alap

The Alap (; ) is the opening section of a typical North Indian classical performance. It is a form of melodic improvisation that introduces and develops a raga. In dhrupad singing the alap is unmetered, improvised (within the raga) and unaccompanied (except for the tanpura drone), and started at a slow tempo. For people unfamiliar with the raga form, it introduces the thaat to the listener. It defines the raga, its mood, and the emphasized notes and notes with a secondary role.

Instead of wholly free improvisation, many musicians perform alap schematically, for example by way of vistar, where the notes of the raga are introduced one at a time, so that phrases never travel further than one note above or below what has been covered before. In such cases, the first reach into a new octave can be a powerful event.