Building science ii report

[ ARC 3413 / BLD61303 ]
PROJECT 1 :
AUDITORIUM - A CASE STUDY ON ACOUSTIC DESIGN

TABLE OF CONTENT
PG
1 Introduction
1.1 Overview 2
1.2 About 3
1.3 Context and Location 4
1.4 History of Cempaka Sari Auditorium 5
2 Methodology
2.1 Data Collection Method 7
2.2 Measuring and Recording Equipment 7-8
3 Architectural Drawings and Photos
3.1 Architectural Drawings 10-12
3.2 Photos 13
4 Acoustical Analysis
4.1 Shape and Form of Auditorium 17-18
4.2 Levelling and Arrangement of Seats 19-20
4.3 Sound Attenuation 21
4.4 Sound Reinforcement System 23
4.4.1 Introduction 23
4.4.2 System Components 23-26
4.4.3 Advantages and Disadvantages 27
4.5 Materiality and Sound Absorption Coefﬁcient 28
4.5.1 Acoustical Treatment and Components 28
4.5.1.1 Walls 28-33
4.5.1.2 Floorings 34-37
4.5.1.3 Ceilings 39-39
4.5.1.4 Stage Curtains 40-41
4.5.1.5 Seatings 42-43
4.5.1.6 Backstage 44-45
4.5.2 Material Tabulation of Cempaka Sari Auditorium 46-47
4.6 Sound Propagation 48
4.6.2 Sound Reﬂection and Diffusion 49-53
4.6.3 Sound Delay and Echo 54-56

PG
4.7 Sound Defects 57
4.7.1 Sound Shadow 57
4.7.1.1 Consideration Taken to Eliminate Sound Shadow 58
4.7.2 Flutter Echoes 59
4.7.2.1 Consideration Taken to Eliminate Flutter Echoes 59-60
4.8 Noise Intrusion 61
4.8.2 Effects of Noise 61
4.8.3 Noise Analysis 62
4.8.4 Background Noise 63-64
4.8.5 Noise Source 65-69
4.8.6 Noise Control 70-72
5 Reverberation Time
5.1 Introduction 74
5.2 Reverberation Time Calculation 74
5.2.1 Volume and Floor Area 75
5.2.2 Area of Floor Materials 76
5.2.3 Area of Wall Materials 77
5.2.4 Area of Other Materials 78-79
5.2.5 Reverberation Time for Cempaka Sari Auditorium 80
6 Conclusion 82-83
7 References 85-87

1.1 Overview
1.2 About
1.3 Context and Location
1.4 History of Cempaka Sari Auditorium

Name: Cempaka Sari Auditorium
Address: Kompleks Perbadanan Putrajaya, 24,
Persiaran Perdana, Presint 3,
62675, Putrajaya.
Type of Auditorium: Multi-purpose Hall
Year of construction: 2001
Year of completion: July, 2005
Seating capacity: 566 seating
Built-up area: 1046.76m2
Volume: 8124.82m3
2

The auditorium is designed as a low-rise medium sized buildings, it is to respond to the
surrounding buildings or developments. Pedestrians links have a system connection between
buildings to another buildings. Another pedestrians links are the boutique retail spaces on the
ground floor of each component. The ceremonial qualities of the Dataran Putrajaya are reflected
in the design of the network of arcades on the Boulevard.
The concept of the conference facilities and auditorium is a “Volume within a box”. The
auditorium has a feature of floating lanterns and a single suspended ‘pebble’ that portray the
meaning of “within a box”.
The auditorium are the main public events area within Putrajaya,.
The design requirement of the auditorium:
1. User friendly approach to all areas and overall building use
2. Integrated I.T. Network systems with facilities for video conferencing and public
information terminals
3. Integrated pedestrian linkages below and above ground levels to all areas of the
development via Galleria
4. Environmentally conscious design with landscaping integrated in the design
5. Comfortable viewing, acoustic and lighting environments suitable for concerts and shows
6. Variable stage system to allow for different use in events and shows
3

The Cempaka Sari Auditorium is located at Precinct 3, Putrajaya, just next to Kompleks
Perbadanan Putrajaya and nearby Masjid Tuanku Zainal Abidin / Masjid Besi and the Palace of
Justice.
4

In the 1980s, Malaysia began search for a new Federal Government administrative centre to
provide a balance development away from Kuala Lumpur. Prang Besar, today’s Putrajaya was
chosen. The word ‘Putrajaya’ was named after the country’s ﬁrst Prime Minister, YTM Tunku
Abdul Rahman Putra al-Haj in 1995. The project of Putrajaya has began in August 1995 with a
target of completion in 2010. The project was designed and constructed by Malaysia companies
and mostly use materials from local. By 2005, most of the government agencies have moved in.
However, the project of the auditorium has started in 2001. The auditorium has named after a
place in the history of classical Malay Literature. The building is designed by aQidea Architect,
and was awarded PAM winning entry for Swissama Structural Steel Award 2005. When the
auditorium block located in the Northern wing of the Putrajaya Corporation Complex in Precinct 3
and completed by the middle of July 2005, a boost has given to the performing arts in Malaysia.
Since there are various universities such as Heriot-Watt University, UNIMY, MMU and etc in the
vicinity, the auditorium serves as a venue for its development and also encourage people who are
living and working in Putrajaya to be aware and appreciate various forms of the performing arts
(eg. Vishu Sadhya and Cultural Show by Putramas and Amma 2019).
5

2.1 Data Collection Method
2.2 Measuring and Recording Equipment

2.1 Data Collection Method
We arranged a site visit to the auditorium that we have chosen, and printed out architectural
drawings for on-site data recording. Before the site visit, we get the tools mentioned below to
measure the sound intensity level and the dimensions of the auditorium. After we have collected
the data on-site then we analysed its acoustic properties.
2.2 Measuring and Recording Equipment
Digital sound meter is used for acoustic measurements. It is typically measured in decibels
(dB), which is a logarithmic unit. We have used sound level meter to measure the
background noise level and sound intensity level at different positions.
2.2.1 Digital Sound Level Meter
The DSLR camera is used to capture photographs of the buildings materials and the views
of the interior space of auditorium for recording and analysis purpose.
2.2.2 Digital Single Lens Reﬂex Camera (DSLR)
7

The laser measuring tool is used to measure the distance from sound source to the sound
level meter. It also uses to measure the height of the auditorium.
Smartphones are use to produce a consistent single frequency sound from the stage for the
measurement of sound intensity level and record at a various points in the auditorium. It
also utilises for as an alternative to capture photographs.
2.2.3 Smartphone
The measuring tape is used to measure the dimensions of the materials and auditorium.
2.2.4 Measuring Tape
2.2.5 Laser Distance Meter
8

3.1 Architectural Drawings
3.2 Photos

Level 3 Plan | 1:500
1
1 Backstage 2 Service Core
2
3 Lobby
4 VIP Lounge
3
4
A A’
B
B’
10

Auditorium Plan | 1:500
1
1 Performance Stage 2 VIP seating area
2
3 Backstage
3
4 Control room
4
11
A A’
B
B’

