rest

Another way to think about it is that the note length is the sum of the note and the pulse subdivisions that follow, until the next note is indicated. The above example would be expressed in this way:

3.3.2

3,3,2 or two dotted eighth notes and an eighth note or; one dotted eighth note, one sixteenth note tied to an eighth note, and an eighth note.  (The tie represents one note that is the length of the two notes together – another way to express a dotted eighth note)

Of particular importance is how the notes in this pattern (or any pattern) relate to the pulse. Notice that the first note is on the “1” – our most important moment in the time – and generally the point that possesses the most resolution. The next note is on the fourth pulse subdivision of the first pulse – the “1a”.  This is a secondary upbeat – and generally possesses the most tension. The last note before the phrase repeats is on the third pulse subdivision of the second (or last ) pulse – the “2&”.  This place in the time (the “&”) generally possesses moderate tension and so begins the return to the resolution. For a deeper exploration into how notes can be applied, please see ” Shapes of Time, Syncopation, and Clusters” and “Structure and Content”.

Summary

By having a clear understanding of the basic elements of the anatomy of rhythm, including tempo, pulse, measure/meter, pulse subdivision, and notes, you are well on your way to being able to explore music from the point of view of a rhythmatist. These concepts are fundamental to developing as a musician and composer/collaborator. You will find that the more you explore this territory (along with its interior components – see “Interior and exterior experience of music “), the more the world of music will become a source of infinite discovery, creativity, and expression. Welcome!