Auditorium: A Case Study on Acoustic Design Report

Chong Hao Foong
Chung How Cyong
Foo Ji Sun
Tang Fu Hong
Tan Yan Jie
Teh Wei Hong
Teoh Zhe Khai
Thomas Ting Shii Kai
0322343
0324152
0323550
0323092
0323906
0323743
0322905
0323962
Calvary
Convention
Centre
Auditorium :
A Case Study on
Acoustic Design
ARC3413
BUILDING SCIENCE II
MR.
EDWIN'S
GROUP

01
INTRODUCTION 1
1.1 Acknowledgement
1.2 Aim and Objective
1.3 Historical Background
1.4 Site Information
1.5 Drawings
02 METHODOLOGY 7
2.1 Measuring Instruments
2.2 Data Collection Methods
03
ACOUSTICAL PHENOMENON 10
3.1 Acoustic in Architecture
3.2 Sound Intensity
3.3 Reverberation
3.4 Attenuation
3.5 Echoes
3.6 Sound Shadow
3.7 Issue of Acoustic Design Studies
3.8 Acoustical Design of Auditorium
04
ACOUSTICAL ANALYSIS 17
4.1 Auditorium Design Analysis
4.2 Materials and Properties
4.3 Acoustic Treatments and Components
3.4 Audio Equipments
3.5 Noise Source
3.6 Sound Propogation and Related
Phenomenon

05 REVERBERATION TIME 41
5.1 Absorption of Surface
5.2 Calculation of Reverberation Time
06 CONCLUSION 43
6.1 Observation and Conclusion
07 REFERENCES 44
7.1 Citation

1.1 ACKNOWLEDGEMENT
First and foremost, we would like to express our gratitude to our beloved lecturers,
Mr. Azim Sulaiman and Ar. Edwin Chan who guide us throughout this project. They
also put much effort by organising a study trip to Malaysian Philharmonic
Orchestra (MPO) and most importantly they are always willing to answer and solve
our questions patiently. Our tutor, Ar. Edwin Chan also guided us with suggestions
that help to increase the richness of our report. Without any doubt, i would also like
to thank School of Architecture Building and Design (SABD) to provide us a
comfortable platform for discussion and gives us the opportunity to carry out our
research topics. Last but not least, we are thankful for all of our fellow friends and
groupmates that support us both physical and mentally throughout the project.
Building Science II | ARC3413 | 01

1.2 AIM AND OBJECTIVES
The aim and objectives of this report is to provide a concise and well-documented
analysis that can showcase our understanding of acoustical theory of our case
study, Calvary Convention Centre, situated at Bukit Jalil.
1. To study and develop an understanding of auditoriums through their design
layout and judge its influence on the effectiveness of the acoustical design for it's
designated purpose.
2. To study the general acoustical characteristics of an auditorium hall and develop
a good understanding of the physics behind their functions.
3. To be able to produce a well-documented report that surmises our findings and
analysis of our case which can then serve as an example of our accumulated
knowledge of the relationship between acoustics and space.
By observing and analysing the types of acoustical design theories applied in the
auditorium, we are then able to develop a better understanding on the
characteristics of architectural space and how it affects the multiplicity of design
approaches that can be taken for said space to be considered “acoustical efficient”.
It is vital to know how different types of designs and their acoustical treatments
influence the sound efficiency and the overall user experiences.

1.3 HISTORICAL BACKGROUND
The Calvary Convention Centre (CCC) is a distinctive convention centre that is
dedicated to the pursuit of holistic activities. These activities include the hosting of
international and local conventions, services, seminars and creative arts
productions, not to mention the provision of educational, spiritual and vocational
development for the Malaysian public, especially its youth. The 6-storey complex
designed by T.R Hamzah & Yeang Sdn Bhd houses a variety of facilities including
an auditorium, theatrettes and a multi-purpose banquet hall. Located on a 4.9 acre
piece of land in Bukit Jalil, the CCC occupies a total built up area of about 600,000
sq. ft. The massive 5,000 seat auditorium is fan-shaped, suitable for great
audience capacities. Two main trusses support the hall roof, each supported by
two mega columns. Sixty metres of column-free space spans within the auditorium,
providing an unobstructed view of the stage throughout the hall. The auditorium
was designed to be a single-tiered floor allowing unobstructed circulation from the
back of the hall to the stage in front. It has multiple features that allow the
auditorium to be modified to suit different functions and events. The hall is
equipped with built-in structures for the future installation of foldable partitions that
divide the auditorium into three smaller halls that may be used for smaller functions.
The front seats of the halls are retractable so that the space can be used as a
speaker area when needed. The splayed side walls of the fan-shaped hall allow for
greater seating area that is close to the stage, and can also effectively reflect
sound energy to the rear of the hall.