Section B-B | 1:500
1 Auditorium 2 VIP Lounge 3 Lobby
4 Backstage
1
2
3
4
1 Auditorium 2 Service Core 3 Lobby
Section A-A | 1:500
1
3
2 2
12

4.1 Shape and Form of Auditorium
4.2 Levelling and Arrangement of Seats
4.3 Sound Attenuation
4.4 Sound Reinforcement System
4.4.1 Introduction
4.4.2 System Components
4.4.3 Advantages and Disadvantages

4.5 Materiality and Sound Absorption Coefﬁcient
4.5.1 Acoustical Treatment and Components
4.5.1.1 Walls
4.5.1.2 Floorings
4.5.1.3 Ceilings
4.5.1.4 Stage Curtains
4.5.1.5 Seatings
4.5.1.6 Backstage
4.5.2 Material Tabulation
4.6 Sound Propagation
4.6.1 Introduction
4.6.2 Sound Reﬂection and Diffusion
4.6.3 Sound Delay and Echo

4.7 Sound Defects
4.7.1 Sound Shadow
4.7.2 Flutter Echoes
4.8 Noise Intrusion
4.8.1 Introduction
4.8.2 Effects of Noise
4.8.3 Noise Analysis
4.8.4 Background Noise
4.8.5 Noise Source
4.8.6 Noise Control

4.1.1 Shape of Auditorium
Cempaka Sari Auditorium is designed in a combination of a pebble shaped plan encased within a
shoebox shaped perimeter of building. The concave surfaces of the horseshoe shaped plan allow
sounds to concentrate towards the centre of the space. However, due to the inconsistency of
the degree of curved walls, sound tends to spread in a non-uniform angle in the auditorium.
Pebble shaped
Shoebox shaped
Concentration of
sound
17

4.1.2 Form of Auditorium
Cempaka Sari Auditorium is meant to built in a egg like structure, hovering from within the
building block. The hovering egg-shell auditorium distances itself from lobby area to decrease
noise destruction from the external environment of the auditorium.
The double layer shell structure creates an air gap between the walls which acts as sound
insulation, preventing sound from entering from external environment.
Air gap with
structures
Lobby
Auditorium
Back stage
18

4.2.1 Levelling of the Stage and Seats
The auditorium uses staggered seatings to allow direct sound to be received by audience
without any obstruction. From another point of view, this allows the audience to obtain
unobstructed views.
Whereas the ceiling above the stage (concave) and seating zones (raked) are used to reﬂect
sound back towards the audience seating zone.
Staggered Ceiling
Concave Ceiling
Stage
Audience Seatings
AV Room
19

4.2.2 Arrangement of Seats
Seats are planned in a concentric layout within 100 degree of sound propagation which results
to high recurrence of sound projected. Whereas the distance between the sound source on the
stage and the last row of seats is within 30m, which is an ideal range for human voices to be
heard clearly. Thus, the sound range of an optimum acoustic quality of a sound is optimally
reached at every angle.
The concentric arc of circle also aids in visual sightline to focus to the stage area from every
seats.
Stage
Concentric shaped
seat arrangements
20

4.3.1 Ceiling Design
Ceiling design and reflective elements are significant for delivering the sound to every corner of
the auditorium. The staggered ceiling configuration accommodates the inclusion of easy access
to the spotlight gantries and most importantly, reflecting the sound towards the audiences. The
ceiling panels serve the function as sound reflectors to ensure that sound waves are evenly
distributed throughout the auditorium.
The front staggered ceiling reflects indirect sound to the VIP seats in the middle of the auditorium
whereas the rear ceiling panels further aid to reflect sound energy to the seats at the back which
is placed in front of the control room.
Sound Source
Direct Sound
Indirect Sound/ Reflected Sound
21

4.3.2 Sound Attenuation
Sound attenuation is a measure of the energy loss of sound propagation in media and in a
particular distance. Sound propagates in a spherical wavefront, and the intensity of sound will be
approximate the Inverse Square Law. The sound distribution intensity is plotted out throughout
the seating area and it shows that there is a distinct sound concentration zone accumulated at
the stage area of the auditorium. This is obvious as the concave shaped auditorium provides a
feedback where it converges sound to the center.
65dB
63dB 63dB
55dB 55dB55dB
43dB 43dB
Control
Room
Stage
22

4.4.1 Introduction
A sound reinforcement system is a system designed for the purpose to capture, amplify the
sound of the source on the stage by utilising electronic effect. It also functions to transmit
sound to a remote location through an audio or video conference or streaming or record it for
later distribution. The span of the auditorium from the centre of the stage till the furthest end of
auditorium is approximately 30m. Therefore, sound reinforcement system is important to amplify
and deliver the sound from the performers to the audience.
Function of sound reinforcement system:
● To amplify and distribute live or pre recorded sound over a wide area
● To minimize sound reverberation
● To retain and enhance the quality of the existing audio
The system components that present in auditorium are:
● Arrayable high Q and mid Q fullrange loudspeaker
● Stage ﬁll loudspeaker
● Stage foldback monitor loudspeaker
● Extended bass subwoofer
4.4.2 System Components
1. Arrayable high Q and mid Q fullrange speaker
Quantity: 2
Placement: Both sides of the stage facing the seatings
Model: MEYER UPA-1P RMS, MEYER UPA-2P RMS
This type of speaker provides uniform attenuation of all
frequencies ranging from 1200Hz to 18kHz. Uniformly
predictable polar behaviour takes much of the guesswork out
of system design and assures arrays that exhibit minimal
destructive interference. Its wide and symmetrical pattern
covers board areas and ampliﬁes sound across a longer
distance. Its position on the both sides of stage permits for a
balanced sound propagation, although it allows higher
concentration of sound towards the centre of auditorium.
40°
5.5m
23

2. Stage ﬁll loudspeaker
Quantity: 2
Placement: At the sides of the stage facing the centre
Model: MEYER UPM-1P RMS
This type of speaker is a small and inconspicuous speaker that
can provide high sound pressure level, extremely low
distortion, and uniform directional control. It sits upright on
the side of the stage and functions to provide sound
feedback to the areas of the stage not covered by the ﬂoor
monitors. It functions the same as the stage foldback monitor
speaker.
100° 100°
100°100°
24

3. Stage foldback monitor loudspeaker
Quantity: 4
Placement: Facing the centre of the stage
Model: APOGEE AE-3Ms2
Equipped at the front stage, it is used for amplifying the
sounds of the performance and hence providing sound
feedback to the performers to assist them in hearing their
own vocals or instruments. It also acts as a foldback system to
avoid the performers on the stage to hear reverberated
reﬂections bouncing off from the walls of auditorium which
will delayed and distorted. Due to the auditorium having a
larger stage with great depth of 12m, hence it is equipped
with four units arranging at the front part of the stage facing
the centre.
45°45° 45° 45°
70°
25

4. Extended bass subwoofer
Quantity: 2
Placement: Both sides of the stage
Model: MEYER USW-1P RMS
This self-powered subwoofer provides ﬂat, low-frequency
response ranging from 35Hz to 180Hz. There are two
subwoofers positioned at each side of the stage dedicated to
reinforce low pitched audio frequencies such as bass and
sub-bass. Unlike the arrayable fullrange speaker, it produces
lower frequencies sound which tends to have slower
attenuation and is easier to reach the audience. It is placed at
each side of the stage to achieve a wider and equal sound
distribution. It is commonly placed at the corners of the stage
in order to increase the bass output.
360°
360° 360°
26

4.4.3 Advantages and Disadvantages of Sound Reinforcement System
Advantages:
● The surround system used is stereo system that allows panning and it adds depth to
acoustic image.
● Speakers and microphones are utilised to reinforce and amplify the sound intensity over
a wider coverage and longer distance so that the audience are able to listen to it.
● Sound reinforcement system is used to enhance or alter the sound source, such as control
the sound reverberation time.
● It can help to cut through the background noise produced internally and externally, such
as mechanical services and outside trafﬁc.
● It also can control the frequencies of the sound from the stage depending on the desired
sound of the performance.
● It can enhance the qualities of the sound when it is connected with the audio mixing
console.
● It can provide sound feedback to the performers so that they can listen to their own
vocals or instruments.
Disadvantages:
● Technical issue or malfunctioning of the sound reinforcement system may cause
disturbance to sound intensity and quality.
● Overlapping of sound may occur as the audience might hear the original sound and the
sound reproduced from the speakers at separate times. The ideal difference should be not
more than 1/30 second.
● It may cause slight distortion of the sound if the sound reinforcement system is in poor
condition.
● Placement of the subwoofer leaning against the wall will help to increase the bass output
but it might be not ideal as the bass sound quality is not the best. The ideal position
should be 8 to 12 inches away from the wall.
● Feedback sound may become a noise source and cause disturbance during the
performances on stage.
27

4.5.1 Acoustical Treatment and Components
Cempaka Sari Auditorium is designed with a combination of various types of materials. The types
of components and treatments are acoustically considered for the performance of the auditorium.
These materials are applied on surfaces where the sound waves would reach to, namely the
walls, floors, ceilings, curtains, seatings and also the backstage.
4.5.1.1 Walls
Walls are the components where the direct contact of sound from its source can reach with the
least amount of obstruction, similar to the ceiling. But yet the wall also plays an important role in
directing the sound waves towards the audience where it affects the final concentration point of
sound. As it will affect the experience of the audience directly, the walls are treated with four
different types of material, namely the Semangkuk Timber Veneer Claddings, the Perforated
Timber Panels, the Polyester Fibrous Plaster Panels and lastly, the Fabric Acoustic Panels.
Fabric Acoustic Panel
Alternation of Perforated Semangkuk Timber Veneer Acoustic
Panel with Rockwool fill and Polyester Fibrous Plaster Panel
Semangkuk Timber Veneer Cladding
28

Material Finishing Surface: Smooth Satin Finish
Core Material : Semangkuk Timber
This type of cladding is mainly laid flat against the wall facing the audience at the stage area
as the sound waves produced from the center of the stage are required to be reflected away
from the stage, towards the audience seatings. Its dense and smooth surface allows the sound
waves to be reflected effectively while providing a formal finish to the stage in terms of
aesthetics. The Semangkuk timber veneer cladding and the stainless steel groove channel are
fixed onto a 2 layered 9mm MDF board.
9mm THK. MDF BOARD BACKING
50mm x 50mm BATTEN
STAINLESS STEEL GROOVE CHANNEL
20mm THK. SEMANGKUK TIMBER CLADDING
1. Semangkuk Timber Veneer Cladding
29

Material Finishing Surface : Semangkuk Timber Veneer Finish, perforated on smooth ﬁnishing
Core Material : MDF board and Rockwool Insulation
This type of panel is mainly installed along the side walls alongside with the Polyester Fibrous
Plaster Panel. The timber panel is perforated with 30mm ⌀ of 100mm apart from each
perforation. It allows partial sound to enter the perforations while the remaining will get
reﬂected away from the timber panel. These perforations act as trapping chambers that
prevent the sound waves from escaping back into the space, while the rockwool insulation
(porous absorber) behind the boards will diminish the sound waves by forming a barrier that
absorbs vibrations between the source and adjacent areas. The air in the cell provides
resistance to the sound waves which then loses energy in terms of heat. These panels are
slightly protruded out from the wall in jagged pattern. The sharp edges tend to disperse the
sounds that strike on it.
2. Perforated Timber Panel
30mm ⌀ PERFORATION @ 100mm c/c
10mm THK. MDF BOARD w/ SEMANGKUK
TIMBER VENEER FINISH
25mm THK. ROCKWOOL INSULATION
6mm THK. PLYWOOD BACKING
50mm X 50mm BATTEN
30

Material Finishing Surface : Rough surface with Copper Paint Finish
Core Material : Polyester Fibrous Plaster
This type of panel is mainly installed along the side walls alongside with the Perforated
Timber Panel. Its rough surface makes them a great diffuser for sound waves. When the sound
waves are reflected from the uneven surface, they tend to disperse in many direction and this
helps to dissipate or break down the sound energy. Observing the details of the polyester
fibrous plaster panel, the panel is not backed with any rockwool insulation. It also stated that
the panel is meant for reflecting purpose, but its rough surface allows the reflected sound to be
dispersed into many direction which contradicts the effect of a smooth sound reflector.
3. Polyester Fibrous Plaster Panel
10mm THK. POLYESTER FIBROUS PLASTER IN
COPPER PAINT FINISH
25mm x 25mm BATTEN
31

Material Finishing Surface : Woven surface
Core Material : Rockwool Insulation
These panels are mainly aligned along the walls at the rear end of auditorium and at the VIP
seating zone in the centre of auditorium. It is an effective sound absorber and functions to
eliminate unwanted sound reflections. It is great at dissipating the sound energy and prevent
deadening of the upper mids and high. Observing from the detail of the fabric acoustic panel,
the core of the panel is filled with rockwool insulation with only a layer of fabric encasing the
core. The polyester fabric allows the sound to approach the rockwool insulation behind instead
of reflecting away the sound. The air in the cell provides resistance to the sound waves which
then lose energy in terms of heat. The timber frame maintains the form of the panel while
maintaining the thickness of the rockwool insulation encased within the panel.
4. Fabric Acoustic Panel
POLYESTER FABRIC
TIMBER FRAMING AT THE EDGES OF THE
PANEL
32

Reflective Material
Absorptive Material
From the layout of the absorptive and reflective wall material, we can notice a pattern of
reflective materials gathering mostly at the stage area where sound reflection is required to
propagate the sound waves further towards the audience.
As for the absorptive materials, they terminate the propagation of sound waves at the walls
with audience nearby to prevent the echoing of sound.
Absorptive and Reflective Material for Walls
33

Flooring takes up the horizontal plane where the users are accessible to. The Cempaka Sari
auditorium mainly utilises two types of ﬂooring material as their main reﬂective and absorptive
material namely the Carpet Flooring and the Laminated Timber Flooring.
Carpet Flooring
4.5.1.2 Floorings
Laminated Timber Flooring
34

