The Magic Epidavros b&w by vasiliosgavrilis

The theatre is admired for its exceptional acoustics, which permit almost perfect intelligibility of unamplified spoken words from the proscenium or skēnē to all 14,000 spectators, regardless of their seating (see Ref., in Greek). Famously, tour guides have their groups scattered in the stands and show them how they can easily hear the sound of a match struck at center-stage. A 2007 study by Nico F. Declercq and Cindy Dekeyser of the Georgia Institute of Technology indicates that the astonishing acoustic properties may be the result of the advanced design: the rows of limestone seats filter out low-frequency sounds, such as the murmur of the crowd, and amplify high-frequency sounds from the stage.