Close
About
FAQ
Home
Collections
Login
USC Login
Register
0
Selected
Invert selection
Deselect all
Deselect all
Click here to refresh results
Click here to refresh results
USC
/
Digital Library
/
University of Southern California Dissertations and Theses
/
Acoustics of the Bing Theater, USC: Computer simulation for acoustical improvements
(USC Thesis Other)
Acoustics of the Bing Theater, USC: Computer simulation for acoustical improvements
PDF
Download
Share
Open document
Flip pages
Contact Us
Contact Us
Copy asset link
Request this asset
Transcript (if available)
Content
ACOUSTICS OF THE BING THEATER, USC COMPUTER SIMULATION FOR ACOUSTICAL IMPROVEMENTS by Suganya Thiagarajan A Thesis Presented to the FACULTY OF THE SCHOOL OF ARCHITECTURE UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree MASTER OF BUILDING SCIENCE December 2004 Copyright 2004 Suganya Thiagarajan Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. U M I N um ber: 1 4 2 4 2 5 6 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI UMI Microform 1424256 Copyright 2005 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGEMENTS I thank Mr. Jerry Christoff of Veneklasen Associates whole-heartedly, without whom this thesis would have been impossible. I would like to specially thank Dr. Goetz Schierle for his excellent support and guidance. Prof. Douglas Noble, who guided me throughout this thesis and helped me to focus, and was always been very patient and constant source of encouragement. I also would like to thank Prof. Karen Kensek for her valuable inputs during the reviews. I would like to thank all my friends and well-wishers for just being there always, and my room mates, of course, who put up with all my mess and cribbing. And, Binny, for all the assistance, constant support and care. I wish my family was there next to me to support and push me to work, especially Amma. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ACKNO W LEDG EM EN TS.......................................................................................... ii LIST OF FIG URES......................................................................................................vi LIST OF TA B LE S......................................................................................................... x A B S TR A C T.................................................................................................................. xi CHAPTER 1 THESIS INTRODUCTION..............................................................1 1.1 BACKGROUND OF ACOUSTICAL STUDIES.......................................1 1.2 HYPOTHESIS.......................................................................................... 3 1.3 OBJECTIVE.............................................................................................. 3 1.4 ORGANIZATION OF THE STUDY....................................................... 4 1.5 CHAPTER CONCLUSIONS AND PRELUDE TO NEXT CHAPTER...............................................................................................5 CHAPTER 2 BACKGROUND RESEARCH ON AUDITORIUM ACOUSTICS . 6 2.1 INTRODUCTION TO AUDITORIUM ACOUSTICS...............................6 2.2 DEFINITION OF IMPORTANT ACOUSTICAL TERMS.........................6 2.3 MAJOR CONCERNS FOR DIFFERENT AUDITORIUM TYPES..................................................................................................... 9 2.4 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER.................... 34 CHAPTER 3 ACOUSTICS - STUDY OF A REAL SPACE............................. 35 3.1 CRITERIA FOR SELECTION OF THE CASE STUDY SPACE.................................................................................................. 35 3.2 IDENTIFICATION PROCESS................................................................35 3.3 DETAILS OF BING THEATRE.............................................................. 37 3.4 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER.................... 43 CHAPTER 4 MEASUREMENTS OF EXISTING ACOUSTICS....................... 44 4.1 MLSSA SYSTEM - AN OVERVIEW.....................................................44 4.2 TESTING BING THEATRE ACOUSTICS WITH MLSSA SYSTEM................................................................................................47 4.3 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER.................... 54 CHAPTER 5 MANUAL CALCULATIONS.........................................................56 5.1 SABINE FORMULA AND EYRING FORMULA....................................56 iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 5.2 REVERBERATION TIME CALCULATION USING EYRING FORMULA.............................................................................57 5.3 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER....................60 CHAPTER 6 COMPUTER SIMULATION OF ACOUSTICS........................... 61 6.1 CHAPTER INTRODUTION....................................................................61 6.2 CATT-ACOUSTIC SOFTWARE - AN OVERVIEW..............................61 6.3 PROCEDURE FOR PREDICTING ACOUSTICS USING CATT-ACOUSTIC.................................................................................65 6.4 COMPUTER MODELING OF BING THEATRE - PROCESS.............................................................................................68 6.5 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER.................... 79 CHAPTER 7 COMPARISON OF THE ACOUSTICAL PARAMETERS 81 7.1 CHAPTER INTRODUCTION................................................................ 81 7.2 COMPARING REVERBERATION TIMES FROM MLSSA, MANUAL CALCULATIONS AND CATT-ACOUSTIC SOFTWARE..........................................................................................81 7.3 COMPARING CLARITY LEVELS FROM MLSSA AND CATT..................................................................................................... 84 7.4 COMPARING UNIFORMITY OF SOUND LEVEL............................... 86 7.5 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER...................88 CHAPTER 8 CONCLUSIONS AND FUTURE STUDY.................................... 89 8.1 CONCLUSIONS..................................................................................... 89 8.2 POSSIBLE ACOUSTICAL IMPROVEMENTS......................................90 8.3 FUTURE STUDY.................................................................................... 90 GLOSSARY OF TERMS (In alphabetic order)...............................................92 Acoustic glare................................................................................................... 92 Brilliance............................................................................................................92 C-80 92 Clarity, Intelligibility...........................................................................................93 Early Decay Time (EDT).................................................................................. 93 Early sound........................................................................................................93 Echogram..........................................................................................................94 Freedom from echo...........................................................................................94 Intimacy or presence.........................................................................................94 Loudness...........................................................................................................95 Reverberation or Liveness...............................................................................95 Texture..............................................................................................................95 Uniformity of sound...........................................................................................96 iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. BIBLIOGRAPHY.................................................................................................. 97 APPENDIX............................................................................................................ 98 APPENDIX A: MLSSA test results.................................................................. 98 APPENDIX B: Problems encountered while modeling The Bing................117 APPENDIX C: Modeling Tips.........................................................................122 APPENDIX D: MASTER geometric file, ‘OBJECT’ files (ceiling panels, wall panels, curtain), Source and Receiver files..............................126 v Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF FIGURES Figure 1: Optimum Reverberation time for different types of Auditorium....................7 Figure 2: Longitudinal section of Grosser Musikvereinssaal, Vienna........................ 11 Figure 3: Plan of the Orchestra Level, Grosser Musikvereinssaal, Vienna 12 Figure 4: Plan of the Balcony Level, Grosser Musikvereinssaal, Vienna..................12 Figure 5: Contemporary photograph of Grosser Musikvereinssaal, Vienna, looking towards the rear.........................................................................................13 Figure 6: Interior view of the Teatro Alla Scala looking towards the stage area 18 Figure 7: Interior view of the Teatro Alla Scala looking at the audience side 18 Figure 8: Plans and section of the Teatro Alla Scala..................................................20 Figure 9: Plan of Festival Stage................................................................................... 26 Figure 10: Sections and balcony plan of Festival Stage.............................................28 Figure 11: Plans and sections of Octagon Theater....................................................29 Figure 12: Exterior View of the Carolyn Blount Theatre..............................................30 Figure 13: Exterior view of the Theater Arts Center...................................................31 Figure 14: Plan and Section of Boston Theater.......................................................... 32 Figure 15: Interior view showing the seating and the stage area..............................33 Figure 16: Exterior View of Bing Theatre.................................................................... 38 Figure 17: Plan of the Bing Theatre.............................................................................39 Figure 18: Interior view of the Bing Theatre showing the seating area...................... 39 vi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 19: Interior view of the Bing Theatre showing the stage.................................40 Figure 20: Seating Locations chosen for the Survey..................................................42 Figure 21: Longitudinal Section of the Bing Theatre...................................................42 Figure 22: Block Diagram of MLSSA System..............................................................45 Figure 23: A close-up of the Omni directional speaker...............................................46 Figure 24: Gary Mange and Jerry Christoff with the MLSSA equipment...................48 Figure 25: Mr. Gary Mange and the author viewing results in the MLSSA screen.. 48 Figure 26: Microphone positions inside the Bing Theatre.......................................... 49 Figure 27: Sample impulse response chart as generated by the MLSSA system... 50 Figure 28: Sample Acoustical Parameters table generated by the MLSSA 51 Figure 29: Screen capture of the model during the developmental stage................ 71 Figure 30: Model with the sloped floor, audience plane and the roof panels...........72 Figure 31: Screenshot of the model with the included ceiling panels and the wall panels...............................................................................................................73 Figure 32: View of the completed model with the added screen for stage area. All the receiver locations are also seen in the audience area............................. 73 Figure 33: Completed model with different surface materials....................................75 Figure 34: Four views of the frame model...................................................................75 Figure 35: Sound Pressure Level (SPL) in audience area (Spatial Uniformity)........75 Figure 36: Sound Pressure Level - a .......................................................................... 76 Figure 37: Audience area mapping - Clarity (C- 80)..................................................76 vii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 38: Audience area mapping - Sound Level (G).................................. 77 Figure 39: Full detailed calculation - T 60 ..................................................................77 Figure 40: Full detailed calculation - Echograms..................................................... 78 Figure 41: Full detailed calculation - RT and EyrT..........................................78 Figure 42: Impulse Response for Position A-1......................................................... 98 Figure 43: Impulse Response for Position A -2......................................................... 99 Figure 44: Impulse Response for Position A-3....................................................... 100 Figure 45: Impulse Response for Position A-4........................................................101 Figure 46: Impulse Response for Position A-5........................................................102 Figure 47: Impulse Response for Position B-1....................................................... 103 Figure 48: Impulse Response for Position B-2....................................................... 104 Figure 49: Impulse Response for Position B-3........................................................105 Figure 50: Impulse Response for Position B-4........................................................106 Figure 51: Impulse Response for Position B-5........................................................107 Figure 52: Acoustical Parameters for Position A-1..................................................108 Figure 53: Acoustical Parameters for Position A-2..................................................109 Figure 54: Acoustical Parameters for Position A-3..................................................110 Figure 55: Acoustical Parameters for Position A-4..................................................111 Figure 56: Acoustical Parameters for Position A-5..................................................112 Figure 57: Acoustical Parameters for Position B-1.................................................. 113 viii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 58: Acoustical Parameters for Position B-2..................................................114 Figure 59: Acoustical Parameters for Position B-3..................................................115 Figure 60: Acoustical..Parameters for Position B-4..................................................116 Figure 61: Acoustical..Parameters for Position B-5..................................................117 ix Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF TABLES Table 1: Survey Results................................................................................................43 Table 2: Various Microphone positions inside the Bing Theatre for testing Acoustics.................................................................................................................48 Table 3: Average Reverberation Times from MLSSA results....................................52 Table 4: Clarity Levels from MLSSA results................................................................53 Table 5: Uniformity of Sound Level..............................................................................54 Table 6: Reverberation Times using Eyring Formula.................................................59 Table 7: Comparison of the Average Reverberation times for different frequencies..............................................................................................................81 Table 8: Comparison of C-80 values from MLSSA and CATT @ 1000 H z............... 84 Table 9: Comparison of Sound Pressure Levels from MLSSA and CATT @ 1000 Hz................................................................................................................... 86 Table 10: Relative values of Sound Pressure Levels @ 1000 Hz..............................87 x Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT The objective of this thesis was to study and analyze the acoustics of an existing theater/auditorium space. Background research and a case study were conducted on different types of auditorium spaces. The Bing Theatre on the University of Southern California (USC) campus was selected as a case study. The Bing, a one level, 551 seat Theater is primarily used for the theatrical performances of USC and occasional opera. Acoustical measurements, manual reverberation time calculations and computer model simulation were performed to determine the most important acoustical aspects for drama - speech intelligibility and uniformity of sound level. A survey was also conducted to find out the audience’s response to the Bing acoustics during a live performance. The results of the study and analysis indicated that the acoustics of the Bing Theatre in general is fine, for its primary uses. A few improvements might be made to the space, but the cost could most likely not be justified in light of the small improvement that might be achieved in the performance. Keywords: Acoustics, Theater, auditorium, CATT-Acoustic, MLSSA, Bing Theatre, Computer Simulation. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 1 THESIS INTRODUCTION 1.1 BACKGROUND OF ACOUSTICAL STUDIES 1.1.1 Acoustics in Building Science In the vast field of building science, acoustics plays an inevitable role. Acoustics is an important form of energy in a building space as it is essential to have efficient distribution of desirable sound as well as the exclusion of the undesirable sound. The days are gone, where acoustical design was only considered for concert halls, major auditoriums and studios as the awareness of good acoustics is growing. In these modern days, everyone is realizing how important it is to consider acoustics in spaces used daily, including classrooms, restaurants, places of worship and even ones own home. 1.1.2 Previous Studies in Acoustics There is plenty of research being conducted in the field of acoustics, especially in the field of auditorium and theater acoustics. With the advancements in technology, computer modeling a space before it’s built, and testing it has become an important aspect, for changing the design/materials before it is actually built. Recent examples are the Walt Disney Concert Hall1 in Los Angeles, USA (Architect: Frank 1 Inauguration in October 2003 1 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. O. Gehry; Acoustical Consultant: Yasuhisa Toyota) and Tenerife Opera House1 in Santa Cruz, Spain (Architect: Santiago Calatrava) where acoustical simulations were done in a large scale before these unusual geometrical spaces where built. A previous Master of Building Science (MBS) student2, at the University of Southern California used the CATT Acoustic software (v 7) to simulate acoustics in an obviously bad acoustical space on campus (Verle Annis Gallery3 ) and provided interesting solutions to solve the problem. 