Material Finishing Surface : Woven surface
Core Material : Pile fiber (Nylon) and Polyester
Carpet flooring is mainly applied at public areas that are directly accessible by the audience,
including the audience seats and access paths in the auditorium. Observing from the detail of
the carpet flooring, the carpet tiles are installed at the surface of the finishing level of the floor
where the carpet flooring can be utilised the most to reduce impact noise created by footsteps
and dropped objects from the audience. It provides a cushion to silence the footsteps. The
carpet tiles are soft and porous which enable the sound waves to penetrate into them and
minimise the reflected sound waves. Carpet tiles are effective sound absorbers because the
individual fibres, pile tufts and underlays have different resonant frequencies at which they
absorb sound waves. The wide range of resonant frequencies enables it to absorb wide
range of sound waves. There are also rockwool insulations installed at 25mm thick below the
deck. The entire floor deck is raised by the floor joists in order to reduce the structural-borne
noise coming from exterior.
1. Carpet Flooring
300mm x 300mm CARPET TILE
ADHESIVE
2 LAYERS OF 12mm PLYWOOD
75mm x 50mm FLOOR JOIST
35

Material Finishing Surface : Smooth surface
Core Material : Timber
Laminated timber flooring is mainly applied at the stage area and VIP seats area to provide
both durability in resistance to load and abrasion and also as a reflective material that reflects
sound from the stage towards the audience. Its smooth and glossy surface, combined with
hard core material allows it to be as a good reflector of sound. Despite its good reflectivity,
impact noise could easily be generated from the footsteps due to the hardness of the
material. The performers at the stage area would also be disturbed by the sound that was
continuously reflected by the flooring material. Observing from the detail of the laminated
timber flooring, the laminated timber tiles are installed at the finishing layer of the floor. This
allows the laminated timber to perform both as a reflector and also as an enhancer in terms of
the aesthetics for the auditorium, despite that it becomes a draw back for the performers on
stage.
2. Laminated Timber Flooring
LAMINATED TIMBER FLOORING
ADHESIVE
50mm THK. SAND CEMENT SCREED
EPDM VAPOUR BARRIER
100mm THK. CONCRETE STRUCTURE
36

Reflective Material
Absorptive Material
From the layout of the absorptive and reflective material, we can see a pattern of reflective
materials gathering mostly at the stage area where sound reflection is needed more to
propagate the sound waves further towards the audience.
The absorptive materials are mostly around the audience seats to prevent echoing of sound by
absorbing sound waves, also to prevent the impact noise from footsteps.
Absorptive and Reflective Material for Floors
37

Ceilings have the largest surface area in direct contact with sound source. As it is positioned
above the audience, its large surface area can act as a good plane of reﬂection to allow sound
waves to reach further towards the audience. Acoustic ﬁbre plasterboard is applied throughout
the ceiling of the Cempaka Sari Auditorium.
4.5.1.3 Ceilings
Fibrous Plaster Ceiling
38

Material Finishing Surface : Smooth Paint Finish
Core Material : Fibrous Plasterboard
Fibrous plaster is composed of gypsum plaster reinforced with sheets of hessian and timber. It
is applied over the entire ceiling of the Cempaka Sari Auditorium. 10mm thick fibrous
plasterboard is used because the stiffness and mass is necessary to resist panel vibrations
which cause low frequency absorption and to achieve good reflections at all frequencies. Its
smooth application helps in delivering the crisp tones and clarity to sound to every member
of the seated audience. Yet, it provides a formal and aesthetic look of the auditorium. Observing
from the detail of fibrous plaster ceiling, the fibrous plasterboard is backed with the 50mm thick
rockwool insulation. Plenum space above the ceilings provides an airspace which minimises
the noise coming from exterior.
1. Fibrous Plaster Ceiling
10mm THK. FIBROUS
PLASTER CEILING c/w
PAINT FINISH
50mm THK. ROCKWOOL
INSULATION
39

Stage curtains are components that are often installed on the stage to be utilised during the
performances. Besides as a tool of aesthetics, stage curtains could also help in absorbing the
sound waves to provide a clearer sound transmission towards the audience for speech. Acoustic
Cotton Velour Curtain are installed in the Cempaka Sari Auditorium.
4.5.1.4 Stage Curtains
Cotton Velour Stage Curtain
40

Material Finishing Surface : Pleated, thick and highly porous surface
Core Material : Cotton Velour
Since the walls of the backstage are made of concrete, hence cotton velour curtains are used
at the backstage to dampen the sound waves and minimise the reﬂection of sound from
the backstage walls. Due to its thick and highly porous properties, it helps in reducing the
reverberation and echo in a large space, as well as reduce interference from outside noise.
These pores act as thousands of tiny sound traps, capturing the sound energy and
converting into heat energy. The thicker the velour curtains, the more effective it will be
against longer wavelength (low frequency) sound. However, a thickness of 25mm to 50mm
is required to absorb the low frequency sounds effectively. Observing from the detail of
cotton velour stage curtain, the pleated curtains increase the surface area for sound
absorption to occur and improve the absorption of low and mid frequency sound. The
bigger the spacing between curtain and wall, the more effective in low frequency absorption.
1. Cotton Velour Stage Curtain
PLEATED COTTON VELOUR
STAGE CURTAIN
41

Seatings are components installed on top of ﬂoorings for audience. Besides being as a furniture,
seatings could also be used as a temporary representation of the presence of a user. Therefore,
even when the auditorium is not in full house, the auditorium could still function the same as if
the auditorium were full with people. The seatings installed in Cempaka Sari Auditorium uses
polyurethane foam material as its core and encased with polypropylene and jacquard
polyester.
4.5.1.5 Seatings
Seating with Polyester Polyurethane Foam and Jacquard
Polyester layering
42

Material Finishing Surface : Jacquard Polyester
Core Material : Polyurethane (PU) Foam
The seatings are arranged in a concentric layout facing the stage. The auditorium seatings
materials comprise of 150mm thick polyurethane foam molded to the seat and backrest with
a lavish 0.5mm thick Jacquard Polyester as a finishing layer and a layer 12mm thick plywood
veneer as back finish. Majority of the sound waves passed through the jacquard polyester
fabric due to its porous material and almost none of the sound waves reflected back. Thus,
this makes the fabric to be highly transparent for sound waves to transmit through.
Polyurethane foam has been regarded as effective acoustic materials due to the effective
sound damping, low density and easy production. It has the ability to absorb sound and
prevent echoes in the case where the auditorium is not fully occupied by allowing the air to
flow into and the absorbed sound energy is converted into heat. These materials are
generally non-porous, elastic material which flex due to excitation from sound energy.
Flexural sound absorbers are typically most effective at absorbing low frequencies, unlike
porous materials.
1. Polyurethane Foam
1mm THK. JACQUARD POLYESTER
12mm THK. PLYWOOD VENEER
FINISH
150mm THK. POLYURETHANE FOAM
43

