I became aware of the potency of mantra after listening to the Gayatri mantra chanted by another Indian Swami Amma Naranyani. When I listened to him chant the mantra, my Crown chakra vibrated vigorously, and I enjoy the dense throbbing sensation on my head. I still get the same effect listening to the same mantra chanted by Swaimi Said Baba (above video). Thereafter, I have incorporated this experience in gauging the effectiveness of any mantra by its effect on my Crown Chakra. Mantra chanted correctly has the Sympathetic Resonance effect on our vibration, especially the energy sub-body Ketheric that is connected to our Crown chakra. Sometimes, some mantra has the resonance effect on our heart chakra. It is like the effect of a piano tuning fork that triggers another unattached object to resonate the sound it produces.
Since then, I have been using this method whenever I learned and chanted a new mantra. I remember a friend of mine, Mr Teng, a professional astrologer skilled in the Chinese Eight Pillar divination. He is a staunched Buddhist, and he has been chanting Amitabhaas his daily meditation practice. At one point, I noticed that he had a well developed Crown Chakra. I rationalized that he has been chanting the mantra correctly, and it has through the process of sympathetic resonance triggered and activated his Crown Chakra. The other method I used to gauge the effective of a mantra is to chant it into a quartz. After that, I gauge the vibration strength of the quartz, to find out if the amplitude of the vibration has significantly boosted. In fact, I have been using the Buddhist mantra, “Mantra of Light” of the Lord Maha Vairocana, The Sun Buddha, to cleanse away the impurities or negative energy of quartz and stones, and material objects such as watches. After my chanting, the quartz or stones became visibly shinning.