SCHOOL OF ARCHITECTURE, BUILDING & DESIGN BACHELOR OF SCIENCE (HONOURS) IN ARCHITECTURE BUILDING SCIENCE II (BLD61303 / ARC3413)
PROJECT: AN ACOUSTIC CASE STUDY ON CALVARY CONVENTION CENTRE, KUALA LUMPUR
GROUP MEMBERS: ANDY HENG WEE XIANG (0327152) CHAN YI QIN (0315964) CHIA CHENG WEI (0322091) KOH SUNG JIE (0318912) KOOI YONG KAI (0323152) LEE XIANG LOON (0322090) NG EE SHIUNG (0314228) NG YI YANG (0319688)
LECTURER: MR AZIM SULAIMAN
SUBMISSION DATE: 2 MAY 2017
An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
TABLE OF CONTENTS Pages Declaration of Submission
4
Acknowledgment
5
List of Figures and Tables
6–7
Abstract
8
1.0
Introduction
9
1.1
Aims and Objectives
10
1.2
Site Introduction
11 – 12
2.0
3.0
Literature Review 2.1
Sound
13
2.2
Architecture Acoustic
13
2.3
Sound Pressure Level (SPL)
13 – 14
2.4
Reverberation Time (RT)
14
2.5
Sound Reduction Index (SRI)
15
Methodology 3.1
3.2
Equipment and Specifications 2.1.1
Sound Level Meter
16
2.1.2
Camera
17
2.1.3
Measuring Tape
18
Data Collection Methods 2.2.1
Site Study
18 – 22
2.2.2
Procedure
23 – 24
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.0
Findings 4.1
Selection of Site
25 – 27
4.2
Materials and Specifications
28 – 32
4.3
Noise
4.4
4.3.1
Outdoor Noise
33 – 35
4.3.2
Indoor Noise
36 – 37
Fixtures and Specifications
38
4.4.1
Zoning and Tabulation
38 – 39
4.4.2
Audio Systems
40 – 41
4.5
Sound Propagation
42 – 43
4.6
Absorption of Surfaces
44
4.7
Reverberation Time
45
5.0
Conclusion
46 – 47
6.0
References
48
7.0
Appendix
49
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
DECLARATION OF SUBMISSION
This is to certify that the submitted paper has not been published previously, nor is it under consideration for publication elsewhere. We also certify that its publication is approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out, and that, if accepted, it will not be published elsewhere including electronically in the same form, in English or in any other language, without the written consent of the copyright-holder.
Name
Student ID
ANDY HENG WEE XIANG
0327152
CHIA CHENG WEI
0322091
CHAN YI QIN
0315964
KOH SUNG JIE
0318912
KOOI YONG KAI
0323152
LEE XIANG LOON
0322090
NG EE SHIUNG
0314228
NG YI YANG
0319688
Signature
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
ACKNOWLEDGEMENT
First and foremost, we would like to thank Taylor’s University for giving us the opportunity to conduct this case study. From this project, we were able to comprehensively learn about how acoustics work within an actual auditorium space. Also, we would like to express our gratitude towards our tutor, Mr. Azim Sulaiman, for patiently guiding us throughout this assignment while providing necessary equipment to conduct our studies. He also helped us understand the scope of our project so that we would not waste time doing unnecessary work.
Moreover, we would like to thank Ms. Chin Yoke Yee from Calvary Convention Centre for not only invited us to ‘The Call’, an Easter event held in the Calvary Convention Centre, but also allowed us access into the auditorium when it was empty. Therefore, we were able to capture photos and experience the space when in use and not in use. We also want to thank Mr. David as he brought us into the auditorium during the second visit. Mr. David is the assistant sound engineer in the centre and he was able to provide us valuable information on the acoustics of the space. Ms. Chin and Mr. David took the time off from their busy schedule to aid us in our research and we are grateful for that.
