## 3 Model of the Eszterhaza Opera House for Geometrical Acoustic Simulations
### Assumptions and Acoustic Simulations  
In this study, the calibration of the model was not conducted, because the original Opera House was destroyed during the Second War World and, currently, it is possible to visit an auditorium that differs considerably from the original theatre. Consequently, to assign material properties, some consideration about the materiality of the original theatre was necessary. The absorption and scattering coefficients were attributed considering usual values from the literature [21,22], possibly combining them with those resulting from research on acoustic simulations of similar buildings [23]. Researches and some historical documents [11] confirm the similarity of Eszterhaza Opera House with the Schonbrunn Theatre. The exterior walls of the building were considered made by masonry, while the interior of the hall was lined with a variety of materials including plaster along the walls and wooden parquet on the floors. The parquet of the balcony and the columns on walls were made by hard stone, whereas the timber ceiling structure supported painted plaster work in the main hall. Moreover, French windows were lined up along the gallery. Once defined the materials of the theatre, the absorption and scattering coefficients were selected from the database accordingly with the values employed during the acoustic virtual reconstruction of the Theatre Ideale by [PERSON] and considering usual literature values [23,24, 25]. Consequently, the defined materials and their absorption and scattering (s) coefficients were reported on a specific file as in Table 1. For the audience, the values are higher than in other cases, since in that time, the spectators used to wear full skirts and wigs. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Materials**} & \multirow{2}{*}{\
\begin{tabular}{c} **Surface** \\ **(\%)** \\ \end{tabular} } & \multicolumn{6}{c}{**Absorption**} & \multirow{2}{*}{**s**} & \multirow{2}{*}{**Reference**} \\ \cline{3-3} \cline{5-8}  & & **250** & **500** & **1** & **2** & **4** & **kHz** & **kHz** \\ \hline Wood (hall and floor) & 27.4 & 0.100 & 0.080 & 0.080 & 0.100 & 0.100 & 0.05 & Adapted \\ \multicolumn{1}{c}{
\begin{tabular}{c} Lime plaster (hall and \\ fly tower) \\ \end{tabular} } & 33.5 & 0.230 & 0.240 & 0.240 & 0.250 & 0.340 & 0.50 & [25] \\ Marble (columns, half pilaster, \\ and balustrade) & 10.5 & 0.010 & 0.010 & 0.020 & 0.020 & 0.020 & 0.05 & [25] \\ Light wood (stage ceiling) & 7.9 & 0.040 & 0.060 & 0.120 & 0.100 & 0.170 & 0.05 & [24] \\ Decorated stucco (hall ceiling) & 12.6 & 0.340 & 0.360 & 0.360 & 0.380 & 0.400 & 0.05 & Adapted \\ Curtains & 0.4 & 0.120 & 0.350 & 0.450 & 0.380 & 0.360 & 0.05 & [24] \\ Glass (windows) & 3.5 & 0.250 & 0.180 & 0.120 & 0.070 & 0.040 & 0.05 & [24] \\ Chandeliers & 0.9 & 0.060 & 0.040 & 0.030 & 0.020 & 0.020 & 0.05 & [24] \\ Wooden chairs & 3.4 & 0.040 & 0.060 & 0.120 & 0.100 & 0.170 & 0.05 & [24] \\ Audience & 3.4 & 0.740 & 0.820 & 0.900 & 0.900 & 0.780 & 0.70 & [23] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Absorption and scattering coefficients (s) for all the materials involved in the simulation. The scattering coefficient is referred to 707 Hz. Two omnidirectional sources (A and B) were placed on the stage and the 106 receivers were uniformly distributed throughout the stalls and balcony (from R1 to R85 in the stalls and from R86 to R106 in the balcony), see Figure 7. The signals were simultaneously emitted from the stage to simulate the performance of actors and musicians. Then, the architectural acoustic software made the energetic sum of the impulse response A and B. Once the total IR was obtained, the acoustic parameters were calculated. Once the model was validated for the empty theatre (Scenario 1, as Figure 8a), the absorption coefficient of the chairs was modified to simulate the presence of the audience in the hall (Scenario 2).