The particular sound is called nad

Who has not heard the sound, the gurgle of the springs, the chirping of birds. The nad lahari that is given by nature is produced, it is the form of an infinite nad, which is a natural process of nature. But the sound that is created by the friction or collision between two objects is called cosmic sound.
In order to disperse the sound on the atmosphere, the weighty air produced by the larynx on the external air collapses, while at the same time the 'vocal cords' in the throat produce the sound. Thus, the sound produced by human beings is cosmic.

The name of a Upanishad is 'Nad Bindu' Upanishad. In which many verses are based on this sound. What is the sound, how the sound goes, what is the benefit of listening to the sound, all of these are discussed in it. When you do nad, this is its first stage. On reading: While practicing the pronunciation of ॐ, there comes a time when there is no need to pronounce, you just close your eyes and ears and listen to it inside and that sound will start to be heard. In the beginning, it will be heard very subtle and then it will grow. Sage says

The literal meaning of nad is - 1. Word, sound, voice. According to the acharyas of music, the combination of Akashastha Agni and Marut originated Senad. Where the state of prana (air) resides, it is called Brahmagranthi. It is written in Sangeetdarpan that the Chitta Dehaj strikes the fire by being inspired by the soul and Agni inspires the cosmic life. Prana, inspired by fire, starts climbing again. After reaching the navel, he is very subtle in the heart, athletic in Galadesh, unconfirmed in the top and in the mouth ...