When I vibrate anything, it's not via an extension of the sounds, but rather by an internalized projection of them. This is hard for me to describe to a non-vocalist, since it's something carried over from singing, but I will try.
It's primarily chanting from the diaphragm, instead of the chest. With a fullness of air, one can truly project what one is speaking. This projection will, in all literality, cause vibrations within their system (IMG:
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I know that after I've been singing
properly for any length of time, my face plate thrums for a while afterwards.