Basic Rhythm & Its Notation
Rhythm is represented in written music by notes
of varying shapes. The notes specify time values,
relative durations
for which the notes are held, or sustained.
| time value |
semibreve | minim | crotchet |
quaver | semiquaver |
| note |
 |
 |
 |
 |
 |
Although it is possible
for any note to represent a single beat, in the early stages of
learning to read music a single beat is usually represented by a
crotchet, also known as a quarter-note
(see the equivalent terms (below) for the corresponding European and
North American terminology).
The American terminology makes the relative values
of the notes very clear - 16 sixteenth notes will take up the
same amount of time as a whole note, as will 8 eighth notes,
or 4 quarter notes, or two half notes.
A note typically has a note-head
and a stem, and may also have one or more flags (also
called tails). [In the chart above, a semibreve has a note-head
but no stem or flag; a quaver has one flag and a semiquaver has two.]
The vast majority of music has some sort of pulse, or
beat, that you can clap or tap your foot
to. Usually you can hear that some of the pulses are stronger, or
louder than others - we say that these stronger pulses are
accented. The number of pulses from one accent to the
next divides the music into bars, or
measures.
If the accent comes every two beats, like in
a march, then the music is in 'two time' - one
two one two.
If the accent comes every three beats, as in a waltz, then the music
is in 'three time' -
one two three one two three.
The grouping of regular accents and the notes between them is shown in written music by placing
a 'bar-line' before each accent; that is, the first note after every bar-line is always the
first beat of the bar, and is therefore accented. (Composers sometimes break this rule in
order to create a special rhythmic effect called syncopation.) Written at the start of a piece
of music, the 'time signature' looks like a fraction
(without the dividing line). The top number (numerator) tells us how many beats are in each bar -
that is, whether the piece is in 'two' or 'three' time (or 'four', etc.);
and the bottom number (denominator) tells us the type (duration) of note that gets one beat.
As mentioned above, in the early stages of learning to read a crotchet will represent one beat
and the denominator for this is 4. The following table lists the most
frequently used Simple Times (music also uses Compound Times and Irregular Times).
Simple Time Signatures
| Duple | 2
8 | 2 eighth-notes per bar |
|---|
2
4 | 2 quarter-notes per bar |
2
2 | 2 half-notes per bar |
| Triple | 3
8 | 3 eighth-notes per bar |
|---|
3
4 | 3 quarter-notes per bar |
3
2 | 3 half-notes per bar |
| Quadruple | 4
8 | 4 eighth-notes per bar |
|---|
4
4 | 4 quarter-notes per bar |
4
2 | 4 half-notes per bar |
equivalent terms
| North America | Europe |
|---|
| sixteenth note | semiquaver |
| eighth note | quaver |
| quarter note | crotchet |
| half note | minim |
| whole note | semibreve |
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