Unraveling the remarkable secrets of the Ancient Greek theaters’

By Dimitra Pontoporou
The National Herald
Vol.20 Issue 1017, p.12
April 8-14, 2017
Viewpoints

How did Greeks succeed in transmitting the sound so well in their open air theaters withoutthe aid of amplifiers? If one drops a coin in the centre of the performance space, the sound can be easily heard throughout the Epidauros’ theater -which can sit 14000 people- including the top row, located 60 meters far from the stage. This is a question many scientists have long speculated and try to answer.

Amphitheater (amphitheatron) comes from the Greek proverb amphi, which means on both sides or around. This architectural arrangement increased the sound of the voices. Located outdoors ancient theaters had to be acoustically vibrant performance spaces, ideal for musical and theatrical performances.

Greeks experimented with acoustics reaching high standards in conveying the sound to every corner of the large auditorium, unthinkable today for open air theatres. But they sought more than sound amplification. As Vitruvius, Roman architect, 1st c. BC, wrote: “By the rules of mathematics and the method of music, they sought to make the voices from the stage rise more clearly and sweetly to the spectators’ ears”.

If clarity and harmony were additionally their goals, has it been possible to achieve them?
Measurements carried out the last years by Prof. Yiannis Mourjopoulos, Polytechnic School of Patras, at one of the best preserved ancient Greek theaters that of Epidauros, built in the 4th century BC as a part of the Asclepios Healing Center, have shown that besides the sufficient amplification of stage sound, uniform spatial acoustic coverage,low reverberation, and enhancement of voice timbre are qualities of the theater, even 1500 years after its construction.

How that was made possible? Till recently scientists had difficulty to replicate in small scale and in wooden models the elements that contributed to the acoustics quality, because the sound is being transmitted in a different way in wooden scale models than in the actual stone theaters.

In 2008, researcher Nico Declerco and his team from the Georgia Institute of Technology conducted in the same theater a series of experiments with ultrasonic waves. They found that the steps acted as “acoustic traps,” filtering out background noise, like the wind and the movement of people. The steps also filtered the lower frequencies of the actors’ voices and the listeners experienced a phenomenon called “virtual pitch,” in which the human brain is able to fill in the missing tone. The result is a higher clarity of sound, which makes it easier for the people in the back row to hear sounds coming from the
front.

The use of acoustic simulation software and of sophisticated computer models has allowed a better understanding of the open amphitheatre acoustics. According to Prof. Mourjopoulos these acoustically important functions are a result of the large truncated-cone amphitheatrical shape, the hard materials of the theater’s surfaces, the specific slope of the rows, the dimensions for seating width and riser height, which can ensure minimal sound occlusion by lower tiers and audience and result to the fine tuning of in-phase combinations of the strong direct and reflected sounds.

In his recent lecture at the Megaron, Athens, Prof. Georgios Karadedos, from the Architecture School of Thessaloniki, presented designs showing how the ancient Greek theaters could be “tuned” by placing large cauldrons in the tiered rows. These sounding vessels are mentioned several times by Vitruvius: “In theatres, likewise, there are the bronze vessels (in Greek echeia) which are placed in niches under the seats in accordance with the musical intervals on mathematical principles. These vessels are arranged with a view to musical concords or harmony, and apportioned in the compass of the fourth, the fifth, and the octave, and so on up to the double octave, in such a way that when the voice of an actor falls in unison with any of them its power is increased, and it reaches the ears of the audience with greater clearness and sweetness.” Concerning the principles behind the sounding vessels and the musical scales used for the tuning, Vitruvius refers to the ancient Greek music theoretician and philosopher Aristoxenus, who lived in Athens around 350 BC.

Greeks gave the world the word for Acoustic, the branch of physics that studies the sound, from the Greek verb akouo, I listen, and tangible examples of perfect acoustics. Though Vitruvius thanks Ancient Greeks because “It was a wise and useful provision of the ancients to transmit their thoughts to posterity by recording them in treatises…, and they did not pass on in envious silence,” none of these texts, which explain the precise mathematics and acoustics of their theaters, has survived to our days. Scientists are now searching the secrets of the Greek theaters’ acoustics aiming at applying them to modern stadiums and amphitheaters.