Time signatures chart

Overview

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 the meter of a musical movement at the bar level.

In a music score the time signature appears as two stacked numerals, such as 4/4 (spoken as four–four time), or a time symbol, such as 𝄴 (spoken as common time or cut time). It immediately follows the key signature (or if there is no key signature, the clef symbol). A mid-score time signature, usually immediately following a barline, indicates a change of meter.

Most time signatures are either simple (the note values are grouped in pairs, like 2/4, 3/4, and 4/4), or compound (grouped in threes, like 6/8, 9/8, and 12/8). Less common signatures indicate complex, mixed, additive, and irrational meters.

Time signature notation

Most time signatures consist of two numerals, one stacked above the other:

• The lower numeral indicates the note value that the signature is counting. This number is always a power of 2 (unless the time signature is irrational), usually 2, 4 or 8, but less often 16 is also used, usually in Baroque music. 2 corresponds to the half note (minim), 4 to the quarter note (crotchet), 8 to the eighth note (quaver), 16 to the sixteenth note (semiquaver).
• The upper numeral indicates how many such note values constitute a bar.

For instance, 2/4 means two quarter-notes (crotchets) per bar, while 4/8 means four eighth-notes (quavers) per bar. The most common time signatures are 2/4, 3/4, and 4/4.

Symbolic signatures

By convention, two special symbols are sometimes used for 4/4 and 2/2:

• The symbol 𝄴 is sometimes used for 4/4 time, also called common time or imperfect time.
• The symbol 𝄵 is sometimes used in place of 2/2 and is called alla breve or, colloquially, cut time or cut common time.

These symbols derive from mensural time signatures, described below.

Simple versus compound

Simple meters are those whose upper number is 2, 3, or 4, sometimes described as duple meter, triple meter, and quadruple meter respectively.

In compound meter, the note values specified by the bottom number are grouped into threes, and the upper number is a multiple of 3, such as 6, 9, or 12. The lower number is most commonly an 8 (an eighth-note or quaver): as in 9/8 or 12/8.

Other upper numbers correspond to irregular meters.

Beat and subdivision

Musical passages commonly feature a recurring pulse, or beat, usually in the range of 60–140 beats per minute. Depending on the tempo of the music, this beat may correspond to the note value specified by the time signature, or to a grouping of such note values. Most commonly, in simple time signatures, the beat is the same as the note value of the signature, but in compound signatures, the beat is usually a dotted note value corresponding to three of the signature's note values. Either way, the next lower note value shorter than the beat is called the subdivision.

On occasion a bar may seem like one singular beat. For example, a fast waltz, notated in 3/4 time, may be described as being one in a bar. Conversely, at slow tempos, the beat might even be a smaller note value than the one enumerated by the time signature.

Mathematically the time signatures of, e.g., 3/4 and 3/8 are interchangeable. In a sense all simple triple time signatures, such as 3/8, 3/4, 3/2, etc.—and all compound duple times, such as 6/8, 6/16 and so on, are equivalent. A piece in 3/4 can be easily rewritten in 3/8, simply by halving the length of the notes.

Other time signature rewritings are possible: most commonly a simple time-signature with triplets translates into a compound meter.

The choice of time signature in these cases is largely a matter of tradition. Particular time signatures are traditionally associated with different music styles—it would seem strange to notate a conventional rock song in 4/8 or 4/2, rather than 4/4.

Duple and quadruple metre

In duple metre, each measure is divided into two beats, or a multiple thereof (quadruple metre).

For example, in the time signature 2/4, each bar contains two (2) quarter-note (4) beats. In the time signature 6/8, each bar contains two dotted-quarter-note beats.

Corresponding quadruple metres are 4/4, which has four quarter-note beats per measure, and 12/8, which has four dotted-quarter-note beats per bar.

Triple metre

Triple metre is a metre in which each bar is divided into three beats, or a multiple thereof. For example, in the time signature 3/4, each bar contains three (3) quarter-note (4) beats, and with a time signature of 9/8, each bar contains three dotted-quarter beats.

More than four beats

Metres with more than four beats are called quintuple metres (5), sextuple metres (6), septuple metres (7), 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 5/4, is assumed to either be equivalent to a measure of 3/4 followed by a measure of 2/4, or the opposite: 2/4 then 3/4. Higher metres which are divisible by 2 or 3 are considered equivalent to groupings of duple or triple metre measures; thus, 6/4, for example, is rarely used because it is considered equivalent to two measures of 3/4. 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 (LCD) of the two or more metric divisions. For example, much African music is recorded in Western notation as being in 12/8, the LCD of 4 and 3.

