*INFO source:
Naif Haddad, Talal Akasheh.
VITRUVIUS AND ANCIENT THEATREShttp://www.cultech.org/Vetruvius.pdf
"2.3 The Theatre Acoustic and the Vitruvian Resonating Vessels
One reason for the success of the ancient Greek and Roman theatres was that
disturbing environmental noise was generally quiet when they were in use. However,
it is reported that the unoccupied seats and the heads of the audience also scattered
sound to adjacent area. [7].
The acoustics of open-air theatres was mentioned by Vitruvius, but he did not mention
anything about the acoustics of roofed theatres. This earliest documentary discussion
by Vitruvius shows, interestingly, that his overriding concern is for acoustics, rather
than vision, and this even extends to the rules he gives for seating design. Vitruvius
presents us with an elegant theory for the manner in which theatre sites can be
unsuitable, namely if they exhibit acoustic dissonance, circumsonance, or resonance,
in which the voice is supported from below, increases as it goes up and reaches the
ears in words which are distinct and clear in tone. Hence, there has to be careful
attention in the selection of the site to be perfectly suited to the purposes of a theatre.
However, there are some suggestions about the acoustic qualities of the theatres
raised by Vitruvius as to the advantages of placing bronze vases round the auditorium
of theatres. ".... let bronze vessels be made, proportionate to the size of the theatre,
and let them be so fashioned that, when touched, they may produce with one another
the notes of the fourth, the fifth, and so on up to the double octave. [6]"
