These genres are all used in a compound form also known as dastgah (not to be mixed up ''dastgah'' as related to ''avaz'' as mode). The order of its components (comparable to Nuba, Walsa, Fasil) is like this: 1) Pishdaramad, 2) chaharmezrab, 3) avaz (improvisatory, instrumental or vocal), 4) tasnif, and 5) reng. Occasionally Daramad of dastgah is interested between pishdaramad and chaharmezrab.
Contemporary musicians, however, do not follw this ''compoundform'' and decided over the content and order of their concert components.
Recently pishdaramad has been retained in the order, and tasnif is moved to the end of the program. Between these two, the alternation between improvisatory and composed (instrumental or vocal) pieces could increase the total number of tasnifs to three to four in a concert.
Source: An Introduction to Iraninan music booklet from Mahoor Institute of Culture and Art