1.1.3 Why are acoustical studies important? It is important that the speaking/performing and listeners’ hearing experience should be pleasing, in terms of clarity, intelligibility, loudness etc. The main aim is to provide an acoustical environment that is conducive to a good hearing experience in a space. The acoustics in a performing space is a high priority and should be a primary design consideration when preliminary plans are being drawn. The auditorium layout, shape, volume and ceiling profile are all key factors in determining the acoustics. So, it becomes important to delve into the details of acoustics, which plays the vital role in a theater auditorium space along with sight. 1 1nauguration in September 2003 2 Rebecca Vital graduated in May 2000 from University of Southern California with a Masters in Building Science. 3 Multipurpose seminar room with capacity of about 50 people, in School of Architecture, University of Southern California. 2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1.2 HYPOTHESIS Measured and computed model results can be compared and can be used to test the acoustics of a given enclosed space, and can be studied in concert with each other. Further more, depending on the results, design solutions can be proposed for improvement in acoustics in that space. This will be achieved by modeling the key acoustical factors (Reverberation time, Speech Intelligibility, Uniformity of sound level etc.) in an existing space using various methods, including a computer prediction software for simulating room acoustics called CATT Acoustic v8.01 . 1.3 OBJECTIVE The objective of this thesis is to study a space that may need improvement in acoustics and recommend acoustical solutions that might be possibly implemented and tested in the future. To achieve that, various methods to analyze and simulate acoustics in a theater will be explored. In this process, CATT-Acoustic skills will be acquired. 1 Computer Aided Theater Technique (CATT). The latest version of 8.0 was released in February 2002. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1.4 ORGANIZATION OF THE STUDY This whole thesis is a learning process itself. This thesis is split into eight steps, as follows: The first step is to identify the scope of this master’s level thesis and define it. This is stated in the form of objective and hypothesis in this chapter (Chapter 1). The second step is to learn about the theater acoustics in general and the main aspects and the factors governing the quality of performance in the theater space (Chapter 2). The third step is to identify and select the USC Bing Theatre, an existing theater space that may require acoustical improvement. Then, observe the acoustics in the space, by sitting in several positions while a live performance takes place (Chapter 3). The fourth step is to measure acoustics in the Bing Theatre using MLSSA (Maximum-Length Sequence System Analyzer) equipment testing (Chapter 4). The fifth step is to calculate the reverberation time in the space using the Eyring Formula based on the geometrical and material properties of the space (Chapter 5). The sixth step is to study and simulate the acoustical properties of the space using the computer program, CATT Acoustic, using the existing drawings of the space (Chapter 6). 4 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The seventh step is to compare all the results, and validate the computer simulation for accuracy (Chapter 7). Depending on the results and based on the observations made, the Bing Theatre surface areas and configuration that may need possible modification will be evaluated. The eighth step is to provide solutions/ modifications to improve the acoustical performance of the Bing Theatre (Chapter 8). 1.5 CHAPTER CONCLUSIONS AND PRELUDE TO NEXT CHAPTER The overview of this thesis and objective was discussed in this chapter. This gives a guideline to proceed further with the research for this thesis. In the second chapter of this thesis, definition of important terms, different auditorium types, and their major concerns, with respect to acoustics will be discussed. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 2 BACKGROUND RESEARCH ON AUDITORIUM ACOUSTICS 2.1 INTRODUCTION TO AUDITORIUM ACOUSTICS In this chapter, the research conducted for acquiring more knowledge in the acoustics of performance spaces is discussed. First, some of the important acoustical terms that will be used throughout this thesis are defined. Then, the different types of auditoriums where acoustics plays a major role and some examples with really good acoustical qualities are discussed. 2.2 DEFINITION OF IMPORTANT ACOUSTICAL TERMS1 ■ Reverberation time-T30: (Related terms - Reverberance, Live-ness) Reverberation refers to sound that persists in a room after a tone is suddenly stopped. “Reverberation time (RT)” is the number if seconds it takes for a loud tone to decay to inaudibility (60 decibels) after being stopped. A hall that is reverberant is called a “live" hall. A room with a short reverberation is called “dead” or “dry”. The RT requirement differs for various spaces depending on the use as indicated in Figure 1. RT is usually determined separately at a number of frequencies, such as, 125, 250, 500, 1000, 2000 and 4000 Hertz (Hz). 1 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ”Live-ness” is related primarily to the reverberation times at the middle and high frequencies, those above about 350 Hz. A hall can sound live and still be deficient in bass. However, if a room is sufficiently reverberant at low frequencies, it is said to sound “warm". Below is the chart showing optimum Reverberation time in seconds for different types of auditorium with volume of the space ranging from 10,000 cubic feet to 1,000,000 cubic feet, at 512 Hz. 20 50 40 S O 60 80 IOC 200 300 400500 700 1 0 O 0 V O L U M E IN THOUaWDS O P C U D IC P B E T Figure 1: Optimum Reverberation time for different types of Auditorium1 1 Source: Vern O Knudsen and Cyril M Harris’ “Acoustical Design in Architecture.” page 194, Figure 9.11 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. * Early Decay Time (EDT) The first 10 dB of the sound decay after a source is cut off is called “early decay time” (EDT). EDT becomes very important when comparing the acoustical quality of halls. ■ C-80 (Clarity) C-80 is the clarity factor measured in decibels (dB). It is the ratio of the sound energy in the first 80 m-sec (80/1000 of a sec) of sound arriving at a listener’s position to the sound energy occurring after 80 m-sec. The initial sound energy leads to clarity and intelligibility. The latter sound energy reduces clarity and intelligibility. “Clarity” is the degree to which the discrete sounds in a musical performance stand apart from one another. Clarity depends critically on musical factors and the skill and intention of the performers, but it is also closely related to the acoustics of the room. ■ Loudness (Related term - Sound Pressure Level-SPL) Loudness is a function of the total energy in a sound divided by the number of people who must share it. Loudness also decreases due to the sound absorption caused by the people, furnishings and materials. Clearly, a sound emitted in a concert hall searing 1000 listeners would be louder than that in a hall seating 3000 to 5000 persons if both halls had the same reverberation time. Music also sounds 8 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. louder in a highly reverberant hall than in a dead hall, even though both may be of the same size. ■ Early Sound Early sound is the direct sound and those reflections that take place within 80 m-sec after the arrival of the direct sound. ■ Lateral Energy Fraction (LEF) LEF is equal to the ratio of the weighted energy in the sound that does not come from the direction of the source to that which comes from all directions including that of the source. This factor is significant in a concert or recital hall, but not significant in a drama theater. 2.3 MAJOR CONCERNS FOR DIFFERENT AUDITORIUM TYPES 2.3.1 Speech and Theater design The two major acoustical requirements for theaters used primarily for dramatic performances are: (1) Excellent speech intelligibility and (2) Uniform sound level. The primary requirement for speech in subjective terms is that it should be intelligible. This almost uni-dimensional requirement makes searching for design resolutions admirably suited to trail and error. The good acoustic performance of the many theaters built in the boom years before the First World War is an inspiration, which testifies to the extensive appreciation of acoustic factors by theatre architects of the time. 9 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. In enclosed spaces, the proportion of early sound energy as a fraction of all received energy must be large enough for intelligible speech. This will occur close to the actor and in small auditoria. In large auditoria a reverberation time that is too long will provide too much late energy and intelligibility will be undermined. The usual recommendations for speech are a maximum reverberation time of 1 second, but in critical situations shorter reverberation times down to 0.7 seconds are worthwhile. Adequate early energy is achieved by provision of strong early reflections arriving within 1 /20th of a second after the direct sound. These are particularly important in theatres where members of the audience are regularly facing the back of an actor. Suitably designed suspended ceilings are valuable though there is often a conflict between stage lighting and acoustic requirements. 2.3.2 The concert hall While the subjective situation with speech is relatively straightforward, it is now universally accepted that the listening experience with music has to be treated as multi-dimensional. What these dimensions are will long remain a topic of discussion. To the sophisticated listener, this compartmentalization of response into five dimensions or so will seem very restrictive. Subjective tests show however that listeners do not place the same significance on the different subjective qualities. Some listeners, for instance, prefer good intimacy, while others seek full reverberance. For the best concert acoustics it is therefore necessary to optimize the various subjective attributes, as far as is possible. Reverberation times of 1.8 to 2.2 seconds are optimum for symphony concerts, with 10 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. shorter values being acceptable for halls with volumes below 330,000 cubic feet (10,000 m3 ). In most small halls the room surfaces often automatically provide suitable conditions to satisfy the other subjective concerns. The reasons for this are that in small halls the density of sound reflections is high, even within the important early period, and the sound level is also loud. Adequate bass sound will always be a concern, which depends on a sufficiently massive auditorium shell. CASE STUDY: Grosser Musikvereinssaal, Vienna1 Since the opening of Grosser Musikvereinssaal in 1870, the pulse of any orchestra conductor quickens when he first conducts in this renowned hall. The Vienna Philharmonic, the parade of famous conductors, and the fine music played there makes this the Mecca of the old halls of Europe. ir T'li H 'i r n n nr w ; i ^ w It :. I ■ • ■' I Figure 2: Longitudinal section of Grosser Musikvereinssaal, Vienna1 1 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. Pages 181-184 11 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 3: Plan of the Orchestra Level2 , Grosser Musikvereinssaal, Vienna Figure 4: Plan of the Balcony Level1 , Grosser Musikvereinssaal, Vienna 1 http://www.ioa.org.uk (Featured article - Reflections on an Ideal: Tradition and Change at the Grosser Musikvereinssaal, Vienna, 2000; Author: Pamela Clements) - 09/07/2003, 7pm PST. 2 http://www.ioa.org.uk (Featured article - Reflections on an Ideal: Tradition and Change at the Grosser Musikvereinssaal, Vienna, 2000; Author: Pamela Clements) 09/07/2003, 7pm PST. 12 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The side walls are made irregular by over forty high windows, twenty doors above the balcony, and thirty-two tall, gilded buxom female statues beneath the balcony. Everywhere are gilt, ornamentation, and statuettes. Less than 15% of the interior surfaces are of wood. Wood is used only for the doors, for some paneling around the stage, and for trim. The other surfaces are plaster on brick or, on the ceiling and balcony fronts, plaster on wood lath. Figure 5: Contemporary photograph of Grosser Musikvereinssaal, Vienna, looking towards the rear2 1 http://www.ioa.org.uk (Featured article - Reflections on an Ideal: Tradition and Change at the Grosser Musikvereinssaal, Vienna, 2000; Author: Pamela Clements) 09/07/2003, 7pm PST. 2 http://www.ioa.org.uk (Featured article - Reflections on an Ideal: Tradition and Change at the Grosser Musikvereinssaal, Vienna, 2000; Author: Pamela Clements) 09/07/2003,7pm PST. 13 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The superior acoustics of the hall are due to its relatively small size (volume 530,000 ft3 (15,000 m3) and seats 1680), its ceiling with resulting long reverberation time (2.0 sec, fully occupied), the irregular interior surfaces, and the plaster interior. Any hall built with these characteristics would be an excellent hall, especially for symphonic music of the Romantic and Classical periods. Nearly every conductor echoes Bruno Walter, “This is certainly the finest hall in the world. It has beauty of sound and power. The first time I conducted here was an unforgettable experience. I had not realized that music could be so beautiful.” Herbert von Karajan, added, “The sound in this hall is very full. It is rich in bass and good for high strings. One shortcoming is that successive notes tend to merge into each other. There is too much difference in the sound for rehearsing and the sound with audience1 .” The sound is this hall is much louder than in Boston Symphony Hall, and some feel that this is a disadvantage for a touring orchestra, which may not be in the habit of restraining itself. Also, it is overly easy for the brass and the percussion to dominate the strings. The strings and woodwind tone are delicious and the sound is uniform throughout the hall. 1 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. Page 181 14 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Architectural and Structural details Use: Orchestra and soloist. Ceiling: Plaster on spruce wood. Side and rear walls: plaster on brick, except around the stage, where walls are of wood; doors are of wood; balcony fronts are plaster on wood. Floors: Wood. Carpets: None Stage floor: Wood risers over wood stage. Stage height: 39 in. (1 m) above floor level. Added absorbing material: 200 ft2 of draperies over front railing on side loges. Seating: Wood structure on main floor and side balconies, except the tops of seat bottoms are upholstered with 4 in. (10 cm) of cushion covered by porous cloth; rear balcony seats, plywood. Architect: Theophil Ritter von Hansen Photographs: courtesy of Sekretariat, Gesellschaft der Musikfreunde in Wien. 15 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Technical details: V=530,000 ft3 (15,000m3); N=1,680 SA=10,280 ft2 (955 m2); So=1,754 ft2 (163 m2) L=117 ft (35.7 m); W=65ft (19.8 m) H=57ft (17.4 m); L/W=1.8 L=12 msec; SA/N=6.1 ft2 (0.57m2) Legend: V=Volume of hall; N=Number of seats in the hall; SA=Acoustical audience area So=Area of stage; L=Average room length; W=Average Width; H=Average room height; t-, =the initial-time-delay gap. 2.3.3 The opera house Of all auditorium types, opera house design is the most constrained. With a proscenium opening determining the limits of seating for visual reasons and the need for a pit separating the stage from the stalls seating, the options are highly limited. The two needs, to project the singer’s voice with reasonable intelligibility and for orchestral sound to be supported by the acoustics of the auditorium, appear irreconcilable. Though more easily stated than realized in practice, the solution lies 16 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. in providing a reverberant auditorium for the orchestral sound but designing the form to enhance the singer’s sound as far as possible, principally with early reflections. For reverberation time, values intermediate between speech and music of 1.3-1.81 seconds are appropriate, with the optimum being somewhat a matter of taste., ed. (1998). USA, John Wiley & Sons, Inc. CASE STUDY: Teatro Alla Scala, Milan2 August 3, 1778, La Scala opened its doors to a future of great music, glamour, and unequalled tradition. Great opera composers, Verdi, Rossini, Puccini, Donizetti, have been intimately identified with La Scala. Its lineage of famous conductors includes Arturo Toscanini, Cleofonte Campanini, Herbert von Karajan, and Carlo Maria Giulini. Singers include Adelina Patti, Enrico Caruso, Renata Tebaldi, Maria Callas, and scores of others. 1 Source: William J. Cavanaugh and Joseph A. Wikes’ “Architectural Acoustics - Principles and Practice”. 2 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. Pages 339-342 17 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 6: Interior view of the Teatro Alla Scala looking towards the stage area Figure 7: Interior view of the Teatro Alla Scala looking at the audience side2 1 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. Page 222-223 2 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. Page 222-223 18 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The architect of La Scala was Giuseepi Piermarini. He designed and built the largest and best equipped theater of his day. The exterior of La Scala looked in 1778 very much as it does today. Until World War II it experienced only minor changes - in 1883 it got electric lights. In 1943 La Scala was victim of a bombing attack; the walls remained standing, but little else. In May 1946 it reopened, its appearance almost as before. Today it has 2,289 seats, including 154 unnumbered seats from which the stage is not visible. With standees the number is augmented. La Scala is a beautiful and engaging theater. It is a horseshoe in plan with high balcony faces and a vaulted ceiling 6 ft higher at the center than at the sides. Intimacy is conveyed by its narrow main floor. Nevertheless the hall has a regal air that derives from the great height of its ceiling. The theater is lighted by a huge central chandelier of 365 lights and white glass globes in groups of five placed at intervals along the bases of the balcony faces. 19 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. • Mato curtaic i i agj i gi ai g«gi i i Figure 8: Plans and section of the Teatro Alla Scala1 The acoustics are excellent for those lucky enough to sit either at the front of the boxes, on the main floor, or in the galleries. The openings to the boxes are only 4.5 feet square (1.37 m) so that the wall they present is only about 40% acoustically absorbent. The large reflecting faces of the boxes and the resulting small cubic volume of the house achieves unexpected acoustical spaciousness. The reverberation time is a little lower than in other large opera houses. The sound is clear, warm, and brilliant. Sound is returned to the stage from the faces of the boxes with an intensity that is not reached in any other large opera house. The vaulted ceiling returns the sound of the orchestra and the singers to the conductor, clear and loud. Both singers and conductors are enthusiastic about the acoustics. 1 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. Page 222-223 20 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Architectural and Structural details Use: Opera and ballet Ceiling: Vaulted, 6ft (1.8 m) higher at the center than the sides; plaster on lath attached to 1x4 in (2.5x10 cm) longitudinal boards; there are no irregularities (coffers) on the ceiling. Walls: Box faces are of plaster 42 in. (1.07 m) high; vertical columns at railings are plaster 6 in. (15.2cm) wide; each box opening is 54x54 in (1.37x1.37 m) Floors: Wood over 3ft (0.91 m) airspace over concrete. Carpets: on all floors Pit floor: Wooden floor, flat, elevator type; often located about 10 ft (3 m) below stage level Stage height: 60 in. (1.52 m) above floor level at the first row of seats Seating: On the main floor the seats are of solid wood except that the front of the backrests and the top of the seat-bottoms are upholstered; the boxes have upholstered stools (no backs). Architect: Giuseppe Piermarini References: plans, details, and photographs courtesy of the management of La Scala. 21 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Technical details: V=397,300 ft3 (11,252m3 ); N=2,289 Sa=14,000 ft2 (1,300 m2); So =2,550 ft2 (136.4 m2 ) L=99 ft (30.2 m); W=66 ft (20.1 m) H=63 ft (19.2 m); L/W=1.5 ti=20 msec; Sa/N=6.1 ft2 (0.57m2 ) Legend: V=Volume of hall; N=Number of seats in the hall; SA =Acoustical audience area; S0 =Are of Pit and pit floor; L=Average room length; W=Average Width; H=Average room height; L =The initial-time-delay gap 2.3.4 The multi-purpose hall To summarize acoustics for multi-purpose halls is like attempting to hit a randomly moving target. The mix of uses and priorities for individual halls are seldom alike. The purpose-built multi-purpose hall is a recent phenomenon. It has risen from the need to maximize the usage of expensive auditoria and from the ability to supply more flexible facilities. 22 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. For physically variable acoustics, the most common elements are variable volume and absorption. Variable absorption is easy to include in small quantities, difficult in large quantities; in the condition with substantial absorption, there are risks of low sound levels and that vital sound reflections have been eliminated. 2.3.5 Theater Acoustics The design of performance spaces is and always had been an attempt of synergizing the needs, dreams and fantasies of performing artists with the creative abilities of the architect, the theater consultant and acoustician, albeit modified by realities and economics. Theater is construed to be the presentation of a play in an audience environment where the actor is viewed with no obstructions and is clearly heard. The audience environment usually requires a sense of intimacy so that the actor can communicate and express his/her character with subtle expression. The true art of theater building is an often precarious balancing act of weighing programmatic, technical, artistic and architectural demands against available finances. Acoustics is a fundamental part of this art. In any performing space, the essence of the encounter between performers and audience is fundamentally theatrical. The space itself should define and reinforce this relationship through its architecture, whether it be multi-purpose, lyric theater or concert hall. The constant attraction for the audience is in the organized observation of selective human behavior. Even in a concert where the primary 23 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. focus is on music, there is a strong fascination with how the artist or musicians communicate the music physically. The sense of immediacy, also referred to as ‘intimacy’, of ‘being there’ is equally important. Traditionally, intelligibility has been the chief theater acoustic requirement, and the appropriateness of the reverberant field has, sometimes been ignored. However, when the house lights dim, the theater visually goes away and the audience becomes immersed in the dramatic scene. This is not true for the acoustic space. What looks like a drawing room sounds like a theater. To provide maximum control and flexibility for productions, theaters must be limited in size. Although it is not necessary to deliver the same spatial information to every seat in the house, there does need to some uniformity of perception. This can best be accomplished in houses seating less than 600 people. Ideally, theaters should provide total control over the apparent size and shape of the space. This means less and less reverberant spaces, so reverberation character and quality can be provided artificially through electronic enhancement, if necessary. Only in these environments, will naturalistic sounds and spaces be acoustically viable. It is fortunate that in drama space design, intimate human scaled spaces are desired by both acoustical and theater consultants. Acoustical consultants typically want to preserve the performer’s vocal energy within as small a volume as possible, while theater consultants want viewing distances to be as short as possible, and also the audience chamber ceiling to be as low as practically possible, so as to permit use of the smallest and least expensive lighting equipment. 24 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Often, containing sound energy within the performance space is important in the design of speech theaters as well as in music facilities. The acoustician will probably want to assist the theater consultant and the architect with the design of the audience chamber lighting positions to the extent of ensuring that the positions are either very small in area or that any sound energy that passes into the positions will be returned to the audience chamber in a useful manner, rather than being lost in the volume above the ceiling. This may require enclosing the rear of all ceiling lighting positions with plaster, plasterboard or gypsum board, and incorporating sealed access doors so that valuable sound energy does not pass into the attic. This enclosure and the roof will also significantly reduce noise from aircraft, sirens and thunder. Evolution of theater audio is all about finding better and better ways to invent, develop, refine and execute sound in a production that is as much alive and integrated, as the characters and ideas themselves. 2 5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CASE STUDY: Alabama Shakespeare Festival - Wynfield Park, Montgomery. •0 v t 5 1 MAIN LOBBY LEVEL Figure 9: Plan of Festival Stage1 Details: Owner: Alabama Shakespeare Festival Finance Authority Architects: Blount/Pittman Architects, Atlanta, GA Acoustics & Theater Planning: Artec Consultants, Inc., New York, NY. Approx. Cost: $22,500,000 1 Theatres for Drama Performance: Recent experiences in Acoustical Design-Edited by: Richard H. Talaske and Richard E. Boner 26 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The architects were commissioned in October, 1982, to plan a cultural park which was to include a theater complex for the Alabama Shakespeare Festival (ASF). The ASF Theater is located on the estate of the clients, Mr. and Mrs. Winton M. Blount, who funded the entire facility. The recently completed ASF Theater contains 97,000 square feet, including two theaters, scenery, property and costume shops, two rehearsal halls, dressing rooms, company offices and refreshment stands. The Festival Stage is a 750-seat modified thrust stage adaptable for proscenium use. The steeply raked seating and single balcony ensure excellent sightlines and preserve the intimacy required for drama. 2 7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IE LONGITUDINAL SECTION BALCONY PLAN CROSS SECTION Figure 10: Sections and balcony plan of Festival Stage1 Theatres for Drama Performance: Recent experiences in Acoustical Design-Edited by: Richard H. Talaske and Richard E. Boner 28 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The flexible 250-seat Octagon Theater was designed to be adaptable for arena, thrust and end-stage use. It is equipped with a tension wire grid and flexible telescopic seating. GRID PI* AN FLOOR PLAN SECTION Figure 11: Plans and sections of Octagon Theater1 Both theaters are completely sound isolated from the balance of the building by structural breaks. All mechanical systems are housed in two mechanical equipment rooms, which are structurally separate from the rest of the facility. Wall constructions for the theaters include many grout filled concrete block walls. All of the performance lighting dimmers have special custom wound toroidal chokes to reduce lamp filament noise. 1 Theatres for Drama Performance: Recent experiences in Acoustical Design-Edited by: Richard H. Talaske and Richard E. Boner 29 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 12: Exterior View of the Carolyn Blount Theatre1 The variable acoustics elements in the festival stage are provided by motorized banners on the sidewalls, and manually operable curtains along the rear wall. The room design provides for high loudness levels of un-reinforced speech coupled with strong early lateral reflections. These room acoustics, coupled with wide dynamic range and an extremely low background noise level, provide for a chilling dramatic environment. The Octagon Theater is also an acoustically “live” space with an extremely low background noise level. There are provisions for hanging velour curtains along the walls from the grid above; however as a rule, no additional absorbing material is added, other than the backdrop behind the set. Owing to the room’s small size and shape, loudness is excellent and reverberance is not excessive, and intelligibility is excellent in all seating positions (which often cover an arc of 180°). 1 http://www.asf.net/mission.html 30 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CASE STUDY 2: Theater Arts Center-Boston College, Chestnut hill, Massachusetts Details: Completed: 1981 Architect: Sasaki Associates, Inc., Watertown, MA. Owner: Boston College Acoustical Consultant: Bolt Beranek and Newman, Inc., Cambridge, MA. Theater Consultant: Harvard Enoch, Boston College. Cost: $4,200,000 Figure 13: Exterior view of the Theater Arts Center1 1 http://www. bc.edu/offices/robsham/about/tour/frontview/ 31 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. This is a conventional proscenium theater - the first major theater to open in Boston since 1925. Though designed chiefly for drama, it also accommodates musicals and even serves as “home" for the University Chorale of Boston College. Acoustical variability is confined to simple demountable stage shell. The forestage converts into orchestra pit. m m W ' i -w u io s Figure 14: Plan and Section of Boston Theater1 All principal surfaces in the tapered, rectangular house are acoustically reflective. The ceiling, in particular, provides strong, early reflections. The side walls, largely 1 Theatres for Drama Performance: Recent experiences in Acoustical Design-Edited by: Richard H. Talaske and Richard E. Boner 3 2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. covered with wood slats are acoustically diffuse. Only the rear wall is absorptive, to control discrete echoes. Figure 15: Interior view showing the seating and the stage area1 The relative lack of reverberation (see data) is entirely consistent with the theater’s main uses, but one misses it when listening to the Chorale. The sound is not “large” in but choral diction is excellent, even in the last row, 80’ from the curtain line. If the first impressions upon the theater’s opening were good, then a more recent assessment may be even better. AMERICAN SCHOOL AND UNIVERSITY (June 1983) calls it a sound showcase, with “first rate acoustical qualities...excellent speech acoustics.” 1 http://www. bc.edu/offices/robsham/about/tour/stage/ 33 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The center also contains a 53-foot square studio theater, a scenery shop, classrooms, offices, dressing rooms and a spacious lobby, totally nearing 30,000 square feet. For the quality of design and construction, its architects and contractor received a “Build Massachusetts” award from the Associated General Contractors of Massachusetts. 2.4 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER After learning and reviewing the various auditorium types and case studies, with a fairly better knowledge about the major acoustical concerns, following criteria were inferred for the selection of the real space case study: i. The case study space could be any one of the above-mentioned categories of the auditoria. ii. The capacity of the hall would be within 500-1000 seats, to stay within the scope of this thesis. iii. Clearly, the acoustics in the space should need improvement. With that said, the third chapter of this eight chapter thesis addresses the process in selecting the space. In addition, the details of the selected space for the study and test purposes are discussed. 3 4 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 3 ACOUSTICS - STUDY OF A REAL SPACE 3.1 CRITERIA FOR SELECTION OF THE CASE STUDY SPACE For the purpose of this study and simulation process, a space, which needs acoustical improvement, had to be chosen. The main criterion was that the space should be up to and within the scope of a master’s level thesis. It had to be a space with a capacity of 500-1000. To start with, the space had to have the minimal required drawings to scale, i.e. floor plans and cross-sections. The potential space had to be a challenge for this thesis, in terms of the acoustical problems in the space and there should be scope to provide solutions, which can be implemented in real world practice. 3.2 IDENTIFICATION PROCESS The location of the space was one of the main concerns for choosing. A location that is remote was not feasible as frequent visits to the space and studying it was the most important criterion. So, the location of the space had to be limited to the districts in and around the residence of the author, which was in University of Southern California, Los Angeles. This location of Downtown Los Angeles actually turned out to be positive, as there were a lot of theaters that were in the process of restoration and remodeling in the old district of Downtown. 3 5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3.2.1 The Los Angeles downtown tour The best way to get an overview of the theaters/auditoria in Downtown Los Angeles was to take a tour of these spaces. It was done with the help of the organization called LA conservancy1 . This organization offers walking tours to the “Broadway Theaters” in the Los Angeles downtown district on a regular basis. This tour was taken full advantage to get a glimpse of the 11 theaters in the downtown; otherwise this would have been a nearly impossible task as general public access to most of these theaters is prohibited now. In this tour, a guide explained history of each theater, showed the current conditions and the future plans for these theaters were briefed. Some of them were converted to storage spaces and commercial spaces, and some were undergoing renovation and restoration process as most of them were built in the early 1900’s. After the tour, all the theaters undergoing renovation were listed and studied. Among all the others, the Palace Theater2 appeared to be a challenging choice for this thesis purposes. Presently, the Palace Theater is owned by Gilmore Associates for renovation. As this theater was not open for public for shows, it would be the best place for this thesis case study. The renovation was not started yet due to administrative reasons. But, after few visits to the Gilmore Associates office in Downtown Los Angeles, it 1 http://www.laconservancy.org/tours/tours_main.shtml is the link for the tours page of LA conservancy. 2 Location: 630 South Broadway, Los Angeles. Architect: G. Albert Lansburgh, 1911. Marked as Los Angeles Historic-Cultural Monument #449 36 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. was clear that the architectural drawings, if they exist, were not available. All that was obtained was the drawing made in the year 1947, after which the theater underwent several modifications. As time was running out, decisions had to be made. And, as suggested by a committee member, a building inside USC campus seemed to be a wise choice. After learning about the various theater and auditorium spaces inside the USC campus, the Bing Theatre was chosen. 3.2.2 Reasons for Selecting Bing Theatre After careful consideration of the choices that were available, the Bing Theatre was selected for case-study purposes of this thesis. One of the main reasons being, that this space was rumored to need acoustical improvements. The drawings for this space were available from the campus CADD Services and the latest modified drawings were available from the theater manager. Though the latest sections of the space were not available, the building was easily accessible for making observations, taking measurements, test readings and to study the different type of materials used in the space. 3.3 DETAILS OF BING THEATRE Bing Theatre belongs to the School of Theater in University of Southern California, Los Angeles. At present, this theater has seating capacity of 551, all on one level of seating, with handicap access in the front of the theater. There is no balcony. The internal area of the theater is approximately 10,000 square feet, including the stage. The theater itself has undergone many stages of renovation and the latest major 37 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. one being the one in 1997, where the handicap access was added, and carpet, railing and LED lighting were added to the aisle steps. Figure 16: Exterior View of Bing Theatre Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 17: Plan of the Bing Theatre1 Figure 18: Interior view of the Bing Theatre showing the seating area 1 Source: CAD Services - Facilities Management Services, USC. 3 9 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 19: Interior view of the Bing Theatre showing the stage 3.3.1 Survey of audience/performers experience in Bing Theatre As an initial informal test to confirm our selection, a live performance on the March 1s t 2003 was chosen and a survey was taken based on that day’s production. “The Winter’s Tale” by Shakespeare, was chosen, in which the students of School of Theater performed. Then a survey was taken from the audience and performers about their acoustical experience in that space. The survey included the following choices: i. Clarity (Intelligibility) iv. Very Intelligible (1) V. Fairly intelligible (2) vi. Intelligible (3) vii. Sometimes unintelligible (4) viii. Usually unintelligible (5) 40 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ii. Sound Level ix. Too loud (1) x. Loud (2) xi. Just right (3) xii. Soft (4) xiii. Too soft (5) iii. Any other comments in particular. Different seats were selected and the acoustical conditions were observed. The seat positions were very close to the ones that were chosen for the acoustical measurements and acoustical modeling. It is important to note that the performers themselves were students and are in the learning process of how to project their voices. Therefore, some of the acoustical problems in the hearing may not be actually due to the space, but due to the performers. The results and findings are as follows: Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 20: Seating Locations chosen for the Survey i .. : ! I ; j ! # i...... & : ; ! L J j Figure 21: Longitudinal Section of the Bing Theatre1 1 Source: Sue Brandt, Bing Theatre Manager. 