1. Investigation of Open-air theatre design
BEng thesis Thomas Dimasi
Supervisor: Dr Bruno Fazenda

2. Theatre of Epidaurus Evolution of Open-Air Theatres
Source:

3. Measurements of Epidaurus
Ancient Acoustics
Source: C. van Loenen et al, INFLUENCE OF GEOMETRICAL AND MATERIAL ASSUMPTIONS ON RAY-BASED ACOUSTIC SIMULATIONS OF TWO ANCIENT THEATRES, ICSV23, Athens (Greece), July 2016
T20 [s]
EDT [s]
C80 [dB]

4. Classic Greek Open-Air Theatre
Evolution of Open-Air Theatres
Classic Greek Open-Air Theatre
Source: K. Chourmouziadou, J. Kang. Acoustic evolution of ancient Greek and Roman theatres. Applied Acoustics 69 (2008) 514–529

5. Hellenistic Open-Air Theatre
Evolution of Open-Air Theatres
Hellenistic Open-Air Theatre
Source: K. Chourmouziadou, J. Kang. Acoustic evolution of ancient Greek and Roman theatres. Applied Acoustics 69 (2008) 514–529

6. Roman Open-Air Theatre
Evolution of Open-Air Theatres
Roman Open-Air Theatre
Source: K. Chourmouziadou, J. Kang. Acoustic evolution of ancient Greek and Roman theatres. Applied Acoustics 69 (2008) 514–529

7. Modelling the Cavea Simple Model Detailed Model
Geometrical Acoustic Modelling of Open-Air Theatre
Note: validation performed against 1:20 scale model reported in INVESTIGATING THE ACOUSTICS OF ANCIENT THEATRES
BY MEANS OF A MODULAR SCALE MODEL, Farnettani et al, ERATO Project Symposium, 20th January 2006, Istanbul (Turkey)
Simple Model
Detailed Model

8. Modelling the Cavea More accurate T30 when only the Cavea is present.
Geometrical Acoustic Modelling of Open-Air Theatre
Note: validation performed against 1:20 scale model reported in INVESTIGATING THE ACOUSTICS OF ANCIENT THEATRES
BY MEANS OF A MODULAR SCALE MODEL, Farnettani et al, ERATO Project Symposium, 20th January 2006, Istanbul (Turkey)
Simple Model
Detailed Model
More accurate T30 when only the Cavea is present.
Cannot predict T30 if Stage Building is present.
More accurate T30 and C50 for model with Stage Building.
Overestimates T30 when only the Cavea is present.

9. Modelling the Cavea Simple Model Detailed Model
Geometrical Acoustic Modelling of Open-Air Theatre
Source: M. Lisa et al, PREDICTING THE ACOUSTICS OF ANCIENT OPEN-AIR THEATRES: THE IMPORTANCE OF CALCULATION METHODS AND GEOMETRICAL DETAILS, BNAM, July 2016, Mariehamn (Åland).
Simple Model
Detailed Model

10. Theatre of Syracuse Roman Model
Validation against measurements
Note: validation performed against 1:20 scale model reported in INVESTIGATING THE ACOUSTICS OF ANCIENT THEATRES
BY MEANS OF A MODULAR SCALE MODEL, Farnettani et al, ERATO Project Symposium, 20th January 2006, Istanbul (Turkey)

11. Theatre of Aspendos Model
Validation against measurements
Note: validation performed against measurements reported in PREDICTING THE ACOUSTICS OF ANCIENT OPEN-AIR THEATRES:
THE IMPORTANCE OF CALCULATION METHODS AND GEOMETRICAL DETAILS, M. Lisa et al, BNAM, July 2016, Mariehamn (Åland).

12. Validation against measurements
Conclusions
Detail modelling of the Cavea yields best overall predictions.
It is the only method for simple geometries.
Gives overestimations if only the Cavea is modelled.
Has issues with lower octave bands.
Requires Scattering based on surfaces dimensions.
1st order diffractions improve predictions.
Cavea behaviour cannot be accurately simulated because:
some Diffraction effects are omitted.
interactions between Cavea and Surfaces are simulated partially.
More deterministic algorithms lead to worse predictions.

13. New Designs
Core Cavea Model

14. Stage Reflectors Model
New Designs
Stage Reflectors Model

15. Stage Reflectors Model
New Designs
Stage Reflectors Model
T30 No Audience
T30 With Audience
Blue model without Reflectors Red model with Reflectors

16. Stage Reflectors Model
New Designs
Stage Reflectors Model
T30 No Audience
T30 With Audience
Blue model without Reflectors Red model with Reflectors

17. New Designs
Clouds Model

18. T30 Three layers of Clouds
New Designs
Clouds Model
T30 Three layers of Clouds
T30 Top Clouds layer
Blue model without Clouds Red model with Clouds

19. T30 Three layers of Clouds
New Designs
Clouds Model
T30 Three layers of Clouds
T30 Top layer of Clouds
Blue model without Clouds Red model with Clouds

20. New Designs
Balcony Model

21. Balcony Model C50 No Audience C50 With Audience New Designs
Blue Core Cavea Model Red Balcony Model

22. Balcony Model T30 No Audience T30 With Audience New Designs
Blue Core Cavea Model Red Balcony Model

23. Validation against measurements
Conclusions
Reflective Surfaces Location on T30 frequency balance.
Near Stage Area 500Hz Upwards
Near Top of the Cavea 250Hz Under
Balcony Design.
Remove Orchestra Reflections Lower C50
Receivers Near Back Wall Higher C50 with Audience.
However
Opposite Wall Reflections Lower C50
Focusing Effects are Amplified in GA with Detailed Cavea Modelling.

24. Further Work GA modelling of Open-Air Theatres
Validation against measurements
Further Work
GA modelling of Open-Air Theatres
Cavea/Backwall interactions: Assess the limitations of GA
Improve simulation of Cavea behaviour in GA.
Address focusing Effects.
Other Designs and Features
Cavea Slope
Vineyard Design …
Modern times:
Integrated Acoustics and Electroacoustic Open-Air Theatre Design

25. Questions?
Theatre of Aspendos Source: