Since ancient times, the yogis of India know that not only the body is receptive to sound, but also that it is formed and sustained by vibratory frequencies (mantras). The simple mantras (from the Sanskrit 'manas' meaning 'thought' or 'conscience'; and 'tra', 'what protects') are phonemes, sound units, of the Sanskrit mantric alphabet. They are used at the highest levels of tantra and raja yoga and protect from the constant mental flow of thoughts, fears, apprehensions, illusions... Practised with assiduity, the intonation of mantras activates the psychic energies. This chart explains the use of the mantric alphabet and illustrates the zones of resonance for healing of the body and energetic dynamisation.