The macro-structure of an instrumental Alap consists of three main parts: Alap, Jod and Jhala. Each has distinctive musical characteristics, and flows seamlessly from one part to the next.
The first part introduces the raga, a modal formula that characterizes the work. The rhythm is free and without a regular pulse. The performer begins introducing important notes or phrases of the raga in the low-to-middle pitch range, gradually expanding the range and adding embellishments.
In this part, the performer continues to develop the raga, but with a distinct rhythmic pattern. The music seems to move faster, first at a medium tempo, then even faster and the level of musical emotion increases.
The final part is very brief, usually characterized be a sudden relaxing of the rhythmic tension created in the Jod. There may be cursory repetitions of the free-flowing music similar to the beginning of the Alap, but the Jhala usually is a somewhat abrupt ending.
The two important musical components of an Alap are the drone and solo part. Some instruments, such as the sitar or vina, allow the same musician to play both drone and improvisation. For a flute, violin or other instrument incapable of producing the drone, a second musician is required to play an instrument, such as a tambura.