The auditorium backstage consists of structural wall enclosed the back area. As the backstage
may indirect influence the acoustical performance, hence the material used for the wall is taken
into consideration. The wall used in the auditorium is concrete wall finished with plastering and
skim coat.
4.5.1.6 Backstage
Concrete Wall with plastering and skim coat finish
44

Material Finishing Surface : Plastering and skim coat
Core Material : Concrete
The walls of the backstage are made up of concrete wall. Due to its smooth and yet hard
surface, the sound waves that projected from the stage will be directed and continue to
reflect off to the backstage wall surfaces until it loses energy and dies out. The wall also acts
as a partition or sound barrier that deflect the noise back away but yet at the same period
sound could be heard on the other side of the wall. From the observation of the materiality
of the concrete walls, they are able to reflect most of high frequencies sound and only a
low percentage of it is absorbed by the wall. The remaining low frequency energy that is
not reflected or absorbed passes through the wall. It also promote flutter echoes around the
backstage, which makes quite amount of unwanted sound effect.
1. Concrete Wall
110mm THK. CONCRETE WALL
20mm THK. CEMENT PLASTER
6mm THK. SKIM COAT
45

4.5.2 Material Tabulation of Cempaka Sari Auditorium
Among the various types of material applied in the Cempaka Sari Auditorium, we tabulated a
table to clearly point out the role of each material to showcase the way these materials contribute
to the acoustic performance of the auditorium.
Table 4.1: Absorption coefﬁcient of materials across the auditorium
(Adapted from http://www.acoustic.ua/st/web_absorption_data_eng.pdf)
Location Component Material Description Finishes Absorption Coefﬁcient
125Hz 500Hz 2000Hz
House Wall MDF Perforated
Timber Panel
NIL 0.41 0.58 0.68
Polyester
Fibrous
Plaster
Polyester
Fibrous Plaster
Panel
NIL 0.20 0.10 0.04
Fabric &
Rockwool
Fabric Acoustic
Panel
NIL 0.46 1.0 1.0
Floor Nylon Carpet Flooring NIL 0.10 0.62 0.63
Apron Stainless
Steel
HT. Stainless
Skirting
Satin Finish 0.15 0.06 0.04
Timber Semangkuk
TImber Skirting
NIL 0.02 0.05 0.10
Railing Stainless
Steel
Tubular
Stainless Steel
Railing
Timber Tubular Timber
Railing
Varnish 0.02 0.05 0.10
Seating PU Foam Polyurethane
Foam
Woven 0.60 0.88 0.93
Ceiling Fibrous
Plaster
Fibrous Plaster
Ceiling
Paint Finish 0.20 0.10 0.04
46

Stage Wall Semangkuk
Timber
Semangkuk
Timber
Cladding
NIL 0.18 0.10 0.08
Floor Laminated
Timber
Laminated
Timber Flooring
NIL 0.10 0.06 0.06
Apron Stainless
Steel
HT. Stainless
Skirting
Timber Semangkuk
TImber Skirting
NIL 0.02 0.05 0.10
Stage Curtain Cotton
Velour
Cotton Velour
Curtain
NIL 0.30 0.40 0.59
Location Component Material Description Finishes Absorption Coefﬁcient
125Hz 500Hz 2000Hz
Table 4.2: Absorption coefﬁcient of materials across the auditorium
(Adapted from http://www.acoustic.ua/st/web_absorption_data_eng.pdf)
47

4.6.1 Introduction
Sound waves propagates through air as a longitudinal waves as the vibration of particles is
parallel to the its direction of propagation. Sound propagates from a point source, travels
outward in a spherical wavefront motions and its intensity decreases via the inverse-square law
(the intensity is inversely proportional to the square of the distance from the source). By utilising
the smartphone playing at constant amplitude and frequency (500Hz), we collected informations
regarding the sound intensity level (SIL) in dB unit and plotted its reading at diagram below. We
noticed that there is a huge reduction in sound intensity level due to great depth and height
which is 31.5m and 14.45m respectively.
Diagram 4.35 : Sound intensity level (SIL) across the auditorium
65dB
63dB 63dB
55dB 55dB55dB
43dB 43dB
Control
Room
Stage
48

4.6.2 Sound Reflection and Diffusion
Sound reflection happens when sound strikes a surface or obstacle. The sound wave undergoes
a change in direction of propagation when it is reflected. The phenomena of reflection of sound
waves obeys the Laws of Reflection where the incident wave, the reflected wave and the
normal lie in the same plane as well as the angle of incidence, i is equal to angle of reflection, r.
It can aid in increasing the efficiency of the sound propagation to the audience. Poor design of
reflections may cause echoes and long reverberation which inhibit legibility of speech. Sound
diffusion is the method of spreading out sound energy with a diffuser for better sound in a
space. It is important as multiple reflections from the flat surfaces combined with original sound
may cause too much echo and reverberation.
The shape of Cempaka Sari Auditorium is a combination of a pebble shaped plan within a
shoebox shaped perimeter of building. It consists of two concave side walls which play a
significant role in sound propagation.
Walls of varying degrees of curvature tend to reflect the sound from the stage towards
different direction because the angles of incidence for sound waves are different from the
front to rear wall. The concave side walls tend to converge the sound waves towards the
centre of the auditorium because the geometry of the surface will force the sound energy
to concentrate.
1
At the rear end, it experiences concentration of sound or loud hotspot as it is the focal
point where the sound waves meet.
1. Shape and Form
1
2
2
49

Reflective material
Alternation of reflective and
absorptive material
Absorbed sound
Absorptive material
Partially reflected sound
2. Materiality
1
2
3
The reflective materials are arranged near the stage whereas the absorptive materials are
arranged near the audience seating. These layouts are arranged to counter the problem
brought by the shape of the auditorium which converges all the sound waves towards the
centre of auditorium, which would result in sound concentration at the centre. By incorporating
absorptive materials along the side walls, the sound that was supposed to be reflected turns out
being absorbed by the absorptive materials, maintaining an even sound intensity throughout
the audience seatings.
The hard sound-reflecting walls at the front portion of the auditorium tend to reflect
the sound towards the audience seatings.
1
Alternation of the reflective and absorptive materials allow partial of the sounds to be
absorbed to avoid concentration of sound at the centre of auditorium.
2
The rear wall is lined with sound-absorbing fabric acoustic panels to prevent and
control excessive reverberation of sound.
3
50

3. Sound Diffusion
1
2
Perforated timber panels that are slightly protruded from the wall in jagged pattern.
The sharp edges of the perforated timber panels tend to diffuse and disperse the sound
waves in many direction, resulting in dispersion of sound energy. As the sound energy
decreases, it further reduces the sound travel distance.
1
It also helps to counter the issue brought by the pebble shaped plan. Concentration of
sound or loud hotspot at the central portion of the auditorium can be avoided.
2
51

