Tones and their pitch are important elements of music, but without time there is no rhythm and there are no melodies.
The Beat and the Measure (or Bar)
In music, a beat divides time into equal lengths. Like the dividers on a clock: For every minute, the clock has 60 seconds and each tick of the second hand is a beat.
Another term is measure or bar. A measure defines one logical unit of a composition. Similar as one minute has 60 seconds, a measure has a given number of beats.
In music, each piece (or section of a piece) has a defined time signature. This time signature defines how many beats one measure has and also how the time in each measure is divided.
The time signature is written in form of a fraction:
While in there are many time signatures, like 2/2, 3/4, 7/8 or even 9/8, in modern pop music 4/4 is used most of the time.
The time signature 4/4 means, there are four beats per measure and the note value for one beat is 1/4 of a whole note.
The next table contains a number of common time signatures and their meaning.
|Beats per Measure:||4||2||3||2||6||9||12|
|Note Value per Beat:||1/4||1/4||1/4||1/2||1/8||1/8||1/8|
Tempo / Speed
The tempo or speed of music is measured in beats per minute, or short BPM. If you read “120 BPM”, it means that there are 120 beats per minute, and therefore two beats per second.