How did Ancient Greek amphitheaters manage sound propagation to attendees?

Their semi-circular seating acted as a natural reflector.

The architectural manipulation of sound evident in Ancient Greek amphitheaters demonstrated an early understanding of spatial acoustics long before electronic methods existed. These structures were deliberately engineered into hillsides. The specific shape of the semi-circular seating area served a crucial acoustic purpose: it functioned as a natural reflector. This design efficiently directed sound originating from the stage toward the thousands of attendees seated around it, ensuring deliberate acoustic clarity across the audience area. This process harnessed natural physical properties to achieve spatial sound distribution without any electronic intervention.