42 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Seat Location Comments Intelligibility Sound Level Other 1 D 1 1 1 2 M 7 3 4 3 J 19 4 3 Echo 4 P 11 4 3 5 R 110 4 4 Extra noise Table 1: Survey Results 3.4 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER In this chapter, the space identification process and the details of the selected space were discussed first. Then, the acoustical observations were made in the Bing theatre and a survey was taken to understand the space better. The acoustical performance of this hall was ok, according to the observation results and the survey conducted. The fourth step is to measure the acoustical parameters of the Bing Theatre, in order to analyze the acoustics of the space. This measurement is done using the MLSSA system. MLSSA system is discussed in detail in the fourth chapter. 43 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 4 MEASUREMENTS OF EXISTING ACOUSTICS 4.1 MLSSA SYSTEM - AN OVERVIEW The first step in evaluating the acoustical parameters in Bing Theatre is, to use the MLSSA equipment system. The MLSSA system is one of the accurate methods that are available for measuring acoustics of an enclosed space. This Equipment was chosen, as Veneklasen Associates was kind enough to lend this to us for the testing purposes. In this chapter, the equipment, the procedure of the testing and the results will be discussed. 4.1.1 Introduction The Maximum-Length Sequence System Analyzer (MLSSA - pronounced Melissa) is an audio and acoustics measurement system based on maximum-length sequences. MLSSA is a single channel analyzer, resulting in an effective doubling of useful bandwidth. Maximum-Length Sequence (MLS) is deterministic and periodic yet still retains most of the desirable characteristics of white noise1 . 1 White noise is a sound that is produced by combining sounds of all frequencies within the range of human hearing (generally from 20 Hz to 20,000 Hz.) 44 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The MLS technique measures the impulse response1 , the most fundamental description of any linear system, from which a wide range of important functions are derived through computer-aided post-processing. 4.1.2 The Equipment MLSSA measurement system is based on the IBM PC and consists of a plug-in board and special software. CARD l/P CARP O P •tWKHtiS ( c B y K ffT f^ E S r n MTU M LSSA CARD) JfJ B R (IAB GRUPfOJ) Vk Ml OMNI P fBRU SUPPLY I Ml m m H O NE- P t iq n a l J O ? ) BLOCK DIAGRAM OF M ISS A SYSTEM flL A R S C m C M VIS MOPep Figure 22: Block Diagram of MLSSA System 1 A narrow pulse is fed to the sound system and the measurement microphone picks up the resulting response. The result is called the impulse response of the system. 45 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The computer produces a MLS signal, the signal is amplified through a power amplifier and then outputted through a loudspeaker. The sound is then received by the microphone and through the microphone power supply; the resulting signal is read by the computer. After that, by running a few commands in the computer, the computer generates the Impulse response charts and the other parameters. Then, the results are saved and retrieved for printing, using a compatible outside computer. 4.1.3 Acoustical Parameters MLSSA measures many acoustical parameters from the Impulse response including the C80 factor, Early Decay Time (EDT) and Reverberation Time. The output is tabulated for different frequency levels from 63Hz to 4000Hz. Figure 23: A close-up of the Omni directional speaker 4 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 4.2 TESTING BING THEATRE ACOUSTICS WITH MLSSA SYSTEM The acoustical measurements of Bing Theatre were taken on December 17th, 2002 with the help of Jerry Christoff1 and Gary Mange2 from Veneklasen Associates, who provided the equipment. 4.2.1 Equipment Setup In the stage, loudspeaker was positioned in two different locations and for each of those positions, five microphone positions were chosen. When the testing was done, the environmental noise conditions were normal, except for some renovation work in the lobby of Bing Theatre. There was some noise due to this ongoing work. But, it turned out to be the workers lunch time as the equipment was setup around noon. So, the test was conducted when there was no disturbance from the noise due to the work. The test was taken with no audience in the hall. 1 Jerry Christoff is the President of Veneklasen Associates, located in Santa Monica, CA (http://www.veneklasen-assoc.com) 2 Gary Mange is the Laboratory Manager of the Western Electro-Acoustic Laboratory (WEAL), located in Santa Clarita, CA (http://www.weal.com). WEAL provides laboratory support for Veneklasen Associates. 47 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 24: Gary Mange and Jerry Christoff with the MLSSA equipment Figure 25: Mr. Gary Mange and the author viewing results in the MLSSA screen. Mic. Row Seat 1 E 110 2 J 108 3 P 111 4 N 9 5 K 13 Table 2: Various Microphone positions inside the Bing Theatre for testing Acoustics 48 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 26: Microphone positions inside the Bing Theatre 4.2.2 Results of the Test Results were read from the network computers and printed. The two main results retrieved were the Impulse Response and the tabular column of Acoustic Parameters. The results were printed for each and every position of the Loudspeaker and Microphone inside Bing Theatre. 49 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Sample of the results are as follows: rtL«: I2-1 T-1 R 2 2:24 W aO.Q 4 0 .C l « !,« Its® - MM djkor ,i - s.ei’Mrss > , l , — S iM y S i, U ts i i f : 1 2 " !‘ i 102 Hits m r r - , r » ' * 2 » i! * -««*0 ■ H i S S « II s. Figure 27: Sample impulse response chart as generated by the MLSSA system The vertical scale of the graph is the amplitude and the horizontal scale is the time. The first large spike is actually the direct sound, which occurs approximately 20/1000th of a second after the sound is produced by the loudspeaker. This means its microphone is approximately 20 feet from the loudspeaker since the velocity of sound is 1130 feet/second. At approximately 50 msec, which is 30 msec after the direct sound, there is a prominent reflection that may be observed as an echo. A graph of this type is called an echogram. 5 0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-O ctave Band A co u stical P a ra n e te rs Hrfiid P o i'd f if . ; i.O i H Z -.T -IE ’ [dB-SPLI idB-SPLl LdB] [d in ' : ' L x J -10dB Is ] TS C B S E I - 2 0 d B l s j 1 - 5 : - 2 5 ) r i: t - d t k i B l s j : ’ . . r. r B I - U S E R l s j f - l . H ; - 2 5 > 58.3 0.69 1.76 54.0 201.4 6.582 4.240 -0.882 4.039 -0.864 1.295 -0.930 69.6 -0 .0 5 0.53 49.7 99.1 1.425 2.148 -0.974 2.370 -0.976 2.576 -0.982 < 1 79.2 50.8 28.4 0.52 2.01 53.0 73.2 1.038 1.051 -0.997 1.004 -0.998 1.017 -0.996 I- " '- 77.7 44.0 33.7 - 0.00 3.66 50.0 62.5 0.848 0.970 -0.996 0.932 -0.998 0.914 -0.998 80.0 46.8 33.3 2.80 5.04 65.6 54.0 1.014 1.029 -0.997 0.993 -0.998 0.960 -0.998 V H B H 81.8 50.4 31.4 0.53 2.77 53.0 69.7 0.991 0.907 -0.999 0.905 -0.999 0.889 -0.999 78.5 54.5 23.9 0.80 3.11 54.6 63.3 0.974 0.827 -0.999 0.752 -0.993 0.811 -0.998 :,m m - M riH H usicihted 1.247 3.947 55.985 61.556 0.944 0.966 -0.998 0.935 -0.998 0.917 -0.998 File: L :\HLSxBIHG\fi2 .11“ 12-17-102 2:29 PH lid L H j H i-S S H : ■ ■ Figure 28: Sample Acoustical Parameters table generated by the MLSSA This table lists out various acoustical parametric values at different octave band frequency levels. From this table, the parameters that were used for comparison purposes in this thesis are RT-20 at octave bands between 125 Hz and 4000 Hz, C- 80 value at 1000 Hz and S value at 1000 Hz for each of the microphone and speaker position. 51 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The parameters that were used for comparison purposes from the MLSSA results are tabulated below: Reverberation time: For each Octave band frequency, the average value of RT 60 for the five different receiver positions and two different source positions is calculated. Octave band frequency, Hertz 125 250 500 1000 2000 4000 Reverberation Time, seconds 1.50 1.07 0.95 0.97 0.91 0.83 Table 3: Average Reverberation Times from MLSSA results The values imply that the Bing Theatre has higher reverberation times in the lower frequency range, which makes it appropriate for the school auditorium purposes. Clarity Level: The clarity levels for the different receiver locations were determined for each of the source locations from the tables generated as a part of MLSSA results. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Seat Location Source A Source B E 110 1.72 1.14 J 108 5.04 4.33 P 111 3.97 3.95 N 9 3.74 4.16 K 13 2.03 1.61 Table 4: Clarity Levels from MLSSA results These values are relatively higher when compared to the C-80 values of various auditoriums measured world wide1 . The reason is that those auditoriums are almost 4 to 5 times bigger in seating capacity. Uniformity of Sound Level: The sound level values in decibels were determined from the table that was generated by MLSSA results. 1 Source: Leo Beranek’s “Concert and Opera halls: How they sound”. Page 479 53 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Seat Location Source A (decibels) Source B (decibels) E 110 80.5 82.7 J 108 80.0 82.0 P 111 80.9 81.2 N 9 80.6 80.8 K 13 79.4 79.8 Table 5: Uniformity of Sound Level The values above indicate that the sound in the Bing Theatre is reasonably uniform throughout the hall with a maximum of 1.5 dB difference from the mean value. These values are normalized in Chapter 7 while comparing with the results from CATT Acoustics program. For detailed charts and tables of all the microphone and speaker locations, refer Appendix A. 4.3 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER In this chapter, the MLSSA system and the acoustical tests that were conducted using the system were discussed. The results of the MLSSA system were tabulated as well. From this MLSSA analysis, the following three conclusions can be drawn. 54 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. i. In the lower frequency range, the reverberation times were higher in this hall. This means, the sound in the room is warm in quality, which is apt for school auditorium purposes. ii. The clarity level was higher in the middle and the back rows than the front rows. iii. Uniformity of sound level values show that the hall is plausibly uniform throughout the hall. All these above results seem not to support the rumor of bad acoustics in Bing Theatre. In the following fifth chapter, the measurement of acoustics using the manual calculations methods is discussed. For this purpose, Eyring formula is used and this method is explained in detail in the fifth step of this eight step process. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 5 MANUAL CALCULATIONS 5.1 SABINE FORMULA AND EYRING FORMULA There are two main formulas widely used in the acoustics field to calculate reverberation time. They are the Sabine formula and the Norris-Eyring formula. The Sabine formula is a simple equation to find reverberation time, where it assumes that the sound decays continuously and smoothly in an enclosed space. This formula works when there is not much of a variation in the room surfaces. Sabine formula results become less accurate when the absorption in the room is increased. This formula is good during initial stages of design of an acoustical space. The Eyring formula is a more accurate formula to calculate reverberation time than the Sabine formula. This is an equation derived from the Sabine’s formula. The Eyring formula assumes intermittent decay with the arrival of fewer and fewer reflections. Since the Bing Theatre has various types of room surfaces and more surfaces due to its unique surface, the Eyring formula is used to calculate the reverberation time in this case. 56 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 5.2 REVERBERATION TIME CALCULATION USING EYRING FORMULA This manual calculation is to compare with the measured and simulated reverberation time (RT60). This method is based on the calculation of the average energy reduction associated with each reflection at each surface. The contribution of a surface to the total absorption is related to the fraction of reflections occurring at the surface, which is assumed to be given as the total surface area of the room. The sound field is assumed to be a random incidence field. This calculation relies on the sound absorption properties of the surface materials used in the space. RT60 = 0.049 V / [- 2.3 S Iog10 (1 - a) + 4mV] where, V = Volume of the space in ft3 a = Average absorption coefficient of the surface materials S = Total Surface area (not including seats) in ft2 m = Attenuation Coefficient at each frequency (depends on humidity) 5 7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. An existing Microsoft excel calculation sheet1 was used to insert appropriate areas and sound absorption coefficients in the values for the Bing Theatre and obtain the Reverberation times for different frequency levels. For the Bing Theatre, the important parameters required for the reverberation time calculations are as follows: Length of the space = 110 ft; avg. width of the space = 87 ft; maximum height measured at front row = 36 ft V = 428,380 cubic feet S = 48,104 square feet A5 0 0 = 0.3 1 Courtesy: Veneklasen Associates, Santa Monica. 58 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The results are tabulated as follows: Material Area (Sq ft) Octave Band Center Frequency (Hertz) 125 250 500 1000 2000 400 0 1” Plaster 14,609 0.16 0.10 0.06 0.04 0.04 0.04 Carpet on Cone. 1,276 0.05 0.07 0.24 0.33 0.28 0.25 Poured conc. 10,352 0.04 0.04 0.04 0.04 0.04 0.04 2” F/G on 1” Gyp brd. 2,027 0.25 0.76 0.99 0.99 0.99 0.97 %” glass 616 0.20 0.15 0.10 0.05 0.04 0.04 V z or 5/8” Gyp board 10,674 0.25 0.15 0.08 0.04 0.04 0.04 Chairs, Unoccupied 3,771 1.60 2.50 2.50 2.50 2.50 2.50 Wood Floor on Joists 4,780 0.15 0.10 0.10 0.06 0.04 0.04 Calculated RT (seconds) 1.40 1.15 1.22 1.31 1.24 1.12 Table 6: Reverberation Times using Eyring Formula The values are, in general higher than the measured RT from the MLSSA results. However, the RT value at 500 Hz is lower than the optimum reverberation time for School Auditorium, as given in Figure 1 (Chapter 2). This discrepancy in values is Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. may be due to the approximation of the absorption coefficients of the surface materials. Also, Eyring formula takes only the properties of the space into account and does not consider the geometry and orientation of the materials used. However, these values still make a good contribution for the comparison purposes of this thesis. The manually calculated reverberation time values had minor discrepancies from the MLSSA values. The results are compared with the MLSSA and CATT results and the discrepancies are detailed in Chapter 7. 5.3 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER This manual calculation was done to compare with the actual measured values obtained from MLSSA and the predictions from CATT Acoustics program. Minor Discrepancies were found in comparing the results with MLSSA results. The discrepancies were due to the assignment of the actual absorption coefficients to the materials in the space. However, the pattern of the reverberation values in the mid-frequency range was very comparable. So, the manual calculation results made a good contribution towards the reverberation time comparison in this research. In the sixth chapter, which is the main part of this thesis, the computer modeling process is discussed in-depth, starting from how the CATT software works, till the Echogram results obtained by simulating the Bing Theatre in CATT Acoustics program. 6 0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 6 COMPUTER SIMULATION OF ACOUSTICS 6.1 CHAPTER INTRODUTION So far, in the previous sections, a measured testing and a manual calculation was done to study the acoustics of the Bing Theatre. Now, in this section, the computer testing will be done to reinforce the studies done so far. In this Chapter, there are four main parts that are discussed and presented in detail. The four parts are: i) Description of the CATT Acoustic software and its acoustic prediction methods, ii) Procedure for using this software to predict acoustics of a room, iii) Computer modeling of the Bing Theatre in CATT and iv) Using the computer model to simulate the acoustics for Bing Theatre. 6.2 CATT-ACOUSTIC SOFTWARE - AN OVERVIEW Computer Aided Theater Technique (CATT)-Acoustic is a computer program for room acoustics prediction and auralization1 . It is based on the Image Source Model (ISM) for early part echogram qualitative detail, Ray-tracing for audience area color mapping and Randomized Tail-corrected Cone-tracing (RTC) for full detailed calculation enabling auralization. Bengt-lnge Dalenback, of the company CATT (Sweden) is the developer of this program. CATT-Acoustic v8.0 is the 6th 1 Auralization is a method of listening to the acoustical characteristics of a performance space based solely on the CATT Acoustic study. 61 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. significant version for Windows (v6.0 June 1996 (16-bit), v6.1 March 1997 (16-bit), v7.0 Feb 1998, v7.1 Oct 1998, v7.2 Oct 1999, and v8.0 Feb 2002). The system consists of ■ A 32-bit Windows MDI (Multiple Document Interface) main program. ■ A customized Notepad-like text editor that communicates with the main program. ■ A stand-alone 3D-viewer application (<100kB) based on OpenGL. ■ A stand-alone PLT-viewer and a set of Auto LISP files for the optionally used AutoCAD interface. 6.2.1 Hardware Requirements CATT-Acoustic requires an IBM PC compatible equipped with a Pentium processor and Windows 95, NT 4.0 or higher. For auralization, a soundcard capable of 16-bit 44.1 kHz stereo replay is required. 