Structures and Forms
The Nature of Music for the Performing Musician

Structures and Forms

The organization of sounds is based on various musical or non-musical structures and forms.

Structure refers to the organization of musical intervals, small groups of sounds, or large patterns which constitute a whole. The elements of musical structure may be grouped according to five general categories which include ratio, repetition, variation, continuity, and simultaneity.

1) Ratio refers to the relations between musical intervals, patterns, or larger structural units. Musical relationships may be contrasting or similar, simple or complex.

2) Repetition refers to recurring musical intervals or patterns and includes recursion, or varied repetition, and imitation. Imitation refers to the literal referencing of previously introduced musical material, or to the direct quoting of other musical sources.

3) Variation includes those patterns which have been previously introduced and are then modified in ways which preserve some recognizable aspect of their original state.

4) Continuity denotes structural coherence or unity, which occurs as a result of the musical direction which evolves from one musical pattern or group of patterns to the next. Continuity presumes the existence of contrasting structural elements such as discontinuity, chaos, or indeterminacy. Substructures of continuity and discontinuity include modulating effects such as expansion, elaboration, prolongation, intensification, interruption, and surprise.

5) Simultaneity refers to the harmonic, vertical, or chordal relationships in music, including multiple voicing and registration, as well as the superposition or layering of musical sounds or patterns. The arrangement of different sounds or 'voices' which coincide with or overlap one another result in various structural effects such as homophony, polyphony, including polytonality and polyrhythms, and heterophony. Like the element of continuity, simultaneity assumes the existence of contrasting structures which, in this case, may produce a single musical line or melody, or a harmonic or rhythmic unison, or on a larger scale, various unaccompanied forms.

Form is the overall pattern which constitutes a musical whole, considered as a single entity. The elements of form are broader than those of structure. While structure is the articulation of various musical patterns, form is the means through which those patterns achieve unity.

Musical forms may be grouped according to three general categories. These include traditional forms, abstract forms, and forms in nature.

Traditional forms are expressed within a wide variety of world music ranging from simple dance forms, such as the 17th-century Minuet, or the 18th-century Tango, to pure musical forms such as Irish fiddle music, American Blues, Bluegrass, and Jazz, the Western classical Suite or Sonata-Allegro form, or the Indian Varnam or Kriti forms, or the Gending form associated with gamelan music. Traditional forms, by definition, are those which have been handed down from musician to musician, and, in many cases, have taken centuries to develop their unique characteristics.

Abstract forms may result from sounds which are organized according to a narrative program, as an expression of various psychological or emotional states, or as an impression of or reaction to external stimuli, including social or cultural patterns. Various abstract forms may emerge from sounds which are arranged according to a predefined number or order of tones which form various musical scales, or from other considerations such as the limitations of, or the 'personality' of a particular musical instrument, or according to an abstract principle or system such as a mathematical set or philosophical idea.

The widespread use of indeterminacy, randomness, and various 'chaos' models has led to the development of a variety of abstract forms which have persisted throughout the latter half of the 20th-century.

Forms in nature occur spontaneously as a result of behavior patterns of various organisms, including speech and vocal patterns of humans and animals, as well as other forms of audible communication. Other musical patterns in the surrounding environment result from natural phenomena such as thunder, earthquakes, wind, water, etc. Yet other patterns are generated by the sounds of various human-made objects ranging from a music-box to a rocket engine.

The various musical patterns which occur in the natural environment may be musically modelled or simulated in a variety of ways.