Text: A notation placed at the beginning of a piece of music consisting of two numbers written one on top of the other. The upper number gives the number of beats (counts) in each measure, while the bottom number indicate the type of note corresponding to one beat. The time of time signature is sometimes called the "time" of a piece of music. The time signature is used in Western rhythmic notation to specify the basic rhythm of a piece of music, also known as its meter. A time signature is a fraction. In "simple" time signatures, the denominator indicates which note is the beat. If the denominator is 2, the half note is one beat; if the denominator is 4, the quarter note is one beat; and so on. The numerator indicates the number of beats in each measure. Examples of simple time signatures include "4/4" ("common time"), "2/2" ("cut time"), "3/4", "5/4", "2/4", and so on. Time signatures where the numerator is a multiple of three (excluding the number 3 itself) are typically "compound" time signatures. In a compound signature, the denominator does not specify which note is the beat. Instead, each beat is divided into three sub-beats, and the denominator of the time signature determines what sort of note makes up a sub-beat. In "6/8" time, the sub-beats are eighth notes, and three of them make up a single beat. This means that the beat is a dotted-quarter note, and there are two beats in a measure. Other examples of compound time signatures include "9/8", "6/16", and so on. It is not uncommon to for listeners to confuse a 3/4 (simple) time signature with a 6/8 (compound) signature, if the former is played rapidly, or the latter is played slowly. Some standard time signatures in Western music are 4/4 or C -- common time 2/2 or ¢ -- cut time, used for marches 2/4 -- used for polkas or marches 3/4 -- used for waltzes 6/8 -- used for fast waltzes or marches 5/4 -- used for Dave Brubeck's "Take Five" and the original versions of the theme from Mission: Impossible1 Meter or Time Signature http://www.sweethaven.com/academic/lessons/060703/00/lessonmain.asp?lesNum=3&modNum=2 The meter or time signature is a musical symbol which indicates metrical stress (meter) and unit of beat (notation). The unit of beat is the value that gets one beat. The meter or time signature is represented by two arabic numerals arranged vertically at the beginning of a staff or rhythm line (single line used for notating rhythm). The upper numeral indicates the metrical stress; the lower numeral indicates the unit of beat or division of beat. In notation, the stronger, more accented beat in a beat grouping is indicated by placing a bar line vertically on a staff or through a rhythm line. The bar line precedes the note that begins the beat group. The space between any two adjacent bar lines is known as a measure. The word bar is commonly used to mean measure. fig0303.gif (5149 bytes) Simple Time Signatures Any note divisible by two may be used as the unit of beat in simple time. Since unaltered note and rest values are normally divisible by two, any undotted note, except the sixty-fourth, may be used as the unit of beat (dividing the sixty-fourth is impractical). The lower numeral in a time signature is always 1, 2, 4, 8, 16 or 32, corresponding to the note value/name, and specifies the unit of beat. The most commonly used numerals, in order of frequency, are: 4, 2, 8, and 16. Duple, triple, or quadruple simple metrical stress is indicated by an upper numeral in a time signature of 2, 3, or 4 respectively. fig0304.gif (11472 bytes) Note that Figure 3.4 lists two symbols (C and cuttime.gif (906 bytes)) as abbreviations for simple time signatures. The symbol C, called common time, functions as 4/4. The symbol cuttime.gif (906 bytes) called cut time or alla breve (according to the breve or half note), functions as 2/2. In Figure 3.5, the 2 indicates that the music is in simple duple time with each beat divisible by two. The 4 indicates that the quarter note is the unit of beat with the division of beat represented by eighth notes. fig0305.gif (4427 bytes) Compound Time Signatures Any note divisible by three maybe used as the unit of beat in compound time. Since dotted note and rest values are normally divisible by three, any dotted note, except the dotted sixty-fourth, may be used as the unit of beat (dividing the dotted sixty-fourth is impractical). In compound time, the lower numeral of a time signature will always be 2, 4,8, 16,32 or 64, corresponding to the note valuelname. These numerals usually specify the division of beat. The unit of beat is derived by finding the dotted note value that is equal to three of the notes indicated by the lower numeral. The most commonly used numerals, in ³ order of frequency, are: 8,4,2, and 16. Duple, triple or quadruple metrical stress is indicated by an upper numeral in a time signature of 6 (2 x 3 divisions of beat), 9 (3 x 3 divisions of beat), or 12 (4 x 3 divisions of beat) respectively. fig0306.gif (12549 bytes) In Figure 3.7, the 6 indicates that the music is in compound duple time with each beat divisible into three parts. The 8 indicates that the eighth note is the division of beat with the unit of beat represented by the dotted quarter. fig0307.gif (4848 bytes) Some contemporary composers indicate compound time signatures with the actual number of beats as the upper numeral and a note value below. fig0308.gif (3195 bytes)

See Also:

Source: