When we chant the Mantra as were presented by the authorities - the process helps communication with the personality of Godhead by the sound waves as we have now experienced in the material world of physical waves vibrations. The powerful Mantras have such potency if they are sounded in the right direction. And by chanting the Mantras only one can spiritualise the whole existence as heat can expand on the spherical objects.
Letter to Sri Padampat Ji, 7 May, 1957