Sequence

What it means

A sequence is the repetition of a melodic or harmonic section on another scale degree. A motif is presented and immediately afterward repeated higher or lower, often several times in a row, so that a chain of like members results. The individual member is called the sequence model, every repetition a sequence link.

Musical use

Two kinds are distinguished. In the tonal sequence, the repetition stays within the stock of notes of the key; the intervals thereby change slightly, because large and small steps are distributed differently in the scale. In the real sequence, the model is transferred exactly, with identical intervals, which requires notes foreign to the scale and often leads into other keys.

Harmonically, the descending-fifth sequence is especially widespread, in which the roots run downward in fifth steps and every sonority works like a dominant of the following one. It is a basic model in Baroque music and is found in interludes of fugues, in concerto movements, and in developments. If the individual links are executed as secondary dominants, the pull intensifies.

The sequence serves Fortspinnung, intensification, and modulation. Because the ear recognizes the pattern after a few links, it creates expectation; it is usually abandoned after the third link, before it seems mechanical.

The sequence is to be distinguished from imitation, in which a motif is imitated in another voice; the sequence repeats a motif in the same voice on another degree. It is likewise to be distinguished from transposition, which shifts a whole piece.

A distinction is made between the melodic sequence, in which a line is repeated on another degree, and the harmonic sequence, which shifts a chord progression. Well known is the descending-fifth sequence, in which the roots each fall a fifth. In the Middle Ages, sequence additionally designated a liturgical genre.

Performance practice

Shape a sequence as an intensification or a calming, not as a uniform repetition. Recognize the model and its limits, in order to phrase the links. And watch where the sequence is abandoned — there the music usually changes direction.