Last but not least, we want to express our special thanks to Ar. Andy Chong from T.R. Hamzah & Yeang. Ar. Andy was the project director in the design and construction of Calvary Convention Centre. We were able to acquire the drawings, such as floor plans, sections and details that were extremely crucial to this case study because of him. Not only that, Ar. Andy invited us to his office and gave us an insight into his project by carefully explaining the design intentions of the building and its interior.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
LIST OF FIGURES AND TABLES
List of Figures
Pages
Figure 1
Exterior of Calvary Convention Centre
11
Figure 2
Sound Level Meter used on site
16
Figure 3
One of the cameras used, Canon EOS 550D
17
Figure 4
Measuring tape used on site
18
Figure 5
Easter performance on stage
19
Figure 6
Speech and the size of the audience during ‘The Call’
19
Figure 7
Sitting positions during the Easter event
20
Figure 8
Gathering data via the sound level meter at the center of the auditorium
21
Figure 9
Mr. David explaining about the acoustic design of the hall
21
Figure 10
Group photo with Ar. Andy Chong
22
Figure 11
TEDxKL hosted in the Calvary Convention Centre
25
Figure 12
Panoramic shot of the auditorium when not in used
26
Figure 13
Fan-shaped floor plan of the auditorium
26
Figure 14
Longitudinal section of the auditorium spanning 4-storeys tall
27
Figure 15
Materials indicated on floor plan
31
Figure 16
Materials indicated on section
32
Figure 17
Detailed section of roof showing roof layers
33
Figure 18
Double door volume and fire escape access acting as air gaps shown on floor plan
Figure 19
34
Section showing sound insulation lining between air-conditioning duct and carpark ceiling
35
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 20
Air-conditioning transmission flow shown on section
36
Figure 21
Air vents underneath the auditorium seats
37
Figure 22
Detailed section showing the ventilation system under the floor
37
Figure 23
Zoning and sound source shown on floor plan
38
Figure 24
Sound transmission of various types of speakers
40
Figure 25
Sound propagation diagram without the aid of speakers
43
Figure 26
View from stage showing the gaps between the acoustic ceiling panels
Figure 27
43
Panoramic shot of Calvary Convention Centre’s auditorium during a performance
47
Table 1
Example of sound sources and their properties
14
Table 2
List of materials and their properties
29
Table 3
Data tabulation from sound level received in every zone
39
Table 4
Types of speakers and specifications
41
Table 5
Total room surface absorption
44
List of Tables
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
ABSTRACT
An auditorium is a special room built to enable an audience to hear and watch performances at venues such as theatres and music halls. A successful design of an auditorium depends on its layout and absorption materials used in order to enhance desired sound while eliminating noise and undesired sound. This paper attempts to understand building acoustics in relation to an auditorium layout design and construction.
The chosen building was Calvary Convention Centre and the area of interest is its auditorium space. Other areas not related to the auditorium’s acoustical design were not considered. The research covers the acoustical materials and fixtures used in the building, design strategies used to counter noise from the outside and inside, sound source and propagation and the relationships between the aspects stated. With the information gathered, a full scope of its design intention based on acoustics can be determined.
To assist the validation of research, literature reviews based on various sources such as articles on the building and site visits were conducted to complete this report. Furthermore, necessary documents such as the building plans were acquired from the related parties such as the centre personnel and the architect. With the findings gathered, the data collected were studied extensively in conjunction to the acoustic design of the building.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
1.0 INTRODUCTION
Acoustic design is defined as an audio component which is related to the control of sound in spaces particularly encased spaces. The necessity shifts in agreement to different functions. Acoustical requirement varies depending on the function of a place or space. Unwanted sounds and noise are eliminated in a good acoustic design in order to provide a better auditory environment for the user. It is imperative as to improve desired sounds and to eliminate unwanted noise and static sounds.
We have decided to select the Calvary Convention Centre as our case study in our group of five. The content of the report follows our group's thoughts and observation, data collection and documentation, as well as the study of the acoustic performances within the famed Calvary Convention Centre. In order to acquire all the necessary data, multiple visits were required with the aid of designated electronic measuring equipment, while permission was also granted in order to acquire measured drawings of the building in question and photographs taken for referencing purposes.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
1.1 Aims and Objectives
The aims and objectives are as followings: 1. To conclude the characteristics and purpose of sound and acoustic within the proposed space. 2. To critically account for and examine the acoustics of the space. 3. To understand ways to improve the acoustic qualities of that place. 4. To be able to yield a complete papers or documentation on study of space relative to acoustic requirements. 5. To comprehend how the auditorium design layout can affect the efficiency of the public address (PA) system in a particular hall. 6. To have the ability to assess and discover creative innovation by applying recent material technology in accordance to the current construction industry.
By discerning and assessing the form of acoustic design used in Calvary Convention Centre, we aim to have a better understanding on the features of a space and how it determines different design approaches for acoustic whilst how different types of acoustic designs and applications affect the working efficacy and user experience of an acoustic space, as well as recommending keys to improve the acoustics qualities in the case study.
This project is focused at providing students a foundational understanding and study of acoustic design layout and arrangements of an actual auditorium. In addition, this project also aims to provide students a way to explore the methodologies of designing a good acoustic system via calculations based on readings and measurements.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
1.2 Site Introduction
Figure 1: Exterior of Calvary Convention Centre (Source: Calvary Church, 2017)
The Calvary Convention Centre is located on a 4.9 acre piece of land within the identified International Zone at Bukit Jalil, in the southern part of Wilayah Persekutuan, Kuala Lumpur. Designed by T.R. Hamzah & Yeang Sdn Bhd, it has facilities that are unique and dedicate to enhancing the convention and educational requirements. The famed Calvary Convention Centre has a built-up area measuring 600,000 square feet, spreading across 4.9 acres of prime land close to the heart of Kuala Lumpur. A 5,000 seat auditorium will play host to world class conventions, banquets, seminars and creative arts productions.
As for the auditorium, it has a column-free span of 60m. Its roof is supported by 2 main trusses spanning from the back to the front of the hall on 4 mega columns. The ceiling space is serviced by a network of servicing catwalks for maintenance of lights and stage rigging. The design of
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
the auditorium was thought to be a single-tiered floor that allows the audience in the back row to walk to the altar area at the front of the stage without exiting the auditorium. Other than that, the auditorium is designed to be sub-dividable into 3 smaller halls, and has built-in structures in the ceiling for future installation of foldable ceiling mounted ‘Skyfold’ partitions, up to 10m in height. The front of the sub-divided halls has retractable seats to convert the space into a speaker area when needed. As for the stage in the auditorium, it is designed for theatrical and musical productions, including a fly tower, orchestra pit, stage proscenium, changing rooms, rehearsal rooms, and green room.
The orchestra pit platform is yet to be operable and is designed to stop at several floor positions. The stage level is designed to increase the stage size, while mid stage level is designed to bring the speaker ‘closer to the audience’. The auditorium level floor position enlarges the hall seating capacity, while below auditorium level as a sunken orchestra pit. The pit platform is also designed to stop at rehearsal room level and at store room level where stage props and other equipment are stored.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
2.0 LITERATURE REVIEW
2.1 Sound The sensation stimulated in the hearing organs by mechanical or natural radiant energy transmitted as longitudinal pressure waves through the air or other mediums.
2.2 Architecture Acoustic Architecture acoustic is the science and engineering of achieving a good sound within a building. This may include achieving good speech intelligibility in a theatre, enhancing the quality of music played through instruments in a concert hall or auditorium, or suppressing noise to make offices and homes more productive and pleasant places to work and live in. Design of spaces, structures and mechanical systems must include acoustic consideration to create a space that is pleasing in sound quality to suit the mood of the space. The acoustic mood designed for a space is also highly affect by the buffer from the building exterior that blocks the outdoor noise and building interior design that buffers indoor noise.
2.3 Sound Pressure Level (SPL) Sound pressure is the local pressure deviation from the ambient atmospheric pressure, caused by a sound wave, using symbol p or p. The sound pressure is usually measure using a microphone. Sound pressure level is used in measuring the magnitude of sound in decibel (dB).
