There are three theories about Persian music intervals. The first one, which was done in 1920 by Ali Naqi Vaziri, identifies Persian musical intervals based on a 24 quarter-tone scale. The second one was done by Mehdi Barkeshli in 1940 and defines Persian music intervals within a 22 tone scale. And a third one was pre- sented by Hormoz Farhat who is representing Persian Musical intervals within five intervals with which all of the Persian Musical modes are constructed and does not recognize any basic scale concept.(Farhat 1990, 7)
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Source : Rhythmitica
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