4. Staggered and Convex Ceilings
1
2
The synthesis configuration of convex shaped ceiling at the front portion of the auditorium and
staggered ceiling helps in propagation of sound. This configuration of ceilings also helps to
prevent flutter echo from occurring and increase the surface area of providing useful
reflections.
2 The ceilings at the central portion of auditorium are slightly recessed in. As there are
elevating levels of the ceiling, the increasing depth of ceiling promotes an angle of
reflection that allows the sound to travel further towards the audience seatings while
yet maintaining an audible sound intensity. This is because the point where reflection of
sound occurs is slightly behind and further away from the stage. It functions to reflect
sound energy to the rear end of the auditorium.
1 Convex shaped ceilings on top of the stage tend to diverge and reflect the sound
further away from the stage towards the audience seatings. It functions to reflect the
indirect sound to central portion of the auditorium especially VIP seating area.
52

Across the short section of the auditorium, the configuration of staggered ceilings help in
delivering the sound evenly throughout the auditorium.
1 The ceilings at the central portion of auditorium are slightly recessed in. This
configuration increases the surface area for sound reflection.
1
2
2 The staggered ceiling helps in distributing the sound evenly throughout the auditorium
especially towards the side of auditorium. It also counters the problem brought by the
egg-shell form of the auditorium where concave surfaces tend to converge the sound
towards the centre. It can prevent the sound from concentrating at the centre of
auditorium from happening.
53

4.6.3 Sound Delay and Echo
Sound delay or echo is the result of sound waves being reflected from a surface and returned
to the listener. The time difference between the direct sound and the reflected sound heard by
the listener is referred to the echo delay time. The delay time depends on the distances between
the sound recipient, sound source and the reflecting surface. The greater the distances, the
longer its delay time.
Direct Sound
Indirect Sound
Sound Source
Sound Recipient
The time delay recorded from this position is 55.3ms.
16300
16300
13800
1. Sound Delay and Echo 1
54

Direct Sound
Indirect Sound
Sound Source
Sound Recipient
55

Direct Sound
Indirect Sound
Sound Source
Sound Recipient
In conclusion, due the absorptive materials are installed along the side walls, when the sound
waves hit the absorptive material, the sound energy is greatly absorbed, hence the reflected
sound waves have reduced its energy magnificently. As result, there are no echoes delay time
because the sound energy have been totally absorbed by the absorptive materials and the
centre of auditorium does not overwhelmed by the reflected sound.
56

4.7.1 Sound Shadow
Acoustic shadow or sound shadow is deﬁned as an area which is highly reﬂective as a result that
sound waves fail to propagate, due to the disruption of the sound waves. It is also happen at the
region which the frequency regions of sound are altered as the sound undergoes diffraction
effects around large pillars and corners or underneath a low balcony. There will be a slight
change in quality of sound as the obstructed design did not consider the transmission of sound to
the far end of the auditorium from the stage. However, Cempaka Sari Auditorium does not have
any balcony above the the gallery level.
Diagram 4.44 : Absence of sound shadow region in Cempaka Sari Auditorium
As shown in the diagram, balcony is absent in Cempaka Sari Auditorium, hence there is no
sound shadow occurred.
57

4.7.1.1 Consideration taken to eliminate sound shadow
Staggered Floor
The ﬂoor is staggered from the entry level after the stage. It is designated in a sensible angle to
provide direct sound source towards the audience, even in the furthest-most seats can be
heard clearly. This is relatively possible as the sound waves travel towards the audience, it does
not interrupted by any obstacles which does not result in diffraction of sound. Moreover, raked
seatings also provide visuality towards the stage from each of the seating. Absorptive carpet is
used in the auditorium as the material of the ﬂooring in order to absorb unnecessary noise.
Direct sound transmitted towards the seating level in section
58

4.7.2 Flutter Echoes
Flutter echo is a rapid series of echoes, produced by sound travelling quickly between two
parallel reflective surfaces. It is a condition in which occurs in acoustical spaces whereby two
parallel surfaces reflecting sound between one another are far enough apart that audiences can
hear the reflections between them as distinct echoes. They are heard with sufficient loudness
compared to the original sound. The 'flutters' are equally spaced in time usually 30-50ms apart.
This phenomenon is probably the most common and immediately noticeable room problem
wherein two portions of walls, ceiling or floor are non-absorptive and face directly at one another.
These hard and smooth parallel surfaces, that allow for the sound to bounce back and forth in a
series of reflections that appear to mimic the source.
In the Cempaka Sari Auditorium, flutter echoes cannot be identified due to several conscious
designs of the auditorium.
Concave wall
4.7.2.1 Consideration to eliminate flutter echoes
As shown in the plan below, Cempaka Sari Auditorium consists a pebble shaped layout. The
side walls are morphed following the curvature and the shape to increase the concentration of
sound at the centre of the auditorium. Therefore, the non-parallel concave walls create a
non-uniform and uneven spreading of sound throughout the auditorium. Hence, there is
absence of flutter echoes.
Absence of two parallel reflective walls
1. Shape
59

Absence of two parallel reflective surfaces
Direct sound path
Reflected sound path
2. Ceiling
The convex shaped ceilings on top of the stage enables sound dispersion, resulting in more even
distribution of sound throughout the auditorium. The synthesis configuration of convex ceilings
and staggered ceilings prevent the flutter echoes from occurring. This is due to the staggered
ceiling in the central portion of the auditorium is slightly angled. Without the presence of two
parallel reflective surfaces on the ceiling compared to floor, the flutter echoes cannot be
identified.
3. Wall Panels
The side wall perforated timber panels are arranged at an angle in order to provide necessary
angle for reflection of sound as well as to eliminate the flutter echoes. The sound waves that
strike on the surface of angled wall panels will direct the sound towards other direction and allow
variety of patterns of sound path.
60

4.8.1 Introduction
Noise is defined as any unwanted sound that you do not need or want to hear, most commonly
judged as undesirable by the recipient. It can be distracting, annoying, or harmful to everyday
activities. Whether or not a sound is considered undesirable will depend not only on the loudness
of the sound but on its frequency, continuity, time of occurrence, place and activity being carried
out. In an auditorium, noise is an unpleasant sound that will affect the hearing experience of the
audience.
Continuous sounds sounds that have little or no variation over a duration of time.
Varying sounds sounds that have differing maximum levels over a duration of
time.
Intermittent sounds sounds that are interspersed with quiet periods.
Impulsive sounds sounds that are characterised by relatively high sound levels over
a very short duration of time.
4.8.2 Effects of Noise
Noise that up to the range of 65 dBA may create annoyance and psychological and physical
effects may occur.
1. Noise will causes distraction of performer, which will affect the quality of the show.
2. Noise during performances, will hinder the concentration of audience.
3. Distraction from a specific task can result in inefficiency, negligence and errors which will
essentially have a detrimental effect on the work produced.
4. Interference with desirable sounds such as music or speech will cause annoyance to the
audiences.
5. Excessive noise will impact the health of performers such as sleep disturbance and increased
stress and anxiety.
Hence, a peaceful acoustical environment is essential in order to produce a perfect sound
experience. It should be assured that noise levels are maintained at a minimum level, or at best,
non-existent level while events are being carried out.
61

