Audio: time signature (0:08)
time signature plays a 4/4 rhythm on congas. The time signature figure, the score, shows the value, or duration, of the beats.
The rhythm of time signature is exactly the same as that in note value. That chapter explains the symbols in more detail, this chapter concentrates on the time signature.
A time signature represents meter.
A time signature consists of two numbers. The numbers are written one on top of the other in a score. In text form, the numbers are written x/y, where a slash symbol separates the top number x from the bottom number y. 4/4 is an example of a time signature.
The top number in a time signature represents the number of beats in a bar. A 4/4 time signature means there are four beats in a bar. A 3/4 time signature means there are three beats in a bar. Any number can appear at the top of a time signature.
The bottom number of a time signature represents the duration of a beat. A time signature is used the same way in both percussion and staff notation, the only difference is that, in percussion notation, the lower number represents the duration of a beat, whereas, in staff notation, it represents the duration of a note. The bottom number is best thought of as the lower figure in a fraction. For example, the number 4 represents the duration of a single quarter-beat in rhythm, or the duration of a single quarter-note in melody and harmony.
The bottom number is always a multiple of two. A time signature of 4/4 means 4 beats in a bar each having a duration of one quarter-beat; 3/2 means 3 beats in a bar each having a duration of one half-beat; 12/8 means 12 beats in a bar each having a duration of one eighth-beat.
A time signature displays relative duration not actual duration. This is where confusion can reign, because the actual duration of a beat is determined by the tempo not by the meter. To know the actual duration of a beat we need to know the tempo of the rhythm. The only way to provide this information is to write it in the score. This is done in time signature which shows the symbol for a quarter-note, or quarter-beat, and assigns it a value of 120bpm. This means each beat has a relative duration of one quarter-beat and an actual duration of half a second.
The tempo in the scores in the guide is 120bpm unless stated otherwise.