Developing new methods to direct music sounds differing from those remained from classic and romantic
era in old systems has always been the main concern of the 20th century composers. Efforts to
achieve a new sounding for expressing issues that descended in this century led to establishing new
systems and using them in creating pieces by composers. Some of those methods have received more
expanded anticipation by music composers and listeners. One of the methods that was first prevailed
in the beginning of the 20th century and after the Second World War received attention again, has been
establishing structures of sounds based on creating sound sets. By this system, the music composer
experiences an extensive freedom in action to express his thoughts in form of a music piece. The present
paper tries to study the structure rules of sets in a simple language. Efforts to establish a theoretic
framework named sets structure has been an effort to analyze works that could not be possible by
tonal or Cyril 12-note systems. Composition of those works started in the first half of the 20th century
and generally, without being carefully studied, they were considered superficially and became classified
under a general title; Atonal”. This type of works could be seen from the music composers of Second
Vienna School to their contemporary composers such as Stravinsky or Ives. Scriabin. In continuation,
efforts have been made to know the concept of sets and understanding the relationship among
sets for opening a better path to understand those pieces.With respects to the subjects discussed in
this paper, it is evident what an open hand music composers have in selecting sounds and directing
them. Music composer knows how to work with this knowledge and form in music to fulfill what he
considered. The re-approach of music composers to this system in post-second world war shows that
the notes sets have high capacities for creating pieces. Extensive use of sets techniques could be seen
in the works of great composers such as Briton, Shostakovich, schnittkeand lutoslawski. Preparing
new sounds as one of the most important materials of composition is what this method provides for
the music composer in a good way. of pitch-class sets, namely, 220. Each of these pitch-class sets
has been assigned a name consisting of the cardinal number of the set followed by hyphen followed
by a number that gives the position of the set on a list of sets, the ordinal number. The set may also
include the character Z, which indicates that the set so designated has a counterpart of a particular
nature. For example 4-Z15, this name indicates that the set contains 4 elements that it is item 15 on the
list of 4-elementpitch-class sets. The interval between two notated pitches is measured by counting
the number of half steps that separate them. The distance from C to E is 4 half steps. Specifically, the
interval between two any notated pitches as represented by pitch-class integers can be reduced to one
of the interval classes represented by the integers 1-6.There is , however, one basic from associated
with each pitch-class set type, and this basic form is called the prime form. It is also possible to define
relations of similarity between pitch class sets of the same cardinal number based upon pitch class
similarity and upon interval class similarity. The notion of pitch class is implicit in ordinary musical
language whenever we speak of 12 notes of the chromatic scale. That is , it is assumed that only 12
different pitches comprise the basic stock of the chromatic system. More precisely, this means that the
12 notes can be represented in a single octave by assuming octave equivalence and that a particular
for a pitch is not unique by assuming enharmonic equivalence.
