1. An Acoustical Study of the Salt Lake Tabernacle Sarah Rollins Timothy W. Leishman Acoustics Research Group Department of Physics and Astronomy Brigham Young University 147 th Meeting of the Acoustical Society of America May 25, 2004

2. Overview Background Background Measurements Measurements Results Results Conclusions Conclusions Further Work Further Work

3. Motivations Characterize the acoustics Characterize the acoustics Modern equipment and techniques Modern equipment and techniques Benchmark measurements Benchmark measurements Spatial variation of parameters Spatial variation of parameters Hall geometry Hall geometry Spatial statistics Spatial statistics

4. Measurements Sources Sources Dodecahedron loudspeaker Dodecahedron loudspeaker Sound reinforcement system Sound reinforcement system Receivers Receivers Omnidirectional microphone Omnidirectional microphone Multi-pattern microphone Multi-pattern microphone KEMAR KEMAR Measurements Measurements Maximum Length Sequence Maximum Length Sequence

5. Source Positions

6. Early Decay Time Average: 4.10Std: 0.68

7. Clarity Factor (C 80 ) Average: - 4.52 Std: 2.92

8. Dietsch Echo Criterion for Music Average: 1.00Std: 0.29

9. Lateral Fraction Average: 0.17Std: 0.09

10. Binaural Quality Index Average: 0.59Std: 0.18

11. Statistics ParameterAverage Standard Deviation EDT4.100.68 C80-4.522.92 Dietsch Music 1.000.29 LF0.170.09 BQI0.590.18

12. Conclusions Hall geometry affects parameters Hall geometry affects parameters Values show focusing effects Values show focusing effects EDT, C 80 more uniform over main floor than in the balcony EDT, C 80 more uniform over main floor than in the balcony Higher LF in the very center of the room Higher LF in the very center of the room

13. Further Work Processing Processing More detailed statistics More detailed statistics Computer Modeling (CATT, EASE) Computer Modeling (CATT, EASE) Current acoustics Current acoustics Historical acoustics Historical acoustics No Balcony No Balcony No Choir Loft No Choir Loft Smaller Organ Case Smaller Organ Case Pine Trees Pine Trees

15. Acknowledgements Timothy W. Leishman Timothy W. Leishman BYU Acoustics Research Group BYU Acoustics Research Group