Nadanusandhana

From Hatha Yoga Pradipika Chapter 4:

1. Quiet place, steady seat (4.67). Svatmarama: sit in Muktasana (a comfortable cross-legged seat) in a silent location, the body still.
2. Adopt Shambhavi Mudra and turn attention to the right ear (4.67). Holding the gaze inward (Shambhavi Mudra — see the separate entry), “the yogi should hear the sound inside his right ear, with a collected/concentrated mind.” The senses are withdrawn from the outside world; hearing is turned inward.
3. Close off the outer senses (the traditional execution — Shanmukhi Mudra). To make the inner sound audible, practitioners block the ears (and often eyes, nostrils, lips) with the fingers — the “six-gated seal.” Svatmarama’s frame is sense-withdrawal so that only the inner sound remains; closing the ears is the standard way to do this.
4. Just listen — let the mind be caught by the sound (4.84–4.93). At first faint, the sound becomes clearer in silence. Svatmarama describes the mind as a restless animal that, “hearing the nada, becomes absorbed in it,” like a bee that drinks nectar and forgets to fly, or a deer charmed by music. You do nothing but attend; the sound does the work of binding the wandering mind.
5. Follow the sound as it changes — the four stages (4.84–4.101). Svatmarama maps a progression. The sounds heard move from gross to subtle: early on, loud sounds — like the ocean, a kettledrum, thunder; then mid-stage sounds — a drum, a bell, a conch; then subtle sounds — flute, vina, the humming of bees. The instruction is always to let go of the grosser sound and attend to the subtler one as it emerges, following it ever inward.
6. Absorption (4.99–4.102). As attention rests ever more finely on the subtlest sound, mind and prana grow “latent” and the practitioner enters laya/samadhi — stillness in which the sense of separate thought dissolves. Svatmarama: the mind merges in the nada “as salt in water.” (Sourcing note: Muktasana + Shambhavi Mudra + “hear the sound in the right ear with collected mind” is HYP 4.67; the bee/deer absorption imagery and the gross-to-subtle stages of nada are HYP ~4.84–4.101, faithfully paraphrased. The finger-sealing Shanmukhi Mudra is the standard traditional execution of “withdrawing the senses to hear the inner sound” and is flagged as the conventional method rather than a verbatim 4.67 instruction. Verse ranges follow common editions and may vary slightly by manuscript.)

Svatmarama’s Hatha Yoga Pradipika (15th c. CE) places nadanusandhana as the culmination of hatha practice — the bridge from physical disciplines to raja yoga’s samadhi. It draws on the older Nada Yoga stream of the Nath siddhas and tantric sound mysticism.

It is foreshadowed within the same text by Bhramari (the self-made hum). Downstream it informs Nada Yoga lineages, Surat Shabd Yoga (Sant Mat’s “listening to the sound current”), and modern sound-meditation.

Nada Yoga (broad) — the whole science of inner sound as a meditative vehicle; HYP is a key source.

• Surat Shabd Yoga / Sant Mat — “listening to the inner sound current (shabd)” as the central practice; structurally parallel.
• Bhramari — generating the sound first, before listening for the spontaneous one.
• Om / pranava meditation — resting attention on the resonance/echo of Om as it fades into silence.
• Open-awareness sound meditation (secular/mindfulness) — using ambient or inner sound as the meditation object.

Straining to hear / manufacturing a sound. You wait and receive; you don’t squeeze your ears or invent a tone. Effort scares the subtle sound away.

• Not enough silence. The practice needs a genuinely quiet environment; ambient noise drowns the faint inner sound.
• Clinging to the loud sounds. Svatmarama’s instruction is to release the gross and follow the subtle. Staying with the dramatic early sounds stalls the progression.
• Turning it into analysis. Naming, judging, or hunting “which stage am I in” reintroduces thought. Just listen.
• Doing it with untreated distressing tinnitus. For some, attending to inner sound amplifies distress — see Safety.