## 4 Results and Discussion
### Facade with Two Walls  
A corner room with two walls having variable plan dimensions was considered in the simulations. The dimensions ranged from 3 m \(\times\) 3 m to 6 m \(\times\) 6 m in steps of one meter for both the sizes. The height of the rooms was the same for all the cases and was equal to 2.7 m. Other geometrical data include the thickness of the floor (0.30 m) and the thickness of the perimeter wall (0.50 m). The overall height of the building was 15 m.  
Different elevations of the target points from the ground were considered. These elevations depend on the floor on which the simulations are carried out: ground (F0), first (F1), second (F2) and third (F3). The centers of the facades were placed at 1.35 m, 4.35 m, 7.35 m and 10.35 m from the ground. In the case of the second and third floor, the centers of the facades were more than 5 m above the ground and then, according to the standard ISO 16283-3, the sound source can be positioned in front of the facade center. In these cases, therefore, unshielded positions were not considered. As concerns the calculation of the attenuation due the building corners or due to the different source-facade distances, an overall number of 96 size/source position combinations were considered, as summarized in Table 1.  
As an application of the adopted procedure, let us consider a ground floor room having dimensions X = 4 m and Y = 6 m (Figure 3). The first number indicates the size of the facade opposite to the sound source, the second number is the length of the facade closer to the sound source. For the case shown in Figure 3, the position of the loudspeaker is denoted by the letter \(A\), which means it is placed 5 m away from the normal to the center of the facade. For the first floor, the offset with respect to the center of the facade is 2.8 m, while for the other floors the offset is zero. Figure 4 shows the sound pressure level maps for the analyzed cases. It can be noted that, for the lower floors, the level difference between the two sides of the room is higher than in the case of the higher floors. It can be also observed that the sound pressure level decreases for higher floor due to the increasing distance between the loudspeaker and the facade. The effect due to the shielding of the \begin{table}
\begin{tabular}{c c c} \hline \hline
**Sound Source Position** & \
\begin{tabular}{c} **Plan Dimension of the Side** \\ **Opposite the Source [m]** \\ \end{tabular} &
\begin{tabular}{c} **Plan Dimension on the** \\ **Source Side [m]** \\ \end{tabular} \\ \hline A (F0, F1, F2, F3) & 3/4/5/6 & 6 \\ E (F0, F1) & 3/4/5/6 & 5 \\ \hline B (F0, F1, F2, F3) & 3/4/5/6 & 5 \\ F (F0, F1) & 3/4/5/6 & 4 \\ \hline C (F0, F1, F2, F3) & 3/4/5/6 & 4 \\ G (F0, F1) & 3/4/5/6 & 3 \\ \hline D (F0, F1, F2, F3) & 3/4/5/6 & 3 \\ H (F0, F1) & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Position of the sound source and geometry of the analyzed rooms. Figure 3: Example of sound pressure levels map. Ground floor F0, source position \(A\), room dimensions 4 m \(\times\) 6 m—Plan view. corner and the not negligible attenuation due to the difference in distance between the source and the facade when the source is \"in view\" of both sides of the facade is clearly visible (see for example F0, position A and E in the sound pressure levels maps of Figure 4). The attenuation of the sound pressure levels of side 1 with loudspeakers at \"2b\" and \"2a\" can be obtained by symmetry. Since in real cases it is uncommon to find a building completely isolated and far from other buildings, the presence of another building placed at 10 m from the facade was simulated with loudspeaker positions \"1a\" and \"1b\" (Figure 5). In this case, the simulations show a lower attenuation of the building corner due to the reflections of the additional building. Figure 4: Sound pressure level for different source positions: A–B–C–D (F0: ground floor; F1: floor 1; F2: floor 2; F3: floor 3); Source positions E–F–G–H (F0: ground floor; F1: floor 1).