What is Nada Yoga, the Inner Sound, the sound of Silence?

The Nada is an inner sound that can be heard in the ears and head and which resembles the murmur of the wind and the continual lapping of the ocean waves.
It is a very precious support for remaining present during meditation and in active life, as it has a continuity which is precisely what human beings habitually do not have.
Edward Salim Michael (1921-2006) described in detail the various ways of using this inner sound in two of his works “The Law of Attention” and “Inner Awakening and Practice of Nada Yoga”.
This video is made up of extracts from Edward Salim Michael’s teachings in relation to the Nada.

Lecture Excerpt 1 :

Why doesn’t the seeker succeed in concentrating? Is he relieved to stop his meditation? Every night, he loses his name, his shape and even the notion of time. What clue does this state reveal to him of what will happen to him after death. It is vital for him to come to familiarize himself, when still living, with the state in which he will be reabsorbed after his physical death. He must arrive at recognizing in his meditation a state of ethereal transparency which will prove to be his Primordial Essence, his Buddha Nature, Nirvana. (extrait de l’Unification des trois aspects de la nature humaine nécessaire à la méditation)