Technique of Nāda yoga: close the ears (typically with the thumbs — śambhavī or yoni mudrā of ears), listen to the inner sound.

Nāda is not imagined; it is real sound that arises when the external senses are closed. It is described as humming, bell, drum, flute — evolving toward subtler sounds.

“Mind absorbed” (līnaṃ manaḥ) — the sound attracts the mind like quicksand. Resistance is useless; absorption is inevitable.