Music can be described as sounds and silences in time:
Rhythm is about when to play and how long to play for.
4 Rhythm: Tricks and traps
It is the combination of durations and silences occurring together over a metrical grouping (a time signature) which gives us rhythm. The durations on their own only indicate how much time must go by before the note that it is related to should stop sounding.
Rhythms can consist of combinations of ordinary durations (those that are un-dotted) like the following (first at 120bpm, then 160bpm, then 108bpm):
Rhythms can also make use of dotted figures to add interest and bounce to the part as in (first at 120bpm, then 160bpm, then 108bpm):
The presence of triplets in a rhythm can give it a more heightened sense of motion if the rhythm has been predominantly quavers or crotchets and the triplets used are quaver triplets at 132bpm.
If crotchet or minim triplets are used in the same style of rhythm they can act to the contrary, slowing down the rhythmic motion.
Other kinds of tuplets
The presence of other types of tuplets such as quintuplets can add to the sense of rhythmic motion as well. As previously noted, in both simple and compound meter we can deny the usual division of the beat.
By dividing Simple meter beats into three (triplets): where is normally divided like this , it is divided like this .
By dividing Compound meter beats into two (duplets) or four (quadruplets): where is normally divided like this is divided like this or this or this .
We can further deviate from the regular division of the beat by introducing divisions of the beat based on any odd number, such as 5, 7, 9, 11 etc. These odd-tuplets, as they are known, usually replace a more regular division of the beat, so that a 5-tuplet would be in place of a four-division of the beat, and so on, a 9-tuplet is used in place of an eight-division of the beat.
They tend to give a sense of rhythmic freedom and enhance any attempts at giving a through-composed work an improvised feel.
Sometimes the use of a dotted figure indicates the practice of swinging a rhythmic phrase. The practice of swinging involves the alteration of the phrase from a straight feeling to a more triplet style of interpretation, e.g.
This is sometimes called a shuffle pattern.
Here are the two patterns played against each other:
Syncopation is the deliberate stressing or accenting of a beat or subdivision of the beat other than those beats that would normally be accented in a given time signature. All kinds of music make use of syncopation but it is especially prevalent in Latin American dances and most jazz styles, as well as amongst many popular tunes:
Cross-rhythms are rhythms that are played in direct contrast to the underlying time signature; where a time signature suggests that the basic division of the pulse is in halves or quarters, etc but the rhythms being played would suggest that the basic division is thirds or vice versa.
Examples of cross-rhythm can be found in “Master Blaster” by Stevie Wonder from Hotter Than July:
and “America” by Leonard Bernstein from West Side Story:
The technical name for this particular type of cross-rhythm is hemiola - the quaver tempo is constant, the accenting changes from two groups of three quavers to three groups of two quavers.
Polyrhythm refers to many rhythms occurring at once. Generally this means that there are many different types of rhythms occurring in two or more parts simultaneously.
Ostinato is related to the word obstinate; it has the sense of continuing insistent rhythmic pattern, sometimes connected with a repeated melodic or harmonic pattern. Rhythmic ostinatos occur in most popular song drum and bass parts. This repetition of pattern helps makes it easy to create music. An example of an ostinato can be found in “Watermelon in Easter Hay” by Frank Zappa from Joes Garage Acts II & III.
Another possibility using the same structure
Probably the most well known example of an ostinato is the snare drum part in Ravel’s Bolero. This starts as soft as possible and goes through a continuous crescendo over the entire piece finishing with a flourish and roll; the piece lasts between 8’ and 11’ depending on which version of the orchestration is used.
A less technical name for ostinato is riff, although a riff may not form the entire basis for a piece of music.
Shifting meter is another device for creating rhythmic interest. This works by changing the focus of the accents in a rhythm on a regular or intermittent basis.
An example might be a metrical structure that consists of two bars of 5/8 followed by a bar of 5/4.
Another example might be a metrical structure consists of a bar of 3/4 followed by a bar of 5/4 in the chorus and bars of 4/4 in the verse.