Samadhi is a state of equanimity in all places. It means calmness of mind; and it can be attained through several ways. Mantras are helpful; these give energy, and purify the consciousness. One can reach to high consciousness through this, and with more concentration and purity come more profound effects. Mantras and meditation are both helpful, and they are like two sides of a coin. Meditation and stillness are wisdom in themselves.

As mentioned in Pranayam topic, mantras are always helpful, but the final goal of pranayam is to go beyond mantras. Equanimity is a great key of Buddhism. Very essential in many places, peacefulness, equanimity, and tranquility.