Numerical simulations (see Sect. 3) of four diffraction classes of the Epidaurus soundfield between the source located at the centre of the orchestra and receiver R7 (as defined in [26, 33]), a) ascending diffraction paths due to the tiers below the listener (purple); b) descending diffraction paths due to the tiers above the listener (yellow); c) reflected and ascending diffraction paths due to reflection at the orchestra and the tiers below the listener (cyan); (d) reflected and descending diffraction paths due to reflection at the orchestra and the tiers above the listener (orange).