1.4 SITE INFORMATION
Name of Auditorium: Calvary Convention Centre
Location: Jalan Jalil Perkasa 1, Taman Teknologi Malaysia, 57000 Kuala Lumpur,
Wilayah Persekutuan Kuala Lumpur.
Type of Auditorium: Multipurpose Auditorium, Holistic-driven events
Total Built Up Area: 600,000 square feet
Year of Completed: 2013
Total Seats: 5,000 seat auditorium, with upholstered tip-up theatre seat covered of
2,965 square metre and timber padded retractable tip-up seat covered of 420
square metre.
Image 1.4.1 shows the main entrance of Calvary Convention Centre.

2.1 MEASURING INSTRUMENTS
2.1.1 Sound Level Meter
Taylor’s University provided us with a 01dB A-
scale Sound Level Meter for this assignment. 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.
Image 2.1.1 shows the 0.1dB A-scale
sound level meter.
2.1.2 Digital SLR Camera
The Canon EOS 5D Mark IV was the camera we
used for photography and documentation during
the site visit. The spatial layout, features as well
as the acoustical design and fixtures of the
building were mainly recorded and documented
on this camera.
Image 2.1.2 shows the Canon EOS
5D Mark IV.
2.1.3 Smartphone
Personal smartphones were used as secondary
cameras so that the tasks can be easily divided
between the group members. Secondary
cameras allow more pictures from different
angles to be taken as evidence of our study and
for later reference.
Image 2.1.3 shows Iphone X for easy
documentary.

2.1 MEASURING INSTRUMENTS
2.1.4 Laser Distance Measurer
The Bosch laser range finder again supplied by
the University was used to calculate distances
such as the ceiling height in the auditorium. This
tool allowed us to quickly and efficiently conduct
our work without risking our own safety.
Image 2.1.4 shows the Bosch laser
distance measurer.
2.1.5 Measuring Tape
We used a measuring tape to determine some of
the measurements which were missing on the
a r c h i t e c t u r a l d r a w i n g s w e f o u n d . T h e
measurements were also used to determine the
correct scale to be used when plotting the
architectural drawings.
Image 2.1.5 shows 8m long
measuring tape.
2.1.6 Portable Bluetooth Speaker
The loud contrasting sound from the speaker was
used to test the acoustic performance of the
auditorium. A high volume and high frequency
noise was produced from a stationary source as
sound levels were taken from different points in
the hall.
Image 2.1.6 shows the Beats by Dre
bluetooth speaker.

2.2 DATA COLLECTION METHODS
Two site visits were conducted to gather information and obtain the measurements
required. Many meetings were held over a one month period to analyse and
compile the data we obtained. Architectural drawings such as the floor plans and
sections were kindly provided to us by the architects at T.R. Hamzah & Yeang Sdn.
Bhd.
After gaining permission from the convention centre’s management, we
conducted our first site visit on the 7th April 2018.The auditorium was
unoccupied at the time which gave us the freedom to carry out our analysis
unhindered and gather as much acoustical data as we can. Besides that, we were
guided and supervised by Mr David, the assistant sound engineer throughout our
visit who was very kind in answering any questions and inquiries about the site.
A second site visit followed the next sunday during the church service. We were
allowed to join in the service and experience the acoustics while the hall was
occupied. We sat in different locations to gain a better perspective and correlated
this experience with the data we collected from the first site visit. However, we
were not permitted to take any measurements at any point during the service.
Using the tools that were described above, we gathered all the data that was
required to the best of our ability, as well as observing and recording the overall
acoustical design, layout, sound proofing methods and materials as well as notable
acoustic components.

3.1 ACOUSTICAL IN ARCHITECTURE
Acoustics may be described as the science of sounds and vibration. Architectural
acoustics refers to the relationship between sound produced in a space and
its listeners, of particular concern in the design of concert halls and
auditoriums. Good sound can be achieved by managing the transmission and
control of airborne and impact sound within the design of a building. There are
many aspects to consider in architecture acoustics such as the building skin
envelope, interspace noise control and interior space acoustics.
Good acoustic design takes into account such issues as reverberation time; sound
absorption of the finish materials; echoes; acoustic shadows; sound intimacy,
texture, and blend; and external noise. Architectural modifications may act as
focusing elements to improve sound quality. Typical sound paths such as wall
partitions, ceiling panels and floor/ceiling assemblies are the primary elements that
designers use to control the sound levels in a building. Technical design solutions
need to be implemented to limit and control the noise transmission from one
building space to another to ensure space functionality and speech privacy.
Surface materials are also a very important factor to the overall acoustic quality of
a building. Interior space acoustics is the science of controlling a room's surfaces
based on sound absorbing and reflecting properties. Reflective surfaces can be
angled and coordinated to provide good coverage of sound for a listener in a
concert hall or theatre.

