Auditorium Acoustic Design Case Study

School of Architecture, Building and Design
Bachelor of Science (Hons) in Architecture
Building Science II (ARC 3413 / BLD 61303)
Project 1:
Auditorium: A Case Study on Acoustic Design
Lecturer: Ar. Edwin Chan
Group Members
Chong Jin Feng 0319645
Chong Yi Qi 0304898
Chow Hong Da 0318571
Clement Chen Kit Seong 0319574
James Tay Jia Chuen 0322210
Janice Lee Juen Yung 0318695
Kong Xhiang Lynn 0317730
Yong Yu Joon 0318299

ARC 3413 Building Science 2
A Case Study on Acoustic Design of an Auditorium
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TABLE OF CONTENT
1.0 Abstract
1.1 Aims & Objectives 3
1.2 Site Study
1.2.1 Site Introduction 4-5
1.2.2 Site History 5-6
1.2.3 Site Selection Reason 6
1.3 Technical Drawings 7-8
2.0 Acoustic
2.1 Literature Review 9
2.1.1 Architecture Acoustic 10
2.1.2 Sound Intensity Level 10
2.1.3 Reverberation Time (RT) 11
2.1.4 Sound Reduction Index (SRI) 11
2.2 Case Study
2.2.1 Elbe Philharmonic Hall 12-13
2.3 Material and Properties
2.3.1 Furniture Material 14
2.3.2 Wall Material 15
2.3.3 Ceiling Material 16
2.3.4 Floor Material 17
2.4 Acoustic Tabulation and Calculation
2.4.1 Table for Absorption Coefficient 18
2.4.2 Reverberation Time (RT) 19
2.5 Sound Analysis
2.5.1 Sound Source 20-21
2.5.2 Sound Reflection 22-25
2.5.3 Sound Echo 26-29
2.5.4 Sound Absorption 30-33
2.5.5 Sound Diffusion 34-37
2.6 Existing Noise Sources
2.6.1 External Noise 38-39
2.6.2 Internal Noise 40-41
2.7 Noise Control 42-46
3.0 Conclusion 47
4.0 Reference 48

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1.0 Abstract
1.1 Aims and Objectives
In this project, students are required to conduct a case study on the acoustic
functions of a local auditorium. We conducted a site visits to our selected auditorium
which is Istana Budaya and documented its history, floor layout, materials used and
other necessary information via photographs, rough measurements and also on site
observations. By analysing the data collected, we are to:
 Study and understand the acoustic characteristics of the auditorium
 Identify the types of sound absorption materials used and describe its properties
 Determine the suitability of the sound absorption materials and acoustic methods used
in relation to the function of the auditorium
 Propose solutions or better ways to improve the acoustic performance of the
auditorium.
After thoroughly analysing the acoustic characteristics of Istana Budaya we are to
compile our findings into an A4 report format as well as preparing slides for an oral
presentation.

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1.2.1 Site introduction
Figure 1.1 An exterior view of Istana Budaya Figure 1.2 An interior view of Istana Budaya
Istana Budaya is Malaysia's National Theatre also known as The Palace of
Culture. The building is located in the heart of Kuala Lumpur, next to the National Art
Gallery on Jalan Tun Razak. It is Malaysia’s main venue for all types of theatre
including local and international performances for musical theatre, operetta, classical
concert and opera. Istana Budaya was rated as one of the world's top 10 most
sophisticated theatres, the first theatre in Asia equipped with cutting-edge stage
equipment that is on par with the Royal Albert Hall in London.
Istana Budaya is designed by local architect, Muhammad Kamar Ya'akub, it’s
one of Kuala Lumpur's most striking structures due to its turquoise-blue tiled roof –
the 'folds' remind one of a giant origami piece. As in traditional Malay house, the
theatre is divided into three areas: the 'serambi' (lobby and foyer), the ' rumah ibu'
(auditorium) and 'rumah dapur' (stage or rehearsal hall). The main building takes the
shape of the 'sireh junjung' - traditional betel leaf arrangements used during Malay
weddings and welcoming ceremonies – with the foyer claiming the spot as the
theatre's most intricately design aspect. Additionally, the main theatre hall
(Panggung Sari) which can accommodate up to 1,370 audiences is a classic opera
house with a twist – its royal boxes open up like traditional Malay-style windows.