SPL = 20 log10
đ?‘? đ?‘?0
where SPL = sound pressure level (dB) đ?‘? = the pressure of the sound being measured đ?‘?0 = the pressure of the threshold of intensity taken as 20 x 10-6 Pa
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Sources at 1m
Lp re 20 µPa*
Sound Pressure
Rifle
200 Pa
140 dB
Threshold of pain
20 Pa
120 dB
Pneumatic hammer
2 Pa
100 dB
6 dB = double the Pa
1 Pa
94 dB
Street traffic
0.2 Pa
80 dB
Talking
0.02 Pa
60 dB
Library
0.002 Pa
40 dB
TV Studio
0.0002 Pa
20 dB
Threshold of hearing
0.00002 Pa
0 dB
* Reference Sound Pressure po in air = 2 x 10-5 Pa = 20 µPa = 0 dB Table 1: Example of sound sources and their properties (Source: Acoustic Glossary)
2.4 Reverberation Time (RT) In acoustics, reverberation is the persistence of sound after a sound is produced. Reverberation or a reverb is created when a sound is reflected causing a large number of reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space – which could include furniture, people, walls and air. This is most noticeable when the source stops but the reflections continue, decreasing in amplitude, until they reach zero amplitude.
The duration it takes for a sound to drop by 60 dB is the reverberation time. Reverberation time (RT) is an important index for describing the acoustic quality of a space.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
RT =
0.16đ?‘‰ đ??´
where RT = reverberation time (seconds) V = volume of room (m3) A = total absorption of room surfaces (m2 sabins)
2.5 Sound Reduction Index (SRI) Sound pressure is the difference, in a given space, between the average local pressure of the space and the pressure in the sound wave. The Sound Reduction Index (SRI) or Transmission Loss (TL) of a partition measure the number of decibels lost when a sound of a given frequency is transmitted through the partition.
SRI = 10 log10 (
1
���
)
đ?‘†1 đ?‘‡đ?‘?1 + đ?‘†2 đ?‘‡đ?‘?2 +. . đ?‘†đ?‘› đ?‘‡đ?‘?đ?‘› đ?‘‡đ?‘Žđ?‘Ł = ( ) đ?‘‡đ?‘œđ?‘Ąđ?‘Žđ?‘™ đ?‘†đ?‘˘đ?‘&#x;đ?‘“đ?‘Žđ?‘?đ?‘’ đ??´đ?‘&#x;đ?‘’đ?‘Ž
where SRI = sound reduction index Tav = transmission coefficient Tcn = transmission coefficient of material Sn = the surface area of the material n
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
3.0 METHODOLOGY
3.1 Equipment and Specifications
3.1.1 Sound Level Meter
Figure 2: Sound Level Meter used on site (Source: C. W. Chia, 2017)
The sound level meter used was the 01dB A-scale Sound Level Meter provided by Taylor’s University. The A-scale frequency weighting corresponds to the way the human ear responds to the loudness of sound and the weighted sound level value is read on the meter.
The stated sound level meter is capable of two ranges: 60-120 dBA and 30-90 dBA. It is mainly used for fast sound pressure level, Lp, measurement and has the option for equivalent continuous sound level, Leq, measurement.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
3.1.2 Camera
Figure 3: One of the cameras used, Canon EOS 550D (Source: Amazon)
The main cameras used for this case study are the Canon EOS 550D, Nikon D90 and Fujifilm XT-10. The digital cameras were used on site to record and capture pictures of the building, acoustic conditions as well as the acoustical fixtures present on site. There were secondary cameras, mainly smartphone cameras, were used when the main cameras were not readily available. All the photos taken are used as evidence of our study and for reference purposes when not on site.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
3.1.3 Measuring Tape
Figure 4: Measuring tape used on site (Source: Wikimedia)
Although we already obtained the floor plans and sections along with their dimensions, we brought a few measuring tapes during the site visit. These tools were used to confirm the measurements on some small-scale details and to acquire missing dimensions not found in the drawings.
3.2 Data Collection Methods
3.2.1 Site Study There are two site visits and a meeting conducted over a 5-week period before the submission. Moreover, we obtained the floor plans and sections from the project architect from T.R. Hamzah & Yeang Sdn. Bhd.
The first site visit was during an Easter event, ‘The Call’. During the visit, we sat in different locations in the auditorium to gather information purely from observation and experience. This is because we were not allowed to conduct any formal analysis during the event. 18 | Building Science II (BLD61303 / ARC3413)
An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 5: Easter performance on stage (A. Heng, 2017)
Figure 6: Speech and the size of the audience during ‘The Call’ (A. Heng, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 7: Sitting positions during the Easter event (Source: Y. Q. Chan, 2017)
The second site visit was on the 25th April 2017, when the auditorium was empty. This visit was applied from the convention centre’s office through emails and phone calls. Without an event occurring, we were able to conduct a formal analysis as well as to gather acoustical data and information. Furthermore, Mr. David, the assistant sound engineer of Calvary Convention Centre was there to supervise the visit and was able to answer most of the questions that we inquired about the site.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 8: Gathering data via the sound level meter at the center of the auditorium (Source: A. Heng, 2017)
Figure 9: Mr. David explaining about the acoustic design of the hall (Source: X. L. Lee, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
In addition, we also met the project director, Ar. Andy Chong on 28th April 2017. He gave us a complete account on the architectural and acoustic design of the building, interior as well as the exterior. Ar. Andy explained the requirements given to him from the client in designing Calvary Convention Centre and the restrictions posed on site. He was also able to answer all our questions that we prepared beforehand.
Figure 10: Group photo with Ar. Andy Chong (Source: A. Heng, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
3.2.2 Procedure
First Site Visit 1. Distribution of seating into three separate locations. 2. Data collection from observation and analysis. 3. Photos of the event taken by allocated team members.
Second Site Visit 1. Photos of materials and fixtures taken in the auditorium. 2. Sound levels of different zones obtained through clapping from source using the sound meter. 3. Time weightings recorded from sound level meter.
Meeting with Architect 1. Preparation of a list of questions for understanding and confirmation of information gathered.
Outside of Visit 1. Investigation of photos taken to identify materials and fixtures used. 2. Proper measurements recorded from the floor plans and sections acquired by project architect. 3. Calculation of volume and surface areas based on measurements taken. 4. Tabulation of data on sound levels and time weightings recorded. 5. Information of fixtures used in auditorium obtained from online sources. 6. Indication of location of materials and fixtures within the site.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
7. Tabulation of additional data based on influence of speakers involved. 8. Compilation of data and production of A4 report.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.0 FINDINGS
4.1 Selection of Site
Calvary Convention Centre is designed to be a world-class intelligent convention centre, built for the future. The auditorium within hosts international, national and regional conventions, seminars, musical and creative arts productions, and provides educational and vocational training and spiritual development. Some of the events hosted include, the recent TEDxKL, concerts by artists overseas and MiED Awards Ceremony.
Figure 11: TEDxKL hosted in the Calvary Convention Centre (Source: Calvary Convention Centre)
Despite its use, it is lauded as one of the biggest indoor auditoriums in Malaysia due to its impressive pillarless spacious fan-shaped hall that has the capacity to house up to 5,000 people. Spanning four levels with multiple entrances, the auditorium is fitted with comfortable theatre
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
seats and state-of-the-art acoustic finishings. The stage is equipped with a fly tower, and ample rehearsal and dressing rooms.
Figure 12: Panoramic shot of the auditorium when not in used (Source: X. L. Lee, 2017)
Figure 13: Fan-shaped floor plan of the auditorium (Source: T.R. Hamzah & Yeang Sdn. Bhd.)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 14: Longitudinal section of the auditorium spanning 4-storeys tall (Source: T.R. Hamzah & Yeang Sdn. Bhd.)
Not only that, the architectural firm associated to Calvary Convention Centre is the famous T.R. Hamzah & Yeang, a KL-based architectural firm that has become internationally known by expanding to China and the United Kingdom. Therefore, all these elements gave us more than enough reasons to choose Calvary Convention Centre as our subject of study.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.2 Materials and Specifications
Room acoustics describes how sound behaves in an enclosed space. In designing rooms for various purposes, the architect will encounter acoustical problems associated with enclosed spaces. This is because propagation and behaviour of sound in enclosed spaces are more complex than in open air.
There are three ways to manipulate sound within the room, to reflect, absorb or diffuse it. The materiality present within the space will play the role of doing either of these, therefore affecting the acoustic quality of the space.
