A sequence is the immediate restatement of a melodic motive or longer figure in the same instrumental or vocal part at a higher or lower pitch. Each separate unit of the sequence forms a segment.
The following list describes some characteristics of sequences:
- A sequence requires at least two segments.
- Most sequences contain no more than three or four segments.
- Sequences usually have only one direction—the segments succeed each other at continuingly higher pitches or continuingly lower pitches.
- Sequence segments usually continue by the same interval distance. As an example, if the first segment begins on C and the next starts with E, then the remainder of the segments will continue in thirds.
A real sequence contains continuing segments that are exact transpositions of the first segment. Every tone is transposed at exactly the same intervallic distance.
A tonal sequence accommodates the diatonic scale, so that only diatonic notes of the scale are used. This means that the transposition of the segments may not be exact.
In a modified sequence some of the segments may be decorated or embellished in a way that does not destroy their original character.
A false sequence repeats part of a figure and states the remainder in sequence—a mixture of sequence and repetition.