The musical form can be studied on micro as well as macro structural level. On macro structural level,
there are, in different musical cultures, some fixed forms which consist of the succession of several
definite pieces. In ethnomusicological literature, these kinds of form are named suite or cycle, but in
the case of the Iranian music and according to the vocabulary of the old treatises of music, one can
call them nowbat. Nowbat is a very important form in different kinds of classical music in the Middle
East, but one can find it as well in the popular music of this reagion, especially in Iranian culture. The
majority of nowbats, in classical music and in popular music as well, follows the principle of generating
successively the tension and the relaxation, although the direction of this succession is different
in these two kinds of music. In any case, there are also some kinds of popular nowbat which do not
follow this principle.