Page 251 - DENG504_LINGUISTICS

Unit 18: Rhythm

Notes

"In music, the rhythm is usually produced by making certain notes in a sequence
stand out from others by being louder or longer or higher. . . . In speech, we find
that syllables take the place of musical notes or beats, and in many languages the
stressed syllables determine the rhythm. . . .

Alternation and repetition
Rhythm is marked by the regulated succession of opposite elements, the dynamics of the strong
and weak beat, the played beat and the inaudible but implied rest beat, the long and short note. As
well as perceiving rhythm we must be able to anticipate it. This depends upon repetition of a
pattern that is short enough to memorize.
The alternation of the strong and weak beat is fundamental to the ancient language of poetry,
dance and music. The common poetic term "foot" refers, as in dance, to the lifting and tapping of
the foot in time. In a similar way musicians speak of an upbeat and a downbeat and of the "on"
and "off" beat. These contrasts naturally facilitate a dual hierarchy of rhythm and depend upon
repeating patterns of duration, accent and rest forming a "pulse-group" that corresponds to the
poetic foot. Normally such pulse-groups are defined by taking the most accented beat as the first
and counting the pulses until the next accent. A rhythm that accents another beat and de-emphasises
the down beat as established or assumed from the melody or from a preceding rhythm is called
syncopated rhythm.
Normally, even the most complex of meters may be broken down into a chain of duple and triple
pulses either by addition or division. According to Pierre Boulez, beat structures beyond four, in
western music, are "simply not natural". Western rhythms are usually arranged with respect to a
time signature, partially signifying a meter usually corresponding to measure length and grouped
into either two or three beats, which are called duple meter and triple meter, respectively. If the
beats are in consistently even or odd groups of two, three, or four, it is simple meter, if by
admixtures of two and three it is compound meter. In other systems of music such as Indian
classical music rhythms may be grouped into various number of beats. In some music styles such
as Yakshagana even group rhythms into fractional beats.
Tempo and duration
The tempo of the piece is the speed or frequency of the tactus, a measure of how quickly the beat
flows. This is often measured in 'beats per minute' (bpm): 60 bpm means a speed of one beat per
second, a frequency of 1 Hz. A rhythmic unit is a durational pattern that has a period equivalent
to a pulse or several pulses. The duration of any such unit is inversely related to its tempo.
Musical sound may be analyzed on five different time scales, which Moravscik has arranged in
order of increasing duration;:
1. Supershort: a single cycle of an audible wave, approximately 1/30-1/10,000 second (30-10,000
Hz or more than 1,800 bpm). These, though rhythmic in nature, are not perceived as separate
events but as continuous musical pitch.
2. Short: of the order of one second (1 Hz, 60bpm, 10-100,000 audio cycles). Musical tempo is
generally specified in the range 40 to 240 beats per minute. A continuous pulse cannot be
perceived as a musical beat if it is faster than 8-10 per second (8-10 Hz, 480-600 bpm) or slower
than 1 per 1.5 - 2 seconds (0.6-0.5 Hz, 40-30 bpm). Too fast a beat becomes a drone, too slow a
succession of sounds seems unconnected. This time-frame roughly corresponds to the human
heart rate and to the duration of a single step, syllable or rhythmic gesture.
3. Medium:? few seconds, This median durational level "defines rhythm in music" as it allows the
definition of a rhythmic unit, the arrangement of an entire sequence of accented, unaccented

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