Since the Indian Classical music is modal music based on relations between a fixed sound, the tonic and the
successive notes. The tonic needs to be heard continuously.The sustained accompaniment of the tonic allows the
performer to check his/ her voice to avoid dissonance. This constant tonic is provided by the instrument Taanpura.
It has four or sometimes 5/6 strings . The drone is accomplished (explained for a four string taanpura) by playing
and (If a particular raag does not include Pancham but has Madhyam eg. Raag Marwa or Malkauns)
Some times it is set to
or if the raag has prominence of Dhaivat or Nishad.