DASTGAH

in the art music of Iran, a set of notes, their special characteristics, and an associated group of traditional melodies that constitute a basis for improvised performance. The dastgah and the Arabic /a>maqam (q.v.) are similar systems, reflecting a period during which the Arabs ruled over Iran. The notes basic to each dastgah, or melodic mode, form a seven-tone scale. Although more than 50 have been widely used, theorists usually describe 12 principal modes. During a performance the musician uses the seven notes of the mode, three notes for changeable pitches within the mode, and several more for modulations (changes from one mode to another). He builds the performance on traditional melodic entities called gushehs. From the group of gushehs associated with a dastgah, a performer chooses which to use, the order in which to play them, and the way of playing them. The total collection of more than 200 gushehs in all 12 dastgahs is known as the radif. The Iranian dastgah represents evolution from the maqam after loss of contact with the Arabic tradition.