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Rhythm (from Ancient Greek ῥυθμός, rhythmos, "any regular recurring motion, symmetry") generally means a "motion marked by the regulated succession of strong and weak elements, or of opposite or different conditions". This general meaning of regular recurrence or pattern in time can apply to a wide variety of cyclical natural phenomena having a Frequency or frequency of anything from microseconds to several seconds (as with the riff in a rock music song); to several minutes or hours, or, at the most extreme, even over many years.
The Oxford English Dictionary defines rhythm as "The measured flow of words or phrases in verse, forming various patterns of sound as determined by the relation of long and short or stressed and unstressed syllables in a metrical foot or line; an instance of this".
Rhythm is related to and distinguished from pulse, meter, and beats:
In the performance arts, rhythm is the timing of events on a human scale; of music that occur over time, of the steps of a dance, or the meter of spoken language and poetry. In some performing arts, such as hip hop music, the rhythmic delivery of the lyrics is one of the most important elements of the style. Rhythm may also refer to visual presentation, as "timed movement through space" and a common language of pattern unites rhythm with geometry. For example, architecture can speak of the rhythm of a building, referring to patterns in the spacing of windows, columns, and other elements of the façade. Rhythm and meter have become an important area of research among music scholars. Recent work in these areas includes books by Maury Yeston, Fred Lerdahl, Ray Jackendoff, Godfried Toussaint, William Rothstein, Joel Lester, Guerino Mazzola, and Steffen Krebber.
Some types of parrots can know rhythm. Neurologist Oliver Sacks states that and other animals show no similar appreciation of rhythm yet posits that human affinity for rhythm is fundamental, so that a person's sense of rhythm cannot be lost (e.g. by stroke). "There is not a single report of an animal being trained to tap, peck, or move in synchrony with an auditory beat",, cited in Sacks write, "No doubt many pet lovers will dispute this notion, and indeed many animals, from the horses of the Spanish Riding School of Vienna to performing circus animals appear to 'dance' to music. It is not clear whether they are doing so or are responding to subtle visual or tactile cues from the humans around them." Human rhythmic arts are possibly to some extent rooted in courtship ritual.
The establishment of a basic beat requires the perception of a regular sequence of distinct short-duration pulses and, as a subjective perception of loudness is relative to background noise levels, a pulse must decay to silence before the next occurs if it is to be really distinct. For this reason, the fast-transient sounds of percussion instruments lend themselves to the definition of rhythm. Musical cultures that rely upon such instruments may develop multi-layered polyrhythm and simultaneous rhythms in more than one time signature, called polymeter. Such are the cross-rhythms of Sub-Saharan Africa and the Kotekan rhythms of the gamelan.
For information on rhythm in Indian music see Tala (music). For other Asian approaches to rhythm see Rhythm in Persian music, Rhythm in Arabic music and Usul—Rhythm in Turkish music and Dumbek rhythms.
A rhythmic gesture is any durational pattern that, in contrast to the rhythmic unit, does not occupy a period of time equivalent to a pulse or pulses on an underlying metric level. It may be described according to its beginning and ending or by the rhythmic units it contains. Rhythms that begin on a strong pulse are thetic, those beginning on a weak pulse are anacrustic and those beginning after a rest or tied-over note are called initial rest. Endings on a strong pulse are strong, on a weak pulse, weak and those that end on a strong or weak upbeat are upbeat.
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 on 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 downbeat as established or assumed from the melody or from a preceding rhythm is called Syncopation 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".
Musical sound may be analyzed on five different time scales, which Moravscik has arranged in order of increasing duration.
Curtis Roads takes a wider view by distinguishing nine-time scales, this time in order of decreasing duration. The first two, the Infinity and the supra musical, encompass natural periodicities of months, years, decades, centuries, and greater, while the last three, the sample and subsample, which take account of digital and electronic rates "too brief to be properly recorded or perceived", measured in millionths of seconds (), and finally the infinitesimal or infinitely brief, are again in the extra-musical domain. Roads' Macro level, encompassing "overall musical architecture or musical form" roughly corresponds to Moravcsik's "very long" division while his Meso level, the level of "divisions of form" including movements, sections, phrases taking seconds or minutes, is likewise similar to Moravcsik's "long" category. Roads' Sound object: and
(2026). 9780262182157, MIT Press. ISBN 9780262182157 "a basic unit of musical structure" and a generalization of note (Iannis Xenakis mini structural time scale); fraction of a second to several seconds, and his Microsound (see granular synthesis) down to the threshold of audible perception; thousandths to millionths of seconds, are similarly comparable to Moravcsik's "short" and "supershort" levels of duration.
