Whenever we chant mantras, do we have to recite them out loud or do we chant silently in our mind, like when we chant Om Namaha Shivaya?
Sri Sri Ravi Shankar:
Both approaches are fine, but one need not chant very loudly. When we chant mantras loudly and together in a group, then it is called as Kirtana. When we recite in a normal or medium tone of the voice, then it is called as chanting. And when you recite quietly or very slowly in the mind, then that is called as Japa.