Bsc final report

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SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN
Centre for Architecture Studies in Southeast Asia (MASSA)
Bachelor of Science (Honours) in Architecture
BUILDING SCIENCE II (ARC 3413 / BLD 61303)
PROJECT 1: A Case Study on Acoustic Design
Tutor: Ar Edwin Chan
Group Members:
Chan Jia Xin 0319565
Chong Yu Xuan 0317950
Leong Yu Shi 0322586
Lee Hui Qin 0322991
Lee Kai Yung 0318314
Ng Hong Bin 0319735
Tan Sheau Hui 0319235
Wong Kai Chiang 0323341

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TABLE OF CONTENT
Acknowledgement 4
1.0 Introduction
1.1 Aim & Objective 5
1.2 Site Information & Historical Background 6
2.0 Technical Drawings
2.1 Floor Plan 9
2.2 Ceiling Plan 10
2.3 Section 11
3.0 Acoustics
3.1 Literature Review 13
3.2 Research Methodology
3.2.1 Site Condition 25
3.2.2 Measuring Device 27
3.2.3 Data Collection Method 29
3.2.4 Acoustic Analysis Calculation Method 32
3.3 Data Collection

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3.3.2 Material Absorption Coefficient 37
3.3.3 Noise/ Identification of existing sound source 57
3.4 Analysis & Calculation
3.4.1 Sound Reflection 66
3.4.2 Sound Absorption 71
3.4.3 Sound Diffusion 81
3.4.4 Sound Echo 84
3.4.5 Reverberation Time (RT) 87
3.5 Solutions 90
4.0 Conclusion 94
5.0 Appendix 95
6.0 References 98

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ACKNOWLEDGEMENT
We would like to express our deepest appreciation to all those who have provided us the
possibilities in completing this case study report. A special gratitude we give to our
project tutor, Ar. Edwin, who has contributed in stimulating suggestions and guidance
throughout this project from helping in our data analysis, calculation and sharing of
knowledge in acoustic design.
Furthermore, we would like to express our gratitude to the people in charge of
Damansara Performing Art Centre (DPAC) who has given us an opportunity to visit and
carry out our study on their art centre and has provided us with all the information we had
requested during the visit and interview. A special thanks to Mr Woon, the theatre
manager who has arranged our visit very well, with a tour in the whole art centre guided
by the designer who has patiently explained about the acoustics and design intention of
the spaces.

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1.0 INTRODUCTION
In an auditorium where live performance of different kinds are being played, the quality of sound
or acoustics of the room is one of the main contributions to an enjoyable performance. A
“successful” auditorium is the one that is able to preserve and enhance the desired sound and
eliminate the exterior undesired sound from entering. In a group of 8, we have chosen Damansara
Performing Arts Centre as our case study. We are to collect data on the acoustic values of its
theatre room and to analyse the sound phenomena’s happening in it. Site visit and interviews
were conducted to acquire data of theatre and photographs and pictures for reference purpose.
The information collected are to be analysed, calculated then documented into a report format.
1.1 AIM & OBJECTIVE
The aim and objectives are as follow:
 To analyse and to understand the acoustic characteristics of an auditorium
 To determine the characteristics and functions of sound absorption materials within the
auditorium.
 To analyse the acoustic qualities of the space and suggest ways to improve it

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1.2 SITE INFORMATION & HISTORICAL BACKGROUND
Under the guidance and direction of Artistic Director, Wong Jyh Shyong (JS), DPAC Dance
Company (DDC) was formed along with the establishment of Damansara Performing Arts Centre
(DPAC), Malaysia. DPAC is choreographic workplace, DDC aims to present DPAC’s in-house
dance productions with local artists and collaborative projects between Malaysian and
international dance artists.
Damansara Performing Arts Centre (DPAC) is an organisation dedicated to promoting arts in
Malaysia, through learning, practising, and appreciating arts. DPAC aims to further enhance
public awareness on the importance of art-forms that enrich our lives while shaping today’s
world.
Images show proscenium theatre (left) and black box (right).

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Images show theatre foyer (left) and dance studio (right)
DPAC has a proscenium theatre, a black box, an experimental theatre, an indoor theatre-foyer and
several dance studios. They are all equipped with state-of-the-art facilities. These facilities cater
to the professional practices of different performing arts practitioners in various forms. DPAC is
prominently located at the main entrance to Damansara Perdana, just off the Lebuhraya
Damansara-Puchong (LDP), opposite PJ Trade Centre. The focus area of our study is the
proscenium theatre of DPAC.
The auditorium is not specially made standalone building, but was fitted into the site, between
the carpark and an office building, multiple changes was made to the site to accommodate the
auditorium. A column blocking the seating was removed to accommodate more seats and is
replaced by metal truss to hold up the roof. Several parts of the room were extended to increase
the sound insulation of the room. It uses an industrial design concept, using industrial metal
containers and plates as finishes for the interiors. The DPAC theatre room can accommodate up
to 200 people. It has two changing rooms, with one at the back stage and one on the level above.

