Question: But in ordinary speech, the air coming out of our mouth produces a sound without striking anything. Is this not the case with AUM?

Sri Chinmoy: Actually, as the linguists will tell you, the various sounds of speech are caused by the impact of the breath upon the vocal cords and upon various parts of the throat and mouth. And of course, the physical sound of AUM when we chant it is made in the same way. On the physical plane, it is a physical sound, like any other. But permeating the physical sound is a higher divine vibration. This spiritual vibration comes from its connection with the inner reality of the universal AUM, which is the life-breath of the whole Creation.

We call AUM the soundless sound although with our ordinary ears we may hear this sound produced in the ordinary way in the outer world. But we can also hear it in the inner world if we have a special kind of hearing. We can hear the unstruck AUM with our spiritual ears. It is not the same sound that we hear with our physical ears. The inner AUM comes from an inner world, and its sound is altogether different. With our human ears we cannot hear it. We must have a different type of hearing if we want to hear the true soundless sound.