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.

[1]  Jian Kang,et al.  Acoustic evolution of ancient Greek and Roman theatres , 2008 .

[2]  Nico F Declercq,et al.  Acoustic diffraction effects at the Hellenistic amphitheater of Epidaurus: seat rows responsible for the marvelous acoustics. , 2007, The Journal of the Acoustical Society of America.

[3]  J. S. Bradley,et al.  On the importance of early reflections for speech in rooms. , 2003, The Journal of the Acoustical Society of America.

[4]  Helmut Haas,et al.  The Influence of a Single Echo on the Audibility of Speech , 1972 .

[5]  Tapio Lokki,et al.  Studies on seat-dip effect with 3D FDTD modeling , 2011 .

[6]  T. Lokki,et al.  Studies of Epidaurus with a hybrid room acoustics modeling method , 2011 .

[7]  Maarten van Walstijn,et al.  Room Acoustics Simulation Using 3-D Compact Explicit FDTD Schemes , 2011, IEEE Transactions on Audio, Speech, and Language Processing.

[8]  Tapio Lokki,et al.  The perceptual effects of dispersion error on room acoustic model auralization , 2011 .

[9]  Tapio Lokki,et al.  INVESTIGATIONS ON THE DEVELOPMENT OF THE FREQUENCY RESPONSE OVER TIME IN CONCERT HALLS , 2023, Auditorium Acoustics 2011.

[10]  Samuli Laine,et al.  Accelerated beam tracing algorithm , 2009 .

[11]  N. Prodi,et al.  Acoustics of ancient greek and roman theatres , 2007 .

[12]  Tapio Takala,et al.  Simulation of Room Acoustics with a 3-D Finite Difference Mesh , 1994, ICMC.

[13]  F. Canac.  L'acoustique des théatres antiques, ses enseignements , 1967 .

[14]  G. E. Peterson,et al.  Control Methods Used in a Study of the Vowels , 1951 .