4.8.3 Noise Analysis
The analysis of noise in buildings can be viewed as the relationship of the path between source
and receiver.
A. Sound sources:
- occupant activity
- operation of building mechanical and electrical services
- environmental sound produced outside a building
Noise sources can be classiﬁed into 2 group:
Interior Noise
● noise produced by people through their activities such as noises from radio/television,
loud conversation, slamming of doors, dragging furniture, babies crying, etc.
● building noise produced by machines and household equipment
● noise produced in certain industrial buildings by manufacturing or production processes
Outdoor Noise
● noise produced by transportation such as road trafﬁc, railway lines, motor boats, aircraft
etc.
● mechanical equipment such as compressors, cooling towers, construction equipment
noise, machinery etc.
● rainfall and thunder
B. Sound path:
- Air-borne sound transmission: Sound is transmitted through the air from its source
- Structure-borne sound transmission: Sound energy from a source sets into vibration
solid parts of the building structure, virtually multiplying the area of the sound radiating
surface.
C. Sound receiver:
In terms of noise control, sound can be received in various ways which include building,
a room in a building or even in person. Noise can be reduced by way of manipulating the
relationship between sound receiver and its transmission.
62

Backstage
Control
Room
AHUAHU
Lift
34dB
35dB
34dB
35dB
34dB 34dB
34dB
37dB
35dB 34dB
With the air-conditioning system turned on, the average reading of background noise in
Cempaka Sari Auditorium is 36dBA. Background noise can be detected from backstage,
ventilation system from AHU rooms, control rooms and seats placed near to the exterior
passenger walkway.
External and internal noise source
Occupancy Max dBA
Small auditoriums (<500 seats) 35 - 39
Large auditoriums, theaters and churches ( >500 seats ) 30 - 35
4.8.4 Background Noise
Background noise or ambient noise is any sound other than the sound being monitored. It is a
form of noise pollution or interference. Room criteria measured have been developed to evaluate
existing background noise levels in enclosed areas, such as rooms as well as to specify required
background levels for enclosed area to be constructed. The simplest noise criteria are determined
by measuring or specifying a maximum A-scale weighted level (dBA).
63

Quality acoustical characteristics are signiﬁcant in auditorium spaces so that performances and
presentations can be clearly heard and understood. For performance spaces and general
presentation spaces, recommended noise criteria (NC) rating ranges from NC-20 to NC-30;
recommended sound transmission class (STC) rating ranges from STC 40 to STC 50.
Cempaka Sari Auditorium with an occupancy of 566 seats and octave band centre frequency at
500Hz, the noise level matches with the noise criteria (NC) of an auditorium.
64

4.8.5 Noise Source
Outdoor Noise
The Cempaka Sari Auditorium is located beside PPJ Complex, facing the 3 lane main road -
Jalan Persiaran Perdana. At the other side of the building is the Royal Customs Department of
Malaysia, sandwiching the street Jalan P3C. Vehicles are driving at a moderate pace on Jalan
Persiaran Perdana, whereas vehicles on Jalan P3C are driving at a slower pace due to the 90°
left-turn-junction and the single lane, two-way drive. These vehicles cause transportation
noises.
65

Lobby & Passageway Noise
Events happening at the lobby and passageway of ground ﬂoor also do generate external
noises, especially when sound speaker gadgets are used. These noise sources are transmitted
through airborne as well as structure-borne transmission.
Airborne noise is transmitted along continuous air paths such as openings and cracks around
doors, which can be identiﬁed in Cempaka Sari Auditorium.
66

120dB
40dB
Weather
Due to the exposed roof of the auditorium, noise effects caused by weather such as rain,
thunder, or storm can be heard in the auditorium as there is a lack of soundprooﬁng. However,
the design of the roof can reduce noise level caused by weather condition. The roof of the
Cempaka Sari Auditorium is a double layer shell structure. The air gap in between acts as a
sound insulator, which aids to reduce the noise of an extreme weather situation i.e.
thunderstorm (120dB) to average 40dB. This noise level will still be heard in the auditorium,
but not very detrimental to the acoustic experience.
67

Human Activities & Movement
Interior noise is generated by physical contact with different surfaces in the auditorium.
Specific noise sources generated by human movement can be identified as:
● Auditorium chairs
● Timber flooring
● Stairs metal capping
These noise are low in volume but noticeable. Some find it disturbing towards the
performances happening on stage.
68

Machinery & Equipments
The equipments employed for lighting such as spotlights and stage lights produce a soft
buzzing sound. The noise is only noticeable at a close distance with the equipments. Interior
noise is generated by the HVAC system as cold air is expelled through the diffuser grills. The
noise is low but still noticeable when the auditorium is silent with the AC turned on. When the
speakers are turned on but not in use, it also produces a soft buzzing sound.
One of the noticeable background noise is from the AHU room, located at the back of the
auditorium. This noise decreases down to the stage, which causes annoyance to audience
sitting at the back row.
69

4.8.6 Noise Control
Noise control aims to reduce the effect of noise in an auditorium. It can be used based on the
sound transmission relationship, from a sound source to sound receiver going through by sound
path.
Here are various strategies can reduce the noise in the auditorium:
1. Suppression of Noise at the Source
2. Town or Site Planning
3. Architectural Design
4. Mechanical and Electrical Design
5. Structural Design
6. Organisation
7. Sound Absorption
8. Masking Noise
9. Sound Insulating Building Construction
4.8.7 Noise Control in Cempaka Sari Auditorium
Town or Site Planning
Cempaka Sari Auditorium is constructed distance away from the main road in front in order to
create a green buffer zone in between which helps to ﬁlter some noise coming from the main
road.
70

Architectural Design
The auditorium is meant to be built in egg like structure, hovering from within the building block.
It is intended to isolate the noise from the ground level. The space in between creates a virtual
buffer zone that can minimise the noise from transmitting into the auditorium.
Auditorium
Buffer Zone
Organisation of Space
Before entering the auditorium, you will ﬁrst entered a buffer zone named as sound and light
lock (SLL). It is a vestibule that separates the auditorium from the lobby or circulation areas. It
helps in minimising the airborne noise and light transmitting into the auditorium.
Sound and
Light Lock
Vestibule
71

Sound Insulation
The egg like structure auditorium is suspended from the building block and is supported by the
steel structure all around the auditorium. The air cavity is between serves as sound insulation.
This is known as mass-air-mass system, which is usually applied as a soundproofing method.
The air molecules in the cavity provides resistance to sound wave which then it slowly loses
energy in forms of heat. Wider cavities will improve low frequency performance, which provide
better insulation against noise from the auditorium.
Air Cavity
Sound Absorption
The interior space of the auditorium has utilised soft floor finishes such as carpets to reduce the
impact noise generated by human movements. Puile carpets are effective sound absorbers as the
individual fibres, pile tufts and underlays have different resonant frequencies at which they
absorb sound waves. The usage of cotton velour curtain also help in reducing the noise that
produced at the back stage. The sound insulating doors have a function of preventing the noise
from entering into the auditorium.
72

