9/1/2020 · Furthermore, solar panels and the height, width, and surface materials of the protrusions affected the urban acoustic environment. The protrusions of the building envelope, such as eaves [ 77 ], louvres [ 76 , 80 , 99 ], screens [ 39 , 51 , 64 , 79 ], and roof solar panels [ 95 ] can reduce specular sound reflections owing to their geometric shape.