A time signature instructs a musician how to count the music. The elements of a time signature include the meter, accent and pulse, or beat. A meter is a set pattern of pulses within a measure, or bar line, of the musical score. The accents are the strong beats within a meter. A time signature looks like mathematical fraction, with the top number indicating the number of beats within a measure and the bottom number indicating what type of note gets the beat. Some of the most common time signatures include 2/4, 3/4 and 4/4. Each of these three time signatures has a unique function and character.
Simple Time Signatures
A simple time signature has a base unit, or bottom number, that's divisible by two. For example, the base unit of a 4/4 time signature is the quarter note. A quarter note can be subdivided into two equal eighth notes. The most commonly used simple time signatures include 4/4, 3/4 and 2/4 time.
Common time, also known as 4/4 time, is the most common meter used in Western music. The base unit of a 4/4 meter is the quarter note, and each measure consists of four quarter notes. A 4/4 meter has strong beats on counts one and three and weak beats on counts two and four. Many types of musical forms, from symphonies to pop songs, are notated in common time. Cut time, or 2/2 time, is a variation of common time. The base unit of a 2/2 meter is a half note instead of a quarter note.
A 3/4 time signature contains three quarter notes within a measure. Music written in 3/4 time is performed in a variety of different tempos. The waltz and minuet are two examples of dances performed in a 3/4 meter. The tempo of a composition in 3/4 time determines where the accents fall. For example, a quick 3/4 has a strong first beat and two weak second beats. A slower 3/4 time has as three equal beats.
A 2/4 time signature contains two quarter notes within a measure. In general, music written in 2/4 time is performed more slowly than music written in 3/4 or 4/4 time. Compositions written in 2/4 contain two equally strong accents on beats one and two. The weak beats fall on the subdivision, or eighth note, after beats one and two. Music written in 2/4 time can also be counted as four equal eighth notes if the tempo is slow. Tangos and polkas are notated in 2/4 time.