musical notation Musical notation is any system used to visually represent music. Systems of notation generally represent the elements of a piece of music that are considered important for its performance in the context of a given musical tradition. The proce ...

, a bar (or measure) is a segment of music bounded by vertical lines, known as bar lines (or barlines), usually indicating one or more recurring beats. The length of the bar, measured by the number of

note values In music notation, a note value indicates the relative duration (music), duration of a note (music), note, using the texture or shape of the ''notehead'', the presence or absence of a ''stem (music), stem'', and the presence or absence of ''flags ...

it contains, is normally indicated by the

time signature A time signature (also known as meter signature, metre signature, and measure signature) is an indication in music notation that specifies how many note values of a particular type fit into each measure ( bar). The time signature indicates th ...

Types of bar lines

Regular bar lines consist of a thin vertical line extending from the top line to the bottom line of the staff, sometimes also extending between staves in the case of a

grand staff In Western musical notation, the staff"staff" in the Collins English Di ...

or a family of instruments in an orchestral score. A ''double bar line'' (or ''double bar'') consists of two single bar lines drawn close together, separating two

sections Section, Sectioning, or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sig ...

within a piece, or a bar line followed by a thicker bar line, indicating the end of a piece or movement. Note that ''double bar'' refers not to a type of ''bar'' (i.e., measure), but to a type of ''bar line''. Typically, a double bar is used when followed by a new

key signature In Western musical notation, a key signature is a set of sharp (), flat (), or rarely, natural () symbols placed on the staff at the beginning of a section of music. The initial key signature in a piece is placed immediately after the cl ...

, whether or not it marks the beginning of a new section. A ''

repeat sign In music, a repeat sign is a Musical notation, sign that indicates a section should be repetition (music), repeated. If the piece has one repeat sign alone, then that means to repeat from the beginning, and then continue on (or stop, if the sign a ...

'' (or, ''repeat bar line'') looks like the music end, but it has two dots, one above the other, indicating that the section of music that is before is to be repeated. The beginning of the repeated passage can be marked by a ''begin-repeat sign''; if this is absent, the repeat is understood to be from the beginning of the piece or movement. This begin-repeat sign, if appearing at the beginning of a staff, does not act as a bar line because no bar is before it; its only function is to indicate the beginning of the passage to be repeated. A

mensurstrich (''plural'' ) is a German term used in musical notation to denote a barline that is drawn between staves, but not across them. It is typically seen in modern editions of Medieval and Renaissance vocal polyphony, where it is intended to allow m ...

is a bar line which stretches only between staves of a score, not through each staff; this is a specialized notation used by editors of early music to help orient modern musicians when reading music which was originally written without bar lines. Lines extending only partway through the staff are rarely used, sometimes to help orient the reader in very long measures in complex time signatures, or as brief section divisions in Gregorian chant notation. 15 bars multirest

Some composers use dashed or dotted bar lines; others (including Hugo Distler) have placed bar lines at different places in the different parts to indicate different stress patterns from part to part. If many consecutive bars contain only rests, they may be replaced by a single bar containing a multirest, as shown. The number above shows the number of bars replaced.

Bars and stresses

Whether the music contains a regular

meter The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of ...

or mixed meters, the first note in the bar (known as the downbeat) is usually stressed slightly in relation to the other notes in the bar.

Igor Stravinsky Igor Fyodorovich Stravinsky ( – 6 April 1971) was a Russian composer and conductor with French citizenship (from 1934) and American citizenship (from 1945). He is widely considered one of the most important and influential 20th-century c ...

said of bar lines: Bars and bar lines also indicate grouping:

rhythm Rhythm (from Greek , ''rhythmos'', "any regular recurring motion, symmetry") generally means a " movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions". This general meaning of regular r ...

ically of beats within and between bars, within and between

phrases In grammar, a phrasecalled expression in some contextsis a group of words or singular word acting as a grammatical unit. For instance, the English expression "the very happy squirrel" is a noun phrase which contains the adjective phrase "very ...

, and on higher levels such as meter.

Numbering bars

The first metrically complete bar within a piece of music is called "bar 1" or "m. 1". When the piece begins with an

anacrusis In poetic and musical meter, and by analogy in publishing, an anacrusis (from , , literally: 'pushing up', plural ''anacruses'') is a brief introduction. In music, it is also known as a pickup beat, or fractional pick-up, i.e. a note or seque ...

(an incomplete bar at the beginning of a piece of music), "bar 1" or "m. 1" is the following bar. Bars contained within first or second endings are numbered consecutively.

History

The earliest bar lines, used in keyboard and

vihuela The vihuela () is a 15th-century fretted plucked Spanish string instrument, shaped like a guitar (figure-of-eight form offering strength and portability) but tuned like a lute. It was used in 15th- and 16th-century Spain as the equivalent of t ...

music in the 15th and 16th centuries, didn't reflect a regular

at all but were only section divisions, or in some cases marked off every beat. Bar lines began to be introduced into ensemble music in the late 16th century but continued to be used irregularly. Not until the mid-17th century were bar lines used in the modern style with every measure being the same length, and they began to be associated with time signatures. Modern editions of early music that was originally notated without bar lines sometimes use a

as a compromise.

Hypermeasure

A hypermeasure, large-scale or high-level measure, or measure-group is a metric unit in which, generally, each regular measure is one beat (actually hyperbeat) of a larger meter. Thus a beat is to a measure as a measure/hyperbeat is to a hypermeasure. Hypermeasures must be larger than a notated bar, perceived as a unit, consist of a pattern of strong and weak beats, and along with adjacent hypermeasures, which must be of the same length, create a sense of hypermeter. The term was coined by Edward T. Cone in ''Musical Form and Musical Performance'' (New York: Norton, 1968),Stein, Deborah (2005). ''Engaging Music: Essays in Music Analysis'', p.18-19 and "Glossary", p.329. New York: Oxford University Press. . and is similar to the less formal notion of a

phrase In grammar, a phrasecalled expression in some contextsis a group of words or singular word acting as a grammatical unit. For instance, the English language, English expression "the very happy squirrel" is a noun phrase which contains the adject ...

Types of bar lines

Bars and stresses

Numbering bars

History

Hypermeasure

See also

References

Further reading