The whole auditorium is intended to be acoustically treated in a way that every surface area to be covered with rock wool insulation coupled with acoustic panelling as a secondary layer of sound absorption. No bare surfaces are seen exposed in the auditorium.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Material
Photos
Absorption Coefficient (α) 125 Hz
500 Hz
1000 Hz
Carpet, Heavy, on Reinforced Concrete
0.02
0.14
0.37
Timber Floor on Joists
0.15
0.10
0.07
Hung Curtain, Heavy
0.14
0.55
0.72
Rockwool Foam
0.15
0.90
0.90
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Acoustic Timber Boards
0.18
0.42
0.59
Solid Timber
0.14
0.06
0.08
Upholstered Tip-up Theatre Seat
0.33
0.64
0.71
Timber Padded Retractable Tip-up Seat
0.08
0.15
0.00
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Plaster Board
0.30
0.15
0.05
Pane Glass
0.18
0.04
0.03
Table 2: List of materials and their properties (Source: Mechanical and Electrical Equipment for Buildings)
Figure 15: Materials indicated on floor plan (Source: Y. K. Kooi, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 16: Materials indicated on section (Source: Y. K. Kooi, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.3 Noise
4.3.1 Outdoor Noise
One of the most prevalent noise that occur in Malaysia is the rain. The sound caused from the impact of rain hitting the roof must be absorbed so that an event can be held regardless of the weather outside. The layers of material used for roofing as shown in Figure 16 is crucial so that the noise is therefore isolated from the interior.
Figure 17: Detailed section of roof showing roof layers (Source: E. S. Ng, 2017)
To isolate noise from outdoor activities and from other rooms, the architect used double doors to prevent noise from the entrance to enter the auditorium space. Moreover, the fire escape access lined at the side of the auditorium doubles as an air barrier to isolate noise from the outside from coming into the auditorium space.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 18: Double door volume and fire escape access acting as air gaps shown on floor plan (Source: Y. Y. Ng, 2017)
The basement carpark of Calvary Convention Centre is located right beneath the auditorium. This basement carpark would potentially cause unwanted noise from cars moving about, thus a thick layer of insulation as shown in Figure 18 is applied between the ceiling of the carpark and the air ducts beneath the auditorium (refer item 4.3.2).
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 19: Section showing sound insulation lining between air-conditioning duct and carpark ceiling (Source: Y. Y. Ng, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.3.2 Indoor Noise
The main concern for indoor noise is the noise caused by mechanical ventilation, the airconditioning system. If a ceiling mounted air-conditioning system was employed, the energy needed to transmit cool air to the seats would be enormous, thus causing more noise by vibrations from the air ducts. This is due to the ceiling height of the auditorium being at around 20 meters.
Figure 20: Air-conditioning transmission flow shown on section (Source: Y. Y. Ng, 2017)
Thus, the solution is to invert the air-conditioning system by transmitting cool air upwards rather than downwards as shown in Figure 19. The front 2/3 of the auditorium employs this system while the back 1/3 of the auditorium uses ceiling mounted system. This not only reduced the noise posed from air-conditioning, but also reduced the energy usage of the building, making the building more sustainable.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 21: Air vents underneath the auditorium seats (Source: A. Heng, 2017)
Figure 22: Detailed section showing the ventilation system under the floor (Source: Y. Y. Ng, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.4 Fixtures and Specifications
A perfect auditorium is able to project sound in a manner that the same level of sound is received by each person. Due to its immense scale, this is not realistically possible for Calvary Convention Centre. Hence, it uses its audio system consisting several types of speakers to achieve this.
4.4.1 Zoning and Tabulation During our site visit, we conducted an analysis on the sound received from the source at various areas of the auditorium. The auditorium is separated into 9 zones while the sound source is at the center of the stage.
Figure 23: Zoning and sound source shown on floor plan (Source: C. W. Chia, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
We positioned one of our members on the stage to produce sound by claps. Each clap is recorded on every zone and its average is determined.
