_/\_ Namaste,
Video guidance of Mantra repetition. More External is Gross, and more internal is more subtle.
https://youtu.be/dRAuRhXghHA
Here listening to mantra in silence means mantra rise from your mind which you listening internally. don't try to listen which is not rise from your inside or external sound which are not spoken. not rised sound hearing lead to hallucination. while listening what rise from mind internally is mantra cleansing.
Example:
Ram (Hindu God) (Pronounciation like aam)