Yoga Sutras of Patanjali translated by Yogi Kalinath - Chapter 3, Verse 41
Pada 3, Sutra 41
Shrotraakaashayoh sambandha-sanyamaad divyam shrotram
Through constraint on the relation between the ear and space, divine hearing.
Divine hearing signifies clairaudience. Space is where vibration happen which is picked up by the ear as sound. By focusing on the subtleties behind sound as it travels through space one will develop the ability to tap into and develop over time and practice the astral sense of hearing which is called clairaudience.
Our senses are limited when operating through their physical apparatuses. However this is not so when they are channeled through the apparatus of the subtle body with the command center being the psyche (hence they become then known as the psychic senses). One develops the ability to hear over great distances as well as hearing the music of the spheres which issue from our psychic vortexes known as the Chakras.