When you tap your foot or dance to music you're following the beat. The beat is a series of evenly spaced pulses. Anything that marks off equal units of time can be used as a beat source, your heartbeat, the sound of your footsteps on a steady walk, a clock ticking, or a metronome. These steady beats (ticks, pulses, clicks) exist outside of the music. The beat serves as the foundation of all musical rhythm and performance by providing a temporal grid on which the rhythm values are placed.
Any note value can represent the beat. The note value that gets one beat is called the beat unit. If you choose the quarter note as the beat unit, then a half note will get two beats. However, if you choose the eighth note as the beat unit, then a half note will get four beats.
The organization of notes with respect to the beat is called rhythm. Sometimes notes will be played on the beat, sometimes between the beats, sometimes one note will last for several beats, and sometimes several notes will be played before the next beat.
The speed of the beat is called tempo. In a fast tempo the beats are close together. In a slow tempo the beats are spaced further apart.
The tempo is indicated by a metronome marking in beats per minute. The notation
M.M. 
=
60 indicates that there are 60 beats per minute, or one beat per second. M.M.
is an abbreviation for Maelzel's Metronome, named after the inventor Maelzel.
The notation M.M. =
120 indicates that there are 120 beats per minute, or two beats per second.
The notation M.M. =
90 indicates that there are 90 beats per minute, or three beats every two seconds.
Tempo indications are often given by Italian terms, sometimes accompanied by a metronome indication in beats per minute. The following chart shows several common tempo markings. The metronome markings are approximate.
|
Beats/minute |
Tempo Marking |
Performed |
|
M.M.
= 40 |
Grave |
Extremely slow |
|
Largo |
Slow | |
|
Larghetto |
||
|
Lento |
||
|
Adagio |
||
|
M.M.
= 60 |
Andante |
Medium slow, literally walking |
|
Andantino |
||
|
Moderato |
Medium | |
|
Allegretto |
Medium fast | |
|
M.M.
= 120 |
Allegro |
Fast |
|
Molto Allegro |
Very fast | |
|
Vivace |
||
|
Presto |
||
|
M.M.
= 208 |
Prestissimo |
As fast as possible |
The arrangement of strong and weak beats into organized patterns is called meter. Metrical patterns are used in poetry and music.
The strong ( S ) and weak ( w ) beats are arranged in groups of 2.
S - w - S - w.
The strong ( S ) and weak ( w ) beats are arranged in groups of 3.
S - w - w - S - w - w.
The strong ( S ) and weak ( w ) beats are arranged in groups of 4.
S - w - w - w - S - w - w - w.
There is a hierarchy of beat divisions. The primary division represents the beat unit. Any note value can serve as the beat unit. After the primary division are the first, second, and third subdivisions. Here's an example.
| Primary Division | First Subdivision | Second Subdivision | Third Subdivision | |
| Whole Note Beat |  |
 |
 |
 |
| Half Note Beat |  |
 |
 |
 |
| Quarter Note Beat |  |
 |
 |
 |
A Time Signature or Meter Signature is placed to the right of the clef and consists of two numbers placed one on top of another. The upper number indicates the number of beats per measure. The lower number indicates both the the number of beat units in each measure and the type of note that gets one beat. In this example there are three quarter note beats in every measure.
The time signature is not a fraction and no line is drawn between the numbers. It is pronounced "three four time" not "three fourths time."
The lower number of the time signature indicates the number of beat units in each measure and suggests the performance beat unit. In three four time every measure will have the rhythmic equivalent of three quarter notes. Depending on the speed of the music, the performer is free to choose a different beat unit. Here are three examples of counting the same musical passage at different tempos.
In a medium tempo the performer would probably choose a quarter note for the beat unit.
At a fast tempo it's too much work to keep counting 123 123 over and over quickly. It's much easier to just count once at the beginning of each measure. The performer would probably choose a dotted half note for the beat unit.
At a very slow tempo, if too much time elapses between the 1 and the 2 and the 3 it's difficult to keep the the beat steady. Assigning the beat unit to the eighth note and counting in "ands" makes it easier to keep the tempo steady. The performer would probably choose an eighth note for the beat unit.
In simple meter the beat unit is a plain (not dotted) note. All subdivisions of the beat unit are divided into two parts. Any note value can serve as the beat unit.
| Primary Division | First Subdivision | Second Subdivision | Third Subdivision | |
| Whole Note Beat | |
|
|
|
| Half Note Beat | |
|
|
|
| Quarter Note Beat | |
|
|
|
The upper number of the time signature can be a 2, 3, 4, 5, or 7. The lower number of the time signature is always a 1, 2, 4, 8, 16, or 32.
Four four time is also called common time and can be written using a "C" for the time signature.
Two two time is also called cut time or Alla Breve time. It's "four four" cut in half. It is written as a "C" with a vertical slash through it.
Here's the same four measure rhythm in duple meter notated in four different time signatures. In each line there are two beats per measure, as indicated by the upper number of the time signature. However, the beat unit is different in each line, as indicated by the lower number of the time signature. Although they look different, the rhythm of each line sounds exactly the same.
Here's the same four measure rhythm in triple meter notated in four different time signatures. In each line there are three beats per measure, as indicated by the upper number of the time signature. However, the beat unit is different in each line, as indicated by the lower number of the time signature. Although they look different, the rhythm of each line sounds exactly the same.
Here's the same four measure rhythm in quadruple meter notated in four different time signatures. In each line there are four beats per measure, as indicated by the upper number of the time signature. However, the beat unit is different in each line, as indicated by the lower number of the time signature. Although they look different, the rhythm of each line sounds exactly the same.
Revised by John Ellinger, Spring 2012.