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Figure 2.1: Floor plan of DPAC at 1:200 scale

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Figure 2.2: Ceiling plan of DPAC at 1:200 scale

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Figure 2.3: Section of DPAC at 1:200 scale

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3.1 LITERATURE REVIEW
Architectural acoustics may be defined as the design of spaces, structures, and
mechanical/ electrical systems to meet hearing needs. With proper design efforts, wanted
sound can be heard properly and unwanted sounds, which is noise, can be attenuated or
masked to the point where they do not cause annoyance. All acoustical situations have 3
common elements, a good source, a sound transmission path or paths, and a receiver of
the sound. Through design, a source can be made louder or softer, and a path can be made
to transmit more or less sound, whereas the receiver’s perception of sound may also be
affected.
To understand acoustics, we must first understand the properties of sound, and what
sound is. Sound is a type of wave, and to be more specific, a longitudinal wave, which is
a type of wave that travels horizontally. There’s also a more limited definition of sound,
which is more appropriate to architectural acoustics, is that it’s simply an audible
pressure variation. This establishes that architectural acoustics is concerned with the
building occupant.

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Figure 3.1.1: The figure above shows 2 types of waves, which is longitudinal and
transverse wave. Sound is a type of longitudinal wave.
(Source: https://socratic.org/questions/how-are-transverse-waves-and-compressional-
waves-alike)
From the figure above, it is shown that compression and rarefaction occurs continuously
when there is a sound source. The distance between two compressions is called a
wavelength, which is the distance sound travels in one cycle. Long wavelength produces
low frequency sounds, whereas short wavelength produces high frequency sound. Human
beings can only hear sounds with wavelengths ranging from 12mm to 15m. As for
frequency, it is the number of times that a cycle of compressions and rarefaction occurs in
a given unit of time. The higher the frequency of sound, the higher the pitch and vice
versa. Human beings can only hear frequency with a range of 20 to 20,000Hz. Also, a
sound is composed of only one frequency which is called a pure tone. Most common
sounds are complex combination of frequencies.

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Figure 3.1.2: Figure above shows the difference in frequency and pitch for long and short
wavelengths.
(Source: https://wikis.engrade.com/a121biology2012/soundcommunication)
SOUND IN ENCLOSED SPACES
The design of room acoustics is to maintain and enhance information intelligibility,
where the sound is not a continuous tone but a series of discrete sounds following one
another while containing information. Because of the behavior of sound waves, sound
can be reflected, refracted and diffracted. Eventually, sound attenuation occurs due to
energy loss when it travels in the air.
When sound waves hit a hard, polished surface, it reflects. When it hits a concave surface,
it focuses the wave into only one spot, which is considered not good in acoustic design.
When it hits a convex surface, it is reflected and spread out, diffusing the sound nicely in

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an enclosed space. Sound reflection is useful in the distribution and reinforcement of
sound in an enclosed space.
Figure 3.1.3: Diagram shows direct sound (black straight line) and reflected sound (green
lines)
(Source: https://continuingeducation.bnpmedia.com/courses/armstrong-commercial-
ceiling-systems/innovations-in-acoustical-ceilings-for-todays-flexible-interiors/5/)
Figure 3.1.4: Diagram shows how sound reflects on different surfaces. Sound is focused
when reflected off concave surface (above) and diffused out when reflected off convex
surface (bottom).

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(Source: https://ask.audio/articles/studio-acoustics-part-4-reflections-ii-flutter-echoes-
ambience)
Diffusion is the converse of focusing and it occurs primarily when sound is reflected
from convex surfaces. Different degrees of sound diffusion can be achieved by inclined
planes, flat planes or convex planes. In a diffuse sound field, the sound level remains
relatively constant throughout the space, an extremely desirable property for musical
performances.
Figure 3.1.5: Sound diffusion can be created by reflectors with different shapes, the
diffusion improves from (a) to (c).
(Source: 12th
edition Mechanical and Electrical Equipment for Buildings)
Sound can also be diffracted, which causes the waves to bent or scatter around objects
such as corners, columns, walls and beams. Sound waves with longer wavelength will not
be diffracted easily by these objects. The diffracted waves create a shadow zone, where
the noise is lower.