Simple metre

Simple metre (or simple time) is a metre in which each beat of the bar divides naturally into two (as opposed to three) equal parts. The top number in the time signature will be 2, 3, 4, 5, etc.

For example, in the time signature 3/4, 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 (two beats) or simple quadruple (four) are also common metres.

Compound metre

Compound metre (or compound time), 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 (two beats, each divided into three) is written as a time signature with a numerator of six, for example, 6/8. Contrast this with the time signature 3/4, 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 6/8 (compound duple metre), 9/8 (compound triple metre), and 12/8 (compound quadruple metre).

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 6/8, 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.

Overview

Alla breve – also known as cut time or cut common time – is a musical meter notated by the time signature symbol 𝄵 (a C with a vertical line through it), which is the equivalent of 2/2, though it has been used to denote 4/2. The term is Italian for "on the breve", originally meaning that the beat was counted on the breve (double whole note).

Alla breve is a "simple-duple meter with a half-note pulse". The note denomination that represents one beat is the minim or half-note. There are two of these per bar, so that the time signature 2/2 may be interpreted as "two minim beats per bar". Alternatively this is read as two beats per measure, where the half note gets the beat.

The name "common time" refers to 4/4, which has four beats to the bar, each of a quarter note (or crotchet).

Modern usage

In contemporary use, alla breve suggests a fairly quick tempo. Thus, it is used frequently for military marches. From about 1600 to 1900, its meaning with regard to tempo varied, so it cannot always be taken to mean a quick tempo. Using alla breve helps the musician read notes of short duration more cleanly with fewer beats.

Complex (odd) time signatures

Signatures that do not fit the usual simple or compound categories are called complex, asymmetric, irregular, unusual, or odd—though these are broad terms, and usually a more specific description is any meter which combines both simple and compound beats.

Irregular meters are common in some non-Western music, and in ancient Greek music such as the Delphic Hymns to Apollo, but the corresponding time signatures rarely appeared in formal written Western music until the 19th century. Early anomalous examples appeared in Spain between 1516 and 1520, plus a small section in Handel's opera Orlando (1733).

The third movement of Frédéric Chopin's Piano Sonata No. 1 (1828) is an early, but by no means the earliest, example of 5/4 time in solo piano music. Anton Reicha's Fugue No. 20 from his Thirty-six Fugues, published in 1803, is also for piano and is in 5/8. The waltz-like second movement of Tchaikovsky's Pathétique Symphony, often described as a "limping waltz", is a notable example of 5/4 time in orchestral music.

Examples from 20th-century classical music include:

• Gustav Holst's "Mars, the Bringer of War" and "Neptune, the Mystic" from The Planets (both in 5/4)
• Paul Hindemith's "Fuga secunda" in G from Ludus Tonalis (5/8)
• the ending of Stravinsky's The Firebird (7/4)
• the fugue from Heitor Villa-Lobos's Bachianas Brasileiras No. 9 (11/8)
• the themes for the Mission: Impossible television series by Lalo Schifrin (in 5/4) and for Room 222 by Jerry Goldsmith (in 7/4)

In the Western popular music tradition, unusual time signatures occur as well, with progressive rock in particular making frequent use of them. The use of shifting meters in The Beatles' "Strawberry Fields Forever" and the use of quintuple meter in their "Within You, Without You" are well-known examples, as is Radiohead's "Paranoid Android" (includes 7/8).

Paul Desmond's jazz composition "Take Five", in 5/4 time, was one of a number of irregular-meter compositions that The Dave Brubeck Quartet played. They played other compositions in 11/4 ("Eleven Four"), 7/4 ("Unsquare Dance"), and 9/8 ("Blue Rondo à la Turk"), expressed as 2+2+2+3/8. "Blue Rondo à la Turk" is an example of a signature that, despite appearing merely compound triple, is actually more complex. Brubeck's title refers to the characteristic aksak meter of the Turkish karşılama dance.

However, such time signatures are only unusual in most Western music. Traditional music of the Balkans uses such meters extensively. Bulgarian dances, for example, include forms with 5, 7, 9, 11, 13, 15, 22, 25 and other numbers of beats per measure. These rhythms are notated as additive rhythms based on simple units, usually 2, 3 and 4 beats, though the notation fails to describe the metric "time bending" taking place, or compound meters.