 Like other forms of jazz it places an aesthetic premium on expressing the "voice" or "sound" of the musician, as opposed to the classical tradition in which the performer is seen more as expressing the thoughts of the composer.Earlier jazz styles typically were built on a framework of song forms, such as twelve-bar blues or the 32-bar AABA popular song form with chord changes.In free jazz, the dependence on a fixed and pre-established form is eliminated, and the role of improvisation is correspondingly increased.