DOI: https://doi.org/10.58874/SAAT.2022.104
Abstract:The effect of edge diffraction in ancient theatres is in vestigated. A cross section of the theater of Epidaurus simplified as right angled steps is considered. A recently presented solution for computing the impulse response around a rigid wedge is em p loyed for the theoretical study of diffraction by the edges of the steps. It is shown that diffracted sig nals coming from edges below a listener come close together and with relative s mall amplitude. D iffracted signals from edges above the listener come further apart, some with very large amplitude and almost all with negative polarity. A new parameter is proposed that predict s the effect of edge diffraction based solely on geometrical characteristics. It is show n that the height of the source and the inclination of the steps affect the diffraction contributions the most. The effect of the various d iffraction contributions to acoustic indices is considered next. For the computation of t he acoustic indices the relative strength between geometrical and diffraction contributions, wh ich are different in nature, must be determined . In the sent work this is done via the unit step responses. U pper diffraction s affect negatively the acoustic indices , considerably more than lower diffractions A source positioned at the height of a deus ex machina improves the acoustic indices com- pared to a source a t the height of a standing actor.Large inclination angles of the steps affect negatively the acoustic indi- ces. Finally, results including the effect of all geometrical and all diffraction contributions are compared with published measured data for the theater of Epidaurus.
Keywords:Edge diffraction
Pages:23-26
Paper: