All music is essentially made up of two elements: Rhythm and Pitch (melody). While some styles, or some individual pieces of music, may emphasise one of these elements, typically both exist. Some exceptions include percussion music using unpitched percussion. (Note: often even so-called unpitched percussion may include some pitch, however, for the sake of discussion here it will be treated as possessing no pitch). While there is music which is composed using rhythm only, music which uses only pitches without rhythm is difficult to find. This is because music needs rhythm so it can be organised into bars, phrases, sections and movements.
Consider the following 8 pitches
On their own the pitches have no relationship with each other, except for the intervallic distances between them and that one pitch follows the next. Organised rhythmically, however, they can create distinctive melodies
such as the opening of Spring from The Four Seasons by Antonio Vivaldi.
Because of rhythm’s importance it is essential to gain an understanding of the ways it is organised and notated.
Rhythm is made up of varying durations of time. In music, each of these durations can be notated using different note values. Each note value has a name; the names in brackets are favoured in Britain while those without a bracket are favoured in the USA.
At its simplest, each note divides into two
therefore, a whole note divides into two half notes; a half note divides into two quarter notes; and so on. Because the American terminology connects the name with the divisions of the notes it will be used throughout this article; an understanding of both American and British terminology should, however, be developed.
As shown above, notes of shorter duration than quarter notes are joined by beams:
Beams can connect the same note types
or different note types
Beams rhythmically organise notes into groups. These groups are then typically organised further into measures, or bars, which group different note types into recurring sets of 2, 3 4 or more. The following is grouped into 4 quarter notes
while the following is grouped into 3 quarter notes.
A time signature is used at the beginning of a piece of music to show how many beats are in a bar – the top note – and what type of notes these beats are – the bottom note. The following time signature shows there are 4 quarter-note beats per bar.
This time signature shows there are 3 eighth-note beats per bar.
This time signature shows there are 5 quarter-note beats per bar.
Time signatures show the overall number of beats per bar. Through beaming, and other notational devices, these beats may be divided and grouped in a multitude of ways.
As you can see in both of these examples, the divisions of each beat are grouped together to show the overall beat divisions of the bar – whether it is in 2, 3 or more – this ensures clarity and ease of reading.
If a piece uses the same time throughout, a time signature at the beginning is sufficient. Occasionally, however, there will be a change of time during a piece which requires a new time signature for every change of time.
Along with indicating the duration of pitches, as notes, notation also indicates silences, shown by rests. Each note duration has a rest sign of equal duration
Notice that the whole note rest hangs below the line while the half note rest sits on top. A whole note rest is also used to show a full bar’s rest in all time signatures. The grouping of rests will be discussed in a later article.
There are two methods of lengthening note values: dots and ties.
Adding a dot to a note lengthens that note by half its value
Dots can also be applied to rests with the same result.
The other method of lengthening a note is with a tie. A tie connects two or more of the same pitches, either across a barline
or, within a bar.
Although, in many instances notes will be divided into two they can also be divided into three, creating a triplet. Triplets use three notes in the same time as would normally be two.
In this example the triplet occupies the same value as two eighth notes (one quarter note)
Triplets always occupy the same note value as the notes divided into two. In the above example the triplet is written using eighth notes because two eighth notes would be used if the quarter note value was divided into two.
In the following example, the triplet is written as three quarter notes because two quarter notes would divide a half note by two.
Triplets can also use rests.
While many pieces use divisions of time in two, called simple time, many pieces are written with the divisions of time in three, called compound time. Compound time includes time signatures such as 6/8, 9/8 and 12/8. In compound time signatures the basic beat is divided into three
A bar of 2/4 with triplets is equivalent to a bar of 6/8.
This is because both have two beats in a bar – called duple time. Because the beat is divided into two in the simple-time 2/4 bar, we need to indicate the beat division into three using triplets, while in the compound-time 6/8 bar a division into three is already the typical beat division. Below is a table listing the three simple time signatures and their equivalent compound time signatures.