Nāda

Nāda refers to sound in its fullest sense, encompassing both struck sound (āhata) produced by physical contact and unstruck sound (anāhata) that exists without any physical cause. In Indian classical music, nāda is the foundational principle from which all musical notes (svara) arise. It is the essential medium through which rāga, tāla, and melody are expressed.

In yogic and tantric traditions, nāda is the subtle inner sound perceived during deep meditation, often described as a progression from gross vibrations to increasingly refined tones. The practitioner of Nāda Yoga traces this inner sound inward through stages — resembling bells, flutes, thunder, and finally a pure hum — until the mind dissolves into its source. It is considered a direct path to samādhi.

At the absolute level, Nāda is identified with Brahman itself as Śabda-Brahman — the Supreme Reality manifest as primordial vibration. Before creation, the undifferentiated Parā Nāda stirs within pure consciousness, giving rise to Paśyantī, Madhyamā, and finally Vaikharī (articulate speech). All of manifest existence is thus an expression of this one eternal vibration, and realizing Nāda as identical with Ātman is liberation.