3.2 SOUND INTENSITY
Sound intensity is defined as the sound power per unit area. The energy of
sound is determined by measuring the intensity of sound waves that are produced
by vibrating objects. The pressure variation, amplitude, is proportional to the
intensity, therefore it is safe to say that the larger the sound wave oscillation, the
more intense the sound will be. Although the units for sound intensity are
technically watts per meter squared, it is much more common for it to be referred
to as decibels, dB. A decibel is a ratio of the observed amplitude, or intensity
level to a reference, which is 0 dB.
Since audible sound consists of pressure waves, one of the ways to quantify the
sound is to state the amount of pressure variation relative to atmospheric pressure
caused by the sound. Because of the great sensitivity of human hearing, the
threshold of hearing corresponds to a pressure variation less than a billionth of
atmospheric pressure. The standard threshold of hearing can be stated in terms of
pressure and the sound intensity in decibels can be expressed in terms of the
sound pressure.
Decibels measure the ratio of a given intensity I to the threshold of hearing
intensity, so that this threshold takes the value 0 decibels (0 dB). To assess sound
loudness, as distinct from an objective intensity measurement, the sensitivity of the
ear must be factored in. The dynamic range of human hearing and sound intensity
spans from 10 W/m² to 1 W/m². This span makes absolute values for sound
intensity impractical in normal use. A more convenient way to express sound
intensity is the relative logarithmic decibel scale with reference to the lowest
human hearable sound -10 W/m² (0 dB).
Sound Intensity Level can be expressed as:
LI = 10 log (I / Io)
-12
-12

3.3 REVERBERATION
Reverberation is the collection of reflected sounds from the surfaces in an
enclosure like an auditorium. It is a desirable property of auditoriums to the
extent that it helps to overcome the inverse square law dropoff of sound intensity in
the enclosure. However, if it is excessive, it makes the sounds run together with
loss of articulation - the sound becomes muddy, garbled. To quantitatively
characterize the reverberation, the parameter called the reverberation time is used.
The reverberant sound in an auditorium dies away with time as the sound energy
is absorbed by multiple interactions with the surfaces of the room. In a more
reflective room, it will take longer for the sound to die away and the room is said to
be 'live'. But the time for reverberation to completely die away will depend upon
how loud the sound was to begin with, and will also depend upon the acuity of the
hearing of the observer. In order to provide a reproducible parameter, a standard
reverberation time has been defined as the time for the sound to die away to a
level 60 decibels below its original level. The reverberation time can be modeled to
permit an approximate calculation.
-
Sabine Formula:
RT = 0.16V
AT
where:
RT = reverberation time (sec)
V = volume of the room (cu.m)
AT = total absorption of room
surfaces (sq.m sabins)

3.4 ATTENUATION
Sound attenuation is defined as the loss of energy from sound waves.
Basically, attenuation is a damping of sound, an interruption that diminishes the
volume and quality of the sound wave. Sound waves interact with different objects
in different ways and sound quality is reduced more by some objects than others.
Sound is created by oscillation of waves. Therefore, that means that attenuation,
the damping of sound, comes from interrupting these waves. Sound is energy, so
in a perfect environment, the oscillation of sound would only lessen naturally over
space as the energy was depleted. This further weakening results from scattering
and absorption. Scattering is the reflection of the sound in directions other than its
original direction of propagation. Absorption is the conversion of the sound energy
to other forms of energy. The combined effect of scattering and absorption is
called attenuation.
3.5 ECHOES
Echo is a distinct, reflected sound wave from a surface. A reflected sound can
be heard separately from the original sound if the sound source is closer to the
receiver while the reflecting hard surface is sufficiently far from receiver. Such
reflected sound is called an echo. Flutter echo is an energy that’s trapped between
two surfaces and the angle that the sound enters between the two surfaces. This
phenomenon occurs when a short burst of sound is produced between parallel
sound-reflective surfaces. Flutter echoes can be reduced by incorporating more
non-parallel surfaces into the building design.

3.6 SOUND SHADOW
A sound shadow is a region of relative silence behind a screen opaque to
sound waves. Disruption of the waves due to obstructions and sound barriers or
phenomena such as wind currents creates an area where sound waves fail to
propagate. A short-distance acoustic shadow usually occurs behind a building or a
sound barrier. Due to diffraction around the object, it will not be completely silent in
the sound shadow. The amplitude of the sound can be reduced considerably,
however, depending on the additional distance the sound has to travel between
source and receiver.
3.7 ISSUES OF ACOUSTICAL DESIGN STRATEGIES
Acoustical conditions in an enclosed space is achieved when there is clarity of
sound in every part of the occupied space. For this to occur, the sound should rise
to a suitable intensity everywhere with no echoes or distortion of the original
sound, and with a correct reverberation time. Therefore, it is important to
identify, analyze and correct any defects that may affect the acoustics within a
building. Acoustical reflectors or diffusers evenly distribute the sound within a
building to provide a balanced sound quality throughout the space. It also helps to
improve the clarity and sound quality for speeches and music productions in
auditoriums by providing a wider sound coverage.