This rhythm is perceived as it is, rather than as the first three events repeated at a double tempo (denoted as R012 = repeat from 0, one time, twice faster):
However, the motive with this rhythm in the Moussorgsky's piece
is rather perceived as a repeat
This context-dependent perception of rhythm is explained by the principle of correlative perception, according to which data are perceived in the simplest way. From Kolmogorov's complexity theory, this means a representation of the data that minimizes the amount of memory.
The example considered suggests two alternative representations of the same rhythm: as it is, and as the rhythm-tempo interaction – a two-level representation in terms of a generative rhythmic pattern and a "tempo curve". Table 1 displays these possibilities both with and without pitch, assuming that one duration requires one byte of information, one byte is needed for the pitch of one tone, and invoking the repeat algorithm with its parameters R012 takes four bytes. As shown in the bottom row of the table, the rhythm without pitch requires fewer bytes if it is "perceived" as it is, without repetitions and tempo leaps. On the contrary, its melodic version requires fewer bytes if the rhythm is "perceived" as being repeated at a double tempo.
| + Complexity of representation of time events | |
| !Complete coding !Coding as repeat | !Complete coding !Coding as repeat |
| ! ! R012 | ! ! R012 |
The metric structure of music includes meter, tempo and all other rhythmic aspects that produce temporal regularity against which the foreground details or durational patterns of the music are projected. The terminology of western music is notoriously imprecise in this area. MacPherson preferred to speak of "time" and "rhythmic shape", Imogen Holst of "measured rhythm".
Dance music has instantly recognizable patterns of beats built upon a characteristic tempo and measure. The Imperial Society of Teachers of Dancing defines the Tango music, for example, as to be danced in time at approximately 66 beats per minute. The basic slow step forwards or backwards, lasting for one beat, is called a "slow", so that a full "right–left" step is equal to one measure. ( See Rhythm and dance.)
The general classifications of metrical rhythm, measured rhythm, and free rhythm may be distinguished. Metrical or divisive rhythm, by far the most common in Western music calculates each time value as a multiple or fraction of the beat. Normal accents re-occur regularly providing systematical grouping (measures). Measured rhythm (additive rhythm) also calculates each time value as a multiple or fraction of a specified time unit but the accents do not recur regularly within the cycle. Free rhythm is where there is neither, such as in Christian chant, which has a basic pulse but a freer rhythm, like the rhythm of prose compared to that of verse. See Free time (music).
Finally some music, such as some graphically scored works since the 1950s and non-European music such as Honkyoku repertoire for shakuhachi, may be considered ametric. Senza misura is an Italian musical term for "without meter", meaning to play without a beat, using time to measure how long it will take to play the bar.
A composite rhythm is the durations and patterns (rhythm) produced by amalgamating all sounding parts of a musical texture. In music of the common practice period, the composite rhythm usually confirms the meter, often in metric or even-note patterns identical to the pulse on a specific metric level. White defines composite rhythm as, "the resultant overall rhythmic articulation among all the voices of a counterpoint texture". This concept was concurrently defined as "attack point rhythm" by Maury Yeston in 1976 as "the extreme rhythmic foreground of a composition – the absolute surface of articulated movement".
John Miller has argued that West African music is based on the tension between rhythms, created by the simultaneous sounding of two or more different rhythms, generally one dominant rhythm interacting with one or more independent competing rhythms. These often oppose or complement each other and the dominant rhythm. Moral values underpin a musical system based on repetition of relatively simple patterns that meet at distant Cross-beat intervals and on call-and-response form. Collective utterances such as proverbs or lineages appear either in phrases translated into "drum talk" or in the words of songs. People expect musicians to stimulate participation by reacting to people dancing. Appreciation of musicians is related to the effectiveness of their upholding community values.
Narmour, cited in describes three categories of prosodic rules that create rhythmic successions that are additive (same duration repeated), cumulative (short-long), or countercumulative (long-short). Cumulation is associated with closure or relaxation, countercumulation with openness or tension, while additive rhythms are open-ended and repetitive. Richard Middleton points out this method cannot account for syncopation and suggests the concept of transformation.
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