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Istana Budaya is vast and opulent, with plenty of white marble and doors
made of high-quality tropical wood with hand-carved flowers and leaf designs. The
entrance hall has lush carpeting, with the lobby prominently displaying the Cempaka
Flower and Beringin tree.
The entrance to the theatre is said to be an imitation of a traditional Malay
palace – noticeably the Balairong Seri at the Istana Budaya. The interiors of Istana
Budaya are intricately designed using the finest quality marbles of the Malay
Langkawi. The interiors doors and windows of the Theatre Hall are made from the
highest quality tropical woods, which are beautifully designed and crafted by
professional hands. The ambience leaves an everlasting impact on visitors.
1.2.2 Site History
In 1971, the National Cultural Congress began discussions and planning for
the creation of the National Theatre. As a result, in 1972 the National Cultural Group
(KBN) was formed under the Arts Development Branch within the Culture Division of
the Ministry of Culture, Youth and Sports (KKBS), and began operations as an
amateur outfit. While its central office is in Wisma Keramat, the group's activities
were conducted at a house in Jalan Ampang. At the end of 1973, the group moved
to the National Cultural Complex in Jalan Tun Ismail, the current home of The
National Academy of Cultural Arts and Heritage (ASWARA).
The National Cultural Group turned professional in early 1974 under the Arts
Development Branch, Cultural Division of the Ministry of Cultural, Youth and Sports.
However, at this juncture, the focus was only on the arts of dance and traditional music.
Then the Youth Symphony Orchestra (OSM) and the National Choir Group were formed
in 1982 and 1992 respectively. Further in 1993, the Experimental Theatre (ET) was set
up at the National Cultural Complex, and the Youth Symphony Orchestra was upgraded
to National Symphony Orchestra (OSK) and began performing professionally.

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In 1994, the Experimental Theatre was officially opened by the YAB Dato’
Seri Dr. Mahathir Mohamad, the fourth Prime Minister of Malaysia. The National
Cultural Group became part of the National Theatre Division under the Ministry of
Culture, Arts and Tourism Malaysia (KKKPM). In the same year, the Prime Minister
has helped realized the creation of the National Theatre with the approval of the
proposed site, the selection of building design and financial planning. Both the
construction of ET together with the establishment of the Tunku Abdul Rahman
Auditorium at the Malaysian Tourist Information Centre (MATIC) in Japan Ampang,
are endeavours to gain experience in administering the National Theatre.
The National Theatre of Malaysia began construction in July 1995 with a cost of
RM210 million, comprising 5.44 hectares and a floor area of 21,000 square meters.
Once completed on December 1 1998, the administration of the National Theatre
was moved to its permanent premise in Jalan Tun Razak. The following year, on
September 15 1999, the National Theatre under the name of Istana Budaya, was
successfully launched by the then Prime Minister, Dato’ Seri Dr. Mahathir Mohamad.
1.2.3 Site Selection Reason
Istana Budaya,is the National Theatre of Malaysia and one of the most
popular tourist spots. Istana Budaya is the first theatre in Asia with stage-of-the-art
stage equipment, it has been rated as one of the world’s top 10 most sophisticated
theatres in the world. The theatre hall Panggung Sari, has its unique design of royal
boxes inspired by the windows of the traditional Rumah Melayu. It is a good
opportunity to study how does a successful design of the theatre much depends on
its acoustic design including the auditorium’s layout and the materials that used for
sound absorption. It is the essential to preserve and enhance the desired sound and
to eliminate noise and undesired sound.