3.8 ACOUSTICAL DESIGN FOR AUDITORIUM
3.8.1 SELECTION OF THE SITE
An ideal site should keep distance from any major sources of noise such as
airports, highways and construction sites. The surrounding buildings and
topography may also act as obstructions to sound waves and affect the overall
acoustics of the building.
3.8.2 VOLUME
The size of the auditorium should remain optimum: small halls leads to irregular
distribution of sound because of the formation of standing waves. On the other
which may large halls create a weaker intensity and longer reverberation time
result in serious issues.
3.8.3 SHAPE AND FORM
The shape of the building is among the most important factors that affect the
acoustic efficiency of a hall or auditorium. Side walls and roofs in the auditorium
create sound reflections of varying degrees depending on the shape and angle of
the walls. Therefore, architects must conduct prior research and planning to
determine the most suitable design for their desired acoustic effects. In certain
situations, splayed side walls might be preferable to parallel walls to reflect sound
energy to the rear of the hall. Concave curved surfaces on ceilings or walls also
help to concentrate the sound intensity in a specific region.
3.8.4 USE OF ABSORBENTS
Sound absorbents take in sound energy when sound waves are encountered, as
opposed to reflecting the energy. Sound absorption is of particular interest in
soundproofing. Soundproofing aims to absorb as much sound energy as
possible converting it into heat or transmitting it away from a certain
location.

3.8 ACOUSTICAL DESIGN FOR AUDITORIUM
3.8.5 REVERBERATION
The reverberation time is the time for the sound to die away after the sound source
ceases, but that of course depends on the intensity of the sound. To achieve the
desired acoustic effects, the reverberation time in the auditorium should be
perfectly balanced. The optimum reverberation time for an auditorium or room of
course depends upon its intended use. Around 2 seconds is desirable for a
medium-sized, general purpose auditorium that is to be used for both speech and
music. The reverberation time is strongly influenced by the absorption
coefficients of the surfaces but also depends upon the volume of the room,
bigger rooms produce longer reverberation times.
3.8.6 ECHELEON EFFECT
Acoustic waves are reflected by walls or other hard surfaces, such as staircases
and hand railings to create a reflection of sound that arrives at the listener with a
delay after the direct sound. Usually in auditoriums this phenomenon is
undesirable as it affects the clarity of the original sound.

4.1 AUDITORIUM DESIGN ANALYSIS
4.1.1 AUDITORIUM SHAPE AND MASSING
The shape of the auditorium is a unique variation of the horseshoe-type hall with
a combination of both curved and flat walls. The walls are flat at the front of the
hall but gradually curve into a concave shape as it leads to the rear. The concave
shape of the walls reflect the sound waves back into areas with less exposure to
the sound source. However, the wall parallel to the stage at the back of the hall is
flat instead of curved like in most horseshoe-type auditoriums.
Image 4.1.1 shows the horseshoe-type hall plan of CCC auditorium.

4.1.2 VOLUME
The optimum size of the auditorium depends on the function of the hall and
the audience capacity. Larger volumes generally produce better acoustics for
music productions as the reverberation time would be longer. However, longer
reverberation times are unsuitable for speakers areas as the voices will sound
murky and unclear. Therefore, it is important to identify the most suitable volume to
satisfy the specific needs of the auditorium. Although the CCC auditorium is
built to accomodate a large audience capacity, the sound absorbent
materials effectively brought down the reverberation time to 0.9 seconds
which is suitable for speeches.
39136.60m³
Image 4.1.2 shows the volume of the auditorium of 39136.60m³ with 0.9s constant reverberation time.

4.1.3 LEVELLING OF STAGES AND SEATS
Correct levelling of the auditorium seats ensures that sound waves reach all the
occupants of the auditorium without obstruction. The seats configuration of the
CCC auditorium is very effective in bridging the relationship between the audience
and the speaker on the stage. Raked seats increases the volume and clarity of
sound especially for audience members sitting near the back. This is due to the
elimination of any interruption of sound waves caused by diffusion or absorption of
the waves by obstructions.
Image 4.1.3 shows the seat arrangement of CCC auditorium to
ensure optimal sound travel to all audiences.

4.1.4 SEATING ARRANGEMENT
The seating arrangement in the auditorium is in a fan-shaped configuration to
allow greater seating area that is closer to the stage. This allows louder and
clearer sound quality to be heard throughout the hall. Since sound travels in
spherical waves, the fan-shaped configuration succeeds in achieving the most
effective acoustic quality. This configuration also decreases the chance of sound
waves being affected by obstructions as compared to shoebox type halls.
Image 4.1.4 shows the fan-shaped seat arrangement.

