(Listen to the sound of what appears to be a didgeridoo at 39.40 into the discussion.)
The Shankhmukhi mudra is often used as a part of the series of steps in achieving a meditative state. Have you ever wondered how this sound “sounds”? Try to listen to your own anahata sounds and decide whether it is your simple affliction with tinnitus of something more and deeper than that!
The Yoga Upanishad (36-38) says ” that when the Nada sound has reached the middle of the head it sounds like a mountain-cataract”. So maybe you hear something akin to this?
I found an interesting piece by Kimba Arem on this topic:
She writes:
“The Nāda yoga system divides music into two categories: internal music, anahata, and external music,ahata. While the external music is conveyed to consciousness via sensory organs in the form of the ears, in which mechanical energy is converted to electrochemical energy and then transformed in the brain to sensations of sound, it is the anahata chakra, which is considered responsible for the reception of the internal music, but not in the way of a normal sensory organ.
The anahata concept refers to one’s own personal sound vibrations, which is thought to be so closely associated with one’s self and the self that a person can not share their anahata with another human being. In other words, this inner sound is sacred and once reached will open the practitioner’s chakras, which ultimately will unite the body to the divine/cosmos.
With continued sounds, a focused mind and controlled breath, the individual can, according to Nāda yoga, “listen in on” their own anahata, their own “inner sound”, which can take up to nine different forms. Such a process of inner awareness and sensitivity leads to increased self-recollectedness and finally to awakening.
To concentrate on this inner sound as a support for meditation is very helpful to tame the mind, and when it has been clearly recognized, used for self-recollectedness in outer life as well. Eventually, it can be experienced as penetrating all matter and indeed vibrates eternally throughout the Creation.”
This is what the classic Sanskrit treatise Hatha Yoga Pradipika has to say on the subject Chapter IV( verses 83-87):
“The sound which a muni hears by closing his ears with his fingers, should be heard attentively, till the mind becomes steady in it.81.
अभ्यस्यमानो नादो|अयं बाह्यमावॄणुते धवनिम |
पक्ष्हाद्विक्ष्हेपमखिलं जित्वा योगी सुखी भवेत || ८३ ||
abhyasyamāno nādo|ayaṃ bāhyamāvṝṇute dhvanim |
pakṣhādvikṣhepamakhilaṃ jitvā yoghī sukhī bhavet || 83 ||
By practising with this nâda, all other external sounds are stopped. The Yogî becomes happy by overcoming all distractions within 15 days.82.
शरूयते परथमाभ्यासे नादो नाना-विधो महान |
ततो|अभ्यासे वर्धमाने शरूयते सूक्ष्ह्म-सूक्ष्ह्मकः || ८४ ||
śrūyate prathamābhyāse nādo nānā-vidho mahān |
tato|abhyāse vardhamāne śrūyate sūkṣhma-sūkṣhmakaḥ || 84 ||
In the beginning, the sounds heard are of great variety and very loud; but, as the practice increases, they become more and more subtle.83.
आदौ जलधि-जीमूत-भेरी-झर्झर-सम्भवाः |
मध्ये मर्दल-शङ्खोत्था घण्टा-काहलजास्तथा || ८५ ||
ādau jaladhi-jīmūta-bherī-jharjhara-sambhavāḥ |
madhye mardala-śangkhotthā ghaṇṭā-kāhalajāstathā || 85 ||
In the first stage, the sounds are surging, thundering like the beating of kettle drums and jingling ones. In the intermediate stage, they are like those produced by conch, Mridanga, bells, &c.84.
अन्ते तु किङ्किणी-वंश-वीणा-भरमर-निःस्वनाः |
इति नानाविधा नादाः शरूयन्ते देह-मध्यगाः || ८६ ||
ante tu kingkiṇī-vaṃśa-vīṇā-bhramara-niḥsvanāḥ |
iti nānāvidhā nādāḥ śrūyante deha-madhyaghāḥ || 86 ||
In the last stage, the sounds resemble those from tinklets, flute, Vîṇâ, bee, &c. These various kinds of sounds are heard as being produced in the body.85.
महति शरूयमाणे|अपि मेघ-भेर्य-आदिके धवनौ |
तत्र सूक्ष्ह्मात्सूक्ष्ह्मतरं नादमेव परामॄशेत || ८७ ||
mahati śrūyamāṇe|api megha-bhery-ādike dhvanau |
tatra sūkṣhmātsūkṣhmataraṃ nādameva parāmṝśet || 87 ||
Though hearing loud sounds like those of thunder, kettle drums, etc., one should practise with the subtle sounds also.86.
घनमुत्सॄज्य वा सूक्ष्ह्मे सूक्ष्ह्ममुत्सॄज्य वा घने |
रममाणमपि कष्हिप्तं मनो नान्यत्र छालयेत || ८८ ||
ghanamutsṝjya vā sūkṣhme sūkṣhmamutsṝjya vā ghane |
ramamāṇamapi kṣhiptaṃ mano nānyatra chālayet || 88 ||
Leaving the loudest, taking up the subtle one, and leaving the subtle one, taking up the loudest, thus practising, the distracted mind does not wander elsewhere.87.”
Ayurkula 