Each gusheh is in itself a musical system, an apparatus the musician uses to create a composition. Like the Indian raga, the Arabian maqam, and the echos of Byzantine music, a gusheh is a melody type—"a traditional repertory of melodies, melodic formulae, stereotyped figures, tonal progressions, ornamentations, rhythmic patterns, etc., that serve as a model for the creation of new melodies." The dastgah is a larger system, or a compound melody type.
To describe the features that characterize a gusheh, let us begin with its range. Most gusheh-ha are confined to a four- or five-note compass located in a specific part of the octave. Thus, a gusheh occupying the lower tetrachord does not often use notes of the upper tetrachord. Another basic feature of the gusheh is the configuration of the notes within its range. If the range is a tetrachord, which is true of a majority of gusheh-ha, the tetrachord may contain either a major, minor, or neutral second, and either a major, minor, or neutral third.
The hierarchy of the notes in its range is an additional distinguishing feature of the gusheh. The most important notes are the one on which the melody stops, and the one that receives special emphasis in the gusheh, or occurs most often, comparable to the finalis and reciting tone of Gregorian chant. These notes have been recognized and labeled by Persian theorists : the note of stopping is the ist (stop), and the note of stress is the shahed (witness). These notes are comparable to the finalis and reciting tone of Gregorian chant.
The location of these preferential tones within the range of the gusheh serves to give the gusheh its particular character. For example, if two gusheh have the same range, say C to F, and one cadences on E, stressing the note F, whereas the other both cadences and stresses the note C, the two will obviously be quite different. All these factors pertaining to the range of the gusheh— its location, configuration, and hierarchy of notes—may be considered modal features of the gusheh. These are the most important characteristics of each gusheh and are well defined in the theoretical literature.
In addition to its modal characteristics, the gusheh has other features that are not so clearly definable. One is a certain melodic shape that remains recognizable throughout the improvisation. Another is a set of characteristic motives and cadence formulae for each gusheh. Finally, there are the extramusical associations that combine to give each gusheh an individual character. In speaking of the opening gusheh of Shur, for example, Farhat mentions its staid character, while a later gusheh, Shahnaz, he considers emotional and exciting.
Gusheh and Dastgah in Persian Music: Classic Framework and Modern Interpretations
