How does a megaphone work?

Answer 1

Normally sound will spread out in as many directions as it can from a source. As it spreads out with distance, it loses energy (loudness). A megaphone is a cone that limits the directions that the sound can spread into. It concentrates the sound in the forward direction, so that it sounds louder in that direction at longer distances. The tradeoff is that the sound is much quieter off to the sides of the cone than it would be if the megaphone weren't used