Procedure for the path simulation using the virtual source method. The virtual source is determined by converting the atmospheric free field path (blue) to an equivalent virtual path (dashed, grey). Then, the image edge model is used to determine the different urban paths (yellow and red) based on this virtual source. In this scenario, the direct path (dashed, grey) is blocked by a building and therefore inaudible. (a) Definition of virtual source based on an atmospheric free field path; (b) Determination of urban paths between virtual source and receiver.