Simple & Compound Time/Meter

We had a preliminary look at time signatures in lesson 4.

A great deal of music, particularly that from the Western musical tradition, has an underlying pulse or beat. Think of the beat as something 'you tap your foot to' when you are listening to a piece of music. Bar-lines and time signatures are used to make the underlying rhythm, the pattern of beats of differing weight (strong, medium, weak), clearer to the performer. So, for example, a bouree which has four beats in a bar starts on the last beat; the gavotte, also written with four beat in a bar, starts on the third beat. Neither of these, unclear where bar-lines are absent, would not be clearer with bar-lines written into the score.

Sometimes time signatures might mislead the performer and we have adopted a 'convention' about how different time signatures relate to particular underlying rhythmic structures. This is illustrated in the three scores below. Two of these are the same piece of music written in two different ways.

This score is in 'three'; we have marked the three beats with dotted bar-lines. The beat is a crotchet (quarter note) and the time signature tells us that there are three crotchets (quarter notes) in each bar. This is an example of simple time or tempo semplice (Italian); the main beat can be divided into two inner beats, in this case quavers (eighth notes).

This score is written in six but 'felt' in two; we have marked the pulse with dotted bar-lines. The beat is actually a dotted crotchet (dotted quarter note) but the beat is divided into three quavers (eighth notes). Therefore, each bar contains six quavers (eighth notes). This is an example of compound time or tempo composto (Italian); the main beat can be divided into three inner beats, in this case quavers (eighth notes).

The third score has a compound time signature. A performer would be confused - should the piece be in two or in three. If the piece is to be played 'three in a bar' then it should be notated in three, as it was in the first example.

We can list various time signatures as simple time signatures or compound time signatures.

Uneven/Asymmetrical Time/Meter

The formal distinction between simple and compound time or meter becomes blurred particularly in the folk music of central Europe and Asia Minor where the pattern of dances steps is complex. Time signatures in which the number of notes in the bar is odd (i.e. 5, 7, 9, 11, 13, 15, etc.) are common. The uneven numbers break down into shorter inner groups of either simple or compound rhythms. So 5 will break down into a group of 2 followed by a group of 3 or, alternatively, a group of 3 followed by a group of 2. This pattern may change from bar to bar. A good editor will note the inner groups clearly so that the performer can quickly ascertain how the internal rhythmic forms should be accented by placing strong beats at the beginning of each of the inner groupings. Jazz and folk-inspired classical music makes use of uneven time signatures and is the richer for it. Meters in which the number of notes in the bar in a multiple of 3 may be compound meters when they break down naturally into equal groups of 3 (e. g. 3 + 3 + 3 = 9). If however they do not break down into equal groups, then the meter is asymmetrical (e.g. 4 + 3 + 2 = 9). The terms complex meter and irregular meter are also applied in these situations.

One of our readers offers as an illustration the song America from West Side Story by the American composer Leonard Bernstein, which is an excellent example of a tune in mixed time (or mixed meter), namely (6/8 + 3/4) where the value of the quaver (eighth-note) remains constant.

See America from West Side Story.

Triplets

In music, the term irrational rhythm is usually applied to a rhythm in which an unusual number of beats is superimposed on the predominating tempo. More precisely, if n evenly-spaced beats are played in the time of m beats of the underlying tempo then the rhythm is irrational if neither of n and m is divisible by the other. The use of the term "irrational" in this context is quite different to the mathematical use of the term: indeed, rhythms of this sort are, in the mathematical sense, rational, as they are precisely defined by the ratio of beats played to beats in the underlying tempo.

One example is the triplet, used when in the context of a simple time signature one wants to subdivide a beat into three. The triplet notation lets you to do this.

The triple notation has been shown in two ways - one, with the number 3 over the group of three quavers (eighth notes); the other, with a bracket as well as the number. The three quavers (eighth notes) are played in the time of two quavers (eighth notes), in other words the three quavers (eighth notes) divide a crotchet (quarter note) into three equal parts. We read the notation as meaning 'three notes in the time of two'. Any note can be divided in this way. For example, three crotchets (quarter notes) can be played in the time of a minim (half note). Any of the three notes can be a rest or can itself be combined with other notes or broken up into shorter notes.

Why not listen to two examples of the triplet rhythm used to great effect. The first is a ten bar extract from Albinoni's Concerto for Two Oboes and Strings.

Notice, in particular, when the triplet rhythm is being played against the quaver rhythm in another line in bars 4, 5 and 6.

The second comes from The Dolmetsch Library, In Dulce Jubilo by J. S. Bach arranged for four recorders.

Here you will find notes tied into and between triplets, triplets containing rests and triplets with minims (half notes) as well as crotchets (quarter notes).

When notes with different time values appear within a triplet (for example, a crotchet (quarter note) and a quaver (eighth note) in place of three quavers (eighth notes)) the result is called a mixed-rhythm triplet.

Duplets

Where triplets are used in simple time to divide beats into three parts. duplets are used in compound time to divide beats into two parts. The notation is very similar except that the number 2 appears above the group which is shorthand for two notes in the time of three.

We give an example below.

On the website Music Notation Questions Answered the following question is posed.

What is the correct note value of a dotted quaver (eighth note) duplet (two quavers (eighths) in the space of three quavers (eighths))?

The website experts comment:

Other-lets

The division of notes into smaller notes using triplets and duplets can be extended to irregular groups of even larger number, known collectively as tuplets or gruppo irregolare (Italian). Again there are 'notational' conventions for writing such grouping and these are listed below. As with triplets, the groupings can include rests and notes of different values (such groups are called mixed-rhythm tuplets). The 'convention' tells us the total time value of the group as written and as played.

The irregular division of compound time is rare and notational 'conventions' are fluid. Simple time division is much more common and this has given time for composers and music publishers to establish and maintain a set of 'notational conventions'.

Grouping Notes and Rests

It would be useful to set out the standard 'conventions' for notating music written in simple or compound time.

How We 'Say' Time Signatures

In England, we name time signatures as follows: