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Author David Luebbert
Posted 3/25/11; 12:02:35 AM
Msg# 5764 (top msg in thread)
Prev/Next 5763/5765
Reads 108996

A new Play Rhythm service and its rhythm description language

I 'm going to describe here a simple language for describing rhythms that hand drummers play. I think this language can be extended to describe any metered rhythm that is used in music.

There is a new service on SongTrellis, the Play Rhythm service that performs and notates rhythms that are described using this rhythm description language.

If you enter the Play Rhythm URL, without any additional parameter specifications, like this:

http://www.songtrellis.com/playRhythm

the service will invent a new single voice rhythm, show it's notation and perform it, with a click track marking the beat. You'll launch this form of the Play Rhythm service if you follow the Play Rhythm link that appears in the link bar at the top of most pages on SongTrellis.

The rhythm examples that are shown below all have links attached that will play the example with accompanying click track using the Play Rhythm service.

If you have comments or questions about any of this, use the following comment link.

SongTrellis Rhythm Descriptions - the simplest building blocks

A lot of rhythmic information can be captured by writing down strings of symbols consisting of the numerals 1 and 0. In this description scheme, a 1 is an instruction to make a sound and a 0 is an instruction to remain silent.

If we can assign separate one syllable word translations for 1 and 0 and then speak those translations in order, we can speak a verbal representation of a rhythm. Since we are trying to describe hand drum patterns, lets agree to say the word "hit' whenever we encounter a 1 in a rhythm symbol string and say "don't" whenever we encounter a 0 in a rhythm string,

So if we saw the rhythm description

10010101

we could verbally translate that as "hit-don't-don't-hit-don't-hit-don't-hit" Similarly when we saw

011101

we could verbally translate that as "don't-hit-hit-hit-don't-hit".

Now if you think of each word as a instruction to perform a particular action with a rhythm instrument, "hit" instructs a musician to strike a drum with your hand or a stick. "Don't' means that during the period of time that word is spoken, no action should be taken to produce sound with the instrument, leaving a gap, which musicians call a rest, in the sequence of rhythm sounds produced.

We can make these lists of rhythm symbols arbitrarily large. 0111010111011000101

would have the verbal translation "don't-hit-hit-hit-don't-hit-don't-hit-hit-hit-dont-hit-don't-don't-don't-hit-hit-don't-hit"

Yikes, we need punctuation

It's good that rhythm symbol lists can be arbitrarily large. This means that long ideas of any length can be represented by this language.

The downside: as symbol strings lengthen they become increasingly difficult to interpret accurately. Reader's eyes get lost in the middle of large strings, and are unable to keep track of the symbol that should be interpreted next.

In printed text, spaces are left between words to mark their boundaries, and punctuation marks mark the boundaries of larger units of text such as phrases and sentences. This accommodate a reader's need to deal with large ideas using right-sized smaller chunks.

There is natural punctuation - rhythms do pulse

Is there a punctuation scheme that works well for rhythms?

Fortunately yes. Nearly always, rhythms pulse. When a musician plays a succession of evenly times hits in a rhythm or notes in a melody, they will regularly emphasize hits or pitches of a sequence at measured intervals. They'll access such hits or notes by playing a sound louder or otherwise distinguishing the emphasized sound from those that come before or after.

Regular pulsation is a phenomena that humans experience second by second as they live. A person's breathing automatically demarcates the flow of their mental life every few seconds as time flows by.

When people sit extremely still or when the exercise vigorously, they frequently can experience the regular thumping of their heartbeat. If they touch a finger to their wrist or neck arteries they can measure their own pulse.

We also experience regular pulse sensations as we move about in the world. When we walk at a fixed rate of speed, our feet hit the ground at a fixed tempo, which we can hear as a bump or thud as our feet touch the ground. If we walk on a noise producing surface like gravel or leaves, we hear a small burst of sound each instants hay we step.

The pulsations we feel in rhythms and melody model our mental life and our experience of the passage of time. Musicians call those pulsations beats

The rhythms and melodies that are played by musicians model a person's mental life. A rhythm that pulses us thought to be lively and becomes memorable because the pulse boundaries allow a person to experience a rhythm as a succession of chunks.

The pulses that listeners hear in music are called beats, because when a percussion player performs a hit in a rhythm to make it pulse, they beat their instrument a little louder to make the sound that marks a pulse.

When musicians hear the sequence of beats that thread throughout a performance, they hear space between beats that they can fill with other sounds following their own imagination and taste. Within a piece of music, you'll frequently hear that the beats of the piece are uniformly subdivided by a certain pre-arranged count through the entire piece.

Rhythm hits and note beginnings always are synchronized to one of the beat subdivisions of the piece. Beats are most frequently subdivided 2, 3, 4, 6, or 8 times but any arbitrary integer subdivision count can be used by a composer or improvising musician.