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1.3 Technical Drawings
1.3.1 Plans
Figure 1.3 Ground plan of Istana Budaya Figure 1.4 First floor plan of Istana Budaya

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1.3.2 Sections
Figure 1.5 Short section of Istana Budaya
Figure 1.6 Long section of Istana Budaya

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2.1 LiteratureReview
Acoustics is defined by the Oxford Dictionary as ‘Relating to sound or the sense
of hearing’. The study of acoustics is defined as the properties or qualities of a room or
building that determine how sound is transmitted in it. Despite the definition, many
mistakenly assume that acoustics is a strictly musical and architectural topic only. While
acoustics does include the study of musical instruments and architectural spaces, it also
covers a vast range of topics, including: noise control, SONAR for submarine
navigation, ultrasounds for medical imaging, thermo acoustic refrigeration, seismology,
bioacoustics, and electroacoustic communication.
Below is the so called "Lindsay's Wheel of Acoustics", created by R. Bruce
Lindsey in J. Acoust. Soc. Am. V. 36, p. 2242 (1964):
Figure 2.1 Lindsay’s Wheel of Acoustics

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The wheel describes the scope of acoustics starting from the four broad fields of
Earth Sciences, Engineering, Life Sciences, and the Arts. The outer circle lists the
various disciplines one may study to prepare for a career in acoustics. The inner circle
lists the fields within acoustics that the various disciplines naturally lead to.
2.1.1 Architecture Acoustics
Architecture acoustics is a branch of acoustical engineering about achieving an
adequate audible experience within a building. Architectural acoustics can be about
achieving good speech intelligibility in a theatre, restaurant or railway station, enhancing
the quality of music in a concert hall or recording studio, or suppressing noise to make
offices and homes more productive and pleasant places to work and live in.
As architects, it is important to understand architecture acoustics and how the
behaviour of sound can affect the space within. Knowing and understanding the
properties of sound help architects to control or manipulate the sound behaviour
through designing the form of the space and materiality of the space.
2.1.2 Sound Intensity Level
Sound intensity is defined as the energy carried by the sound wave per unit area.
The SI unit of sound intensity is watt per square meter w/m2. The sound intensity level is
a logarithmic quantity, measured in relation to the reference value, which is denoted as l
, expressed in dB, and is defined by the formula:
SIL = 10log10
𝑙
𝑙0

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2.1.3 Reverberation Time (RT)
Reverberation is the prolongation of sound as a result of successive
reflections in an enclosed space after the sound source is shut/turn off. Reverberation
Time is the time for the sound pressure level in a room to decrease by 60dB from its
original level after the sound is stopped. It varies due to the following factors, the room
volume, materials used and also the sound sources. RT can only be measured when it
is an enclosed space.
RT = 0.16V / A
Where,
RT = Reverberation time (sec)
V = Volume of the room (m ³ )
A = Total absorption of room surfaces
RT is controlled mainly by the acoustic absorption within the enclosed space and each
material has its own material absorption coefficient. This question allows us to analyse
on the effectiveness of the absorption of materials used in the selected site.
2.1.4 Sound Reduction Index (SRI)
The sound reduction index is used to measure the level of sound insulation
provided by a structure such as a wall, window, door, or ventilator. The process of
designing a space requires an understanding of sound reduction index in order to better
reduce the possibility of sound permeating from loud spaces through the walls into the
quieter space. The sound reduction index can be calculated through the following
formula:
SRI = 10log
1
𝑇
Where, T = Sound transmission

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2.2 Case Study
Elbe Philharmonic Hall, Germany
Figure 2.2.1 The Elbe Philharmonic Auditorium
The recently opened Elbe Philharmonic Hall in Germany shares many
characteristics with our aged Istana Budaya. From Acoustic ceiling panels, acoustic wall
panels and furniture to the stunning design and layout. The spiralling hanging ceiling
panels reflect sound back to the audience while the acoustic wall panels absorbs the
sound echo.
The auditorium—the largest of three concert halls in the Elbphilharmonie—is a
product of parametric design, a process by which designers use algorithms to develop
an object’s form. In the case of the Elbphilharmonie, Herzog and De Meuron used
algorithms to generate a unique shape for each of the 10,000 gypsum fibre acoustic
panels that line the auditorium’s walls like the interlocking pieces of a giant, undulating
puzzle.