6.2.2 CATT-Acoustic v8.0 modules Version 8.0 of CATT-Acoustic comes with seven modules: ■ Prediction Room acoustics prediction, in general, is the process where, using geometrical acoustics, octave-band echograms are predicted based on a 3D CAD model of a room. Frequency dependent material properties (absorption, diffusion) are assigned 62 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. to room surfaces and frequency dependent source directivities are assigned to sound sources. From this information echograms and a great number of numerical measures of e.g. speech intelligibility and reverberation time can be estimated. ■ Directivity The source directivity module allows graphical and numerical editing of source directivity library-files. “OMNI” is a pre-defined natural omni-directional source and need not have a directivity-file and is available in three formats. The loudspeaker used in the MLSSA measurements was omni-directional. ■ Surface properties The surface properties module manages an absorption/scattering coefficient library contained in the Surface properties file. This module can also create a new empty library or a copy of an existing library that then can be extended. In this module, surface properties of different finish materials for frequency range from 250 Hz to 4000 Hz can be inputted into the library. ■ Source addition The multiple source addition module is used for adding echograms of multiple sources together when analyzing one or more loudspeakers interacting with the natural speaker and similar situations. This is an advanced module and is not used in this study. 6 3 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ■ Post-processing The Binaural post-processing (BPP) module synthesizes binaural as well as other types of room impulse responses (IRs) from generic octave-band echograms created by the Prediction module or by the multiple source addition module. This is an advanced module and is not used for this thesis. ■ Sequence (batch) processing This module can handle and perform a sequence of processing steps such as the complete sequence from prediction over binaural post-processing, convolution to WAV-file calibration. This is an advanced module and is not used in this study. ■ Plot-file viewing/WAV-file playing The viewer/player shows results from the other modules including shaded 3D models with selectable palettes, colored 3D-models, color mapping with selectable palettes, and double-buffered smooth 3D transformations with direct mouse control. 6.2.3 Prediction methods CATT-Acoustic offers three independent prediction, or acoustic simulation methods. Audience area mapping utilizes standard ray tracing with a spherical receiver. Ray tracing is a robust method for prediction of numerical measures but the echograms are difficult to use for auralization since the reflection density growth over time is unnatural. 64 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Early part detailed ISM utilizes the Image Source Model with added first-order diffuse reflection. This method is meant for qualitative reflection path analysis and does not estimate any room acoustic parameters. The reason is that diffuse reflection is extremely difficult to include in the ISM in a general manner. For special cases that require high early part detail but no reverberation, post-processing files can be generated. Full detailed calculation utilizes Randomized Tail-corrected Cone-tracing (RTC) that combines features of both specular cone-tracing, standard ray-tracing and the ISM. The RTC is a general and robust numerical prediction method and can as well create echograms that be used for auralization. Since this method (as all other prediction methods) has drawbacks, the direct sound, first order diffuse and specular reflections and second order specular reflections are handled deterministically by the ISM. 6.3 PROCEDURE FOR PREDICTING ACOUSTICS USING CATT- ACOUSTIC This procedure describes one way to model a space using CATT-Acoustic v 8.0. The GEO-format is very flexible and several different procedures can be followed when modeling a hall. 6.3.1 Preparation Before one starts entering the actual data for a new hall, it is useful to draw a simple 3D outline of the hall. As the model progresses one can instead use plots 65 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. generated by the software. If the hall to be modeled already exists and is going to be renovated, it is extremely valuable with photos from the hall since drawings are not always accurate, up to date and/or may be difficult to interpret. Photos are also of great help when deciding on surface properties. 6.3.2 Modeling The steps involved in a new project are: Create a new project, create the geometry and finally perform the prediction. If desired, then also multiple source addition and/or binaural post-processing for auralization can be performed. Step 1: The audience and floor surfaces First, the floor and audience coordinates should be entered. Then the surface planes should be defined. The coordinate system must have the y-axis towards the audience and the z-axis upwards and the x-axis left to right as seen from the stage looking towards the audience. Step 2: Walls and ceiling In this step all ceiling coordinates should be entered and main walls and the ceiling planes should be defined. Step 3: Entrance walls and doors The entrance door is created as a plane sub-division where the door is the first division and the complete entrance wall is the second division. To use plane sub divisions instead of defining separate planes is more logical and more efficient. 66 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Step 4: The stage After creating the space envelope, the stage and the proscenium can be connected. Step 5: Source/Receiver locations All the source and receiver locations should be entered along with their directivity properties. Step 6: Wall/Ceiling Panels and Reflectors These panels/reflectors are separate from the main geometry are best defined in separate files. Such files are declared as OBJECTS and can thereby be translated/rotated. The defined geometry is used as a template and COPY creates further identical copies with various translation/rotation values. 6.3.3 Prediction The three types of prediction may be taken in different orders depending on the type of project. The Prediction module can create any combination of detailed early specular reflection, audience area mapping, full detailed calculation and geometry check. For some projects the shape may be most natural to check first (mapping) but for others the reverberation time may be more natural to check first (full detailed calculation). 6 7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 6.3.4 Multiple Source addition To add the detailed results of multiple sources together, an option in the Full detailed calculation (or for special cases early part detailed ISM) dialog must be set. The audience area mapping adds sources together automatically but only graphically presented numerical results are created while the multiple source addition module enables individual point receiver echogram studies. 6.3.5 Binaural post-processing - Auralization To create an auralization of the results from a prediction, an option in the Full detailed calculation dialog (or for special cases early part detailed ISM) must be set. The prediction module then creates special echogram files. In this study, the theater was not auralized. 6.4 COMPUTER MODELING OF BING THEATRE - PROCESS 6.4.1 Preparation First, the AutoCAD plans were received from Bing Theatre’s manager. But the sections of the Bing Theatre were not to scale. So the section had to be redone after taking the necessary measurements. Please refer appendix A for the 2 drawings. In the next step, the surfaces were simplified for the convenience of modeling. Then, with several field trips, surface properties of the different materials were noted and their absorption coefficients were tabulated. All the units were converted to 68 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. meters since the default of CATT is in meters (Later, it was learned that the units can be changed using the SCALE directive). 6.4.2 Nature of the Space Bing Theatre is a symmetrical space, with complexities in shape of the walls, roof and the sloped floor and all of this had to be taken into consideration. Also, variety of materials was used in the surfaces, and so, all those materials’ absorption and diffusion coefficients had to be gathered. One more area of concern were the wooden wall panels that were placed in intervals along the sides of the wall. CATT-Acoustic has a list of AUTOLISP commands, which are used to work with the AutoCAD interface. 6.4.3 Modeling All the geometry files have the file extension of .GEO and the master file being the MASTER.GEO. GEO.PRD is a Predictions settings-file created by the program for defining various settings to the geometry files to predict various acoustical parameters. Stage 1: Floor surfaces The first step in modeling involved marking the measurements and the corners inside the Theater space. Then, the corners were defined with uniquely identified Numeric values. Next, the planes were defined with unique names and identified 6 9 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. with the respective coordinate values. This way the horizontal surfaces of the audience space and the proscenium were modeled. Stage 2: Wall surfaces First, the coordinates of the wall surfaces at the ceiling level were defined. Then the enveloping planes were defined. The wall heights were not uniform and some were sloping walls. So, in addition to the existing corners, more coordinate points were defined for longer lengths to avoid wrong modeling of the wall surfaces. Stage 3: Roof surfaces The enveloping planes were defined with the already defined coordinates for wall surfaces. It’s a good exercise to make sure all the necessary planes were defined in the floor correctly. By completing this, the basic shell of the theater was created. The developmental stages were viewed using the 3D viewer to check consistency. 7 0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. jC A R R O G R A M FILES\C A TTVTL p aralle l {M a teria l c o to r ^ Figure 29: Screen capture of the model during the developmental stage Stage 4: Sloped floor surface Due to the different height levels in the audience plane, much more planes were defined to break the entire plane into smaller modules. Troubleshooting also becomes easier when there are smaller modules. Stage 5: Wall panels This was created in a different file (an OBJECT) and attached to the main geometric file using INCLUDE command. First a dummy plane is created away from the wall with 100% absorption. Then the ten different panels were defined as plane sub divisions. 71 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TTAcoustic vB.Oa. licensed to Paul S. Veneklasen Research foundation, USA idfc List ^)tk>ns ^rtdow IJeip a] « J M© iM J M j e J ♦ u- u u « * < * > « o « Sti Plot-file viewer - SHADED.PLT C A T T -A e o u a tic vB .O a ________________________________________________________________ B in g T h e a te r Figure 30: Model with the sloped floor, audience plane and the roof panels 7 2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Stage 6: Defining the source and receiver locations and their properties in the SRC.LOC and REC.LOC files respectively. ■ 0 1 IB Figure 31: Screenshot of the model with the included ceiling panels and the wall panels. Figure 32: View of the completed model with the added screen for stage area. All the receiver locations are also seen in the audience area. 7 3 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 6.4.4 Simulation of Acoustics The prediction or simulation was done on CATT-Acoustic, mainly to get information about Reverberation Time (RT), Clarity index (C-80) and Speech intelligibility. It is also a way to compare the results with that of MLSSA system from Chapter 5. For this purpose, the Loudspeaker and Microphone locations used for doing the MLSSA readings were applied to get the predictions. The echograms and the charts were generated for all the ten combinations (2 different loudspeaker positions and 5 different microphone positions for each of the loudspeaker positions). Then the results were tabulated in a column form. To avoid the discrepancies, the geometric model and the surface properties were further modeled to get the Reverberation times (RT) closer to the MLSSA’s Reverberation Times. 6.4.5 Prediction Results 7 4 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 33: Completed model with different surface materials Jj C ATT~Acou*t;** ve.O* ' s m * ; 1 $ £ iO s » * x~i Bxng T h e a t e r Figure 34: Four views of the frame model SPL i m | 1 kHz SPL t m t kHz C,a0<t« 2 0.0 t» s 9 0 * * 6 3 1 S O I ? S 1 70 SFL fciBJ I kHz $PL JcUBJ i kHz 2 0 . 0< t < 5 0 . O b-ps +■ ao- - 751 701 651 J i 751 651 6 D * C A T T ^Jtco sa fcifc v$«0 * J 93416/1000/0.50 3 0 ,0 < t < 2 0 0 . 0 m a ■ 8 Q - - 0 8 1 1 741 7 2 1 70* Sing Theater Figure 35: Sound Pressure Level (SPL) in audience area (Spatial Uniformity) 7 5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. SPL f ciB] I kHz i i C A T T -*c o » a C ic f l . O a 3 3 4 1 6 /1 0 0 0 /0 ,5 Figure 36: Sound Pressure Level - a C - 8 Q I d B ] 1 k H z ' 4‘ * Figure 37: Audience area mapping - Clarity (C- 80) The clarity level appears to be low in the central area of the seating where the relative decibel value is less than 0. The clarity level appears to be medium in the front and back of the central seating area where the relative decibel value is between 0 and 2. The clarity level appears to be higher in the back ends of the 76 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. theater where there is reflected sound from the sloped roof at the back. Also the front rows have decibel values between 1 and 3. (d B ) i fcfiE an • ■ m m 4 m m m m x m m .« iitM B a ia H a a w ^ 2 0 * 15- 101 5* o- - 5 ‘ - 10 * Figure 38: Audience area mapping - Sound Level (G) 1 2 $ m io ■ - - 1 0 - 2 i 40 -4G- -4 ! 50 - 500 1000 1500 ms 500 1 5 0 0 S0Q 1 0 0 0 1 5 0 0 m s -IQ - 4 0 -4CH - S O - $ 0 0 1 0 0 0 1 5 0 0 m s C A T ? - M,® a u s e i c Figure 39: Full detailed calculation - T60 7 7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. * V 6**s«r»r ■ » P . AD._8I I C o s a p la ^ e e e ls o g tra t» 9 lb 80 8 90^ 80- i - k ’M i . . . . . 70' SO L ^ . .. 1 :0 0 ) 60- so B p j f i i ^ J — ........-.............................. SO' 40 (IIL. ... '> v v;. . . . 40' 30 1 ^ 1 ...- |.. . Ug..... ^ 30 m 2 0 - 1 SOD XO C SQ 1SOO wts * & L £ I E a r l y s c h o g r a tfl 2 ll 1 0 0 £ 0 0 3 0 0 4 0 0 2 3 1 33 3 2 3 3 23 423 ~J EDT 1 .9 4 s T - 1 5 1 , S 7 , e T -3 0 1 ,3 9 a 8 -SO 4 9 ,2 % C-~80 o . dB x-rc < 1 , 4 k i t 3 , € % Ts 1 0 9 . 3 m s SPL S 2 .~ dB 0 £ . S d » J j CATT-. E a r l y d a r e c t x o n a i e s k o g ra e fts A Q OHM I 81 * 0 d B 9 4.0 d B at i r i > Ife H s •Aft'OttPCS.C 2 0 0 3 0 0 4 0 0 1 2 3 223 3 2 3 33416/15D8 B in g T h a a te r Figure 40: Full detailed calculation - Echograms FffaMHiraaWtetiM G 1 a b © 1 jre v e c fe e E d C -ia n & • 4' 2 1 0- % ttfl€ % *& % ***** • • O • • ?~39 m m m ;? a 30- a$- 2 0 - 10- B a n d -J • « . * EyrT' SafeT EFF J j aSC SCO 4 * V » 1 , 1 4 .1 .0 4 0 . 9 0 3 1. -n 2 , T f u n c 15 0 0 , 0 R JiS F & y s 3 3 4 1 4 ( u s e d / o c t ) 2 (lost/ccoc) o tabsottbed/occ] A ngla i . i l degrees U . 2 9 1 5 . 8 6 7 1 .7 9 26.20 A to& C g L .11 16.a? 2 0 V \4 0 7 , 4 $ 7 . 4 6 7 . 4 7 D i£ f& 9 * 0 7 9 „ 7 2 9 . 9 9 1 0 . DC 9 ,9 2 C A T T -* A S 0tt**A« V § ,0 a J *T *0 AlH B1s > 9 Th«»«*r j Figure 41: Full detailed calculation - RT and EyrT Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 6.4.6 Using CATT Acoustic - Student’s Perspective One of the email responses from the Program Developer read as follows: “...This is actually a very simple model that should have taken a short time to model but it has much to do in the planning and realizing which corners are most important and then use the lock() command to lock difficult corners. I.e. to realize which corners are the ones establishing e.g. an angled wall or a sloped ceiling and then define those first...” From what he said, it is clear that there has to be much more fore-thought should be put in, in terms of getting a clearer three dimensional idea of the space to be modeled, marking down every single possible corners on a scaled-up model of the space, having accurate measurements of the various lengths in the correct and consistent unit form (feet or meters) and knowing the determining corners before hand. All this, has to be mainly approached in a numerical manner rather than a graphic approach. There was no idea of thinking in terms of corner ids and locking corners etc was known for a student with architecture background. So, this was a challenge to overcome those problems and model the space successfully. 6.5 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER In this chapter, the CATT Acoustics program was introduced and the basics of the program were explained. Then, the procedure for modeling in CATT was discussed. After that, the process of modeling the Bing Theatre using CATT Acoustics was 79 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. elaborately discussed with various stages that were involved in developing the model using CATT. Finally, the prediction results from the resulting model of Bing Theatre were illustrated. In the following seventh chapter, the various parameters that were obtained from the CATT model results, physically measured MLSSA results and the manually calculated Reverberation time are compared and the significance of the results from all these results are discussed. 80 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 7 COMPARISON OF THE ACOUSTICAL PARAMETERS 7.1 CHAPTER INTRODUCTION With the results from Chapter 4, 5 and 6 using the physical, manual and computer methods respectively, the results are tabulated in this chapter side-by-side and compared for validation and analysis of acoustics in the Bing Theatre. For this comparison, MLSSA testing results are considered the most reliable, as that was the only test done by being physically present in the case study space. 7.2 COMPARING REVERBERATION TIMES FROM MLSSA, MANUAL CALCULATIONS AND CATT-ACOUSTIC SOFTWARE Octave band frequency, Hertz Method 125 250 500 1000 2000 4000 Measured (MLSSA) 1.5 1.07 0.95 0.97 0.91 0.83 Calculated (Eyring) 1.4 1.15 1.22 1.31 1.24 1.12 Computer model (CATT) 2.49 1.61 1.28 1.03 .94 .90 Table 7: Comparison of the Average Reverberation times for different frequencies 81 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The values in the mid-frequency range of 250 Hz to 2000 Hz are more stable and reliable in all these tests. So, these values are used for the comparison purposes in this research. Of all the various methods, MLSSA results are more accurate because it is the method where the values are actually measured. In the 250 Hz frequency, the MLSSA and the Eyring results are closer than the CATT result. This is probably due to some inaccuracies in the computer model, in terms of the geometry of the space while modeling. In the next frequency level of 500 Hz, the MLSSA value is lower than the 250 Hz which shows that the reverberation time is lesser than it is required for a space like this. Where as, the Eyring and CATT results are closer this time. This is probably due to the inaccuracies in the absorption values used for the materials in the space. It is interesting to note that in the frequency level higher than 1000 Hz, the MLSSA and CATT values are very close to each other, which explains that this CATT model performed more accurately in the higher frequency range. In the contrary, the Eyring formula findings were precise in the lower frequencies, than in the higher frequencies. This establishes the pattern that the Eyring formula works best in lower ranges, whereas the CATT model works best in the higher ranges. From the Figure 1 (Chapter 2), for a volume of approximately 428,000 cubic feet, the recommended value at 500 Hz is 1.4 seconds. The average RT value from MLSSA at 500 Hz is 0.95 seconds as indicated in Table 4. This shows that the Reverberation time is lesser than that is required for school auditoriums. This 82 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. implies that the space is not that “lively” as it is expected to be. However, the average RT value of the Bing theatre is within the range for school auditoriums, though the RT value is towards the lower part of the range. This is because of the wall panels that are located in the sides of the Theater, which absorb more sound than required. 