In music, metre (Am.
Unlike rhythm, metric onsets are not necessarily sounded, but are nevertheless implied by the performer (or performers) and expected by the listener.
Western music inherited the concept of metre from poetry, where it denotes: the number of lines in a verse; the number of syllables in each line; and the arrangement of those syllables as long or short, accented or unaccented.
The first coherent system of rhythmic notation in modern Western music was based on rhythmic modes derived from the basic types of metrical unit in the quantitative meter of classical ancient Greek and Latin poetry.
The English word "measure", originally an exact or just amount of time, came to denote either a poetic rhythm, a bar of music, or else an entire melodic verse or dance involving sequences of notes, words, or movements that may last four, eight or sixteen bars.
Meter is related to and distinguished from pulse, rhythm (grouping), and beats:
The term metre is not very precisely defined.
However, Justin London has written a book about musical metre, which "involves our initial perception as well as subsequent anticipation of a series of beats that we abstract from the rhythm surface of the music as it unfolds in time".
This "perception" and "abstraction" of rhythmic bar is the foundation of human instinctive musical participation, as when we divide a series of identical clock-ticks into "tick–tock–tick–tock".
"Rhythms of recurrence" arise from the interaction of two levels of motion, the faster providing the pulse and the slower organizing the beats into repetitive groups.
In his book The Rhythms of Tonal Music, Joel Lester notes that, "[o]nce a metric hierarchy has been established, we, as listeners, will maintain that organization as long as minimal evidence is present".
"Meter may be defined as a regular, recurring pattern of strong and weak beats.
This recurring pattern of durations is identified at the beginning of a composition by a meter signature (time signature).
Although meter is generally indicated by time signatures, it is important to realize that meter is not simply a matter of notation".
A definition of musical metre requires the possibility of identifying a repeating pattern of accented pulses – a "pulse-group" — which corresponds to the foot in poetry.
Frequently a pulse-group can be identified by taking the accented beat as the first pulse in the group and counting the pulses until the next accent.
Frequently metres can be broken down into a pattern of duples and triples.
The level of musical organisation implied by musical metre includes the most elementary levels of musical form.
Metrical rhythm, measured rhythm, and free rhythm are general classes of rhythm and may be distinguished in all aspects of temporality:
- Metrical rhythm, by far the most common class in Western music, is where each time value is a multiple or fraction of a fixed unit (beat, see paragraph below), and normal accents reoccur regularly, providing systematic grouping (bars, divisive rhythm).
- Measured rhythm is where each time value is a multiple or fraction of a specified time unit but there are not regularly recurring accents (additive rhythm).
- Free rhythm is where there is neither.
Some music, including chant, has freer rhythm, like the rhythm of prose compared to that of verse.
The music term senza misura is Italian for "without metre", meaning to play without a beat, using time to bar how long it will take to play the bar.
Metric structure includes metre, tempo, and all rhythmic aspects that produce temporal regularity or structure, against which the foreground details or durational patterns of any piece of music are projected.
Metric levels may be distinguished: the beat level is the metric level at which pulses are heard as the basic time unit of the piece.
Faster levels are division levels, and slower levels are multiple levels.
A rhythmic unit is a durational pattern which occupies a period of time equivalent to a pulse or pulses on an underlying metric level.
Frequently encountered types of metre
Metre in song
See also: Musical form § Levels of organization
The concept of metre in music derives in large part from the poetic metre of song and includes not only the basic rhythm of the foot, pulse-group or figure used but also the rhythmic or formal arrangement of such figures into musical phrases (lines, couplets) and of such phrases into melodies, passages or sections (stanzas, verses) to give what calls "the time pattern of any song".
Traditional and popular songs may draw heavily upon a limited range of metres, leading to interchangeability of melodies.
Early hymnals commonly did not include musical notation but simply texts that could be sung to any tune known by the singers that had a matching metre.
This is possible because the texts share a popular basic four-line (quatrain) verse-form called ballad metre or, in hymnals, common metre, the four lines having a syllable-count of 8–6–8–6 (Hymns Ancient and Modern Revised), the rhyme-scheme usually following suit: ABAB.
There is generally a pause in the melody in a cadence at the end of the shorter lines so that the underlying musical metre is 8–8–8–8 beats, the cadences dividing this musically into two symmetrical "normal" phrases of four bars each.
Other terms for this are "additive metre" and "imperfect time".
Metre in dance music
Metre in classical music
Hypermetre is large-scale metre (as opposed to smaller-scale metre).
"Hypermeter is meter, with all its inherent characteristics, at the level where bars act as beats".
For example, the four-bar hypermeasures are the prototypical structure for country music, in and against which country songs work.
In some styles, two- and four-bar hypermetres are common.
The term was coined, together with "hypermeasures", by Edward T. , who regarded it as applying to a relatively small scale, conceiving of a still larger kind of gestural "rhythm" imparting a sense of "an extended upbeat followed by its downbeat" contends that in terms of multiple and simultaneous levels of metrical "entrainment" (evenly spaced temporal events "that we internalize and come to expect", p. 9), there is no in-principle distinction between metre and hypermetre; instead, they are the same phenomenon occurring at different levels.
- 4 4 4 4 4 4 4 4 4 4 4 8 8 8 8 It's been a hard day's night...
See also: Polyrhythm
With polymetre, the bar sizes differ, but the beat remains constant.
Since the beat is the same, the various metres eventually agree.
(Four bars of 4 = seven bars of 4).
An example is the second moment, titled "Scherzo polimetrico", of Edmund Rubbra's Second String Quartet (1951), in which a constant triplet texture holds together overlapping bars of 8, 8, and 8, and barlines rarely coincide in all four instruments.
With polyrhythm, the number of beats varies within a fixed bar length.
For example, in a 4:3 polyrhythm, one part plays 4 while the other plays 4, but the 4 beats are stretched so that three beats of 4 are played in the same time as four beats of 4.
More generally, sometimes rhythms are combined in a way that is neither tactus nor bar preserving—the beat differs and the bar size also differs.
Research into the perception of polymetre shows that listeners often either extract a composite pattern that is fitted to a metric framework, or focus on one rhythmic stream while treating others as "noise".
In the music, the two metres will meet each other after a specific number of beats.
For example, a 4 metre and 4 metre will meet after 12 beats.
In "Toads of the Short Forest" (from the album Weasels Ripped My Flesh), composer Frank Zappa explains: "At this very moment on stage we have drummer A playing in 8, drummer B playing in 4, the bass playing in 4, the organ playing in 8, the tambourine playing in 4, and the alto sax blowing his nose".
King Crimson's albums of the eighties have several songs that use polymetre of various combinations.
Polymetres are a defining characteristic of the djent subgenre of metal, pioneered by Swedish band Meshuggah whose compositions often feature unconventionally timed rhythm figures cycling over a 4 base.
Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Metre (music).