Each chakra responds to a particular sound vibration. If you find this hard to believe, try it out and you will be amazed.
Crown Chakra - "Ng"
Third Eye Chakra - "Mm"
Throat Chakra - "Ee"
Heart Chakra = "Eh"
Solar Plexus Chakra = "Ah"
Sacral Chakra - "Oo"
Root Chakra - "Oh"