4.1.5 LAYOUT OF BOUNDARY SURFACE
The auditorium implements a combination of concave shaped and stepped
ceiling systems that reflect the sound back down to the audience. The concave
shape also helps concentrate the sound intensity and increase the volume of
the sound as it travels towards the audience. Flutter echoes are noticeable on
stage as the ceiling is parallel to the floor.
Image 4.1.5 shows the expected sound reflection from ceiling reflector panels to all audiences.

4.2 MATERIALS AND PROPERTIES
4.2.1 INTERIOR MATERIAL NOISE REDUCTION COEFFICIENT
The Calvary Convention Centre implements a wide range of materials to achieve
the desired acoustic quality. The materials can be divided into absorbent or
reflector, depending on their Noise Reduction Coefficient (NRC) rating, where
the most reflective is 0 and the most absorbent is 1. In order to achieve the desired
level of reverberation time, designers have to balance their choice of materials and
using the NRC ratings, calculate the reverberation time.
Material Photo
Absorption Coefficient (α)
125Hz 500Hz 1000Hz
Thick Piled Carpet,
Heavy on Reinforced
Concrete
0.02 0.55 0.37
Timber Flooring
On Joists
0.15 0.10 0.07
Heavy Curtain,
Hung in Fold Against
Solid Wall
0.14 0.55 0.72
Rock Wool 30mm,
200 kg/m3 over
300mm Air Gap
0.15 0.85 0.90
Table 4.2.1A shows the list of materials and their properties.

Material Photo
Absorption Coefficient (α)
125Hz 500Hz 1000Hz
Acoustic Timber
Board
0.18 0.42 0.59
Plywood, Hardwood
Panels over 25mm
Airspace
0.14 0.06 0.08
Plasterboard on
Battens,
18mm Airspace
0.30 0.15 0.05
6mm
Panel Glass 0.18 0.04 0.03
Upholstered Tip-Up
Theatre Seat
0.33 0.64 0.71
Timber Padded
Retractable
Tip-Up Seat
0.08 0.15 0.00
Table 4.2.1B shows the list of materials and their properties.

Thick Piled Carpet,Heavy on Reinforced Concrete
Timber Padded Retractable Tip-Up Seat
Plasterboard on Battens, 18mm Airspace
Rock Wool 30mm, 200 kg/m3 over 300mm Air Gap
Upholstered Tip-Up Theatre Seat
Timber Floor on Joists
Heavy Curtain, Hung in Fold Against Solid Wall
LEGEND
Image 4.2.1A shows the indication of materials
on floor plan.
Image 4.2.1B shows the indication of materials on section.
Rock Wool 30mm, 200 kg/m3
over 300mm Air Gap
Acoustic Timber Board Heavy Curtain, Hung in
Fold Against Solid Wall
Plasterboard on Battens,
18mm Airspace
LEGEND

4.3 ACOUSTICAL TREATMENTS AND COMPONENTS
4.3.1 STAGE FLOORING
The stage uses timber flooring to reduce the noise transmission to tolerable
levels. An acoustic layer is usually laid under the timber veneer flooring to absorb
the sound waves to a certain degree. The layer reduces vibrations of lower sound
frequencies to prevent the vibration of slabs and walls by lower sound frequencies.
The depth of the floor slab and the perimeter of the floor affects the absorption of
low frequency. This occurs because sound waves have the ability to travel through
floors and walls into adjacent spaces.
Image 4.3.1A shows the timber flooring
of the CCC stage.
An acoustic underlayment material on timber veneer floor finishes usually cause a
sound attenuation of about 10dB to 20dB. It is able to effectively absorb the
sound produced by the sound of footsteps and moving equipment while giving a
sense of solidity to the stage floor. The acoustic underlay is fixed to the sub-floors
of the timber veneer flooring.
Image 4.3.1C shows the construction detail of stage floor.
Laminated Finishes
Veneer Timber
Acoustical Underlayment Material
Concrete Slab
Image 4.3.1B shows the indication of
timber flooring on floor plan.

4.3.2 CARPET FLOORING
There are two main types of noise that are relevant; the first being the higher
frequency noise coming from music, singing and speech. The second type of noise
refers to lighter, lower frequency noises such as footsteps of people walking
around and also the sound that is produced by the subwoofers and speakers in the
speaker system. Thick carpeted flooring contributes to sound absorption. Carpet is
an outstanding sound absorber which serves as an acoustical aid, as well as a
floor cover. Carpet absorbs airborne noise as efficiently as other specialised
acoustical materials. A rubber underlay further improves absorption. Carpet is also
wrapped around all the steps along the aisles of the auditorium to reduce the
noise produced by the footsteps of people walking up and down.
Image 4.3.2A shows the carpet used
in CCC auditorium.
Timber Veneer
Rubber Layer
Concrete
Auditorium Floor
Image 4.3.2C shows the construction
detail of floor.
carpet flooring on floor plan.

