 People who are in a certain state of sadhana which is referred to as the Rithambara Pragyana may hear sounds beyond its spectrum. Pranamaya Kosha is made up of seventy-two thousand nadis, 108 active energy centers in the body or chakras in the body. This dimension of allowing the human system to evolve to its ultimate possibility by using these 108 sounds is called as nada yoga. Today it is common scientific knowledge that the whole existence is a reverberation of energy. Or in other words, the whole existence is oscillating between being physical existence and being a vibration. So the source of all that's physical in the existence today as per modern science is a reverberation or a vibration. This was recognized by the yogic sciences many millennia ago and it was said the whole existence is sound because where there is a vibration there is bound to be a sound. Vibration is only a description but in human experience all vibrations we experience them as sounds. Among the vibrations that happen in the existence not all of it is right now available to the human ear. The spectrum of sounds that the reverberations of creation throws out is not fully available to the human ear. Only a small band of frequency is available. This we call as the sonic sounds. What is above or over that is called ultrasonic. What is below is subsonic. Both the subsonic and the ultrasonic sounds are not available to the human ear unless a human being strives has the necessary sadhana to go beyond these limitations of a small band of frequencies. People who are in a certain state of sadhana which is referred to as the rithambarapragna may hear sounds beyond its spectrum. Otherwise most human beings are limited to this small band of frequencies. What we refer to as music is a more refined arrangement of the sounds that the creation is already making. The Indian classical music particularly comes from a very deep understanding of the human system because all our experience of life is essentially happening within us. Light and darkness is happening within us. Sound and silence is happening within us. Joy and misery is happening within us. Agony and ecstasy is happening within us. Every human experience happens only within ourselves, never outside of ourselves. Because we are the basis of our experience, everything that we do is based upon the nature of the self. Because of this, the music identified certain dimensions of the body which are responsive to the sounds that we generate or the sounds that come towards us. The human system being seen as five koshas or five sheets or layers of body. The Annamaya Kosha, the Manomaya Kosha, Pranamaya Kosha, Vighanamaya Kosha and Anandamaya Kosha. Among these five, Pranamaya Kosha is the most significant one. Pranamaya Kosha is made up of seventy to thousand nadis which meet and redistribute in one hundred and fourteen significant ways. Or there are one hundred and fourteen junction boxes in the human system. Of these, two are outside the physical nature and one hundred and twelve are within. Out of these one hundred and twelve, four are dormant to a large extent. So one hundred and eight active energy centers in the body are chakras in the body. Based on this, these one hundred and eight are divided on the right and the left in the form of Eda and Pingala. They are divided as fifty-four each. Based on this, we form the Sanskrit alphabet of fifty-four sounds. These fifty-four sounds in two manifestations of feminine and masculine, we have one hundred and eight. These one hundred and eight sounds, these fifty-four in two different shades or two different manifestations, amounting to one hundred and eight has a significance and the whole music system evolved out of these one hundred and eight. So the Indian classical music essentially is about touching these one hundred and eight or activating these one hundred and eight chakras or points in the body which will lead to a natural evolution of the human being to a higher level of consciousness. So music has never been just in a form of entertainment. It has been a way of evolving an individual human being into a universal entity. So this dimension of activating the human system, this dimension of allowing the human system to evolve to its ultimate possibility by using these one hundred and eight sounds is called as nada yoga. So the Indian classical music is an evolution of this fundamental process of nada yoga. If one listens to music with the necessary involvement or one involves themselves in the process of what we are referring to as the classical music, it is not just about pleasantness of the body. It is not just about the pleasantness of emotion that one goes through. It is a way, it is a method to move out of compulsive cycles of life and transcend those cycles to achieve an ultimate process of freedom and liberation. The classical music is a very refined and wonderful way of delving into oneself. This is one of the most wonderful ways that one can transcend one's limitations and arrive at an ultimate possibility. There are many ways to do this, but this is a wonderful and beautiful way to do it.