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2.2.1 Comparison of Elbe Philharmonic Hall with Istana Budaya
Figure 2.2.2 Elbe Philharmonic Hall and Istana Budaya Sections
The plastered ceiling of Panggung Sari in Istana Budaya serves as an
aesthetic piece with lack of function as the angles and shape of the ceiling are not
directing sound waves towards the audiences. The ceiling only helps to diffuse and
disperse sound in all random directions, hence, weakening the sound energy towards
the audiences. As compared to the Elbe Philharmonic Hall in Germany, the spiral
hanging ceiling panels reflect sound back to the audience without weakening the sound
energy as much as Istana Budaya.
Figure 2.2.3 Elbe Philharmonic Hall and Istana Budaya Ceilings

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2.3 Material and Properties
2.3.1 Furniture Material
Figure 2.3.1 Istana Budaya seat pictures and dimensions
The Furniture in Panggung Sari consists of 1370 seats ( 745 seats in Stalls, 323
seats in Grand Circle and 302 seats in Upper Circle) which is made up of premier high
density plywood with painted surface on the backrest and seat while the cushion is
made up of polyurethane high flexibility foam. This assists in sound absorption where
the material used is a good sound insulator.

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2.3.2 Wall Material
Diagram 2.3.2 Wall panels and Sectional Detail
The Wall of Panggung Sari reflects many traditional elements of the culture of
Malaysia. The wood carvings add to the elements of the hall providing a more classic
malay style ambience. Besides that, the wooden wall panels are also specially made
acoustic panels which helps absorb and reflect sound using High density fibreglass infill
which has high sound absorption coefficient.

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2.3.3 Ceiling Material
Diagram 2.3.3 Gypsum ceiling board structure
The ceiling, which is approximately 18 metres from the ground is adjustable and
is made up of gypsum ceiling board. They are specifically designed to reflect sound to
the audience and the musicians while at the same time eliminating the echoing effect.
The hall sits on resilient pads and is surrounded by two concrete wall separated by an
isolation joint to eliminate external noise. Therefore, the air-conditioning is virtually
silent. Every element in the hall, every material and finishing, has been designed and
selected to create a flexible performing environment that complements a variety of
performances.

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2.3.4 Floor Material
Figure 2.3.4 Floor carpets and Stage flooring
The flooring of Panggung Sari is made up of woollen carpet consisting of 80%
wool, 20% nylon while the stage is made up of detachable wood to create flexibility
according to different performances. The carpet plays a vital role such that sound
reflected from the ceilings and walls are absorbed, preventing any echo.

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2.4 Acoustic Tabulation and Analysis
2.4.1 Table for Absorption Coefficient
Common Building Materials Absorption Coefficient
500Hz
Carpet Medium pile carpet on sponge rubber
underlay
0.28
Wood Boards Hardwood boards over 25mm airspace 0.1
Plaster Ceiling Gypsum plaster ceiling 0.02
Seats Fabric with wooden panel 0.2
Audience Per Person 0.46
Air Per m3 0.007
Door Solid Timber Door 0.06
Figure 2.3.5 Table of Absorption Coefficient

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2.4.2 Reverberation Time, RT
Volume of Panggung Sari = 30m x 23m x 20m
= 13800m2
Material Absorption Coefficient 500Hz
Component Material Surface Area
(m2 )/ Quantity
Absorption
Coefficient
Sound
Absorption
Floor Carpet 690 0.28 193.2
Wall Wood Boards 1520 0.1 152
Ceiling Plaster 900 0.02 18
Furniture Fabric Seats 1370 0.2 274
Door Solid Timber 48 0.06 2.9
Occupant 1375 0.46 632.5
Air 13800 0.007 96.6
Total Absorption (A) 1369.2
Reverberation Time, RT = (0.16 x V) / A
= (0.16 x 13800) / 1369.2
= 1.61 s