4.3.3 WALL PANEL
The walls of the auditorium feature a concave shape - a form that is
advantageous when used in the context of our building. Concave surfaces have
the tendency to reflect and concentrate sound waves to the centre of its
projection, such as the seating areas in the case of our auditorium. The rear wall
is flat and covered with absorptive wall panels which not only reduces the
reflection of sound but also absorbs the sound waves after they reach the wall to
prevent a second delayed wave or echo from occurring. The surface of the wall
panelling is the fabric, followed by the sponge that functions as a porous material
that absorbs high frequency sounds. The wall is finished with plywood and
rockwool, which is useful in absorbing the low frequency sound waves that hit
the wall.
Image 4.3.3A shows the wall panel finished by
rockwool.
wall panel on floor plan.

4.3.4 GYPSUM BOARD CEILING
The auditorium ceiling is another important factor affecting sound isolation. Ceiling
panels are made of gypsum board as their smooth surfaces help in sound
reflection. They also provide for acoustical intimacy, atmosphere, and
strengthens the overall sound quality. Suspended from the ceiling to provide
short delayed, reflective sound energy, the reflector panels can provide the
stepped ceiling shape that are crucial to avoid reverberation.
Image 4.3.4A shows the gypsum board used by CCC
auditorium.
gypsum board on call-out section.

4.3.5 SEATING
Timber upholstered chairs are used in the CCC to provide seating for its 5,000
capacity audience. The cushioned chairs not only provide viewers with comfort, it
is also an excellent sound absorbent, which helps reduce the overall
reverberation time in the auditorium. The hall is not only aided with acoustical
taming through the room surfaces such as the wall and ceiling, but additional
sound control is also present in the form of the padded seats. It adds to the
acoustic quality of the auditorium and allows the space to achieve a similar quality
of sound whether the auditorium is filled to partial or maximum capacity.
Image 4.3.5A shows the seating type of CCC auditorium.
uphosltered seating on floor plan.
Image 4.3.5C shows the indication of padded
seating on floor plan.

4.4 AUDIO EQUIPMENTS
L-Acoustics provided the three different types of speakers used in the auditorium.
The ARCS Focus is a line array loudspeaker system with the purpose of
projecting sound to the back of the hall. The sound from the bottommost speaker
projecting towards the frontmost audience is slightly delayed to make up for the
time taken for the sound to reach the back of the hall. The second speaker, the
Series 108P targets the front four seating rows. This is because the front four
rows are out of range of the ARCS Focus speakers, thus the 108P is used to
compensate for that matter. Lastly, the four P-Series 112P speakers located on
the stage are used as stage monitors. Stage performers rely on stage monitors
to listen to other instruments as well as their own voices so that they could make
vocal adjustments during the performance.
Image 4.4 shows the sound transmission of various types of speakers.
L-Acoustics ARC Focus L-Acoustics P-series 108P L-Acoustics P-series 112P
LEGEND

4.4 AUDIO EQUIPMENTS
Type of Speakers Dimension Weight Sound
Specifications
L-Acoustics
P-series 112P
390mm x 410 mm
x 540mm
32kg
1 . U s a b l e s y s t e m .
bandwidth of 50Hz to 20
kHz (-10 dB). Generates
conical directivity (-6 dB
points) of 90°
2. Maximum SPL (Sound
Pressure Level), measured
at 1m under free field
conditions is 133 dB.
3. Wedge-shaped design
with a fixed angle setting of
30°
L-Acoustics
ARCS Focus
365mm x 252mm x
759mm
38kg
1 . U s a b l e s y s t e m
bandwidth of 55Hz to 20
kHz (-10 dB). Generates a
symmetrical horizontal
directivity of 150 and a
s y m m e t r i c a l v e r t i c a l
coverage angle of 90 (-6
dB).
2. Maximum peak SPL.
measured at 1m under free
field condition is 139dB.
L-Acoustics
P-series 108P
299mm x 250mm
x 421mm
13kg
1 . U s a b l e s y s t e m
bandwidth of 55 Hz to
20kHz (-10dB). Generates
a conical directivity (-6dB)
of 100°.
2. Maximum peak SPL,
measured at 1m under free
field condition is 125 dB.
Table 4.4 shows the type of speakers and their sound specifications..

4.5 NOISE SOURCE
4.5.1 EXTERNAL NOISES
The external noise that affect the user experience in the auditorium is the event
that located at entrance downstairs. The event uses sound amplifier devices to
amplify the voices hence create noises penetrate into the auditorium. The lobby of
the auditorium before entering the spaces has sitting area and people would gather
around it creates some external noises as well.
Image 4.5.1A shows the event organised at the
entrance of CCC auditorium.
LEGEND
Image 4.5.1B shows the closing
and opening of door.
Opening and closing of the doors and conversation taking place are the main
origin of noise outside the Calvary Church Auditorium. The noise from the waiting
and reception lobby enters the auditorium through the doors as there is no sound-
proofing. However, a sound lock is present between the inner and outer door at the
main entrance of the auditorium which serves to trap the sound waves, bringing
the noise level from the outside down to a low 25dB for the seats next to the door.

4.5 NOISE SOURCE
4.5.1 EXTERNAL NOISES
The basement carpark of Calvary Convention Centre is located right beneath the
auditorium. The basement carpark would potentially cause unwanted noise from
cars moving about, thus a thick layer of insulation is applied between the
ceiling of the carpark and the air ducts beneath the auditorium.
LEGEND
Image 4.5.1C shows the sound insulation lining between air-conditioning duct and carpark ceiling.

4.5 NOISE SOURCE
4.5.2 INTERNAL NOISES
Air conditioning is the main internal noise source as the large auditorium size
requires the air conditioning to run at full fan speed. 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.
LEGEND
Image 4.5.2A shows the air-conditioning flow on the section.

4.5 NOISE SOURCE
4.5.2 INTERNAL NOISES
Thus, the solution is to invert the air-conditioning system by transmitting cool air
upwards rather than downwards. 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.
LEGEND
Image 4.5.2B shows air vents underneath the auditorium seats.
Image 4.5.2C shows the detailed section of the ventilation system under the floor.

4.6 SOUND PROPAGATION AND RELATED PHENOMENON
4.6.1 SOUND CONCENTRATION
The measurement of the sound intensity level (SIL) from the sound source, shows
that a distinct sound concentration zone can be found at the centre-back of the
auditorium.
61db
60db
62db
54db
51db
59db
55db
53db
51db
Image 4.6.1A shows the SIL measurement of CCC auditorium.

4.6.1 SOUND CONCENTRATION
Despite the coverage of acoustic paneling on virtually every wall surface in the
auditorium, the curvilinear form of the auditorium still has a detrimental acoustic
quality that creates auditory foci within, amplifying sound in specific areas. This
sound concentration zone is created by overly excessive usage of sound
absorbent materials; in this case, materials that have a sound absorbency
coefficient lower than 0.1.
Image 4.6.1B shows the sound reflection diagram with materials.
Absorbant
Absorbancy coefficient at
500Hz > 0.1

4.6.2 SOUND REFLECTION
In order to make the use of sound more efficient, it is necessary for the sound to
be reflected back towards the audience. However. the amount of sound reflected,
with the added design of these reflections, must be carefully controlled to minimize
the creation of echoes.
A DIRECT SOUND
REFLECTED
SOUND
Image 4.6.2A shows sound propagation towards subject at Point A.

4.6.2 SOUND REFLECTION
Ceiling reflectors serve to reflect sound effectively back to the audience.
Therefore, the rest of the auditorium must be covered with sound absorbent
materials to minimize the resultant reflected sound, making it almost indiscernible.
B
DIRECT SOUND
REFLECTED
SOUND
C
DIRECT SOUND
REFLECTED
SOUND
Image 4.6.2B shows sound propagation towards subject at Point B.
Image 4.6.2C shows sound propagation towards subject at Point C.

TIME DELAY
= (17m + 31m) - 40m
0.34
= 8m
0.34
= 23.5ms
TIME DELAY
= (16m + 18m) - 21m
0.34
= 13m
0.34
= 38.2ms
4.6.3 ECHOES AND TIME DELAY
An echo is distinctly different from a reverberation as it is a monotonous repetition
of the original sound that reaches subject’s ear in less than 0.1 second. Echo can
also be defined as the nature of the programme influences the desired sound
delay period. For speech-based auditorium, any sound delay above 40ms will be
considered as an echo.
Image 4.6.3A shows a time delay of 38.2ms in Point A.
DIRECT SOUND
16m 18m
21m
#
Image 4.6.3B shows a time delay of 23.5ms in Point B.
17m 31m
40m
16m
45m
56m
DIRECT SOUND
Image 4.6.3C shows a time delay of 17.6ms in Point C.
#
TIME DELAY
= (16m + 45m) - 56m
0.34
= 6m
0.34
= 17.6ms#
A
B
C
DIRECT SOUND

5.1 ABSORPTION OF SURFACE
Materials Area (m2)
Absorption
Coefficient, α
(Sabins) (500Hz)
Absorption of
Surface, as (m2
Sabins)
Thick Piled Carpet, Heavy
on Reinforced Concrete
3295 0.50 1647.50
Timber Floor on Joists 115 0.10 11.50
Heavy Curtain, Hung in Fold
Against Solid Wall
465 0.55 255.75
Rock Wool 30mm, 200
kg/m3 over 300mm Air Gap
1675 0.85 1507.50
Acoustic Timber Board 2480 0.42 1041.60
Plywood, Hardwood Panels
over 25mm Airspace
220 0.15 33
Plasterboard on Battens,
18mm Airspace
2480 0.15 372
6mm Panel Glass 100 0.03 3
Upholstered Tip-Up
Theatre Seat
2965 0.64 1897.60
Timber Padded Retractable
Tip-Up Seat
420 0.15 63
Total Room Absorption, AT (m2 Sabins) 6832.45
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.
Formula to calculate absorption of a surface as following:
Absorption of a Surface = Surface Area (m2) x Absorption Coefficient, α (Sabins)
As = S x αs