Sound Level (dB) Zones 1
2
3
Average
1
60
56
59
61
2
57
66
59
60.67
3
58
60
62
60
4
53
60
54
55.67
5
56
59
60
58.33
6
52
59
54
55
7
54
50
50
51.33
8
56
53
50
53
9
55
46
54
51.67
Table 3: Data tabulation from sound level received in every zone (Source: C. W. Chia, 2017)
We have concluded that the middle zones generally receive a higher sound level than the side zones. Also, the sound level received lowers gradually when it goes to the back end of the auditorium.
39 | Building Science II (BLD61303 / ARC3413)
An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.4.2 Audio Systems There are three types of speakers used in the auditorium and all of them are under a same brand, L-Acoustics.
The ARC Focus is a line array loudspeaker system that is purposed to project sound to the back of the auditorium. To ensure the back of the auditorium receives sound the same time as the front, the sound from the bottommost speaker projecting towards the frontmost audience is delayed by a split-second. Next, the P-Series 108P is used to project sound towards the front 4 seating rows. This is because the ARC Focus sets are unable to reach the 4 rows stated, thus the 108P is used to compensate for that matter. Lastly, the four P-Series 112P located on the stage are used as stage monitors. Stage monitors are used whereby the performers are able to listen to other instruments as well as their own voices so that they could make vocal adjustments during the performance.
Figure 24: Sound transmission of various types of speakers (Source: C. W. Chia, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Type of Speakers L-Acoustics P-Series 112P
L-Acoustics ARCS Focus
L-Acoustics P-Series 108P
Dimension 540 mm height x 410 mm width x 390 mm depth
Weight 32 kg
365 mm width 38 kg at the front x 252 mm width at the rear x 759 mm height x 444 mm depth.
421mm x height, 250mm width x 299mm depth
13 kg
Sound Specifications -
Usable system bandwidth of 50Hz to 20 kHz (-10 dB). Generates conical directivity (-6 dB points) of 90°.
-
Maximum SPL (Sound Pressure Level), measured at 1m under free field conditions is 133 dB.
-
Wedge-shaped design with a fixed angle setting of 30°.
-
Usable system bandwidth of 55Hz to 20 kHz (-10 dB). Generates a symmetrical horizontal directivity of 15° and a symmetrical vertical coverage angle of 90° (-6 dB).
-
Maximum peak SPL, measured at 1m under free field conditions is 139 dB.
-
Usable system bandwidth of 55 Hz to 20 kHz (-10 dB). Generates a conical directivity (-6 dB) of 100°.
-
Maximum peak SPL, measured at 1m under free field conditions is 125 dB.
Table 4: Types of speakers and specifications (Source: C. W. Chia, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.5 Sound Propagation
The auditorium is designed in way that the levels are descending towards the stage. This arrangement allows the audience at the back to have a clear view towards the stage. However, this affects the propagation of sound coming from the stage. Therefore, ceiling panels attached above play a role in reinforcing the propagation of sound.
Firstly, sound travelling forward towards the audience is known as direct sound. Due to the nature of the auditorium, there are no obstructions within and thus the furthest audience is able to receive direct sound. However, as the auditorium is mostly covered with acoustic foam, direct sound hitting the walls is absorbed.
Next, sound travelling upwards is either reflected or absorbed. There are two ceiling surfaces, the upper ceiling surface that is heavily insulated and the lower ceiling surface consisting of acoustic panels. The panelling system is arranged in a manner that there are openings occupying 30% the lower ceiling surface. The sound travelling between the gaps is absorbed by the upper ceiling surface.
The remaining sound travelling upwards is reflected downward by the acoustic panels towards the audience and this sound is known as indirect sound. The indirect sound is much softer than direct sound, however this reinforces the direct sound, making it clear for audience near and far.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 25: Sound propagation diagram without the aid of speakers (Source: C. W. Chia, 2017)
Figure 26: View from stage showing the gaps between the acoustic ceiling panels (Source: A. Heng, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.6 Absorption of Surfaces
Based on the materials identified on site and the measurements obtained from the drawings, we were able to calculate the absorption of each surface and determine the total room absorption of the auditorium, tabulated in Table 5.
