I always wonder about this particular scenario, where in a large area, the lead speaks and all of the audience listen although they are quite far away. In some motivational speeches, the army commander speaks from a long distance and the soldiers get encouraged and respond to it.
This can be observed in many movies/series like:
In Game of Thrones S08E06, "The Iron Throne", Daenerys' speech be audible to everyone. Also in previous episode, Missandei's words were audible for Dany and her army?
In Lord of the Rings: The Two Towers, during Saruman's speech to all the orcs, Even though Saruman is at the top of the tower his words/voice wouldn't naturally be discernible from hundreds of feet away.