The same chakra is responsible for audial communication and perception regardless if physical sound or higher dimensional sound. The Throat chakra. Responsible for adtral hearing as well. When you speak you barely really ficus in how intense those mental energies are pryingvopen areas if the brain to cause you to physically speak. It depends on what goal you are trying to accomplish as physical vibrations are a mix of all 3 spheres of reality the physical immediate world, the astral medium of Ether on the occult soul dimension, and the highest vibrations we deem (spiritual) or aware, consciousness, LIFE. When you vibrate them in the astral temple its a mix if mental and astral mostly. Its too advanced to go in depth here but I can tell you that vibrating in your head as vividly and loudly you can focus without opening your actual physical mouth the closer to astral and thus soul structure you manifest the sound on. It would help to build up your actual bioelectric in this case using breathing exercises and to focus on single pointed thoughts like sounds in the head you should practice void meditation.