I watched '300: Rise of an Empire' yesterday and noticed that Themistocles gives a grand speech just before a naval battle. But even while watching that scene, I wondered how could his voice reach anyone beyond his own ship?
This is something that I have seen in many other ancient war movies, like Braveheart.
I have read through some of the previous posts on this sub which describe that those grand speeches before battles were actually a real thing, but I couldn't understand the mechanics of it - as in, how one person's voice could reach thousands of troops in the battlefield?
On the specific matter of the mechanics of such speeches, here's u/Iphikrates showing the debate on whether they did happen, which goes into mechanical territory; additionally, u/November19 outlines the matter here as well.