## 2 Materials and Methods
### Acoustic Simulation  
#### 2.2.1 Acoustic Model Building and Calibration  
For the acoustic simulation, a simplified model of the environment of the Water Tribunal was used, which includes the Door of the Apostles, Virgin's Square, and Miguelete Street. From the 3D scans and the planimetry, a wireframe of the environment was raised using AutoCAD. This software allows working comfortably with both plans and the generated point cloud. The wireframe model was exported to Sketchup software, where  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Equipment** & **Model** & **Characteristics** \\ \hline Omnidirectional dodecahedral sound source (01 dB) Amplifier (Inter-M) & DO12 M-1000 & Rated power 600 W, sound power \(>\) 120 dB, frequency range: 80 Hz-6.3 kHz Output power level RL = 4 \(\Omega\) bal. 520 W + 520 W \\ Omnidirectional microphone & Behringer C2 & Open circuit sensitivity (at 1 KHz) of \(-\)40 dBV (0 \(\mathrm{dBV}\) = 1 V/Pa), 10 mV/Pa, linear frequency response between 20 Hz and 20 KHz, with 1\% THD \\ Multichannel sound card & Presnous AudioBox 1818 VSL & 24 bit/96 K, USB 2.0, 6 input microphone/line and 2 input microphone/instruments, with pre-amp XMAX with high dynamic range (Class A) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Specific characteristics of the equipment used during acoustic measurement of the environment of the Water Tribunal.  
Figure 1: (**a**) Location of sound sources and measurement points during acoustic measurement of the environment of the Water Tribunal. (**b**) Image of the acoustic measurement equipment used during acoustic measurement of the environment of the Water Tribunal.  
the correctly oriented model surfaces were generated and layered based on actual materials. In order to work later with CATT-Acoustics [26] and ODEON [27] software, the model was closed with surfaces representing the open field, to which 100% absorbent material was applied in the acoustic simulation process. Figure 2 shows final acoustic model, made up of 516 surfaces and with a volume of 150,865 m\({}^{3}\); it also shows the sound source--in red color--and the first receivers (the location of the judges)--in blue color.  
The usual procedure for calibrating an acoustic model of a room is to include the absorption and diffusion of the materials used in such a way that the simulated reverberation time coincides with or is very close to that which is experimentally determined. In numerous studies, the adjustment of the average at frequencies from 500 to 1000 Hz of reverberation time (T30) was followed as a calibration procedure, in such a way that the experimental average and the simulated average are not more than 1 just noticeable difference (JND) (5%) away, that is, at the perceptual level, no difference can be seen. This procedure is considered adequate because the T30 practically does not vary in a room. In the modeling of the acoustic space where the Water Tribunal is performed, it was observed that an adjustment similar to that performed in a closed room is not adequate, since there is a greater variation in parameters such as the T30 and the early decay time (EDT). However, it was observed that in this type of environment the parameters clarity up to 80 ms (C80) and clarity up to 50 ms (C50) show less variation. For this reason, the calibration of the model with C80 (musical clarity) and C50 (speech clarity) was considered adequate.  
The acoustic simulation was carried out with the different software, CATT-Acoustics and ODEON, with the aim of studying the applicability of this type of tool in the study of open and semi-open heritage environments.