The Description of the Four Durgā Mantras
निरोधिकायामर्द्धेंदुनादे नादांतयोः पुनः । उन्नतांसेषु वक्त्रे च ध्रुवमण्डलके शिवे ॥ १२२ ॥
nirodhikāyāmarddheṃdunāde nādāṃtayoḥ punaḥ | unnatāṃseṣu vaktre ca dhruvamaṇḍalake śive || 122 ||
In the nirodhikā (the restraining inner channel), in the sound like a half-moon, and again at the end-points of the nāda; in the raised shoulders, in the mouth, and in the auspicious, steady sphere (dhruva-maṇḍala)—there one should fix awareness.
Sanatkumara (teaching Narada)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: adbhuta
It maps specific inner loci where attention is to be stabilized so that nāda (subtle sound) becomes a support for nirodha (restraint), leading the mind toward steadiness and liberation-oriented absorption.
While primarily yogic/technical, it supports bhakti indirectly by training one-pointedness; a steadied mind can hold divine remembrance without distraction, making devotion continuous and deeper.
This belongs to the technical-yogic instruction stream associated with Vedāṅga-style disciplines (especially Śikṣā and subtle phonetics of sound), using nāda as a practical method of concentration.