In Carnatic Music, Kalpanaswaram (also called swarakalpana, svarakalpana, manodharmaswara or just swaras), is raga improvisation within a specific tala in which the musician improvises in the Indian music solfege (sa, ri, ga, ma, pa, da, ni) after completing a composition.
The kalpanaswaram start may start at any place in the tala, but invariably the artist must end their improvisation at the first note of the first phrase of the composition, at the place in the rhythm cycle, where that note is. To arrive at that note, one has to approach it from the closest note below. There are, however, instances when the kalpana swaras are rendered at various starting points of the composition which may not coincide with the start of the Tala cycle. In such cases, the kalapana swaras should always end at the same position irrespective of where they start. For example: 2 or 4 counts after the start of the Tala Cycle.
Kalpanaswaram improvisations increase in intensity with the tala cycles used. One complete tala cycle is called an avartanam. While improvising, the musician must abide by the rules of the raga and ensure that swaras used in the imaginative phrases are all inclusive in the basic Aarohana (ascent) and Avarohana (descent) structure of the raga. Some ragas omit notes and others have zigzagging ascents or descents. The great musicians develop a vocabulary of phrases in kalpanaswaram as in an alapana, especially when doing kalpanaswaram at low speeds, which allow for more gamaka. The place where the first note of the first phrase of the composition exists in the rhythm cycle is called the eduppu.
Kalpanaswaram is performed in a Carnatic Concert for the main song, the singer chooses to perform the Raga Alapana. However in concerts, artists will choose a difficult raga to perform a Kalpanaswaram in. Although there are no set rules, the artist may decide to expound the expressions of a particular raga in Kalpanaswaram as opposed to Alapana.
In this raga, when the artist improvises, when ascending in pitch after the Pa (Panchamam), the Ma (Madhyamam) needs to be sung, or the raga will be wrong. So with a raga like Sahana or Anandabhairavi, Purvi Kalyani etc., which have Dhattu (jumping) swarams in their arohanam and/or avarohanam the Kalpanaswaram is harder to master and perform.
In her 1992 dissertation on kalpanaswaram, Josepha Cormack wrote that kalpanaswaram improvisations have been around for at least two hundred years. (Cormack 1992: 30)
Cormack, Josepha A. 1992. Svara Kalpana: Melodic/Rhythmic Improvisation in Karnatak Music. PhD Dissertation: Wesleyan University.