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2.5 Sound Analysis & Calculation
2.5.1 Sound Source
The Stage
As Istana Budaya is the main venue for all types of theatre and events, the stage
is the main performing area where the sound is produced and transmitted towards the
audience. The shape of the theatre hall, also called the Panggung Sari, reflects this, as
the audience is oriented to the stage, and the fan shape maximizes the sound traveling
towards every audience evenly.
Speakers
Apart from direct sound from the stage, speakers are installed around the perimeter of
the theatre hall as an alternative. For certain performances that use microphones, such as the
full-house concerts by Dato’ Siti Nurhaliza, having speakers spreaded evenly throughout the
theatre so the audience has the same audio experience regardless the seating location.

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Types of Speakers Used
Curved Speakers
The curved speakers are placed above the upstage, pointed towards the
audience. These speakers are large, and serves to amplify the voice of the performers
on stage, while the position mimics the sound source of the theatre. The curved shape
helps distribute the sound radially to give the audience the similar feeling of listening to
theatre.
P.A.Speakers
Dotted along the theatre are also smaller speakers, which are mounted on the
walls near the back of the theatre. These speakers serve to project the sound from the
stage to the back of the audience, to even out the sound of the performance to the
audience sitting farther back.

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2.5.2 Sound Reflection
Figure 2.5.2.1 is a sound reflection diagram
When sound travels in a given medium, it strikes the surface of another medium
and bounces back in some other direction, this phenomenon is called the reflection of
sound. The waves are called the incident and reflected sound waves. Reflection of
sound waves follows the law of, angle of incidence equals to the angle of reflection.

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Figure 2.5.2. compares the shape of ceiling between Istana Budaya and Elbe
Philharmonic Hall.
As previously mentioned, the plastered ceiling of Panggung Sari in Istana Budaya
serves as an aesthetic piece with lack of function as the angles and shape of the ceiling
are not directing sound waves towards the audiences. The ceiling only helps to diffuse
and disperse sound in all random directions, hence, weakening the sound energy
towards the audiences.
By changing the shape and the material of the ceiling, it will affect the direction of the
sound that hits the ceiling and the reverberation time. Although it may require a long
period of time to reconstruct the shape of the ceiling, we could also implement reflective
acoustic ceiling panels in Panggung Sari. By doing so,it helps to direct sound reflection
to the audience.
Figure 2.5.2.1 shows a staggered ceiling shape
Having a staggered ceiling shape with reflective acoustical panels is highly
recommended to maximise the area of useful ceiling reflections towards users.

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2.5.3 Sound Echo
Figure 2.5.3 is a Sound Echo diagram
Echoes are probably the most serious of room acoustical defects. Echo is a
reflection of sound that arrives at the listener with a delay after the direct sound. The
delay is proportional to the distance of the reflecting surface from the source and the
listener. Therefore the longer the hall, the longer the Delay/Echo.
There are two kinds of south paths which plays a role in defining time delay or
echo of the enclosed space namely, direct sound path and indirect sound path. In a
concert hall, reflected sound beneficially reinforces the direct sound if the time delay
between them is relatively short, that is a below 100msec. A time delay of 100msec for
music perceived as a sound distinct from that travelling directly from source to listener is
deemed as an echo.
Echoes should not be confused with reverberation. Echoes are distinct repetition
of the original sound whereas reverberation is multiple blended sound images created
from reflection. For example, when you stand in a huge room and yell “hello”, the very
first sound you hear reflected off the walls is a Delay/Echo whereas for reverberation
that Delay/Echo quickly turns into reverberation as the sound is reflected off a second,
third and fourth surface.

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2.6.3.1 Time Delay & Echo Analysis
Time Delay Formula:
Figure 2.6.3.1 shows plan view of direct sound and indirect sound path

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Figure 2.6.3.2 shows section view of direct and indirect sound path
Time Delay Calculations:

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Good:
T1, T3, T4 and T5 would experience reinforcement of the direct sound at optimum
levels as all the time delays are below 100msec.
Bad:
T2 would experience some echo effect which may affect pleasure of music as the time
delay is more than 100msec.

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2.5.4 Sound Absorption
Figure 2.5.4 is a sound absorption diagram
Sound absorption is defined, as the incident sound that strikes a material that is
not reflected back. Sound absorption is the change in sound energy into some other
form, usually heat when it passes through a material or strikes a surface.
An open window is an excellent absorber since the sounds passing through the
open window are not reflected back but makes a poor sound barrier. Painted concrete
block is a good sound barrier but will reflect about 97% if the incident sound striking it.
In Room Acoustics, surfaces of walls, floors and ceilings, room contents including
people contribute to sound absorption.

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2.5.4.1Medium Pile Carpet (Absorption)
Figure 2.5.4.1 is a cross section diagram of sound absorption on medium pile carpet
Of all flooring materials, carpet offers the best noise reduction. It strongly reduces
sound reverberation and absorbs over ten times more airborne noise than any other
flooring material.
When a sound wave strikes an acoustical material like carpet, the sound wave
causes the fibres or particle makeup of the carpet to vibrate. This vibration causes tiny
amounts of heat due to the friction and thus sound absorption is accomplished by way
of energy to heat conversion. The more fibrous the carpet, the better the absorption;
conversely denser materials are less absorptive. The sound absorbing characteristics of
acoustical materials vary significantly with frequency. In general low frequency sounds
are very difficult to absorb because of their long wavelength.

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By creating more quietness, carpet considerably enhances the feeling and offers
audience a more pleasurable and quality music played in the concert hall.
Used in Panggung Sari
Figure 2.5.4.2 shows a comparison graph on the absorption coefficient of different flooring
Besides Panggung Sari, the whole concert hall is covered with medium pile
carpet with sponge rubber underlay having an absorption coefficient of 0.28. Medium
pile carpets have moderate length fibres whereas the sponge rubber underlay, also
known as rubber waffle underlay also allows air circulation and support for the carpet,
minimising dampness and condensation under the carpet.

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2.5.4.2 Wood Panel Absorber
Figure 2.5.4.2.1 is an image of the panel Figure 2.5.4.2.2 is a cross section diagram
of the panel absorber absorbers in Panggung Sari
Typically, panel absorbers are non-rigid, non-porous materials which are placed
over an airspace that vibrates in a flexural mode in response to sound pressure exerted
by adjacent air molecules. Common panel (membrane) absorbers include wood
panelling over framing, lightweight impervious ceilings and floors, glazing and other
large surfaces capable of resonating in response to sound. Panel absorbers are usually
most efficient at absorbing low frequencies. This fact has been learned repeatedly on
orchestra platforms where wood panelling traps most of the bass sound, robbing the
room of "warmth."
In Panggung Sari, panels of plywood panels are placed over a spacer of 25mm
air space. When mounted on a wall with a spacer, sound gets behind the wood panels
so its rear surface can absorb. This air gap increases absorption as much as 50%,
causing it to have an absorption coefficient of 0.1 and also extends absorption to lower
frequencies when compared with flat wall mounting.

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2.5.5 Sound Diffusion
Figure 2.5.5 is a diagram of sound diffusion
When a sound wave hits an irregular surface like foam or carpet, the vibration
breaks up and travels along many much smaller paths. This divides the energy of the
wave, sending it in many different directions which deplete its energy faster.
Adequate sound diffusion is essential in many types of rooms because it
promotes uniform distribution of sound, accentuates the natural qualities of music and
speech and prevents the occurrence of undesirable acoustical defects. Sound diffusion
may be achieved with the aid of surface irregularities and scattering elements, alternate
application of sound reflective and sound absorptive treatments.

