These modal structures have developed over time, starting as seven in the Sassanian period to twelve in the 16th century with many many derivative modes and pieces. Within each song, there are 5-6 pieces generally which make up the entrance and the end, second entrance, ending with two pieces in the middle making up the general structure.
In terms of modals, the growth was vertically rather than horizontally, but the interesting thing is that notation has never been the strength in this region of the world. Therefore a wide range of improvisational options were left out to the players and singers. This has emphasized the importance of the artist much more. Modern theoreticians have tried quite hard to put these modals into notations with exact timing to be calculated. However, in practice they heartbrakingly found out that nobody much cared. In this sense there is a similarity with the ancient Folk music in Europe as well. We don't have to be able to write down everything in exact science. Somethings are better left vague to make it more interesting and artistic.
Maybe as a result of this improvisation options, Iran has been a dominant figure in the development of contemporary music in the 20th century. Before the revolution, Iranian music scene was flourishing with experimental artists and with Chinese artists, these composers take the leading stage apart from Us and Europe.
The record provides two Dastgah modals, Mahur and Segah. These are also present in the Turkish Classical music which in turn is actually not classical but rather palace music. The instruments are also similar. Tar, Ud, Kamanche, Santur, Nay and Tombak are present in the recording. Kamanche is native to the NorthEast Anatolia region which did appear in the folk songs, but not within the palace repertoire while Santur was never ever quite present in Turkey. Instead Kanun was apparent in the Turkish music. There is also a need to note that Turkish music got some of it's derived modals by reshaping Egyptian music into Persian music. This vast combination option increased the number of modals significantly and superficially.
The pieces are very very limited in terms of giving an idea about Persian music. The material is quite vast and even covering the 12 modals are not enough due to numerous derivatives. I don't know the exact number in Persian music, but in Turkish music, the total number of modals + derivatives reached upto over 500 with probably 50 or so remaining in use today. On the other hand, the music is totally different from the modern notation music we are used to. Even abstract music is quite simple compared to this musical culture since rhythm is a complex phenomenon and varies even during pieces of a modal. Apart from all the complexity of the system, the music is absolutely refreshing and different from the music of other regions. It is certainly a feat to delve into.
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