The secret of the magic transmission ability of the Greek theater

The sound of the famous ancient Greek theater Epidaurus is wonderful: The voice of an actor standing on an open stage can be heard in rows of seats 60 meters away.

Architects and archaeologists have long speculated on the secret to making this strange transmission. Recently, a study revealed it was achieved by exploiting the complex physical properties of acoustics.

The Epidaurus theater was discovered under a layer of land on the Peloponnese in 1881, and was excavated later. It has a classic semicircle of a Greek amphitheater, with 34 rows of stone seats (later added by 21 Romans).

The sound here is extremely good. Singing no microphone of a stage actor can be heard by listeners in the rear seats 60 meters away.

Recently, Nico Declercq and Cindy Dekeyser from the Georgia Institute of Technology in Atlanta said their key is the arrangement of rows of seats in steps . According to their calculations, this structure is the perfect shape for sound filtering, noise suppression of low-frequency sounds (the main component of background noise in theaters) while amplifying the high-frequency voice of cast.

Declercq does not know whether this feature was created intentionally or unintentionally during the design process. But anyway, he still thinks that the ancient Greeks and Romans appreciated the ability of the theater Epidaurus to transmit sound and copied them to other places.

In the theater Epidaurus : listeners can hear the actors
60m away in the day without wind. (Photo: uni.edu)

T. An