Material
Area (m2)
Absorption Coefficient, Îą (sabins)
Absorption of Surface, AS (m2 sabins)
Carpet, Heavy, on Reinforced Concrete
3291.95
0.14
460.87
Timber Floor on Joists
112.98
0.10
11.30
Hung Curtain, heavy
464.13
0.55
255.27
Rockwool Foam
1673.4
0.90
2634.98
Acoustic Timber Board
2482.43
0.42
1042.62
Solid Timber
223.65
0.06
13.42
2964.95
0.64
1897.57
417.88
0.15
62.68
Plaster Board
2482.43
0.15
372.36
Pane Glass
99.84
0.04
3.99
Upholstered Tip-up Theatre Seat Timber Padded Retractable Tip-up Seat
Total Room Absorption, AT (m2 sabins)
6715.06
Table 5: Total room surface absorption (Source: Y. K. Kooi, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
4.7 Reverberation Time
During the meeting with the architect, we asked Ar. Andy Chong about the reverberation time of Calvary Convention Centre. He stated the reverberation time is 0.9s.
V = Volume, m3 = 39136.60 m3 AT = Total Room Absorption, m2 sabins = 6715.06 m2 sabins
�� =
0.16đ?‘‰ đ??´đ?‘‡
0.16 Ă— 39136.60 đ?‘š3 = 6715.06 đ?‘š2 đ?‘ đ?‘Žđ?‘?đ?‘–đ?‘›đ?‘ = 0.93đ?‘ ≈ 0.9đ?‘ ∴ Thus, the reverberation time calculated is the same as the reverberation time stated.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
5.0 CONCLUSION
We are very grateful that we could perform a case study in this module as we could only learn so much from lectures and books. When we experienced the space for itself and talked to people who designed the space, we were able to truly understand and appreciate a full scope on acoustics.
Calvary Convention Centre had many challenges when it was being designed. Its sheer scale of having around 5,000 occupants for its maximum capacity, its location being on a disproportionate land area, the tropical climate as well as the requirements given by the client to be multipurpose.
Smart and efficient design strategies such as isolation by air gaps and restructuring of systems had to be employed to counter noise emanating from outside and the inside. Material choice is essential as to not only cut down excess sound, but also to make the space comfortable and welcoming for visitors. Application of sound systems helps reinforce sound transmission when necessary. Also, consideration of the type and position of loudspeakers used is crucial so that every audience can receive sound at the same time. To us, it is rather impressive that the auditorium managed to keep the reverberation time to 0.9 seconds, an optimal number for speech-based rooms.
We are glad that we picked Calvary Convention Centre as our case study topic. The flexibility of the auditorium makes us understand both the demands for speeches and music performances. Ultimately, this assignment has, in a short period of time, enabled us to be aware of how sound behaves in various conditions and how to manipulate sound levels to our advantage.
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
Figure 27: Panoramic shot of Calvary Convention Centre’s auditorium during a performance (Source: X. L. Lee, 2017)
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An Acoustic Design Case Study On Calvary Convention Centre, Kuala Lumpur
6.0 REFERENCES
Grondzik, W. T., & Kwok, A. G. (2015). Mechanical and electrical equipment for buildings (12th ed.). Hoboken, NJ: Wiley.
Hardy, H. (2006). Building Type Basics for Performing Arts Facilities. Hoboken, N.J. : J. Wiley.
McMullan, R. (2012). Environmental science in building (5th ed.). Houndmills, Basingstoke, England: Palgrave Macmillan.
Moore, J. (1961). Design for Good Acoustics. London: Architectural Press.
Schmolke, B. (2011). Theatres and Concert Halls: Construction and Design Manual. Singapore: Page One.
Shuai, Y. (2011). Green Office Building: Acoustic Installation, Natural Ventilation, Green Roof, Sustainable Architecture. Hong Kong: Hong Kong Polytechnic International Pub. Ltd.
Sound
Absorption
Coefficients.
(n.d.).
Retrieved
April
25,
2017,
from
https://www.acousticalsurfaces.com/acoustic_IOI/101_13.htm
Sound Pressure: Definitions, Terms, Units and Measurement. (n.d.). Retrieved April 25, 2017, from http://www.acoustic-glossary.co.uk/sound-pressure.htm
Trevor, J., & Peter, D. (2009). Acoustic Absorbers and Diffusers: Theory, Design and Application. London: Taylor & Francis.
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