Rhythm

Tap out on the table the opening of a song you know well, without singing the notes, just tapping. Whoever is listening will probably recognise the song. What is left once the pitches are gone is the rhythm: the way durations follow one another, short and long, with silences between them (Lacerda 1966, ch. X).

The rhythm of a melody

Every melody has a rhythm underneath. Here is a short melody:

Hear the passage

And here is only its rhythm, every note replaced by a single pitch:

Hear the passage

The pitches are gone, but the shape of the music is still there: a beat and a half, half a beat, two equal beats; then two long ones. Med does exactly this to define the word: he takes the durations out of a melody and shows that they, on their own, are the rhythm (Med 1996, ch. XIX).

Rhythm is not meter

People often say "the rhythm of this song is three-four". Lacerda gives a whole section to undoing that confusion: meter, tempo and rhythm are three different things (Lacerda 1966, ch. X).

• Meter is the division of music into measures: the ruler.
• Tempo is the speed at which the music goes by.
• Rhythm is the way the values follow one another.

To see that they are independent, change one without touching the others. Here is the same four-beat measure with three different rhythms:

Hear the passage

The meter is the same in all three: four beats, with the weight on the first. What changes is what happens inside.

And the other way round: the same rhythm, divided into different measures. Med notes that one sequence of values can take more than one metric organisation (Med 1996, ch. XX). Six equal quarter notes, first grouped in measures of three, then in measures of two:

Hear the passage

Hear the passage

The same six durations, the same notes. Listen for where the weight falls: in the first, always on C; in the second, every two beats, first on C, then on E, then on G. The rhythm is the same; the meter changes what you feel.

Tempo, finally, only stretches or squeezes everything: the same rhythm in the same meter, played faster or slower, is still the same rhythm.

The small formulas

A rhythm is not a loose queue of durations. It is built from small groups that make sense, and Med calls each such group a rhythmic formula. The smallest, with at least two values, he calls the rhythmic minimum, a kind of musical syllable (Med 1996, ch. XX).

From a duple minimum, two quarter notes, many formulas are born: by dividing one of the values, by adding a dot, by turning a sound into a rest.

Hear the passage

Each measure here is a different formula drawn from the same two-beat syllable. Formulas like these, repeated and varied, are what the rhythms of music are built from.

Where rhythms come from

Blatter points out that many basic rhythms of Western music come from the body in motion: dance, marching, people working together. Baroque suites were made of dances, the minuet was a movement in most classical symphonies, and the nineteenth century belonged to the waltz (Blatter 2007, part 1, art. 5). The other source is speech: the feet of ancient poetry, the patterns of stressed and unstressed syllables, became rhythmic figures, above all in vocal music.

What comes next

When a rhythm puts a sound on a weak beat and holds it over the strong one, it pulls against the meter, and that pull has a name: syncopation. When two different rhythms sound at once, the word is polyrhythm.