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2.5.5.1 Coffers
Figure 2.6.5.1 shows how sound diffuses on surface of coffers in Panggung Sari
In Panggung Sari, coffers can be found at the rear and sides of the concert hall
at all 3 floors. Sound that enters these coffers of irregular shape diffuses and scatters
everywhere evenly. Consequently, the sound diffused back to the audience will be
weaker hence reducing the echo effect.

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2.5.5.2 Curved Edges
Figure 2.5.5.2 shows how sound diffuses on the curved edge design of VIP boxes
The design of the VIP boxes are of curved edges which acts as a surface to
diffuse or disperse sound in all directions uniformly. Diffusion is very effective for high to
medium frequencies, as the vibration strength is less than that of a low frequency
sound, and therefore easier to disperse. As a result, this is a great way to reduce
echoes.

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2.5.5.3 Medium Pile Carpet (Diffusion)
Figure 2.5.5.3 is a diagram of sound diffusion on carpet surfaces
Carpet, other than having the role of absorption of sound, also acts as an
element of diffusion. The irregular shape of the medium pile carpet as seen from the
cross section of figure above allows sound wave to be scattered uniformly in all
directions after sound hits it.

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2.6 Existing Noise Sources
2.6.1 External Noise Source
2.6.1.1 Vehicles
Figure 2.6.1.1 is a picture of Jalan Tun Razak
Istana Budaya is located at the adjacent highway of Jalan Tun Razak, which is
one of the main road connecting to the heart of Kuala Lumpur and it is mainly
congested during the peaks hours including lunch time. However, Istana Budaya sits
comfortably 100m away from the highway, increasing the sound travelling distance and
therefore reducing the noise. Furthermore, Istana Budaya is also surrounded by many
trees and bushes which act as a partial sound absorber that helps in aiding the
reduction of background sounds. When one is inside Istana Budaya, you could hardly
hear any noises from the busy road.

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2.6.1.2 People
Figure 2.6.1.2 is a picture of the entrance hall
On the inside, one of the main noise sources is the interaction between the
receptionist and the audience, and also interaction between the performers and the staff
at the backstage. Although it is crowded with visitors when there are performances or
events, the sound lock system lengthens the traveling distance which made it possible
to minimize the noise travel into the auditorium.

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2.6.2 Internal Noise Source
2.6.2.1 Backstage Activity
Figure 2.6.2.1 is a picture of the back stage
The preparation and communication between the staffs and the performers at the
backstage are the main sources of noise. This issue is again easily tackled by using
sound lock system where there are masking and drapery seals used by increasing the
sound travelling distance and thus reducing the noise.
2.6.2.2 Air conditioning
Figure 2.6.2.2 are pictures of the air vents
The indoor cassette unit used in the auditorium are rather quiet as they have
ensured that all of the units are running at a low speed to prevent any noise. Despite
that, the linear diffusers used in the auditorium does the opposite as air had to force
through the tiny gaps which in return creates whooshing noises that might affect the
user’s experience.

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2.6.2.3 Seats
Figure 2.6.2.3 is a picture of the auditorium seats
The seats used in the auditorium are mostly noise free but that does not apply to
all as some of the seats are found to produce squeaky noises when pulled down. This is
due to the fact that the internal connections may have rusted and needed maintenance
and if it is not done so, it might disrupt the performance and affect the user’s
experience. Therefore, the auditorium will undergo maintenance every 6 months to
ensure all of the furniture, systems, and insulation is working well.

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2.7 Noise Control
2.7.1 Noise Control Methods
2.7.1.1 Mechanical and Electrical Design
Figure 2.7.1.1 is a picture of the mechanical ventilation
For the Istana Budaya’s air conditioning, the shapes of the diffusers are carefully
chosen as to reduce the noise produced that might affect the audience’s experience.
Using circular or square diffusers with the power set to low, the air conditioning needs
can be met, while the noise from high pressure air being forced out of smaller openings
can be reduced to inaudible levels.

