Sri Raju Sastrigal asked Sri Bhagavan about nada, bindu and kala.
M.: They are in Vedanta terminology prāna, mano, buddhi (the life-current, mind and intellect). In the Tantras is said to be subtle sound with tejas—light —in it. This light is said to be the body of Siva. When it develops and sound is submerged, it becomes bindu. To be full of light (tejomaya) is the aim. Kala is a part of the bindu.