Project Ancient Acoustics Part 4 of 4 : stage acoustics measured in the odeon of herodes atticus and the theatre of argos

The stages of ancient theatres can be characterized by their circular shape called the ‘orchestra’, in front of a rectangular elevated stage with a highly decorated back wall. During some performances, a group of musicians was located in the circular shape, while actors were positioned on the elevated stage. In modern concert halls or theatres, acoustic support from the room is required for such performers to be able to play together properly. It can be assumed that in the ancient theatres, acoustic support must have been beneficial for performers as well. As part of the Ancient Acoustics project, stage acoustic measurements have been carried out in the Odeon of Herodes Atticus and the theatre of Argos. The goal of this paper, is to study the behavior of the early and late reflected sound level on ancient stages in their current state, measured by the extended early
and late support parameters STearly,d and STlate,d. Comparing the two stages is particularly interesting, because in Argos the back wall is missing. However, the absolute value of the parameters might have limited value because both the audience area and stage were unoccupied during the measurements. Also, the theatre of Argos has a severely damaged seating area and the back wall
has not been restored, and at Odeon Herodes Atticus, the stage floor was missing. It is well known that the typical concentric shape of the audience area gives focused reflected sound back to the stage. This can be confirmed by the measured results that show a strong increase in reflected sound level when the source and receiver are positioned point-symmetrically along the center of
the circle. This might have had an effect on performers, but whether the extra ‘support’ was beneficial is uncertain, because the ‘chirping’ and focussing of the reflected sound can cause colouration and poor balance.