Magnitude transfer functions for infinite double edges with a systematic change of receiver angle θ_r2. The geometry is sketched on the right, with the blue cross indicating the source position and the colored circles indicating the receivers to which the traces in the left column correspond. θ_s1 is 45° for all traces. Each row corresponds to a different value for d_w, with 0.1 m, 1 m, and 10 m from top to bottom. The 10th-order BTMS reference is shown as thick, faint solid traces, and 2nd-order BTMS is shown as thin solid traces. The filter-based approximation according to equation (11) is shown as dashed traces. The dotted traces show the results for sequential diffraction filtering. The results are normalized to the shortest unobstructed distance from source to receiver.