The Dastgah Concept in Persian Music

The Dastgah Concept in Persian Music by Hormoz Farhat is an exceptional work that deals with the fundamental principles of Persian music and thoroughly analyzes its musical modes and melodies. Farhat's particular contribution lies in his groundbreaking theory, that challenges the conventional understanding of musical modes in Persian music. He argues that the intervalsAn interval is the distance between two pitches. It can be measured as a ratio between their frequencies or in cents.Visit the link to learn more in Iranian music are not rigid but rather flexible, an idea that has sparked great interest and debate among scholars.

The book consists of seventeen chapters covering a wide range of topics, including terminology, intervals, historical context, a detailed examination of twelve Dastgāh (musical modes), various aspects and the general structure of Persian music. Farhat introduces the concept of "flexible intervals" and emphasizes the stability of the minor second (256/243 or 90 centsA cent is a unit of measurement for intervals and is defined as 1/1200th of an octave.Visit the link to learn more) and the whole tone (9/8 or 204 cents) in different modes and interpretations as PythagoreanPythagorean tuning is an approach to tuning based on stacking pure fifths (i.e. fifths with an exact frequency ratio of 2:3).Visit the link to learn more intervals. He identifies two types of "neutral tones" of variable sizes, one between 125-145 cents and another between 150-170 cents, suggesting the use of their mean values at 135 and 165 cents respectively. He also introduces the “plus-tone" (270 cents) and adds that the plus tone is a very unstable interval, larger than the whole tone but not as large as the augmented tone. It is only found in a limited number of modes and is always preceded by a small neutral tone.

Interval size
Quarter tone -
Minor second (m) D♭ 90
lesser neutral second (n) D koronA koron is an accidental that lowers the pitch by a quarter-tone. The koron was designed by Ali-Naqi Vaziri (1886-1979).Visit the link to learn more 135
greater neutral second (N) 165
Major second (M) 204
Plus tone 270

Farhat's 17-tone scale

Farhat's approach takes into account instruments such as tar and setar, whose fingerboards have fixed frets, resulting in minimal pitch variations. His research leads to the introduction of the unequal 17-tone scale, which offers a new and culturally authentic perspective for understanding and analyzing Persian music, free from the influences of Western musical traditions.

(* see soriA sori is an accidental that raises the pitch by a quarter-tone. The sori was designed by Ali-Naqi Vaziri (1886-1979).Visit the link to learn more)

Although all contemporary Iranian theorists before Farhat have attempted to theorize Iranian music in a Western way, comparing the Iranian modal system with Western 12-tone scales, Farhat rejects this approach. He stresses that there is no concept of scale in Iranian music. He goes on to say that the scale he mentions should be understood as a palette of all possible pitches used in Iranian classical music and as a source for creating modes. The modes created usually have four or five pitches and occasionally up to seven. He also reminds the reader that there is no chromatic movement in the melodies of classical Iranian music and that there are no intervals smaller than 90 cents in the structure of classical Iranian modes.

In Persian music culture, the Radif forms a core repertoire of classical music in Iran that is understood holistically. A complex network of more than 250 melodic patterns, called Gusheh, which are organized into twelve main groups according to their modal relationships, bears the name Dastgāh. Each Dastgāh is associated with a unique tonal space, and it is precisely this network that connects all twelve Dastgāh-hā, which are called Radif. The origin of the term Dastgāh comes from the old method of describing the position of the pitches on the instrument by the allocation of the fingers on the fingerboard. It literally means "the position (gāh) of the hand (dast)."