You are not one person sitting; you are only a little drop in the ocean of universal force, and because you cannot think it properly, one creates a symbol in the mind.
You start with a deep sonorous sound, and slowly it tapers off, like a ripple in water. When you throw a stone in water, it makes circles which will become wider and wider. Like that, you start the vibration here. Then you feel as if it is expanding little by little, by circles, until it reaches the top of the universe.
(Source: The Divine Life Society Sivananda Ashram,