Metre (music)
In music, metre or meter refers to regularly recurring patterns and accents such as downbeats and beats. Unlike rhythm, metric onsets are not necessarily sounded, but are nevertheless implied by the performer and expected by the listener.
A variety of systems exist throughout the world for organising and playing metrical music, such as the Indian system of tala and similar systems in Arabic and African music.
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 metre of classical ancient Greek and Latin poetry.
Later music for dances such as the pavane and galliard consisted of musical phrases to accompany a fixed sequence of basic steps with a defined tempo and time signature. 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.
Metre is related to and distinguished from pulse, rhythm, and beats:
Metric structure
The term metre is not very precisely defined. Stewart MacPherson preferred to speak of "time" and "rhythmic shape", while Imogen Holst preferred "measured rhythm". 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, "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.... 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 subdivided into a pattern of duples and triples.
For example, a metre consists of three units of a pulse group, and a metre consists of two units of a pulse group. In turn, metric bars may comprise 'metric groups' - for example, a musical phrase or melody might consist of two bars x.
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, and normal accents reoccur regularly, providing systematic grouping.
- Measured rhythm is where each time value is a multiple or fraction of a specified time unit but there are not regularly recurring accents.
- Free rhythm is where the time values are not based on any fixed unit; since the time values lack a fixed unit, regularly recurring accents are no longer a possibility.
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
Metres classified by the number of beats per measure
Duple and quadruple metre
In duple metre, each measure is divided into two beats, or a multiple thereof.For example, in the time signature, each bar contains two quarter-note beats. In the time signature, each bar contains two dotted-quarter-note beats.
Corresponding quadruple metres are, which has four quarter-note beats per measure, and, which has four dotted-quarter-note beats per bar.
Triple metre
is a metre in which each bar is divided into three beats, or a multiple thereof. For example, in the time signature, each bar contains three quarter-note beats, and with a time signature of, each bar contains three dotted-quarter beats.More than four beats
Metres with more than four beats are called quintuple metres, sextuple metres, septuple metres, etc.In classical music theory it is presumed that only divisions of two or three are perceptually valid, so a metre not divisible by 2 or 3, such as quintuple metre, say, is assumed to either be equivalent to a measure of followed by a measure of, or the opposite: then. Higher metres which are divisible by 2 or 3 are considered equivalent to groupings of duple or triple metre measures; thus,, for example, is rarely used because it is considered equivalent to two measures of. See: hypermetre and additive rhythm and divisive rhythm.
Higher metres are used more commonly in analysis, if not performance, of cross-rhythms, as lowest number possible which may be used to count a polyrhythm is the lowest common denominator of the two or more metric divisions. For example, much African music is recorded in Western notation as being in, the LCD of 4 and 3.
Metres classified by the subdivisions of a beat
Simple metre and compound metre are distinguished by the way the beats are subdivided.Simple metre
Simple metre is a metre in which each beat of the bar divides naturally into two equal parts. The top number in the time signature will be 2, 3, 4, 5, etc.For example, in the time signature, each bar contains three quarter-note beats, and each of those beats divides into two eighth notes, making it a simple metre. More specifically, it is a simple triple metre because there are three beats in each measure; simple duple or simple quadruple are also common metres.
Compound metre
Compound metre, is a metre in which each beat of the bar divides naturally into three equal parts. That is, each beat contains a triple pulse. The top number in the time signature will be 6, 9, 12, 15, 18, 24, etc.Compound metres are written with a time signature that shows the number of divisions of beats in each bar as opposed to the number of beats. For example, compound duple is written as a time signature with a numerator of six, for example,. Contrast this with the time signature, which also assigns six eighth notes to each measure, but by convention connotes a simple triple time: 3 quarter-note beats.
Examples of compound metre include , , and .
Although and are not to be confused, they use bars of the same length, so it is easy to "slip" between them just by shifting the location of the accents. This interpretational switch has been exploited, for example, by Leonard Bernstein, in the song "America":
File:Alternating time signatures2.gif|center|thumb|340x340px|"I like to be in A-mer-i-ca" from West Side Story
Compound metre divided into three parts could theoretically be transcribed into musically equivalent simple metre using triplets. Likewise, simple metre can be shown in compound through duples. When conducting in, conductors typically provide two beats per bar; however, all six beats may be performed when the tempo is very slow.
Compound time is associated with "lilting" and dancelike qualities. Folk dances often use compound time. Many Baroque dances are often in compound time: some gigues, the courante, and sometimes the passepied and the siciliana.
Metre in song
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 and of such phrases into melodies, passages or sections 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. For example, The Blind Boys of Alabama rendered the hymn "Amazing Grace" to the setting of The Animals' version of the folk song "The House of the Rising Sun". This is possible because the texts share a popular basic four-line verse-form called ballad metre or, in hymnals, common metre, the four lines having a syllable-count of 8–6–8–6, 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.
In some regional music, for example Balkan music, a wealth of irregular or compound metres are used. Other terms for this are "additive metre" and "imperfect time".