8 3 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 7.3 COMPARING CLARITY LEVELS FROM MLSSA AND CATT Seat location MLSSA CATT Source A Source B E 110 1.72 1.14 0.80 J 108 5.04 4.33 1.25 P 111 3.97 3.95 1.50 N 9 3.74 4.16 2.00 K 13 2.03 1.61 0.75 Table 8: Comparison of C-80 values from MLSSA and CATT @ 1000 Hz In this table, the C-80 values from MLSSA results with two different sources and CATT results are tabulated for the 1000 Hz octave band. The Clarity level values of the CATT measurements are determined from the color co-coordinated echogram for clarity level. Due to the nature of the colors used, determining a numeric value for C-80 is more challenging. Discrepancies between the MLSSA measurements and the CATT Acoustic model results are probably due to the inherent limitation in the computer program compared to actual measurements. Also, approximation of the surface characteristics in Bing Theatre while simulating in CATT may have affected the 84 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. results. Though the values themselves do not match accurately, the pattern of the values in the chosen seat positions is comparable for both the methods used. So, for this thesis purposes, the results from CATT simulation, make a good contribution in analyzing the clarity level of the Bing Theatre along with the measured MLSSA system. For C-80, the higher the number, the better the clarity level is. From the above values from MLSSA and CATT results, it is clear the row E and K values are lesser than the rows J, P and N. This implies that the seats towards the front and back parts of the Theater are not as clear as the seats in the middle of the Theater. This table also suggests that the seats towards the far end of the aisle, near the walls are also not very clear. This is explained by the angle of seating with relationship to the stage and the materials used in the wall surface. 8 5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 7.4 COMPARING UNIFORMITY OF SOUND LEVEL Seat location MLSSA CATT Source A Source B E 110 80.5 82.7 8 J 108 80 82 7.5 P 111 80.9 81.2 6.6 N 9 80.6 80.8 6.8 K 13 79.4 79.8 6.2 Table 9: Comparison of Sound Pressure Levels from MLSSA and CATT @ 1000 Hz The Sound Pressure Levels from MLSSA results and the CATT results at 1000 Hz are compared in Table 6. Like the Clarity level, the Sound Pressure levels of the CATT measurements are also determined from the colored echogram. So, there were difficulties in accurately determining the accurate values from CATT. For comparison purposes, relative sound pressure values are required to be derived from the actual values tabulated above by normalization. A mid-value is taken from each of the results and all the other values are listed in a relative + or - manner. For MLSSA Source A, 80.5 is the mid value. For MLSSA Source B, 81.2 is 86 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. the mid-value. For CATT, 6.6 is the mid-value. Now, taking these values as reference, relative Sound Pressure Levels are tabulated again in the following table. From the comparison table of the relative sound pressure level values, the sound level is uniform throughout with only 1dB difference most of the times. This is extremely uniform. Clearly, there are no obvious bad seats in the Bing Theatre, in Seat location MLSSA CATT Source A Source B E 110 0 + 1.5 + 1.4 J 108 -0.5 + 0.8 + 0.9 P 111 + 0.4 0 0 N 9 +0.1 -0.4 + 0.2 K 13 -1.1 -0.4 -0.4 Table 10: Relative values of Sound Pressure Levels @ 1000 Hz terms of the Uniformity of Sound. This high degree of uniformity in sound is primarily attributed to the relatively small seating capacity in the Bing Theatre. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 7.5 CONCLUSIONS AND PRELUDE TO NEXT CHAPTER Tabulating and comparing the various test results in the Bing Theatre provided a valuable resource to study the acoustics of the space. The outcome also helped to discover some interesting details on the sound behavior of the space especially with the uniformity of sound. Overall, the results verify that the acoustics in the Bing Theatre is satisfactory for the school auditorium purposes. With the comparison done on the results, the eighth chapter discusses the significance of the test results, with acoustic improvement suggestions and future study directions. 88 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 8 CONCLUSIONS AND FUTURE STUDY 8.1 CONCLUSIONS This concluding eighth chapter summarizes the experience and physical, measured and computer simulated results. Furthermore, the possibilities of improvement and future study in the acoustics of Bing Theatre are explored. Due to limited knowledge in the CATT-Acoustic program, the complexity in modeling a space like Bing Theatre was not anticipated. As, more and more planes appear, the intricacies in the model were overwhelming for a person with very little computer encoding knowledge. But, when everything in the model is done, the simulation of acoustics is the really exciting part. So, it is possible to study acoustics of a space by the use of computer modeling. Reverberation Time: From the comparisons between the results of CATT, MLSSA and Calculated, and the graph for the optimum Reverberation time for school Auditoriums, the Reverberation time of Bing Theatre is near optimal. Clarity: Measured and calculated values of C-80 in the Bing Theatre are in general higher than the values measured in other auditoriums world wide1 , which are significantly larger in seating capacity. 1 Source: Leo Beranek’s “Concert and Opera Halls -How they sound”. Page 479 89 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Uniformity of Sound Level: The sound level in Bing Theatre is remarkably uniform, approximately ±1dB after normalizing the Sound level values. A 1 dB difference is not discernable in auditoriums. 8.2 POSSIBLE ACOUSTICAL IMPROVEMENTS There could be many different types of improvements made in this space. Taking the feasibility and the impact of the sound quality changes in the space into account, the following suggestions were made to improve the acoustics in Bing Theatre: ■ Reduce the gaps in the ceiling provided for lighting instruments, if possible. ■ Analyze the possibility of reconfiguring the sidewalls to eliminate the sound absorption and provide early lateral sound reflections. The cost benefit of these potential improvements does appear to be justified in light of the measured and computed acoustical parameters. 8.3 FUTURE STUDY A study in acoustics field and the computer simulation area is very exciting. With respect to the study of Bing Theatre acoustics, the following could be interesting areas of exploration. The CATT model can be modified and tested in CATT-Acoustic for some physical modifications in the space. For that purpose, the existing geometrical (GEO) files could be used as starting point (Refer to Appendix C for the master geometric file). 90 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Also, if feasible, the modifications could be built in the real space to improve the current acoustic performance in Bing Theatre as discussed in the paragraph above. For future students, who would like to use CATT Acoustic, the program is complicated, but the key is simplifying the space and making one change/addition at a time. It is helpful to communicate with the CATT program developer, Bengt Inge Dalenback. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. GLOSSARY OF TERMS (In alphabetic order) ACOUSTIC GLARE If the sidewalls of a hall or the surfaces of ceiling panels are flat and smooth and are positioned to produce early sound reflections, the sound from them may take on a brittle or hard or harsh quality, analogous to optical glare! “Acoustical glare” can be prevented by adding fine-scale irregularities to these surfaces or by curving them. In the eighteenth and nineteenth centuries, fine- scale irregularities on sound-reflecting surfaces were provided by baroque carvings or plaster ornamentation. BRILLIANCE A bright, clear, ringing sound, rich in harmonics, is called “brilliant.” In a brilliant sound the treble frequencies are prominent and decay slowly. This means that the high frequencies are diminished only by the natural absorption of the sound in the air itself. The sound may become overly brilliant if electronic amplification is improperly used or if there is excessive sound absorption at low frequencies. C-80 C-80 is the clarity factor measured in decibels (dB). It is the ratio of the sound energy in the first 80 msec (80/1000 of a sec) of an impulse sound arriving at a listener’s position to the sound energy in the sound after 80 msec. 92 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The initial sound energy leads to clarity and intelligibility. The latter sound energy reduces clarity and intelligibility. The higher the value, more clear the sound. CLARITY, INTELLIGIBILITY “Clarity” is the degree to which the discrete sounds in a musical performance stand apart from one another. Clarity depends critically on musical factors and the skill and intention of the performers, but it is also closely related to the acoustics of the room. For a theater, where the sound source is speech, the issue is speech intelligibility. EARLY DECAY TIME (EDT) The first 10 dB of the sound decay after a source is cut off is called “early decay time” (EDT). EDT becomes very important when inter-comparing the acoustical quality of concert halls and opera houses. The early decay is important because in “running” musical passages one rarely hears a longer decay except in an ending chord. EARLY SOUND The sound transmitted from an orchestra is radiated in all directions and travels through the air at about 1,128 ft (344 m) per sec and within 1 or 2 sec is reflected many times over from the different surfaces of the space. To understand the effect of the acoustical attributes of a hall on the music, we must consider the reflections as divided into two time intervals. First the “early 93 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. sound,” defined as the direct sound and those reflections that take place within 80/1000 of a sec (80 msec) after the arrival of the direct sound. Second, the reverberant sound that is created by many reflections that occur subsequently. See also C 80. ECHOGRAM The echogram is the impulse response of the room. It shows the distribution of sound energy vs time. It is particularly useful in detecting echoes. FREEDOM FROM ECHO “Echo” describes a delayed reflection sufficiently loud to annoy the musicians on stage or the listeners in the hall. Ceiling surfaces that are very high or that focus sound into one part of the hall may create echoes. They may also result from a long, high, curved rear wall whose focal point is near the front of the audience or on the stage. Echoes are more likely to be obtrusive in halls with short reverberation times. INTIMACY OR PRESENCE A hall that is small has visual intimacy. A hall is said to have “acoustical intimacy” if music played in it gives the impression of being played in a small hall. For some, it represents the closeness to the performer. In the special language of the recording and broadcasting industry, an intimate hall has “presence”. It is related to the earliest sound reflections. 94 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LOUDNESS Clearly, a sound emitted in a concert hall seating 1000 listeners would be louder than that in a hall seating 3000 to 5000 persons if both halls had the same reverberation time. Music also sounds louder in a highly reverberant hall than in a dead hall, even though both may be of the same size. REVERBERATION OR LIVENESS Refers to sound that persists in a room after a tone is suddenly stopped. “Reverberation time (RT)” is the number if seconds it takes for a loud tone to decay to inaudibility (60 decibel) after being stopped. A hall that is reverberant is called a “live” hall. A room with a short reverberation is called “dead or “dry”. RT requirement differs for various spaces depending on the purpose. RT is usually determined separately at a number of frequencies, such as, 63, 125, 250, 500, 1000, 2000 and 4000 Hertz (Hz). ”Live-ness” is related primarily to the reverberation times at the middle and high frequencies, those above about 350 Hz. A hall can sound live and still be deficient in bass. If a room is sufficiently reverberant at low frequencies, it is said to sound “warm”. This is a major issue in the design of concert halls and not in a theater. TEXTURE “Texture” is the subjective impression the listeners derive from the patterns in which the sequence of early sound reflections arrive at their ears. In 95 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. an excellent hall those reflections that arrive soon after the direct sound follow in a more-or-less uniform sequence. In other halls there may be a considerable interval between the first and following reflections. Good texture requires a large number of early reflections, uniformly but not precisely spaced apart, and with no single reflection dominating the others. UNIFORMITY OF SOUND Another requisite of a good hall is “uniformity of sound” level and quality. The quality of a hall suffers if part of the audience is subjected to reduced sound level, for example, under a deep overhanging balcony, or at the sides of the front of the hall. Sound quality may vary from seat to seat due to the number of sound reflections and worse of all, if echoes occur. Musicians sometimes speak of “dead spots” - where the music is not as clear or as live as it is in other parts of the hall. Acousticians usually use that term only in reference to locations where the music is especially weak. 9 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. BIBLIOGRAPHY Beranek, Leo (1996) Concert and opera halls: how they sound. USA, Acoustical Society of America. Cavanaugh, J. William and Wikes, A. Joseph, ed. (1998) Architectural Acoustics - Principles and Practice. USA, John Wiley & Sons, Inc. Knudsen, O. Vern and Harris, M. Cyril (1950) Acoustical designing in Architecture. New York, John Wiley & Sons, Inc. Talaske, H. Richard and Boner, E. Richard, ed. (1985) Theatres for Drama Performance: Recent experiences in Acoustical Design. REFERENCES Dalenback, Bengt-lnge (2002) CATT Acoustic User Manual. Sweden. (Email: bengt@catt.se) Rife, D. Douglas (1998) MLSSA Reference Manual Version 10W [Internet] USA. Available from <http://www.mlssa.com> [Accessed 13 December, 2002] Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX APPENDIX A: MLSSA TEST RESULTS F i l e : L :\M L S \B IN G \fll.T IM 1 2 -1 7 -1 0 2 2 :2 4 PM In p u ls e Response - v o lt s o.io o .05 o.oo -o .05 - o . io -O . 15 - 0 .2 0 -0.25 -O .30 -O .35 -O .40 auto 60.0 80.0 T in e - nsec Figure 42: Impulse Response for Position A-1 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. F ile : L:\MLS\BING\fi2.TIM 12-17-102 2:29 P M Inpulse Response - v o lts ______________ __ o .20 o . 15 o. 10 O .05 -O . lO -0 . 15 ; -O . 20 - i -O . 25 ; -O .30 auto _ 40.0 60.0 80.0 T in e - n s e c •'•••• . ii = m ......... ' • • - I. : ; ! • • i !, . 1 2 - 1 3 - 1 0 2 1 1 : 1 4 fW Figure 43: Impulse Response for Position A-2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Fite: L:\MLS\BING\A3.TIM 12-17-102 2:33 P M In p u lse Response - v o lts o .20 0.1 5 -0 .0 5 - o . io -O .20 -O .25 60 .O M iK S n F : u = R RHHHRHRR x - 1 4 9 9 9 8 h M b ? M -Is iu ii i nearer -huh i t ion a a 12 19-102 11:12 HH hi-SSH: I:: Dunu i 5 Figure 44: Impulse Response for Position A-3 100 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. x > c n 0 0 z File: L:\MLS\BING\fl4.TIM 12-17-102 2:3 6 P M Inpulse Response - m o I ts o . 15 o.io 0 .0 5 i o.oo h o . 15 •0.25 •O .30 4 0 .0 6 0 .0 8 0 .0 100.0 Tine - nsec 140 .o Figure 45: Impulse Response for Position A-4 101 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. File: L:\MLS\BING\A5.TIM 12-17-102 2:40 P M Inpulse Response - v o lts 0.20 : 0.15 - 0 .20 -i -O .25 J -0 .3 0 ^ auto L _________ . . ........... ...................................... 4 0 .0 6 0 .0 8 0 .0 100.0 120.0 l i n e - n s e c Figure 46: Impulse Response for Position A-5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. File: L:\MLS\BING\B1.TIM 12-17-102 2:55 P M InpuIse Response - wo I ts — -O . 10 -O . 15 -O . 20 -O .25 -O .30 -O . 35 -auto M L S :s a 40 .0 60 .0 80 .0 lOO . O Tine - nsec Figure 47: Impulse Response for Position B-1 1 0 3 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. File: L:\MLS\BING\B2.TIM 12-17-102 2:52 P M Inpulse Response - v o lts 0.1 5 o. 1 0 0 .0 5 - i o.oo -i -O . 05 - 0.10 - 0 .15 -i -O .25 -0 .3 0 - -0 .3 5 40 .O 80 .0 Tine C u P r.n R : I. u j :. - i J i i i h - r u j i s- s - i i 1 . 2 - 1 ^ - 1 8 2 1 1 : 0 5 - 0 0 8 5 1 7 7 4 s 1 4 0 0 1 U :H I " H I i i H L S S h : f \Obnai Figure 48: Impulse Response for Position B-2 104 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. File: L:\MLS\BING\B3.TIM 12-17-102 2:49 P M In p u lse Response - v o lts 0.20 - 0.1 5 o.io- 0.0 5 j 0.0 0 - -0 .0 5 J -O . 10 1 -O . 15 -j - O .2 0 - -0 .2 5 -0 .3 0 H auto 40 .0 6 0 .0 8 0 .0 100.0 120.0 140.0 T ine - nsec Figure 49: impulse Response for Position B-3 1 0 5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. s -a c/3 < /) < x File: L:\MLS\BING\B4.TIM 12-17-102 2:46 P M In p u lse Response - v o lts _________________ -o .30 auto O .20 0.10 -i 0.05 - 0.00 Tir 100.0 - nsec rHKr™ ■ U O v . = “r i J L 1 L i L i i i 1 2 1 3 1 0 2 M :H J : r . v r QQ h H . > • • • hlbi'1 Dona i n Figure 50: Impulse Response for Position B-4 1 0 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. File: L:\MLS\BING\B5.TIM 12-17-102 2:43 P M Inpu Ise Response - v o lts o .20 0.1 5 ; i O .IO h i ; 0.0 5 J ! O .0 0 - -0 .0 5 -i - 0.10 - o .i5 • ; i - 0 .20 -i -O . 25 - = ; -0 .3 0 - auto _ 8 0 .0 100.0 Tine - nsec 120.0 c h r s p s - • M H f l z n e i n ? •••: q q q n r i v c m ix -ia -1 8 2 11 ; < art n ; * * r ■ l i n e : • Figure 51: Impulse Response for Position B-5 1 0 7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-Octave Band Acoustical Parameters Band 2 3 4 5 6 7 8 503- Parameter 63 125 250 500 1000 2000 4000 4000 S [dB-SPL] 59.9 72 . 3 80 . 2 77 .8 80 . 5 83 . 2 81. 6 SPL- N [dB-SPL] -- -- 43 .4 46.5 53 .3 57 . 0 weighted SNR [dB] -- -- 34 .4 34.0 29.8 24 .6 Averages C50 [dB] -1.01 -0.02 1. 77 2.41 0.31 2 .62 5. 25 2 . 358 0)0 [dB] 0 . 73 1.63 3.33 4.24 1. 