Question: Occasionally during meditation I momentarily hear a soft voice. How can I hear this voice more clearly?Sri Chinmoy: You can hear this voice more clearly if you try to feel that inside the physical heart there is a divine heart, an inner spiritual heart. First try to feel it inside you and then try to see it. Once you can see it you will hear this voice most clearly. Now you have to know that the heart that you are going to see is not smaller than the physical heart. We always feel that something must be smaller in order for it to fit inside something else. If I have a vessel and I want to put another one inside it, naturally the vessel that I am putting inside must be smaller. But in the case of the spiritual heart, it is not like that. The spiritual heart, which is inside the physical heart, is infinite. How can something infinite be inside the finite? Your mind will not be able to understand it. But God the Infinite Himself is within us; that is why we are praying and meditating. Similarly, the inner heart which is inside the heart is infinitely more powerful and infinitely larger than the physical heart. If you can see it once, then immediately you will be able to hear most clearly its strength, its capacity in the form of sound. When we enter inside the spiritual heart we can hear this sound most powerfully and constantly. To create this sound we don't have to strike anything. We call it anahata, unstruck sound. Here on the physical plane we must strike two hands together to produce a sound, but this most powerful inner sound is not struck by anything or anyone. This is the difference between earthly sound and inner sound.
Sri Chinmoy, The height of silence and the might of sound, Agni Press, 1974