Question: I know that the mantra Aum is supposed to be very powerful. Please tell me the proper way to chant Aum.Sri Chinmoy: It is better to repeat Aum aloud, not silently. I tell my disciples that the sound should not come from the throat; it should come directly from the heart. The ‘m’ sound should last three times as long as the ‘au’ sound, and you should feel it vibrating inside your heart. Again, let the mantra vibrate all over your body; let the sound permeate your body.
Sri Chinmoy, Transformation-Night, Immortality-Dawn, Bhakti Press, Ottawa, 1975