Maqam
The Arabic modal system, known as maqam, uses pitches not found in Western harmony; the violin, however, is capable of playing these frequencies because there are no fixed pitches on the instrument.
Another important feature of this opening is the use of varied melodic material. Repetitions of a melody may occur, but it is common to introduce new themes through- out a performance to make the music more interesting. Doing so also allows the vocalist more ideas with which to work in his or her own improvisations. Instrumentation may change in the performance of a melody, again to provide contrast rather than repetition, even if the melody is the same as in an earlier passage.