Common time is another way of notating and referring to the 4/4time signature, which indicates that there are four quarter note beats per measure. It may be written in its fraction form of 4/4 or with a c-shaped semicircle. If this symbol has a vertical strike-through, it’s known as “cut common time.”
How Time Signatures Work
In music notation, the time signature is placed at the beginning of the staffafterthe clef and the key signature. The time signature indicates how many beats there are in each measure, and what the value of the beat is. The time signature is typicallydisplayed as a fractional number — common time being one of the exceptions — where the top number indicates the number of beats per measure, and the bottom number indicates the value of the beat. For example, 4/4 means four of a beat. The bottom four symbolizes a quarter note value. So there will be four quarter-note beats per measure. However, if the time signature were 6/4, there would be six quarter-notes per measure.
Mensural Notation and Origins of Rhythmic Value
Mensural notation was used in music notation from the late 13th century to around 1600. It comes from the wordmensuratawhich means "measured music" and was used to bring definitions in a numerical system that could help musicians, primarily vocalists, define the proportions between note values. During its development throughout the centuries, different methods of mensural notation emerged from France and Italy, but eventually, the French system became systematicallyaccepted across Europe. This system introduced ways of notes to be given values of units, and whether a note would be read as ternary, which was considered to be "perfect," or binary, which was considered to be "imperfect." There were no bar lines used in this type of notation, so time signatures were not yet relevant for reading music.
Development of the Common Time Symbol
When mensural notation was being used, there were symbols that indicated if the unitvalues of the notes were perfect or imperfect. The concept has roots in religious philosophy. A complete circle indicated atempus perfectum(perfect time) because a circle was a symbol of completeness, whereas an incomplete circle that resembled the letter "c" indicatedtempus imperfectum (imperfect time). Eventually, this led to the triple meterbeing represented by the circle, while imperfect time, a type of quadruple meter, was written using an incomplete, “imperfect” circle.
Today, the common time symbol represents the simplest duple time in music notation—and perhaps the most frequently used with pop musicians—which is the earlier mentioned 4/4 time signature.
Resources and Further Reading
Fox, Dan. Write It Right! Alfred Music, 1995.
