In the Vedic tradition, Sound vibrations are called Nada. Nada Yoga employs sound not only to restore physical and mental health, the Sound practices are also regarded as a path to spiritual awakening. Nada Yoga distinguishes external sounds (Ahata) and internal sounds (Anahata).
INTERNAL SOUND (NADA)
Internal sounds, unlike external, are perceived not through the physical body but through the Anahata Chakra, the Heart Chakra. Nada Yoga teaches that each human body has its own unique vibration, or inner Sound. By regulating the breath and blocking the noise from the outside by closing the ears with the thumbs, the attention can be gently turned inwards, then, if listening carefully, the inner Sound can be perceived. Over time the Sound becomes easier to hear, experienced practitioners can hear the Nada sound even without closing the ears. Aligning your mind with this Sound helps to balance your energetic body and, entering a deep meditative state, connect you with your divine nature.