An Approach to Harmonizing Based on the Structure of Intervals in the Dāstgah Segāh

This paper attempts to suggest a new method for harmonizing Persian classical music according to the interval structure of Dastgāh Segāh. One of these requirements was made when performing solo was overshadowed and then the tendency to use ensembles was increased. Each sort of ensemble needs polyphonic music, and scholars have sought to find a way to produce polyphony in Persian harmonic format. From 1954, (1314) this criteria has been used to examine polyphonic Persian harmony. However these examinations have been generally based on principles of western music and as a result there are some deficiencies. The phenomenological method which is going to be used here is a method that replaces the current external framework of examination of Persian harmony with a different framework from within Persian music. Considering that and the potential and structure of Iranian music the method presented here is to investigate phenomenon internally; the reason for selecting the Dastgāh Segāh is that it, compared to other Dastgāhs, has the most "Mojanab interval" (135-145 cent). In this method all the notes in each main Gūshe of the five credible Radif are taken into account, and considering usage statistics of them as well as the books analyzing Radif, the most significant notes for composing a chord for that specific Gūshe are chosen. The chosen Gūshes are those with specialized modal qualities, which we have called them the main Gūshes of Dāstgah Segāh, which include: Darāmad, Zābol, Mūye, Mokhālef, Mağlūb. The modal ambience of Dastgāh Segāh is formed by unifying the component modes of each main Gūshe, and representing an appropriate harmony for the whole Dasgāh. For a more accurate analysis of these Gūshes the five credible Persian music Radif (Radif Sāzi Mirzā Abdollāh, Aghā Hosseingholi, Mūsā Maroufi, Montazem-ol-Hokamā, and Radif Avāzi Abdollāh Khān Davāmi) are compared with each other. The assumptions of this paper can be summarized as follows: 1- the possibility of composing some chords with interval Mojanab (wider than a minor second and narrower than a major second) can be found by structural analysis of the currently available intervals of Dastgāh Segāh in different Radifs; 2- the main chords of Dastgāh Segāh can be explained based on the structure of modal Gūshes of that Dastgāh, since a Dastgāh is formed by the modes which are arranged in a particular order; 3- for composing chords proportional to Dastgāh Segāh the role of notes such as Shāhed, the final and other important notes in each Gūshe, needs to be considered. The findings suggest two types of chord for each Gūshe. The first chord contains the main notes, and the second one suggests the main notes are accompanied by the notes which play a melodic role in that Gūshe. Thus, for making a connection between these chords considering the arrangements of Gūshes in Dastgāh Segāh, melodic notes in an appropriate harmonic connection are used.