* The Shape of the Theatre: The semi-circular shape of the *theatron* (the seating area) and the carefully designed *orchestra* (the circular performance space) helped to naturally focus and reflect sound towards the audience. The sloping nature of the seating also helped prevent sound from being absorbed by the audience itself.
* The Material of the Theatre: While the materials used varied across theaters, the use of stone in the construction contributed to the acoustics. Stone surfaces reflect sound better than softer materials.
* The Location of the Theatre: Greek theatres were often built on hillsides, which provided a natural amphitheater effect. The natural slope of the land aided in sound projection.
* The Actors' Vocal Training: Actors underwent rigorous vocal training to ensure they could project their voices effectively across the large space. This was crucial, as there were no microphones or amplification systems.
* Masks and the Chorus: The large, resonant masks worn by actors likely helped to amplify their voices. The chorus, with its multiple voices, added to the overall sound volume.
In short, the ancient Greeks relied on a combination of architectural design, natural features, and vocal technique to achieve sound projection, rather than technological solutions. The effectiveness varied somewhat depending on the specific theater's construction and the ambient conditions.