5.2 CALCULATION OF REVERBERATION TIME
As told by the architects from T.R. Hamzah and Yeang Sdn. Bhd., the reverberation
time of Calvary Convention Centre is approximately 0.9s.
Sabine Formula:
RT = 0.16V
AT
where:
RT = reverberation time (sec)
V = volume of the room (cu.m)
AT = total absorption of room
surfaces (sq.m sabins)
V = Volume, m3 = 39136.60 m3
AT = Total Room Absorption, m2 sabins
= 6832.45 m2 sabins
RT = 0.16V
AT
= 0.16 (39136.60)
6832.45
= 0.91 ≈ 0.9s#

6.1 OBSERVATION AND CONCLUSION
As a conclusion, based on our accumulated findings and subsequent analysis,
Calvary Convention Centre has the ability to cater to demands for both speeches
and musical or theatrical performances. A multipurpose auditorium with an
audience capacity of 5,000 occupants, the CCC is situated in an area with
relatively loud surroundings, located right next to a busy highway and a few
residential buildings.
Isolation from outside noise through air gaps and the restructuring of
systems is employed to reduce the transmission of sound from external and
internal sources. Choosing the most suitable materials aids the overall noise
control of the building and creates a conducive environment for event hosting.
Consideration was also taken on the type and position of speakers in the hall
as a vital factor on the overall acoustical control achieved. The designers of the
Calvary Convention Centre have successfully achieved their desired optimum
reverberation time of 0.9s, perfect for a speech-based auditorium, while still being
suitable for musical performances which were a regular feature in the auditorium.
Through working on this project, we were able to experience and understand the
complications and processes behind acoustics design in the context of our site, the
Calvary Convention Centre. There were many factors that come to play when it
comes to building acoustics which we have identified such as the shape and form,
surface materials, seat levelling and etc. We learned to appreciate the importance
of acoustics in a building design, and how it affects the function, atmosphere and
efficiency of a space.

7.1 CITATION
1. Building Design + Construction. (2015). Enhanced acoustical design, from
https://www.bdcnetwork.com/enhanced-acoustical-design.
2. Hardy, H. (2006). Building Type Basics for Performing Arts Facilities. Hoboken,
N.J. : J. Wiley.
3. Inc., T. (2005). Auditorium Design: Complete Intro Guide | Theatre Solutions
I n c . . [ o n l i n e ] T h e a t r e S o l u t i o n s I n c . , f r o m
http://www.theatresolutions.net/auditorium-design/
4. Kwok, A. G.& Grondzik, W. T. (2015). Mechanical and electrical equipment for
buildings (12th ed.). Hoboken, NJ: Wiley.
5. Learning, L. (n.d.) Sound Intensity and Sound Level. Retrieved September 29,
2017, from https://courses.lumenlearning.com/physics/chapter/17-3-sound-
intensity-and-sound-level
6. NetWell. (2016). Auditorium Acoustic Soundproofing Panels | NetWell, from
https://www.controlnoise.com/treatment/auditorium/
7. Marialorenalehman.com. (2013). 7 Design Tips for Best Architectural Acoustics,
from https://marialorenalehman.com/post/7-design-tips-for-best-architectural-
acoustics [Accessed 7 May 2018].
8. McMullan, R. (2012). Environmental science in building (5th ed.). Houndmills,
Basingstoke, England: Palgrave Macmillan.
9. Moore, J. (1961). Design for Good Acoustics.London: Architectural Press.
10.Schmolke, B. (2011). Theatres and Concert Halls: Construction and Design
Manual. Singapore: Page One.
11.Shuai, Y. (2011). Green Office Building: Acoustic Installation, Natural Ventilation,
Green Roof, Sustainable Architecture. Hong Kong: Hong Kong Polytechnic
International Pub. Ltd.
12.Sound Absorption Coefficients. (n.d.). Retrieved April 25, 2017, from
https://www.acousticalsurfaces.com/acoustic_IOI/101_13.htm
13.Sound Pressure: Definitions, Terms, Units and Measurement. (n.d.). Retrieved
April 25, 2017, from http://www.acoustic-glossary.co.uk/sound-pressure.htm
14.S o u n d I n t e n s i t y ( n . d . ) . R e t r i e v e d S e p t e m b e r 2 9 , 2 0 1 7 , f r o m
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/intens.html
15.S o u n d S h a d o w ( n . d . ) . R e t r i e v e d S e p t e m b e r 2 9 , 2 0 1 7 , f r o m
https://www.sfu.ca/sonic-studio/handbook/Sound Shadow.html

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