Why the Greeks could hear plays from the back row

Nature : Nico Declercq and Cindy Dekeyser of the Georgia Institute of Technology in Atlanta believe they have discovered why ancient Greek theaters have such wonderful acoustics: The key is the arrangement of the stepped rows of seats reports Philip Ball.A performer in the ancient Greek theatre of Epidaurus for example, can be heard 60 meters away in the back row. The stepped rows of seats act as a low-frequency filter, suppressing background noise, while passing on the high frequency of the performers voice.