72 4 . 51 ■ 6 . 83 4 .087 D50 [%] 44 .2 49.9 60. 1 63.5 51. 8 6 4 . . 6 77 . C 61.609 TS [ms] 198 .4 81. 1 6 0.0 49. 5 66 . 8 49.4 31.5 52.908 LDT-lOdB [s] 4 .445 1. 147 1.261 1. 116 1. 063 1.198 1.300 1 . 141 RT-20dB [s] 3 . 117 1.486 1.061 0. 957 0 . 932 0.908 0 . 932 0 . 93 3 (-5:-25) r -0.987 -0.994 -0.998 -0.999 -0.999 -0 . 999 -0.995 -0.999 RT-30dB [s] 3.054 2.130 1.118 0. 966 0.957 0.875 0 .818 0 . 924 (-5:-35) r -C.978 -0.979 -0.998 -0.999 -1.000 -0.999 -0.984 -0.998 RT-USER [s] 2 .655 1.553 1. 055 0. 940 0.921 0.862 0 .839 0 . 903 (-10:-25) r -0.967 -0.988 -0.997 -0.999 -0.999 -0.999 -0.996 -0.999 File: L:\MLS\BING\A1.TIM 12-17-102 2:24 PM 'JSC Bing Theater Position A-l MLSSA: Acoustics Figure 52: Acoustical Parameters for Position A-1 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1 /1-Octave Band A co u stical P a ra n e te rs Band 5 4 Fa i a tii F fe : 53 : • s LaB- 3PLJ 58.3 69.6 79.2 H LdH-SPLJ — — 50.8 SNR [dB] — — 28.4 C 58 ; :3- 0.69 -0 .0 5 0.52 CO0 ■ • : 1.76 0.53 2.01 Bse L x J 54.0 49.7 53.0 TS Lnsl 201.4 99.1 73.2 EB i- IBdB i ; 6.582 1.425 1.038 ET-20dB LSJ 4.240 2.148 1.051 i- : j :-2 5 ) X -0.882 -0.974 -0.997 LSJ 4.039 2.370 1.004 f -5: -35 > r -0.864 -0.976 -0.998 RI-USER Lsj 1.295 2.576 1.017 r-1.0 :-25 ) if -0.930 -0.982 -0.996 F i l e : L :'-.H LSxi3lN G % n2,IIM 1 2 -1 7 -1 0 2 2 :2 C ..................... r ■ _ ? 6 V ■ • i 588 • • 77.7 80.0 81.8 78.5 sp L - 44.0 46.8 50.4 54.5 u0 i ghted 33.7 33.3 31.4 23.9 :n -0.00 2.80 0.53 0.80 1.247 3.66 5.04 2.77 3.11 3.947 50.0 65.6 53.0 54.6 55.905 62.5 54.0 69.7 63.3 61.556 0.848 1.014 0.991 0.974 0.944 0.970 1.029 0.907 0.827 0.966 -0.996 -0.997 -0.999 -0.999 -0.998 0.932 0.993 0.905 0.752 0.935 -0.998 -0.998 -0.999 -0.993 -0.998 0.914 0.960 0.889 0.811 0.917 -0.990 -0.998 -0.999 -0.998 -0.998 PH DPP hiliy i NcatS: -p o s itio n A Figure 53: Acoustical Parameters for Position A-2 109 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1 /1-Octave Band A co u stical P a ra n e te rs Band V 3 4 5 6 7 R b J 12b 250 •••: 1000 200B 1008 4000 S LuH-SPLj 58.6 74.0 80.8 77.6 80.9 83.0 78.9 SFL- N r.iB-SPLj — — 52.9 43.6 48.5 53.1 54.8 ueicihted SNR Ldnj — — 27.9 33.9 32.4 29.9 24.1 Averages C58 idBj -0 .2 8 -7.17 -2 .1 6 -0.10 0.91 0.01 -0 .5 3 0.283 CSO LdHJ 1.84 2.83 3.05 1.73 3.97 4.16 3.56 3.408 I>50 : . 48.4 16.1 37.8 49.4 55.2 50.0 47.0 51.463 IS fn sj 162.3 91.2 80.1 74.6 63.0 68.3 71.1 68.655 EDT-IBdB L s j 3.734 0.961 1.028 1.156 0.939 0.861 0.919 0.987 R I-28dB l s j 3.364 1.042 1.032 0.855 0.942 0.913 0.862 0.902 ( - 5 :- 2 5 ) r -0.956 -0.988 -0.996 -0.996 -0.999 -0.998 -0.997 -0.998 RT JQdB r s ] 2.544 1.832 0.971 0.908 0.936 0.874 0.770 0.901 L -b ;-3 3 i r -0.898 -0.955 -0.996 -0.998 -0.999 -0.998 -0.990 -0.998 K! USER ls j 2.188 1.176 1.006 0.837 0.962 0.856 0.788 0.883 L- 10 i 33) r -0.965 -0.994 -0.993 -0.993 -0.999 -0.998 -0.999 -0.997 F i l e : L ; xM LS\BIH C N h 3 ■ II M 1 2 - 1 7 102 2 : 3 3 PM • • • - P o s i t ir::: H -3 :::/ ’ . • , ■ • • Figure 54: Acoustical Parameters for Position A-3 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-O ctaue Band A co u stical P a ra n e te rs Hand 2 3 4 S 6 V 0 bob- • • :: : ■ • G3 - ;. i ; 23b 1000 2H00 4366 1000 S IdB-5PLJ 58.2 71.3 80.0 76.6 80.6 82.7 79.1 GPL - N [dB-SFL] — — 51.8 42.2 47.6 52.1 53.6 ye ifjM ed SNR rdB] — — 28.2 34.4 33.1 30.6 25.5 Rvera-jes CSB TdBJ 0.25 -6.84 -3 .0 2 0.19 0.53 -0.96 -0 .2 9 -0.008 C8H [dB J 1.89 3.01 2.12 3.31 3.74 4.11 3.98 3.751 B50 : • : 51.5 17.1 33.3 51.1 53.0 44.5 48.3 49.716 IS TnsJ 174.2 90.0 80.1 69.5 66.1 65.0 62.5 66.513 EBI-iedB l s j 4.634 0.912 0.921 0.989 0.881 0.845 0.934 0.905 BT-20dB LsJ 3.984 1.545 0.980 0.970 0.991 0.957 0.865 0.967 C-5 :-25 ) r -0.952 -0.995 -0.994 -0.998 -0.999 -0.999 -0.997 -0.999 RI-30dB l s j 3.605 1.910 1.018 0.961 0.946 0.903 0.780 0.928 r-5 :-35) r -0.900 -0.990 -0.997 -0.999 -0.999 -0.998 -0.993 -0.998 RT-USO? LSJ 2.310 1.587 1.019 0.976 0.960 0.949 0.800 0.951 (-1 8 :-2 5 ) r -0.954 -8.992 -0.988 -0.996 -0.999 -0.999 -0.998 -0.998 F ile ; L ING\A4. TIH 12-17--102 2:3o P M i • - •: ' - p o s itio n • MLGbrV ■ sties Figure 55: Acoustical Parameters for Position A-4 1 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-O ctave Band A co u stical P a ra n e te rs Band 2 3 4 5 H 7 6 50@- Paraneter 62 125 250 500 1000 4 fins S EdB-SPL.1 59.8 71.6 78.2 75.7 79.4 83.6 79.4 N LdB-SPLJ — — 49.2 43.8 47.4 53.2 56.1 UR 1 • 7 ■ . SNR CdBj — — 28.9 31.9 32.1 30.4 23.3 Rveraqes C50 EdBJ -2.73 -1 .0 7 -0 .4 6 -0 .9 6 -1 .0 3 2.07 -0 .0 1 0.509 €80 • - r i 1.29 0.57 1.85 2.76 2.03 4.73 3.11 3.485 D50 i y .J 34.8 43.9 47.4 44.5 44.1 61.7 49.9 51.417 IS In s 3 191.8 95.6 86.5 75.9 76.9 53.3 67.9 66.896 EBI-10dB Lsj 5.725 1.152 1.103 1.031 0.959 0.917 0.858 0.954 RT~2BdB l s j 5.364 2.112 1.175 1.002 0.955 0.920 0.818 0.943 (-5 :— 25) r -0.905 -0.975 -0.999 -0.996 -8.996 -0.997 -0.997 -0.997 RT-0RiiB Lsj 5.260 2.241 1.144 0.966 0.950 0.884 0.733 0.913 (-5 :-35) r -0.889 -0.985 -0.997 -0.998 -0.999 -0.998 -0.991 -0.998 RI-USER Csj 1.799 2.405 1.172 0.937 0.878 0.901 0.778 0.894 C -10;-25) r -0.928 -0.984 -0.998 -0.994 -0.998 -0.995 .. .. . -0.996 -0.996 F ile : L :vMf.S\BIHGxfl5.IIH 12-17-102 2:40 PH . • - B illy :: . 1 ; ' Figure 56: Acoustical Parameters for Position A-5 1 1 2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-O ctave Band A co u stica l P a ra n e te rs Band 2 3 4 5 ,6 7 8 586- P aranersr 63 125 256 bB O 1B0H mm 4008 S LdB-GPLJ 58.6 71.6 80.4 79.5 82.7 83.9 82.3 SPL- N idD-GPLj — — 47.4 45.5 50.5 59.3 61.1 u eiglilad SNR CdBJ — — 33.0 34.0 32.2 24.5 21.2 Averages C56 TdBi 3.88 -0 .7 2 -1 .0 5 -0 .5 8 -0 .4 0 -0.70 2.12 -0.251 CUB LdB3 4.81 1.69 0.74 3.09 1.14 1.50 4.18 2.258 V 5 B [ v ] 71.0 45.8 44.0 46.7 47.7 46.0 62.0 48.117 I S L r i s j 88.6 90.6 77.3 66.7 68.2 70.2 50.6 66.732 EDT-18dB l s j 2.128 1.517 1.077 1.082 1.120 1.069 1.186 1.101 RI-20dB LsJ 4.055 1.288 1.156 0.944 0.927 0.892 0.821 0.916 i -5 :-25) r -0.969 -0.992 -0.992 -0.999 -0.999 -0.998 -0.991 -0.998 BI-30dB T p j 3.600 1.657 1.117 0.974 0.938 0.815 0.716 0.904 (-5 :-35) r -0.924 -0.983 -0.994 -0.999 -0.999 -0.994 -0.977 -0.996 KT-USER l s j 4.195 1.148 1.097 0.947 0.948 0.841 0.786 0.909 ( “ 16 =-25 j r -0.934 -0.992 -0.988 -0.998 -0.999 -8.999 -0.979 -0.997 F ile : L:xHLS\BINCxBl.TIH 12-17-102 2:5 5 P M U se . : . ' • - f o s i t i u n s: 1 : •• .. . Figure 57: Acoustical Parameters for Position B-1 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-O ctave Band A co u stical P a ra n e te rs Band 2 3 4 5 7 . H 530 a-"-4 - B 3 325 238 5BH 498-M 4HaH S CdB-SPLJ 58.9 72.9 81.4 78.6 82.0 84.0 81.0 - N LdB-SPLI — — 54.4 47.3 51.1 59.5 60.3 we iffiil..ed SNK L s tts J — — 27.0 31.3 30.8 24.5 20.7 Auer a-'ios CbB EdBl 4.15 0.25 -1.25 0.63 2.31 -0.48 -0 .5 7 0.978 C80 CdBi 5.54 1.76 1.22 3.73 4.33 2.74 3.48 3.692 D50 i • 72.2 51.4 42.8 53.6 63.0 47.2 46.7 54.607 IS [n s ] 73.5 79.2 78.7 65.1 58.0 70.6 62.9 64.017 EBT-lBdB LsJ 1.682 1.168 0.979 1.065 1.239 0.987 0.913 1.094 J?T-20dB EsI 4.132 1.261 1.027 0.931 0.973 0.833 0.767 0.908 ( -5 :-2 5 ) r -0.974 -0.994 -0.996 -0.997 -0.998 -0.997 -0.997 -0.997 RT-30dB Esl 3.872 1.708 1.029 0.897 0.939 0.773 0.680 0.863 (-5 :-3 5 J r -0.950 -0.979 -0.997 -0.999 -0.999 -0.995 -0.983 -0.997 Kl-USER lsj 4.883 1.338 1.013 0.872 0.990 0.851 0.729 0.897 C-18 :-25 ) r -0.965 -0.991 -0.993 -0.996 -0.998 -0.997 -0.995 -0.997 F i l e ; L:\HLS\RINGnB2.TIH 12-17-182 2:5 2 P M ' ' ijj u y • • - P o s i t i o n •• • . Figure 58: Acoustical Parameters for Position B-2 114 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-O ctave Band A co u stica l P a ra n e te rs Band 2 J 4 5 6 7 3 580- Pararief hi 63 125 258 580 10H0 2000 4H«H 4HRR S tdB SPLj 59.5 73.5 80.2 78.6 81.2 82.3 80.4 .. ; N fdB-SPLJ — — 52.6 46.1 49.7 55.6 58.4 UR i : SNR CdBJ — — 27.6 32.5 31.5 26.8 22.0 f t ’. ’O i a q e s CSS LdBJ 2.01 -0.72 -1.44 1.19 0.94 -1 .2 2 0.43 0.620 C B S CdBl 2.67 1.77 2.47 4.85 3.95 2.98 3.47 4.098 DS0 1 > : j 61.4 45.9 41.8 56.8 55.4 43.0 52.5 53.022 IS In s 1 140.9 90.9 81.3 60.9 63.9 78.6 67.4 66.230 EDT-18dB C s j 3.457 1.457 1.110 0.972 0.973 1.087 0.924 0.994 RT-20dB l s j 3.957 1.271 0.996 0.951 0.997 0.948 0.810 0.956 ( -5 : - 251 r -0.963 -0.984 -0.997 -0.998 -0.999 -0.996 -0.992 -0.998 Kl-3BdB Tc;! 3.406 1.887 1.008 0.920 0.994 0.863 0.736 0.921 : - 5 : - 3 5 i r -0.916 -0.972 -0.998 -0.998 -0.999 -0.995 -0.987 -0.997 Rf-USER l b ] 3.453 1.520 1.009 0.911 0.963 0.872 0.698 0.905 (-1 0 ;-25 ) r -0.903 -0.987 -0.993 -0.998 -0.999 -0.998 -0.996 -0.998 f i l e : I. :'-MLSnBIHG\B3 , 1 IK 12- 17-182 2:49 P M Figure 59: Acoustical Parameters for Position B-3 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1 /1-Octave Band A co u stical P a ra n e te rs Band Paraneter 2 •- 3 125 4 b see fi TiiM H 7 2000 3 506- 4H00 S Ldri-SPl ] 56.7 71.8 80.0 77.3 80.8 83.3 81.6 SPL N rdB-SPL] — — 51.9 45.6 50.2 56.9 60.0 or i nhted SNR Ldfij — — 28.1 31.7 30.6 26.5 21.6 fi-or acies C5B EdB3 -2.58 1.00 -0 .0 6 -0 .2 9 0.92 -0 .1 3 1.16 0.332 C80 LdBj 8.59 3.51 4.19 3.59 4.16 4.10 4.86 4.065 D50 I xJ 35.6 55.7 49.7 48.3 55.3 49.2 56.6 51.666 IS rnsj 166.2 78.1 73.7 69.6 66.9 62.6 52.5 65.023 EBT-lHdB L s j 3.993 1.177 0.847 0.940 0.983 0.895 0.876 0.935 RT-28dB CsJ 4.808 1.419 1.120 0.957 1.005 0.920 0.801 0.947 f 5 : 25 l r -0.892 -0.997 -0.997 -0.997 -0.998 -0.999 -0.993 -0.998 RI-38dB LsJ 4.546 1.834 1.092 0.951 0.944 0.863 0.700 0.899 (-5 :-3 5 ; ■ ■ -0.866 -0.988 -0.998 -0.998 -0.998 -0.995 -0.981 -0.996 RI-USER is ! 2.729 1.510 1.105 0.914 0.959 0.882 0.729 0.901 C-13 25 J r -0.830 -0.996 -0.995 -0.995 -0.998 -0.999 ... _________ -0.992 -0.997 F ile ; I . : - .M!.S'--BIHGvB4, TIH 12-17-182 2-46 PH USC -IS in n ih e a im - P o s it io n , r: - • . ; . Figure 60: Acoustical Parameters for Position B-4 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IEC 1/1-O ctave Band A co u stical P a ra n e te rs Band “ jL . 3 4 5 G 1 i G 508- Pavaneter to 125 25B 5HH 1800 2000 H0M0 <1000 S CdB-SPLj 56.3 70.9 78.6 76.5 79.8 83.8 81.1 s. : H LdB-SPLj — — 52.4 44.4 50.5 57.6 6B.6 weighted SHE LdBl — — 26.2 32.1 29.3 26.2 20.4 1 'jvsiai-iys C50 CdBj -2.42 -6.73 -3 .3 6 -2 .6 7 -2 .2 4 1.45 -1.16 -0.543 C88 LdBJ 0.53 1.93 3.42 1.26 1.61 4.93 3.99 3.247 B58 ; 36.4 17.5 31.6 35.1 37.4 58.3 43.3 44.778 TS m si 220.3 104.3 81.5 83.9 81.4 51.9 61.7 co ccn Do.ODD EDT-lBdB ls j 5.574 1.323 1.012 1.080 1.071 0.983 0.823 1.019 KI-20dB Csl 3.341 1.404 1.131 0.986 0.949 0.934 0.802 0.940 (-5 :-25) r -0.063 -0.995 -0.998 -0.998 -0.995 -0.998 -0.996 -0.997 RT-30dB Lsj 3.075 1.804 1.078 0.974 0.887 0.867 0.722 0.888 (-5 ;-3 5 ) r -0.851 -0.988 -0.997 — 0.999 -0.997 -0.995 -0.984 -0.995 RT-USEK LsJ 0.858 1.540 1.085 0.940 0.854 0.895 0.754 0.882 (-1 8 :-2 5 ) r -0.994 -0.997 -0.997 -0.997 -0.998 -0.998 -0.995 -0.998 F ile : L:nHLS\BINIXB5.T!H 12-17-102 2:43 PH UbL '• •••• ' - • . .. B-b • '• t ics Figure 61: Acoustical Parameters for Position B-5 APPENDIX B: PROBLEMS ENCOUNTERED WHILE MODELING THE BING When all the above six stages were completed, the debug file was four pages long and the geometry file had to be debugged to locate the bugs and to fix them. Starting with the main file without the OBJECTS and turning off most of the surfaces, bugs were easy to locate. Then, using trial and error method by paying attention to small details and exploring the help files more, the bugs were fixed one by one. 1 1 7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Also, there was communication with the Program Developer Mr. Bengt-lnge Dalenback via email (bengt@catt.se) for suggestions, help and feedback. With his feedback, some of the bugs were fixed. Some of the crucial problems and how they were solved is listed below. Problem 1: Duplicate corner identification (ids). There were inconsistencies in the corner id numbering, due to the mirror command that resulted in duplicate corner ids. Solution: The offset number for the mirror command was changed as required, to avoid duplication. Problem 2: Duplicate Corners. They were essentially same or nearly same x, y, z but different corner ids. This occurred due to the close proximity of two corners. Solution: The plan was simplified to avoid corners, which were too close to each other. And, in result some of the corners were deleted. Problem 3: Duplicate plane ids. There were inconsistencies in the plane id numbering, due to some inconsistencies that resulted in same plane ids in the OBJECT files. Solution: The number in the offset command for the plane ids was changed as required, to avoid duplication. Problem 4: Duplicate Planes. Same corners and same normal were used for different planes. 118 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Solution: Double sided surfaces like reflectors use the same plane corners but have opposite normals. This was located and the normals were reserved. Problem 5: Inaccurate plane corners in some planes. For e.g. one line in the debug file looks like the following: INACCURATE PLANE CORNERS: Corner 8 is OUT by 0,5119 in plane 2: slope floor surface Solution: Used lock () command to lock difficult corners in the master GEO file. That automatically brought down most of the inaccurate plane corners. Note: It is not necessary that the displayed corner is the cause of the error. If the plane equation is built from one inaccurate corner and two accurate corners, a fourth accurate corner will seem to be out of the plane. This must be corrected or rays will be lost and an open room may be declared. Problem 6: Some of the plane edges were intersecting with other planes (e.g. a reflector through a wall). Touching planes are not critical but penetrating planes will confuse the pre-processing of the geometry. Solution: The lengths were rechecked for consistency and that helped to fix few of the overlapping problems. Then, the planes were again broken into smaller planes with only for corners making a plane. Apparently, when there are more than four corners in defining a plane, the program gets confused and does not model the 119 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. planes as desired. And, the corners/nodes that touch the edges of adjacent planes were included in both planes. Corners 13 and 14 should be included in both plane 1 and plane 2. Problem 7: All the materials’ absorption coefficients defaults to 0.1% even when different values (like 85% and 63%) were entered in the Surface Materials library. Solution: This one turned out to be a bug in the program itself. So, the work around was to define the materials absorption and diffusion coefficients in the master geometry file itself directly. Problem 8: For many planes, the outer surfaces were modeled instead of the inner surface side (i.e. where the sound hits). All the planes that can be reached by sound must be modeled, and only those planes must be modeled and only those parts that can be reached by sound. Solution: In Colored.PLT and Shaded.OGL plot files, only the ‘ modeled* side is shaded, so it is easy to see which surfaces have been modeled. To change the side, plane definitions has to be \ \ instead of II in some plane definitions. So, plane by plane was checked and fixed (started with the master without inclusion of the OBJECT files). Problem 9: There were ten wall panels and they were modeled as separate planes ‘on’ the wall surface. This is not true since the panels were projecting 2’ from the wall surface. 120 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Solution: The sidewall panels were modeled as plane subdivisions instead of separate planes. For this, each small plane definition was made as a sub-division and then the whole containing plane (a dummy plane with 100% absorption) as the last sub-division. Problem 10: Single-connected corners. Some of the corners were used in only one plane. This should never happen in a closed room. Solution: Single-connected corners were listed in the debug file. Then, all the corners were solved and were made sure that all the corners are used in 3 planes. Problem 11: There were errors in floor surfaces, when a horizontal plane was connecting with a sloped plane. This problem rose due to the change in the floor height. Also, because the model was so incredibly interdependent of each other corner due to the usage of x () and y () in so many levels Solution: Lock () command was used to lock difficult corners, i.e. realized which corners are the ones establishing e.g. an angled wall or a sloped ceiling and then defined those first and locked the ones that has to connect in the middle somewhere. Problem 12: There were floating audience planes, which were single-sided and not boxed-in. And the floor of audience was also modeled. General rule is that all surfaces that can be reached by sound should be modeled but any surfaces or parts of surfaces that cannot be reached by sound should not be modeled. 