Acoustical measurements in ancient theatres: uncertainty in prediction models

Although the remarkable acoustical apparatus of Greek and Roman theatres is generally recognized, it is difficult to assess it nowadays with objective measurements. In fact, actual conditions of most ancient theatres do not allow objective acoustic characterization, since buildings are often strongly damaged or architecturally incomplete. Only for the best-preserved ones, ISO 3382-1 was used to perform acoustical measurements, even though it refers to indoor environments. Thus, ancient theatres acoustics needs to be evaluated with alternative methods. One possible option consists in using prediction models, which could simulate theatres’ lost acoustic characteristics. In this study, two kinds of prediction software, Odeon and CATT-Acoustic, were investigated comparing the reliability of their results. The Greek theatres of Syracuse and Tyndaris were chosen for a measurement campaign: uncertainty in measured results was established based on the GUM recommendations. Then, attested the compatibility of simulations results to in situ measurements, the uncertainties of both software were calculated too.