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2.7.1.2 Sound Absorption
Figure 2.7.1.2 is a picture of the soft surfaces in the auditorium
There are multiple ways Istana Budaya implements sound absorption strategies
to reduce noise affecting the audience’s experience. For minor noises from the
audience such as moving seats, people walking, and etc., the cushioned seat and
carpet floors can absorb these noises, reducing its power and keeping it localised.

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2.7.1.3 Sound locks

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Figure 2.7.1.3 is a diagram of the sound locks used in Istana Budaya
The presence of compartmentalization of spaces using hallways acts as a sound
buffer to reduce overall sound exiting the outside of Panggung Sari vice versa. Due to
the separation of compartments, noise could not enter the concert hall as easily, giving
audiences the comfort of focusing only the performance.

46 | P a g e
2.7.1.2 Sound Insulation
Figure 2.7.1.4 is a diagram of the stage and its backdrop
For the noise produced backstage, the backstage is sound locked, so as to
prevent noise escaping to the audience. The Masking and drapery seals the backstage,
making noises from the backstage preparations would not be too loud as to distract the
event up front.

47 | P a g e
3.0 Conclusion
In this project we have learnt of the many characteristics that can affect the acoustic
performance of an auditorium. Things like materials, sound analysis, noise control,
existing noise and noise control play a big part in designing a good auditorium.
After this case study and analysis we have determined that the reverberation time of
this Panggung Sari is 1.61s. The optimal amount of reverberation for a concert hall
should be 2s and above. This value would be suitable for halls that conduct mostly
speeches and talks but not in this case. We would suggest using more sound reflective
materials on the ceiling and walls as mostly sound absorbing and diffusing materials are
present.
The ceiling and wall ornaments also should be more focused on its acoustic
properties rather than just being a grand aesthetic feature of the auditorium. The ceiling
and wall ornaments are supposed to be designed to reflect sound to improve the user
experience but the present ones in Panggung Sari mostly diffuse sounds at every
direction.
The rest of the features of Panggung Sari such as noise control, material choice and
noise control can be considered as good choices as there is the hall is relatively quiet
when everybody is silent in the auditorium.

48 | P a g e
4.0 Reference
1. Portal Rasmi Istana Budaya. (n.d.). Retrieved March 31, 2017, from
http://www.istanabudaya.gov.my/#!slide-1
2. W. (n.d.). Reverberation Time. Retrieved April 23, 2017, from
http://www.phy.mtu.edu/~suits/reverbtime.html
3. Inc., T. S. (2017, February 21). Auditorium Seating Layout & Dimensions Guide.
Retrieved April 21, 2017, from http://www.theatresolutions.net/auditorium-
seating-layout/
4. Cilento, K. (2011, October 18). Update: Elbe Philharmonic Hall / Herzog and de
Meuron. Retrieved April 01, 2017, from http://www.archdaily.com/177177/update-
elbe-philharmonic-hall-herzog-and-de-meuron-2
5. Reverberation Time. (1941). A. Madigan.
6. Sound Source Localization. (Springer, 2005.). P. Arthur, F. Richard.
7. Sound- Joseph Midthun-Samuel Hiti - World Book， 2012
8. Absorption Coefficients. (n.d.). Retrieved April 20, 2017, from
http://www.acoustic.ua/st/web_absorption_data_eng.pdf
9. Sound absorption. (n.d.). Retrieved April 23, 2017, from
http://www.paroc.com/knowhow/sound/sound-absorption
10.Reflection, Refraction, and Diffraction. (n.d.). Retrieved April 20, 2017, from
http://www.physicsclassroom.com/class/sound/Lesson-3/Reflection,-Refraction,-
and-Diffraction

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