121 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Solution: The floor plane was removed and the audience plane was completed by boxing, i.e. both the surfaces of the audience plane were modeled and so were the vertical surfaces that were used to box the audience plane. APPENDIX C: MODELING TIPS The following are few recommendations and examples on how to get the most out of CATT-Acoustic. (Most of the useful tips were compiled after experiencing the problem in the case study of this thesis. ■ Work in steps - first build the main parts of the hall then the details. View the geometry as often as possible between changes. Don’t add too much new geometry between viewing. ■ Use constants (LOCAL, GLOBAL) to define various lengths - it is much easier to make changes. Use constants especially where you suspect changes. It might seem to be a great effort to plan the use of constants and to do other structuring of the geometry but this initial effort almost always pays off in the long run. ■ If one corner’s z-value (for example) always has the same z-value as another corner use the z () function (or x (), y () for x, y-values): id x y z 10 -3 5 12 20 -7 12 z (10) 1 2 2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ■ This signals that corner 20 does not just happen to have the same z as corner 10 but it is always the same z and should automatically follow any changes in corner 10. This makes the model both simpler to build, change and interpret. ■ Use the lock () tool whenever possible, typically for slanted floors or ceilings but also for walls. ■ The x (), y (), z () functions can be used to create a copy of a part of the model, which then can be treated as an abject and be “lifted off’. ■ The COPY function can be used to create multiple identical reflectors. As the structure of the reflector is defined in one file only, the structure can, initially, be made very simple (typical rectangular) for rough tests and then, towards the final calculation, be changed to a more realistic shape. If the 'coadd’ and ‘pladd’ values, from start are chosen to accommodate for the realistic shape, all that is needed is to create the shape (around the same origin) and the result will be instant multiple realistically-shaped reflectors. ■ The possibility to define one surface property to equal another (ABS name1=name2) can be used for fast and secure absorption changes. If e.g. all parts of the ceiling that will have the same absorption are assigned to e.g. ceilingabs, then ceilingabs can be defined as e.g. wood and when changed to e.g. plaster all ceiling parts will change absorption. This works in a similar manner to “styles” in a word-processor. ■ With symmetrical designs where the MIRROR directive can be used, add the ceiling and other “bridging’ planes as single planes instead of utilizing the 123 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. mirroring to avoid potentially dangerous edges in the middle of the ceiling. Since the mirror function creates all corners, it is just a matter of defining the plane. It can be defined in the same file, since planes bridging over from the negative x side to the positive x side are not mirrored. If all parts are mirrored, more planes are generated which increases the calculation time and also makes wire-frame plots harder to interpret. INCLUDE GEO-files - especially for parts of the hall one would like to compare with and without. It is also possible to include alternative version of e.g. ceiling reflectors and compare them without having to make a complete new version of the hall. One should use subset of planes or disable INCLUDES by turning them into comments when one builds the model. This makes geometry plots and the debug-file easier to interpret as one can view/check parts instead of the whole hall. Always define reflectors as objects. They are always separate from the main geometry and are usually moved and rotated. If multiple identical reflectors are needed, the COPY directive will simplify the job. Audience areas should be simulated at about shoulder height (about 3’), having the normal pointing up. The audience should be "walled-in’ by planes and the floor below should NOT be modeled. The backside of the audience plane must also be defined and assigned the pre-defined absorption TOTABS. The reason for this is that this plane will then catch some impossible rays running under the 124 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. audience. The audience should typically have a high degree of diffusing properties assigned to it (30 to 80% ascending from 125 Hz to 4 kHz). ■ If the hall has audience areas, the ‘lock ()’ tool can be used to set the receiver positions at an exact height over the audience plane. First, three help corners at a fixed height should be created above three audience plane corners. Then, the z-coordinate of all receiver positions should be locked (using ‘lock ()’) to a plane defined by these three corners. ■ Typically, one should use the “sum” or “1k” for octave-band plot-file output. All bands should be selected only if one wants a detailed check (e.g. for a certain receiver position) or else a lot of plot-files will be generated. ■ To create a soffit-mounted source, the source position must not be placed exactly inside a wall but slightly in front of it and an absorbing patch must be placed behind it on the wall. Soffit mounted sources are difficult to handle, since the directivity of a source, when placed in a large baffle, changes from that of the free source. If a directivity measured in a large baffle is not available, a free- field directivity must be used with great caution. ■ Avoid placing both source and receiver exactly on the symmetry-line of a model. Same rule applies for measurements also since it may introduce interference effects. 1 2 5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX D: MASTER GEOMETRIC FILE, ‘OBJECT’ FILES (CEILING PANELS, WALL PANELS, CURTAIN), SOURCE AND RECEIVER FILES Master Geometric file ;MASTER.GEO ;PROJECT=Bing Theatre ;AII measurements in metres INCLUDE curtains INCLUDE ceiling panels INCLUDE wall panels ;INCLUDE audi ;OFFSETCO ;OFFSETPLs ABS carpet <4 10 20 30 30 30> ABS concrete <4 4 4 4 4 4> ABS fiberglass <30 80 60 55 50 50> ABS fireproofing <5 15 50 70 90 90> ABS glass <20 15 10 5 4 4> ABS gypsumboard <25 15 8 4 4 4> ABS openings <100 100 100 100 100 100> ;ABS openings_sidewa <70 100 100 100 100 100> ABS plaster <16 10 6 4 4 4> ABS plywood <40 70 30 10 5 5> ABS seats <16 25 25 25 25 25> ABS fabric <7 31 49 75 70 60> ; medium velour pg77 william ;ABS wood <15 20 15 10 10 6> GLOBAL ah = 0.5 ;audience height GLOBAL rh = 0.6 ;receiver height above audience plane GLOBAL sh = 0.4313 ;stage height from lowest floor lever GLOBAL aww =1.2 ;audience sidewalk widths 126 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. GLOBAL sd = 14.8406 ;stage depth GLOBAL sw = 29.7 ;whole-stage width GLOBAL swj = 14.2287 ;x-axis distance between the junction of stage and side wall GLOBAL faw = 17.2621 ;front audience width GLOBAL w =26.7371 ;max hall width GLOBAL ft1 = 0.281 ;first side floor tilt height GLOBAL ft2 = 3.344 ;second side floor tilt height GLOBAL wl1 = 2.4414 ;first side wall length from audience floor start GLOBAL wl2 = 12.9962 ;second side wall length from point 6 GLOBAL ww1 = 1.8871 ;first side wall width from audience floor start GLOBAL ww2 =2.8513 ;second side wall width from point 6 GLOBAL thd = 34.4945 ; total hall depth GLOBAL ad = 17.6917 ; audience plane depth GLOBAL bcw = 9.5822 ; back side central wall length of audience floor ;STEP 2: ceiling GLOBAL tsh = 18.4625 ; total stage height from lowest level GLOBAL thh = 10.7031 ; total hall height from the lowest level ;MIRROR co_add pl_add MIRROR 100 600;corner and plane offsets for mirrored part CORNERS ;floor corners 1 -swj/2 0 0 2 -sw/2 0 0 3 x(2) sd 0 4 x(1) sd 0 5 -faw/2 y(4)+1.9621 0 ;one of the lock corners 7 -w/2 32.2403 ft2 ;one of the lock corners 16 0 thd ft2 ;one of the lock corners 6 x(5)-ww1 y(5)+wl1 lock(5 7 16) 8 -bcw/2 thd lock(5 7 16) 1 2 7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ;audience lower corners 9 x(5)+1.5167 y(5) lock(5 7 16) 10 x(6)+1.111 y(6)+.5205 lock(5 7 16) 11 x(7)+1.4189 y(7)-.8679 lock(5 7 16) 12 x(8) y(8)-1.2407 lock(5 7 16) 13 x(8)+1.2 y(8)-1.2407 lock(5 7 16) 14 x(13) y(5) lock(5 7 16) 15 x(8) y(5) lock(5 7 16) 17 x(15) y(io) lock(5 7 16) 19 -12.9075 30.1782 lock(5 7 16) ;audience upper corners 55 x(5) y(5) ah ;one of the lock corners 57 x(7) y(7) ft2+ah ;one of the lock corners 66 x(16) y(i6) ft2+ah ;one of the lock corners 59 x(5)+1.5167 y(5) lock(55 57 66) 60 x(10) y(io) lock(55 57 66) 61 x(11) y(H) lock(55 57 66) ;z(7)+ah 62 x(12) y (i2 ) lock(55 57 66) ;z(8)+ah 63 x(13) y(13) lock(55 57 66) 64 x(14) y (i4 ) lock(55 57 66) 65 x(15) y (i5 ) lock(55 57 66) ;z(5)+ah 67 x(17) y(i7) lock(55 57 66) ; stage surface 42 x(2) y(2) sh 43 x(3) y(3) sh 44 x(4) y(4) sh 45 x(2) y(2) 5 ;lower stage wall rear 46 x(2) y(4) 5 ;lower stage wall side ;roof corners 21 x(2) y(2) tsh 128 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 22 x(2) 11.6531 tsh 23 x(2) y(22) tsh-12.0344 24 x(2) y(23)+1.325 z(23) 25 x(2) y(24)+1.3055 z(24)+2.1522 26 x(3) y(3) thh 27 x(4) y(4) thh ; lock corner 28 x(6) y(6) thh ;lock corner 30 x(7) y(7) 9.6117 29 lock(6 7 30) 30.1782 thh 31 x(8) y(8) 6.525 ;glass panel 33 0 thd z(31) ;one of the lock corners ;32 x(31) y(30) thh 32 x(31) 33 lock(30 31 33) receiver positions ;51 x(41) y(41) z(41)+rh ;52 x(42) y(42) z(42)+rh PLANES ;floor surface ;[1 flat floor surface /1 0 4 105 109 115 114 14 15 9 5 4 / concrete] [51 flat floor surfacel \ 4 5 9 \ concrete] [52 fiat floor surface2 \ 4 9 15 \ concrete] [53 flat floor surface3 \ 4 15 14 \ concrete] [54 flat floor surface4 \ 4 14 114 104 \ concrete]s [2 carpet surfacel \ 5 6 10 9 \ carpet] [3 carpet surface2 \ 6 7 11 10 \ carpet] [4 carpet surface3 \ 15 12 13 14 \ carpet] [5 carpet surface4 \1 1 7 8 12 \ carpet] ;[6 carpet surface5 \ 12 8 108 112 \ carpet] [55 carpet surface5 / 8 12 13 / carpet] [56 carpet surface6 / 8 13 113 108 / carpet] 129 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ;stage [41 stage top \ 42 43 44 144 143 142 \ wood] [42 stage side \ 144 44 4 104 \ wood] ;audience plane ;[7 audience lower surface leftl / 9 10 17 15 / seats] [8 audience upper surface leftl \ 59 60 67 65 \ seats] ;[9 audience lower surface Ieft2 /1 0 11 1 2 1 7 / seats] [10 audience upper surface Ieft2 / 67 62 61 60 / seats] ;[11 audience lower surface center/13 113 114 1 4 /seats] [12 audience upper surface center \ 64 63 163 164 \ seats] ;audience seat heights [13 audience height leftsideouterl \ 59 9 10 60 \ seats] [14 audience height leftsideouter2 \ 60 10 11 61 \ seats] [15 audience height leftrear \ 61 11 12 62 \ seats] [16 audience height leftsideinner/6 5 15 12 6 2 /seats] [17 audience height leftfront / 59 9 15 65 / seats] [18 audience height centerside \ 64 14 13 63 \ seats] [19 audience height centerrear \63 13 113 163 \ seats] [20 audience height centerfront / 64 14 114 164 / seats] ;roof surface [22 stage roof surfacel \ 121 122 22 21 \ concrete] [23 stage roof surface2 \ 122 123 23 22 \ concrete] [24 stage roof surface3 \ 123 124 24 23 \ concrete] [25 stage roof surface4 \ 124 125 25 24 \ concrete] [26 stage roof surface4 \ 125 126 127 27 26 25 \ concrete] [27 roof surface5 \ 127 128 129 29 28 27 \ concrete] [28 roof surface6 \ 129 130 30 29 \ concrete] [29 roof surface7 \ 130 131 132 32 31 30\ gypsumboard] 130 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ;wall surface [31 stage wall lower \ 45 42 142 145 \ concrete] [32 stage wall upper \ 21 45 145 121 \ fireproofing] [33 left stage wall lower / 45 42 43 46 / concrete] [34 left stage wall upper / 21 45 46 26 25 24 23 22 / fireproofing] [35 front stage wall / 26 43 44 27 / concrete] [36 side hall walU / 27 44 4 5 6 28 / gypsumboard] [37 side hall wall2 / 28 6 7 30 29 / gypsumboard] [38 rear hall side wall / 30 7 8 31 / gypsumboard] [39 rear hall center wall / 31 8 108 131 / gypsumboard] [40 rear glass wall \ 31 32 132 131 \ glass] Ceiling Panels Geometric file ;ceiling panels.GEO ;PROJECT=Bing Theatre ;AII measurements in metres LOCAL unit = TRUE ;OFFSETCO ;OFFSETPL OFFSETPL 100 O FFSETCO 80 LOCAL tx = 0 ; translate x value LOCAL ty = 14.8 ; translate y value LOCAL tz = 10.7 ; translate z value OBJECT ROTATE 0 0 0 TRANSLATE 0 14.8 10.7 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. I ;MIRROR co_add pl_add MIRROR 100 200;corner and plane offsets for mirrored part CORNERS IF unit THEN ;lock corners 16 -swj/2 0 ; 17 10.5094 17 -(faw+swj)/4 18 x(17) y(17) 0 4.4035 0 ;6 in original 1.9621 0 thh 15 10.0094 4.4035 ft2 ; 15 10 4.4035 ft2 20 x(15) y(15) thh 19 12.4075 15.3876 thh ;19 10 15.3876 thh ENDIF IF unit THEN ;first ceiling panel corners 0 lock(16 17 18) 0.9 -2.54 1 lock(16 17 18) y(0)+1.1 -2.4 2 lock(16 17 18) y(1)+0.96 -1.97 3 lock(16 17 18) y(2)+0.8 -1.25 4 lock(16 17 18) V(3) 0 ENDIF IF unit THEN ;second ceiling panel corners 1 3 2 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 5 lock(19 20 15) C O I s- o -2.54 6 lock(19 20 15) y(5)+1.47 -2.48 7 lock(19 20 15) y(6)+1.4 8 lock(19 20 15) y(7)+1.17 -1.1 9 lock(19 20 15) y(8) 0 ENDIF IF unit THEN ;third ceiling panel corners 10 lock(19 20 15) y(9)+0.45 -2.45 11 lock(19 20 15) y(10)+1.56 -2.52 12 lock(19 20 15) y(11)+1.5 -2.27 13 lock(19 20 15) y(12)+1.44 -1.64 14 lock(19 20 15) y(13)+1.2 0 ENDIF PLANES ;first ceiling panel surface facing audience [0 panel surfacel /1 0 0 101 1 0 / plaster] [1 panel surface2 /1 0 1 102 2 1 / plaster] [2 panel surface3 /1 0 2 103 3 2 / plaster] [3 panel surface4 /1 0 3 104 4 3 / plaster] ;first ceiling panel surface facing ceiling [13 panel surfacel \ 100 101 1 0 \ plaster] [14 panel surface2 \ 101 102 2 1 \ plaster] [15 panel surface3 \ 102 103 3 2 \ plaster] [16 panel surface4 \ 103 104 4 3 \ plaster] ;second ceiling panel surface facing audience [4 panel surfacel /1 0 5 106 6 5 / plaster] 133 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. [5 panel surface2 /1 0 6 107 7 6 / plaster] [6 panel surface3 /1 0 7 108 8 7 / plaster] [7 panel surface4 /1 0 8 109 9 8 / plaster] ;second ceiling panel surface facing ceiling [17 panel surfacel \ 105 106 6 5 \ plaster] [18 panel surface2 \ 106 107 7 6 \ plaster] [19 panel surface3 \ 107 108 8 7 \ plaster] [20 panel surface4 \ 108 109 9 8 \ plaster] ;third ceiling panel surface facing audience [9 panel surfacel /1 1 0 111 11 10 / plaster] [10 panel surface2 /111 112 12 11 / plaster] [11 panel surface3/1 1 2 113 13 1 2 / plaster] [12 panel surface4 /1 1 3 114 14 13 / plaster] ;third ceiling panel surface facing ceiling [21 panel surfacel \ 110 111 11 10 \ plaster] [22 panel surface2 \ 111 112 12 11 \ plaster] [23 panel surface3 \ 112 113 13 12 \ plaster] [24 panel surface4 \ 113 114 14 13 \ plaster] Geometric file of Projecting wall panels ;wall panels.GEO ;PROJECT=Bing Theatre ;AII measurements in metres ;OFFSETCO ;OFFSETPL OFFSETPL 200 O FFSETCO 210 134 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LOCAL tx = 0 ; translate x value LOCAL ty = 14.8 ; translate y value LOCAL tz = 7.58 ; translate z value OBJECT ROTATE 0 0 0 TRANSLATE 0 14.8 7.58 ;MIRROR co_add pl_add MIRROR 500 600;corner and plane offsets for mirrored part CORNERS ;first wall panel corners 0 9.42 3 -4.1 1 10.04 y(0)+0.75 z(0) 20 x(0) y(0) 0 21 x(1) y(1) 0 ;second wall panel corners 2 10.5 y(1)+0.75 -6.7 3 10.66 y(2)+0.75 z(2) 22 x(2) y(2) 0 23 x(3) y(3) 0 ;third wall panel corners 4 10.82 y(3)+0.75 -6.43 5 10.98 y(4)+0.75 z(4) 24 x(4) y(4) 0 25 x(5) y(5) 0 ;fourth wall panel corners 6 11.14 y(5)+0.75 -6.16 1 3 5 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 7 11.3 y(6)+0.75 z(6) CO ' x CD CM y(6) 0 27 x(7) y(7) 0 ;fifth wall panel corners 8 11.46 y(7)+0.75 -5.82 9 11.62 y(8)+0.75 z(8) 5 x ' 0 0 CM y(8) 0 29 x(9) y (9 ) 0 ;sixth wall panel corners 10 11.78 y(9)+0.75 -5.5 11 11.94 y(10)+0.75 z(10) 30 x(10) y(10) 0 31 x(11) y(i 1) 0 ;seventh wall panel corners 12 12.1 y(11)+0.75 -5.4 13 12.26 y(12)+0.75 z(12) 32 x( 12) y(12) 0 33 x(13) y (1 3 ) 0 ;eighth wall panel corners 14 12.42 y(13)+0.75 -4.68 15 12.58 y(14)+0.75 z(14) 34 x(14) y(14) 0 35 x(15) y(15) 0 ;ninth wall panel corners 16 12.74 y(15)+0.75 -4.2 17 12.9 y(16)+0.75 z(16) 36 x(16) y(16) 0 37 x(17) y(17) 0 1 3 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. .tenth wall panel corners 18 13.06 y(17)+0.75 -3.78 19 13.22 y(18)+0.75 z(18) 38 x(18) y(18) 0 39 x(19) y(19) 0 ;the main sub-division bottom corners 40 10.5 y(1)+0.75 -6.5 41 13.22 y(18)+0.75 -3.88 PLANES ;wall panel surfaces ;[1 panel surfacel \ 20 21 1 0 \ fiberglass] ;[2 panel surface2 / 20 21 1 0 / plywood] ;sub-divisions of the planes ;first one is the whole of all the small planes [3 subpanel surface \ 22 40 41 39 \ (a panel surface2 \ 2 3 23 22 \ plywood) (b panel surface3 \ 4 5 25 24 \ plywood) (c panel surface4 \ 6 7 27 26 \ plywood) (d panel surface5 \ 8 9 29 28 \ plywood) (e panel surface6 \ 10 11 31 30 \ plywood) (f panel surface7 \ 12 13 33 32 \ plywood) (g panel surface8 \ 14 15 35 34 \ plywood) (h panel surface9 \ 16 17 37 36 \ plywood) (i panel surfacel 0 \ 18 19 39 38 \ plywood)] [4 subpanel surface reverse side / 22 40 41 39 / (a panel surface2123 2322 I fiberglass) (b panel surface3 / 4 5 25 24 / fiberglass) (c panel surface4 / 6 7 27 26 / fiberglass) (d panel surface5 / 8 9 29 28 / fiberglass) 137 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. (e panel surface6 /1 0 11 31 30 / fiberglass) (f panel surface7 /1 2 13 33 32 / fiberglass) (g panel surface8 /1 4 15 35 34 / fiberglass) (h panel surface9 /1 6 17 37 36 / fiberglass) (i panel surfacel0 /1 8 19 39 38 / fiberglass)] Geometric file of Curtains in the stage ;curtains.GEO ;PROJECT=Bing Theatre ;AII measurements in metres ;OFFSETCO ;OFFSETPL OFFSETPL 300 OFFSETCO 310 LOCAL tx = 0 ; translate x value LOCAL ty = 1 ; translate y value LOCAL tz = 0 ; translate z value OBJECT ROTATE 0 0 0 TRANSLATE 0 1 0 ;MIRROR co_add pl_add MIRROR 700 800;corner and plane offsets for mirrored part CORNERS ;curtains in the sides of the stage 0 -swj/2 0 sh 1 -swj/2 10.5 sh 2 x(1) y(i) thh 3 x(0) y(0) thh 1 3 8 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. PLANES ;curtain surface in the sides [0 stage curtain / 0 1 2 31 fabric] [1 stage curtain2 \ 0 1 2 3 \ fabric] ;curtains in the rear of the stage [2 stage curtain3 \ 0 3 703 700 \ fabric] [3 stage curtain4 / 0 3 703 700 / fabric] Source Position file ;PROJECT=Bing Theatre ;Case I = position A SOURCEDEFS ; a natural source ;id position directivity aim-position [roll] ;A0 0.0 3.0 1.7 OMNI 0.0 5.0 1.7 ;Lp1 m_a = Lp_white 94 ; white spectrum, 94 dB at 1 kHz ; an electro-acoustical source (syntax 1 specifying Gain_a) A0 -1.5 13.3 1.5 OMNI 0.0 0.0 0.0 Lp1m_a =<85 88 91 94 97 100> ;Lp1m_ea = <75 80 82 85 88 88> ; at 1m on source axis ;Gain_a = <20 20 20 20 20 20> ; calculates Lp1 m_ea ;Delay_e = 0 Receiver Description file ;PROJECT=Bing Theatre RECEIVERS 1 2.63 20.03 2.14 ;2 0.75 23.41 2.71 ;3 2.63 28.51 4.03 ;4 9.83 26.83 3.54 ;5 10.58 24.29 2.85 1 3 9 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Linked assets
University of Southern California Dissertations and Theses
Conceptually similar
PDF
A case study comparing measured and simulated acoustical environments: Acoustical improvements of Verle Annis Gallery
PDF
Catalyst: A computer-aided teaching tool for stayed and suspended systems
PDF
A method for glare analysis
PDF
A proposed wood frame system for the Philippines
PDF
Computer aided design and manufacture of membrane structures Fab-CAD
PDF
Bracing systems for tall buildings: A comparative study
PDF
Interactive C++ program to generate plank system lines for timber rib shell structures
PDF
Guidelines for building bamboo-reinforced masonry in earthquake-prone areas in India
PDF
Determine the optimum block type for use in Saudi Arabia
PDF
Eccentric braced frames: A new approach in steel and concrete
PDF
Emergency shelter study and prototype design
PDF
Computer modelling of cumulative daylight availability within an urban site
PDF
Shading mask: a computer-based teaching tool for sun shading devices
PDF
Computer aided design and analysis of anticlastic membranes and cable nets
PDF
Comparison of lateral performance: Residential light wood framing versus cold-formed steel framing
PDF
DS(n)F: The design studio of the (near) future
PDF
Hebel design analysis program
PDF
Color and daylighting: Towards a theory of bounced color and dynamic daylighting
PDF
Characteristic acoustics of transmyocardial laser revascularization
PDF
A visual and digital method for predicting discomfort glare
Asset Metadata
Creator
Thiagarajan, Suganya
(author)
Core Title
Acoustics of the Bing Theater, USC: Computer simulation for acoustical improvements
School
School of Architecture
Degree
Master of Building Science / Master in Biomedical Sciences
Degree Program
Building Science
Publisher
University of Southern California
(original),
University of Southern California. Libraries
(digital)
Tag
Architecture,OAI-PMH Harvest,Physics, Acoustics,Theater
Language
English
Contributor
Digitized by ProQuest
(provenance)
Advisor
Schierle, G. Goetz (
committee chair
), Kensek, Karen (
committee member
), Noble, Douglas (
committee member
)
Permanent Link (DOI)
https://doi.org/10.25549/usctheses-c16-322672
Unique identifier
UC11337817
Identifier
1424256.pdf (filename),usctheses-c16-322672 (legacy record id)
Legacy Identifier
1424256.pdf
Dmrecord
322672
Document Type
Thesis
Rights
Thiagarajan, Suganya
Type
texts
Source
University of Southern California
(contributing entity),
University of Southern California Dissertations and Theses
(collection)
Access Conditions
The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...
Repository Name
University of Southern California Digital Library
Repository Location
USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA
Tags
Physics, Acoustics