Magnitude transfer functions for infinite double edges with example variations of different parameters (see geometry sketches on the right). Unless stated otherwise: θ_w1,2 = 90°, and θ_s1 is 45°. In panel a), the incidence angle φ is varied for two θ_r2 = 170° (dark purple) and θ_r2 = 225° (green), in panel b), the wedge angle θ_w1 is varied for a fixed θ_r2 = 225°, and in panel c) the distance of the source d_s1 is varied for θ_r2 = 170° (dark purple) and θ_r2 = 225° (green).