Duration in depth: beat and pulse, tempo and tempo change, simple, compound and irregular metres, note and rest values, and rhythmic devices such as syncopation, dotted rhythms, ostinato, augmentation and diminution

What this dot point is asking

Duration is one of the six concepts of music, and it is the concept that controls everything to do with time. In the aural exam you must hear and name the metre, the tempo and the rhythmic devices an excerpt uses, and in composition you must manipulate them deliberately. This dot point asks you to go beyond the overview and command duration in detail: to count metre confidently, label tempo with the right vocabulary, and recognise rhythmic devices the moment you hear them.

The answer

Beat, pulse and tempo

The beat or pulse is the steady underlying throb you would tap your foot to. Tempo is how fast that pulse moves, usually given as beats per minute or with an Italian character word. The standard terms run from slow to fast: Largo (very slow and broad), Adagio (slow), Andante (walking pace), Moderato (moderate), Allegro (fast and lively), Vivace (lively) and Presto (very fast). Tempo can also change: accelerando speeds up, rallentando or ritardando slows down, and rubato is expressive flexing of the pulse for musical effect. When you describe duration, always name the tempo character first, then say whether it is steady or changing.

Metre: simple, compound and irregular

Metre is how beats group into bars, shown by the time signature. In simple metre each beat divides into two: simple duple is 2/4, simple triple is 3/4, simple quadruple is 4/4. In compound metre each beat divides into three: compound duple is 6/8, compound triple is 9/8, compound quadruple is 12/8. The trick for hearing compound time is the lilting, swung "1-and-a, 2-and-a" feel of beats split into threes. Irregular or asymmetric metres group beats unevenly, such as 5/4 (often felt as 3+2) or 7/8 (often 2+2+3); these are common in twentieth and twenty-first century art music and some world and progressive styles. To find the metre by ear, locate the strongest recurring accent, count to the next one, and decide whether the beat splits in two or three.

Note and rest values

Rhythm is built from note values: the semibreve (whole note), minim (half), crotchet (quarter), quaver (eighth), semiquaver (sixteenth) and demisemiquaver (thirty-second), each worth half the one before it. Rests mirror these values as silence. A dot after a note adds half its value again, so a dotted crotchet equals a crotchet plus a quaver. A tie joins two notes into one sustained sound across a beat or bar line. Triplets squeeze three notes into the time of two, an example of tuplet writing that crosses the simple and compound boundary.

Rhythmic devices

The devices that give rhythm its character are where marks are won. Syncopation places accents off the main beat, on weak beats or between beats, and is central to jazz, funk and much popular music. Dotted rhythms create a long-short or short-long swagger. An ostinato is a short rhythmic or melodic pattern repeated persistently, often in the bass or percussion, holding a groove together. A riff is a related repeated figure in popular and rock styles. Augmentation lengthens a rhythm (usually doubling note values) and diminution shortens it (usually halving), both common developmental tools in composition and fugue. Hemiola briefly reorganises the beat, for example three groups of two heard against two groups of three.

Duration and the other concepts

Duration rarely acts alone. A change of tempo or metre usually signals a change of structure, such as the move from verse to chorus or from one section of an art-music form to the next. Rhythmic density (how many notes are sounding per beat) interacts with texture, and a driving ostinato can underpin a crescendo in dynamics toward a climax. Strong aural answers link a duration observation to its effect, for example noting that syncopation creates forward momentum or that a rallentando prepares the final cadence.

How to write about duration

Use point, evidence, effect. Name the feature precisely (compound duple metre, syncopated melody, dotted rhythm in the bass), pin it to a moment in the excerpt, and say what it does to the music. Never settle for "the rhythm is fast" when you could write "the Allegro tempo and continuous semiquaver ostinato create relentless drive".