The document discusses acoustical analysis of an amphitheater geometry imported into Ecotect from Revit. Several trials were conducted by modifying reflector heights and material properties. The best results used a ceiling height of 12m and an NRC value of 0.56 for reflector material, producing good sound quality variation without dryness. The output graphs showed sound decay and reverberation times meeting optimum values for the room volume and occupancy.

2. Importing Model to Ecotect Anaysis.

3. .3ds geometry--Ecotect

4. .3ds geometry--Ecotect

5. Conclusion: Analysis will retard or take long time.

6. Revit and Ecotect
Tag the object carefully in Revit for
gbxml filetype!

7. Revit model tagged as shaded part and untagged as un-shaded part.
To import gbxml format from revit for analysis, whole part should be completely tagged

8. Conclusion: Analysis will work but cylindrical geometry will be a mess as ecotect
converts it into triangular components.

9. Avoid Complex Geometry as far as possible.
Cylinder computed by Ecotect becomes more complex triangular geometry

10. More Simplified geometry for Ecotect Model
Carefully deleted the outer cylindrical from imported xml file and
created cylinder surface on ecotect so that analysis is done smoothly.

11. Acoustical Analysis

12. Set Sound Source and Reflectors (ceilings)

13. Generate Rays

14. Acoustical Analysis
Reflector position and orientation calculation

15. Trial 1
Default

16. Trial 1
12m

17. Trial 1
Default
12m

18. Trial 1
Default
12m

19. Trial 1
Default
12m

20. Conclusion of Trial 1
• More REVEB sound was detected.
• Hence need to modify
-Geometry
-Orientation (incident angle etc.)
• Material quality is kept as default.
• Hence parameters to control in the analysis
are Reflectors (ceilings) property.

21. Trial 2
Lowering ceiling
Decreased by 3m
9m

22. Trial 2
Lowering ceiling
Decreased by 3m
9m

23. Decreased by 3m
Trial 2
Lowering ceiling
9m

24. Trial 3
Increased by 3m
15m

25. Trial 3
15m

26. Conclusion of Trials 2 and 3
• As we change the heights of the ceiling, just
above the stage, quality changes drastically
• As we lower more noise is observed
• As we higher the ceiling good quality is
observed for same directed ray generated.

27. Acoustical Analysis
Material assignment to the Reflectors
at height of 12m

28. Assigning all reflectors as Acoustical Tile.

29. Table to feed different NRC Values

30. Feeding different Absorptive value for different frequency.

31. Adding Material-NRC.03
dia=30m
12m

32. Adding Material-NRC.03
12m
dia=30m

33. Adding Material-NRC.61
dia=30m
12m

34. Adding Material-NRC.85
dia=30m
12m

35. Conclusion of different NRC Values
• For Higher Noise Reduction Coefficients (NRC
0.6 and above) most of the sound waves are
observed that leads to Dryness of Sound
which seems to be bad of an amphitheatre.
• For lower NRC(0.3) we have variety of sound
variation which is not desired
• Hence selected NRC 0.56 which is 12 mm
Mineral Fiber Material which is also fire
resistant.

36. Adding Material-NRC.56
12m
dia=30m

37. Adding Material-NRC.56
12m
dia=30m

38. Acoustical Analysis
Results or Output from Ecotect Analysis.

39. Acoustical Response

40. Sound Decay for different frequency

41. Reverberation Graph
TOTAL SABINE NOR-ER MIL-SE
FREQ. ABSPT. RT(60) RT(60) RT(60)
------- -------- ------- ------- -------
63Hz: 104.349 3.35 2.80 4.87
125Hz: 110.039 3.21 2.70 1.70
250Hz: 206.346 1.53 1.39 1.13
500Hz: 519.030 0.86 0.68 0.57
1kHz: 579.543 0.80 0.60 0.49
2kHz: 485.506 0.86 0.71 0.62
4kHz: 390.240 1.04 0.90 0.82
8kHz: 390.551 1.02 0.90 0.82
16kHz: 308.554 1.14 1.07 0.99

42. STATISTICAL ACOUSTICS - 18 Room
Volume: 4070.390 m3
Surface Area: 761.794 m2
Occupancy: 680 (850 x 80%)
Optimum RT (500Hz - Speech): 0.99 s
Optimum RT (500Hz - Music): 1.65 s
Volume per Seat: 4.789 m3
Minimum (Speech): 5.329 m3
Minimum (Music): 9.129 m3
Most Suitable: Norris-Eyring (Highly absorbant)
Selected: Sabine (Uniformly distributed)