# Indoor Acoustic Requirements for Autism-Friendly Spaces
## 3 Results and Discussion
This means that placing sensors adjacent to the ceiling is not the best choice because of the reverberation increasing. Preferably, an installation of several devices is suggested. Since simulations demonstrate that corner positions have to be avoided, central points on vertical partitions have to be preferred. At the same time, the definition of the most probable caregiver-individual position inside the room is helpful to select the correct layout. This is to ensure that autistic individuals will not suffer from indoor sound field localization or huge variations when moving around in a room or echo and/or annoying reverberant phenomena. Furthermore, it is possible to highlight that reverberation time does not change sensibly when varying position and height within the room. Thus, this parameter cannot be sufficient to choose appropriate positions for sensors and to describe optimal indoor acoustic conditions for autistic individuals. Conversely, C\({}_{50}\) and D\({}_{50}\) also provide variation along the \(z\)-axis. For this reason, they are essential for the determination of final sensors and the individuals' locations. Accordingly, they provide very useful indications on the best sound field within rooms, thus highlighting where it is better to sit or place individuals on the spectrum. The same results obtained for therapy room no. 2 can be applied to therapy room no. 4. Conversely, the atelier may require the application of several devices in order to better acquire soundwaves. The soft room presents the lowest values of reverberation time because of the contained \"soft\" furnishing, composed of sound-absorbing materials like polyurethane foams. Spatial distribution of reverberation time and definition at 1000 Hz frequency band (Figure 8) were quite good and it can be highlighted that when corner focusing is still present, the phenomenon is very limited. This means that the indoor sound field can be considered homogenous. In this case, the absence of furnishing accessories and the possible movement of the user inside the room will not affect the sensor positioning. For the same reason, when individuals are stepping around in the room, they do not perceive sensible clarity and definition alterations because no JND was found (Figure 8). Figure 6: Simulated C\({}_{50}\) for therapy room no. 2: spatial distribution at 1000 Hz (graduation range from purple = 7.5 to red = 14). The red line marks the section plan. Figure 7: Simulated D50 for therapy room no. 2: spatial distribution at 1000 Hz (graduation range from purple = 0.85 to red = 0.97). The red line marks the section plan. From this investigation, it can be concluded that even if some rooms fairly fulfil the acoustic requirements in terms of RT, C\({}_{50}\), and D\({}_{50}\) (Figure 3, Table 1), they failed to correctly host both devices and individuals because of the sound field distribution issues. Thus, dedicated optimization is needed. Most of the analyzed rooms need to be studied in order to optimize reverberation for both the requirements of acoustic sensors and autistic people. In order to improve the values of the objective parameters (RT, C\({}_{50}\), and D\({}_{50}\)), sound absorption units can be increased by using suitable walls and ceiling finishing materials, or appropriate furnishing accessories. The living space acoustics can be controlled by the insertion of sound absorbing elements of various types, but in the case of autistic users, it could be helpful to follow the fundamental concept of \"simplicity\" [69,70]. In few words, this implies the reduction in the furnishing accessories in the rooms and avoiding the insertion of suspended sound absorbing elements such as buffers.