5.1 Introduction
5.2 Reverberation Time Calculation
5.2.1 Volume and Floor Area
5.2.2 Area of Floor Materials
5.2.3 Area of Wall Materials
5.2.4 Area of Other Materials
5.2.5 Reverberation Time for Cempaka Sari
Auditorium

5.1 Introduction
The reverberation time is deﬁned as the time taken for the reverberant sound in a room to fade
away due to the sound energy bouncing off and being absorbed by multiple surfaces. To
determine the period of this time, different parts of the reverberation curve are 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.
Reverberation time deﬁned as the time for the sound pressure level to decrease by 60dB from
its original level after the sound is stopped.
= RT 60 =Reverberation
time
Time to drop 60 dB
below original level
5.2 Reverberation Time Calculation
The reverberation time can be calculated using the Sabine Formula;
RT = 0.16 V
A
where,
RT = reverberation time (sec)
V= volume of room (cu.m)
A= total absorption of room surfaces (sq.m sabins)
74

5.2.1 Volume and Floor Area
Referencing the plan and sections in CAD drawing, we intersected the three drawings in 3D to
obtain the form of the auditorium to calculate its volume.
75
The outcome is that the Cempaka Sari Auditorium is a small auditorium with a volume of
8124.82 m³ meanwhile the ﬂoor area of the auditorium is approximately 839.78m².

5.2.2 Area of Floor Materials
Component Material Absorption
Coefﬁcient, as
500hz
Effective
Surface Area
(m²)
Abs. Units
(m² sabins)
Total Absorption (A) for Floor Material 501.27
Nylon Carpet Flooring
Laminated Timber Flooring
76

5.2.3 Area of Wall Materials
Coefﬁcient, as
500hz
Effective
Surface Area
(m²)
Abs. Units
(m² sabins)
Total Absorption (A) for Wall Material 180.746
Fabric Acoustic Panel
Alternation of Perforated
Semangkuk Timber Veneer
Acoustic Panel with
Rockwool ﬁll and Polyester
Fibrous Plaster Panel
Semangkuk Timber Veneer
Cladding
77

5.2.4 Area of Other Materials
Fibrous Plaster Ceiling
Seating
Double Glazed Window
Single Solid Acoustic Door
Double Solid Acoustic Door
Stage Curtain
Railing
78

Coefﬁcient, as
500hz
Effective
Surface Area
(m²)
Abs. Units
(m²sabins)
Ceiling Plaster Ceiling 0.10 1069.45 106.95
Stage Curtain Acoustic Velour
Curtain
0.40 229.69 91.88
Railing Timber Railing 0.05 25.82 1.29
Seating NIL 0.46 per occupants 566 seats 260.36
Double Solid
Acoustic Door
Timber and Steel 0.06 13.86 0.83
Single Solid
Acoustic Door
Timber 0.06 11.34 0.68
Double Glazed
Window
Insulating Glass
and PVB
0.03 0.8 0.024
Total Absorption (A) for Other Materials 462.014
Besides wall and ﬂooring, there are also other various types of absorption material applied in
the Cempaka Sari Auditorium, including ceiling, stage curtain, seating, railing, window and
doors. We have tabulated a table to clearly point out the role of each material to showcase the
way these materials contribute to the acoustic performance of the auditorium.
79

5.2.5 Reverberation Time for Cempaka Sari Auditorium
Absorption Units (A) of each materials used in the auditorium:
Total Absorption Units for all materials:
= 1144.06 m² sabins
According to Sabine’s Formula, RT=
Reverberation time for the auditorium is , RT =
0.16 x V
A
0.16 x 8124.82
1144.06
= 1.136s
Cempaka Sari Auditorium may function as a small theatre for speech and ampliﬁed music. The
Reverberation Time of the auditorium is calculated as 1.136s which is considered low and not
conducive for music or electronic audio reinforcements to deliver the sound across the
auditorium. The auditorium may fairly good for speech delivering rather than musical and
instrumental performances.
RT
80

As we are almost reaching the end for this project, we have obtained a lot of knowledge
regarding acoustics. We have learned the way to analyse an auditorium based on its form, its
plan, its levels, and materials used to elevate the acoustical performance of the auditorium.
With these knowledge, we are able to communicate with our fellow colleagues professionally
when it comes to a design for an auditorium. Be it the design considerations, location and
material consideration, we have had the basic knowledge as our base to understand further
when it comes to the real world when everything gets more complicated.
These knowledge that we have obtained now could also aid us as an architect ourselves in the
future. Not just for an auditorium, any space that would require a certain degree of acoustical
insulation provided for the space. We as architects could evaluate the degree of acoustical
insulation that are needed to allow the space to perform well.
The reverberation time that we have learnt could also help us to determine if our space is suitable
for the specific function that we have designed for. Vise versa, we could also determine the
amount of additional components needed to fine tune the acoustical performance of the
auditorium to reach a specific figure of reverberation time. For example speech is below 1 sec and
orchestra is above 2 due to the difference in effects each figure could provide as an experience
for the audience. This way we could constantly calculate and determine the exact amount of
components that was needed to be added or removed from the auditorium to reach the specific
reverberation time required for the function. This would save us a lot of time and cost if compared
to the trial and error way of determining the amount of components needed which is very
ineffective.
Lastly, we would like to thank our fellow tutors for educating us the right way to understand
acoustics. From here, we could do our best to become an architect that is more knowledgeable
and more considerate in terms of designing a space for user experience.
82

Suppression of Noise from Source
Cempaka Sari Auditorium shall choose machines and equipments with relatively low operating
noise. Maintenance of machinery is also very important to reduce noise. The noise of the
machinery can be reduced by isolating the vibration noise generated by machinery by using
restrained or housed spring vibration isolators.
Suggestion of noise control
Architectural Design
The design layout of the auditorium shall be well organised by separating noise from quiet space.
The AHU room and service room are just close to the last row of seating and next to the control
room. Those service rooms shall be far apart from the auditorium so the audience can have a
better acoustical experience in the auditorium. AHU room and service room can be relocated to
other space such as behind the backstage.
Sound Insulating Building Construction
Increasing the sound insulating enclosure of the buildings materials for walls, ﬂoors, doors or
windows can reduce the noise levels. Higher STC rating of materials have a better insulation
against the airborne noise. For the AHU room or service room in the auditorium, more absorptive
material can be added along the partition wall. Roof shall be installed with insulating materials to
reduce the sound when there is bad weather.
83

1.0 Introduction
Cempaka Sari Auditorium. (n.d.). Retrieved from
http://www.aqidea.com.my/main/project/38-cempaka-sari-auditorium-putrajaya-
About Putrajaya. (2006, December 24). Retrieved from
http://www.ppj.gov.my/portal/page?_pageid=311,481418&_dad=portal&_schema=PORTAL
Putrajaya - The making of a new city. (2013, September 16.). Retrieved from
https://www.thestar.com.my/travel/malaysia/2013/09/16/putrajaya-the-making-of-a-new-city/
4.0 Acoustic Analysis
Sound Reinforcement Systems. (n.d.). Retrieved from
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