Rig Veda · Rig Veda (Yoga Upanishad group) · 56 mantras
Nada Bindu Upanishad
Nāda-bindūpaniṣad
Central theme: The yoga of inner sound — meditation on the unstruck cosmic vibration (nada) heard within, leading from gross sound through subtle to the soundless Brahman
A specialised yoga Upanishad devoted entirely to nada-anusandhana (the inquiry into inner sound) — the technique of closing the external ears and listening to the spontaneous unstruck sound (anahata nada) within. The text describes ten progressively subtler stages of inner sound: chini (like the sound of "chin"), chini-chini (more refined), bell (ghanta), conch (shankha), tantri (lute), tala (cymbals), venu (flute), bheri (drum), mridanga, and finally the soundless meghadhwani (cloud-thunder dissolving into silence). Each stage corresponds to a deeper layer of the mind: the lute-stage steadies the prana, the flute-stage absorbs the chitta, the thunder-stage dissolves the manas itself. The Upanishad opens with a remarkable Vedic cosmology — the Pranava (Om) is the swan whose feet are the four states (waking-dream-sleep-turiya), whose body is the three matras (a-u-m), and whose flight is the upward journey of consciousness from the muladhara to the sahasrara. This Upanishad is the primary scriptural source for the Nada Yoga of the Hatha Yoga Pradipika (Chapter 4) and for the entire Sant tradition (Kabir, Nanak, Dadu — all reference inner sound as the surest path to liberation).
Nada Bindu Upanishad — Mantra 51
अन्तःस्थं मनसा पश्येद्ब्रह्माणं निष्कलं ध्रुवम्। नादे लीनं मनो यस्य स याति परमां गतिम्॥
Antaḥsthaṁ manasā paśyed brahmāṇaṁ niṣkalaṁ dhruvam, nāde līnaṁ mano yasya sa yāti paramāṁ gatim
One should see within, by the mind, the partless and changeless Brahman. He whose mind is absorbed in the inner sound — he attains the supreme goal.
Close the ears and listen. The bell, the conch, the flute, the thunder — and then silence. The shortest road home is the unstruck sound.