Acoustics of Epidaurus – Studies With Room Acoustics Modelling Methods

The 3D model of Epidaurus is simulated with two room acoustics modelling methods. The low frequencies up to 1000 Hz are simulated with a 3D FDTD method able to predict the wave-based phenomena such as diffraction and interference. The high frequencies are predicted with a beam tracing method. The early parts of the computed impulse responses are analyzed to explain the well-known acoustics for speech in the ancient theatres. The prediction results are compared to real measurements and visualized with various methods both in the time domain and in the frequency domain. The results suggest that when an actor was on the stage (which does not exist anymore) his direct sound was supported by several early reflections from the ground, from the stage, and from the staircases of the audience area. All this early energy is assumed to fuse well with the direct sound resulting in a strong voice being perceived at every seat in the audience.