Reducing geometry or detailing? Comparison between measured and modeled microscale urban spaces

One of the requirements for noise mapping elaboration is to reduce geometry due to large-scale coverage and to the simplified algorithms methods of calculation. However, this simplification can neglect some important acoustic information that can influence the outdoor sound propagation. This research aims to compare the acoustics results between a reduced geometry model and a detailed one, verifying which scenario better represents the reality of the urban space. In order to do that, Room Acoustics software Odeon v13 was used, since traditional macroscale noise mapping software does not allow the production of accurate detailed geometry. Thus architectonic details were considered in the detailed model and scattering coefficient was gradually changed in the reduced geometry model. In situ measurements were also performed using the Impulse Response technique. Simulation results were compared with measured ones. Analyzed parameters were T30, EDT and SPL. Energy-Time Curves were also compared. Results showed that the change of scattering coefficients in the simplified model does not achieve the same good agreement with measurements as the detailed model. The addition of the details increased accuracy; therefore the presence of the details can enhance the representation of the actual urban space.