The sound of AUM is unique. Generally we hear a sound when two things are struck together. But AUM needs no such action. It is anahata, or unstruck; it is the soundless sound. A Yogi or spiritual Master can hear AUM self-generated in the inmost recesses of his heart.

There are many ways to chant AUM. When you chant it loudly, you feel the omnipotence of the Supreme. When you chant it softly, you feel the delight of the Supreme. When you chant it silently, you feel the peace of the Supreme. The universal AUM put forth by the Supreme is an infinite ocean. The individual AUM chanted by man is a drop in that ocean, but it cannot be separated from the ocean, and it can claim the infinite ocean as its very own. When one chants AUM out loud, one touches and calls forth the cosmic vibration of the supreme Sound.
      When chanting AUM, the "M" sound should last at least three times as long as the "AU" sound.