Seven Primary Modes
The seven primary modes or dastgah are: Shur, Mahur, Homayun, Nava, Segah, Chahargah, and Rast-Panjgah. The five secondary modes or avaz are: Abu-ata, Bayat Turk, Afshari, Dashti and Esfahan. Avaz is derived from dastgah, and hence is shorter in length of composition. These twelve modes comprise the entire “radif” or the collection of modes dealt with in Persian classical music today.
Each dastgah reflects a certain mood or emotion. Mood is Western music is usually limited to active or passive according to its two main scales, major and minor. But Persian music, like other Eastern music, provides a wide range of shades and grades of emotion. The mode Shur has an intense, fiery quality, but also may be used to express a tranquil mood. Isfanhan, a minor mode, is endowed with a feeling of romantic nostalgia.