In the rhythm descriptions that produce rhythms that you are most used to hearing, dashes mark the boundaries between beats and a fixed subdivision count is used for every beat of the rhythm

In our rhythm descriptions, we'll place the dash character between symbols to mark the beginnings of beats in a rhythm:

1011-0111-0101-0111 (each beat divided into four subdivisions)

or

101-110-011-111 (each beat divided into three subdivisions)

The hit following a dash is always interpreted with an accent or emphasis to demonstrate that a new beat is starting. The first symbol of string is accented to show that it marks the very first beat of the rhythm.

The textual interpretation of

1011-0111-0101-1001

would be "Hit-don't-hit-hit-Don't-hit-hit-hit-Don't-hit-don't-hit-Hit-don't-don't-hit"

The textual interpretation of

101-110-011-111

would be "Hit-don't-hit-Hit-hit-don't-Don't-hit-hit-Hit-hit-hit"

The pulse marked hit and don't syllables would be spoken a little louder to mark the presence of the beat in that rhythm interpretation.

Performing musicians would anticipate that any other instruments that sound during the accented beat subdivisions would be played with a slight accent or a little louder on emphasized hits or rests.

Rhythm patterns repeat

You have a choice when you see this kind of notation, you can interpret the list of sounds encoded by the pattern string and stop after interpreting it once or, more often, you can loop the pattern by jumping back to it's beginning and repeatedly running it over and over in your mind, repeating it verbally, or repeating it in actual performance.

So verbally looping

0110 would cause you to speak the words

Don't-hit-hit-don't-Don't-hit-hit-don't-Don't-hit-hit-don't-Don't-hit-hit-don't

If 1011-0111-0101-0111 were looped,

each repetition of the pattern would mark out a repeating cycle of four distinguished beats like this:

Hit-don't-hit-hit-Don't-hit-hit-hit-Don't-hit-don't-hit-Don't-hit-hit-hit-Hit-don't-hit-hit-Don't-hit-hit-hit-Don't-hit-don't-hit-Don't-hit-hit-hit-Hit-don't-hit-hit-Don't-hit-hit-hit-Don't-hit-don't-hit-Don't-hit-hit-hit...

Frequently, any sounds that synchronize with the first instant of a rhythm cycle would be accented more strongly than any of the other beat counts with the cycle.

The number of subdivisions played within beats can vary from beat to beat

For example, we can have beats in a rhythm that all divide differently, like this:

11-101-1111-11011-101101-1001111-11111111

which plays one additional subdivision in each beat. The increasing subdivision sequence here is 2,3,4,5,6,7 and 8, which gives an impression of an ever accelerating sequence of hits in the rhythm, until it restarts.

When this kind of scheme is used, the beats of the rhythm fall in fixed tempo as always, but the beat subdivisions can vary, leading to the sensation of a rhythm speeding or slowing momentarily for particular beats. A musician's time sense has to be more finely developed to accurately perform these kinds of rhythms.

To verbally perform this rhythm, a musician would still follow the sequence of hits and rests that is notated but would speed or slow the tempo at each subdivision change to ensure that the first sound of each beat grouping is played precisely on the beat, and that the subdivisions occur at the correct evenly spaced intervals with the beat.

Polyrhythms

When polyrhythms are played, rhythm sequences that count their beat at different tempos are played at the same time. The sequences all begin with a synchronized beat that serves as the 1 beat for each pattern, but then diverge at different speeds until they reconverge when they all return to their common 1 count.

If you have a rhythm that plays over a certain count of beats like this four beat pattern, which clicks along with each click of the accompanying click track:

1111

you can ask the Play Rhythm service to stretch it to play over a different number of beats by bracketing the entire pattern with square brackets, and writing an integer number that is different than the pattern's beat count in front of the left square bracket, like this:

3[1111]

or like this

7[1111]

Polyrhythms that play only over certain beats of a pattern

You can add specifications for beats in front or in back of a polyrhythm specification. For instance adding a beat in from of and in back of the three beat pattern

3[1111]

we can create the five beat pattern

1111-3[1111]-1111

where a polyrhythm is experienced on beats 2, 3, and 4 as the background click track is performed.

Subdividing a single hit inside of a beat

In a busy rhythm, we might want to play several hits within the time of a single hit of the outer pattern.

We can create this effect by replacing a single hit (a 1 or 0 symbol) with a square bracketed pattern of hits, like this:

10[1011]1-1[110]10

This plays a sequence of the four hits 1011 during the time of the third hit of beat 1, and plays the triplet 110 during the time of the second hit of beat 2.

We can play a sequence of hits over the time of a certain number of hits in the outer pattern - polyrhythms over beat subdivisions

If we place an underscore character and an integer in front of a bracketed pattern that takes the place in the time of a single hit, we can stretch the bracketed pattern so that it plays over the time of several hits, like this

10_3[1011]1-1_2[110]10

This causes the first beat to be subdivided into six hits with the pattern 1011 played over the time of hits 3,4, and 5, and causes the second beat to be subdivided into five subdivisions, with the pattern 110 played over the time of subdivisions 2 and 3.

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Last update: Friday, March 25, 2011 at 12:47 AM.