An Acoustic Case Study on Calvary Convention Centre Report

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
2 | Building Science II (BLD61303 / ARC3413)
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 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
3.0 Methodology
3.1 Equipment and Specifications
2.1.1 Sound Level Meter 16
2.1.2 Camera 17
2.1.3 Measuring Tape 18
3.2 Data Collection Methods
2.2.1 Site Study 18 – 22
2.2.2 Procedure 23 – 24

4.0 Findings
4.1 Selection of Site 25 – 27
4.2 Materials and Specifications 28 – 32
4.3 Noise
4.3.1 Outdoor Noise 33 – 35
4.3.2 Indoor Noise 36 – 37
4.4 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

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and that, if accepted, it will not be published elsewhere including electronically in the same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 Signature
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

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.

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 34
Figure 19 Section showing sound insulation lining between air-conditioning
duct and carpark ceiling 35

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 43
Figure 27 Panoramic shot of Calvary Convention Centre’s auditorium
during a performance 47
List of Tables
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

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.

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.

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.

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

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.

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
𝑝
𝑝0
where SPL = sound pressure level (dB)
𝑝 = the pressure of the sound being measured
𝑝0 = the pressure of the threshold of intensity taken as 20 x 10-6
Pa

Sources at 1m Sound Pressure Lp re 20 µPa*
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.

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
𝑇𝑎𝑣
)
𝑇𝑎𝑣 = (
𝑆1 𝑇𝑐1 + 𝑆2 𝑇𝑐2+. . 𝑆 𝑛 𝑇𝑐𝑛
𝑇𝑜𝑡𝑎𝑙 𝑆𝑢𝑟𝑓𝑎𝑐𝑒 𝐴𝑟𝑒𝑎
)
where SRI = sound reduction index
Tav = transmission coefficient
Tcn = transmission coefficient of material
Sn = the surface area of the material n
RT =
0.16𝑉
𝐴

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.

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.

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.

Figure 5: Easter performance on stage (A. Heng, 2017)
Figure 6: Speech and the size of the audience during ‘The Call’ (A. Heng, 2017)

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.

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)

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)

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.

7. Tabulation of additional data based on influence of speakers involved.
8. Compilation of data and production of A4 report.

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

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.)

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.

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.

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

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

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)

Figure 16: Materials indicated on section (Source: Y. K. Kooi, 2017)

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.

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).

Figure 19: Section showing sound insulation lining between air-conditioning duct and carpark ceiling

4.3.2 Indoor Noise
The main concern for indoor noise is the noise caused by mechanical ventilation, the air-
conditioning 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.

Figure 21: Air vents underneath the auditorium seats (Source: A. Heng, 2017)
Figure 22: Detailed section showing the ventilation system under the floor

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)

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.
Zones
Sound Level (dB)
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.

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)

Type of Speakers Dimension Weight Sound Specifications
L-Acoustics P-Series 112P 540 mm height
x 410 mm
width x 390
mm depth
32 kg - 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°.
L-Acoustics ARCS Focus 365 mm width
at the front x
252 mm width
at the rear x 759
mm height x
444 mm depth.
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,
139 dB.
L-Acoustics P-Series 108P 421mm x
height, 250mm
width x 299mm
depth
bandwidth of 55 Hz to
20 kHz (-10 dB).
Generates a conical
directivity (-6 dB) of
100°.
- Maximum peak SPL,
125 dB.
Table 4: Types of speakers and specifications (Source: C. W. Chia, 2017)

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.

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)

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, α (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
Upholstered Tip-up
Theatre Seat
2964.95 0.64 1897.57
Timber Padded
Retractable Tip-up Seat
417.88 0.15 62.68
Plaster Board 2482.43 0.15 372.36
Pane Glass 99.84 0.04 3.99
Total Room Absorption, AT (m2
sabins) 6715.06
Table 5: Total room surface absorption (Source: Y. K. Kooi, 2017)

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
𝑅𝑇 =
0.16𝑉
𝐴 𝑇
=
0.16 × 39136.60 𝑚3
6715.06 𝑚2 𝑠𝑎𝑏𝑖𝑛𝑠
= 0.93𝑠 ≈ 0.9𝑠
∴ Thus, the reverberation time calculated is the same as the reverberation time stated.

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.

Figure 27: Panoramic shot of Calvary Convention Centre’s auditorium during a performance
(Source: X. L. Lee, 2017)

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.

An Acoustic Case Study on Calvary Convention Centre Report

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to An Acoustic Case Study on Calvary Convention Centre Report

Similar to An Acoustic Case Study on Calvary Convention Centre Report (20)

More from douglasloon

More from douglasloon (20)

Recently uploaded

Recently uploaded (20)

An Acoustic Case Study on Calvary Convention Centre Report