Mohsen Renani in the preface of his book entitled “The Political Economy of nuclear conflict; an introduction to traversing the civilizations” writes:

Finding a way to harmonize the Iranian music has been the subject of controversy among Iranian musicians for a long time. Some believe in the creation of harmonies for Iranian music based on a method which is similar to the tierce harmony; while others have either selected or invented some other methods. There are also some musicians who do not basically agree with the harmonization of the Iranian music.

Regarding the classification of a new instrument in an instrument family, one can point to a number of fundamental issues, one of the most obvious of which is the instrument’s visual features. If we look at how the new instrument has changed compared to its historical versions, the set of visual elements that link the instrument to the Qeychak family becomes apparent. But other characteristics such as the geometric dimensions of the instrument, characteristics of the instrument’s various parts and how they relate to each other, its systematic performance, its sound range (compared to modern versions), the material and color of the sound, the way it is played and the like, can be considered in order to classify the instrument in the Qeychak family.

Despite the fact that Iranian folk music (regional music of Iran), like the Radif of Iranian traditional music, is monophonic and follows heterophony in principal, we experience polyphonic forms, albeit, majorly unconscious.

With its simple physical structure and captivating sound, the Daf never belonged to a particular culture or location, and every nation had different usages for this instrument considering their dominant customs and traditions.

In the tradition of classical music, it is generally tried to use the same technical terms related to music in all countries. Even in the cultures in which native terms exist to refer to musical terms, usually the better known universal terms are employed.

4.3.1. To practice playing of doubles of notes involving two different fingers, each note is played at separate bows with slow tempo, each note is played perfectly regarding its bass and tenor sounds and then the considered double is played at another bow while considering the resulted sound of the double.

At the end of the Qajar era and as Iran entered the power transition period, known as the constitutional era, the Iranian music went through a lot of changes. These changes gained momentum as the students and followers of Ali Naqi Vaziri’s entered the musical scene. These changes greatly influenced designs of instruments, playing methods, singing, composing, etc.

Music as an art has its own special history; emergence of a singer, of an instrumentalist and then the emergence of the strong character of a composer covers three significant phases of the art of music. With the emergence of composer which was simultaneous with the emergence of the language of music, this art managed to offer a domain for criticism for its composer; a procedure which led to a magnificent variety and evolution in musical production. Even though the conflicts between singers and instrumentalists have not met their end in the Iranian society and while singers can achieve high, instrumentalists have yet to play behind curtains . In a special era, with the efforts of musicians such as Ali Naghi Vaziri (1887-1979) and Rouhollah Khaleghi (1906-1965), glimmers of a composing era started to glow bearing fruit in Khaleghi’s achievement as Iran’s first professional composer. Khaleghi made his reputation as a composer while Vaziri deserved to pioneer this path. By then Vaziri was well-known as a Tar player.

In addition to the above-mentioned, polyphony can be also formed when a melody is performed by several singers in different ambiances or different sound registers according to their physiologic abilities. An example of this has been performed in rituals of Khanqah of Ghaderi darawish of Mahabad[i].