Question: What is the most meaningful sound for spiritual awakening?
Sri Chinmoy: The most meaningful sound is AUM, which is the mother of all Indian mantras. Mantra means incantation. But if we say that AUM is an Indian mantra, it will be an act of injustice to God's most sublime and unparalleled Message to humanity. God's Message in the form of AUM will always remain unparalleled. AUM is the combination of three letters, A-U-M, which represent the three principal figures in the heart of the Supreme: Brahma the Creator, Vishnu the Preserver and Shiva the Transformer. The moment we start chanting or pronouncing AUM, 'A' is purifying the physical in us. When we pronounce 'A' soulfully, it purifies the ignorance of millennia within us. When we chant 'U' most soulfully we have to feel that all our vital emotions from time immemorial are illumined. And when we chant 'M' most soulfully, we have to feel that our limited, sophisticated, earthbound mind is totally freed from the meshes of ignorance. So if you can pronounce, if you can chant most soulfully A-U-M, then the body consciousness is purified, the vital consciousness is illumined and the mental consciousness is perfected. When this is done, we become undoubtedly the supreme instruments of the Absolute Supreme.
Sri Chinmoy, The height of silence and the might of sound, Agni Press, 1974