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Figure 3.1.6: Diagram which shows the diffracted sound, and a shadow zone is created.
(Source: http://www.esi-engineering.com/resources/blog/seven-ways-reduce-noise/)
Back to the reflection of sound, although it is stated that sound reflection is useful in
distribution and reinforcement of sound, but if the time delay of reflected sound is long,
the sound waves will not be reinforced, but instead bring negative reactions. The time of
delay where the reflected sound reaches the listener after they hear the direct sound is
30msec. Halls with different functions are able to have different time delays. For a lecture
hall which is used for speech and lecture, the time delay can be 40msec, while for a
music or concert hall, the time delay can be 100msec.
Figure 3.1.7: Diagram shows the first reflected sound.

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(Source: http://hyperphysics.phy-astr.gsu.edu/hbase/Acoustic/refdel.html)
However, what if the time of delay is even longer? Echo can be formed, which could
seriously affect the room acoustics. The time delay for an echo to occur is 50ms. Echo
should not be confused with reverberation as they are distinct repetition of the original
sound. Typical echo-producing surfaces in an auditorium are the back wall and the
ceiling above the proscenium. The energy that produces echoes can be redirected to
places where it becomes useful reinforcement, such as the audience seating area. Another
type of echo is flutter, perceived as a bussing or clicking sound, which occurs when
repeated echoes transverse back and forth between two non-absorbing parallel (flat or
concave) surfaces. Flutters usually occurs between shallow dome and hard, flat floors.
Figure 3.1.8: An auditorium section showing the causes and treatments for echoes.
(Source: 12th

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Figure 3.1.9: Diagram shows difference between echo and reverberation.
(Source: http://hearinghealthmatters.org/waynesworld/2016/echo-has-the-last-word-part-
2/)
Figure 3.1.10: Diagram shows the acoustical defects in an auditorium.
(Source: https://www.pinterest.com/pin/561683384751617137/)

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Another acoustical phenomenon in enclosed spaces is the reverberation. Reverberation is
the persistence of sound after sound source has ceased. This is a result of repeated
reflections in an enclosed space. Reverberation time is defined as the time required for
the sound level to decrease 60dB after the source has stopped producing sound.
Reverberation can be considered as a mixture of previous and more recent sounds. The
converse of reverberation is articulation. An articulate environment keeps each sound
event separated rather than running them together. Spaces for speeches should be less
reverberant than those designed for music performances. Reverberation can be solved by
adding absorbers to the side walls and ceilings to absorb the energy of a few sound rays.
Figure 3.1.11: Diagram shows reverberation in an enclosed space.
(Source: http://hearinghealthmatters.org/waynesworld/2016/echo-has-the-last-word-part-
2/)
Speaking of sound absorption, it happens when sound energy impinges on a material,
where part of it is reflected and the remainder is absorbed. There are 3 broad families in
sound absorption, fibrous materials, panel resonators and volume resonators. All of them

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absorb sound by changing sound energy to heat energy. Only fibrous materials and panel
resonators are commonly used in buildings, while volume resonators are used principally
as devices for absorbing a narrow band of frequencies. People also absorb a considerable
amount of sound energy. Sound absorption is a major factor in producing good room
acoustics, especially in controlling reverberation as stated before.
Figure 3.1.12: Image shows a porous absorber, which is part of the fibrous materials
family. These are materials with open pore structures such as mineral wool, glass fiber,
cellulose fiber and plastic foams. The sound energy is converted to heat energy. This
small amount of heat are the results from frictions and resistance of materials to
movement and deformation. Porous absorbers are mostly effective for high frequencies
sound.
(Source:
http://www.proav.de/index.html?http&&&www.proav.de/acoustic/absorber.html)

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Figure 3.1.13: Image shows a panel absorber mounted on a wall.
(Source: http://acousticsfreq.com/how-to-build-your-own-acoustic-panels/)
Figure 3.1.14: A cavity absorber, which is a type of volume resonator, is mounted on the
wall. It consists of an enclosed body of air confined within rigid walls and is connected
by a narrow opening and the surrounding space in which the sound travels.
(Source: http://hub.salford.ac.uk/acoustics/2016/12/05/acoustics-of-new-adelphi/)
(Source: https://en.wikibooks.org/wiki/Engineering_Acoustics/Noise_control_with_self-
tuning_Helmholtz_resonators)

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Figure 3.1.15: In (a), reverberant sound constitutes a large portion of received sound in
much of the room. In (b), the reverberant sound is greatly reduced by the wall and ceiling
absorption. (Source: 12th

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3.2 RESEARCH METHODOLOGY
3.2.1 SITE CONDITION
The theater that we have investigated is Damansara Performing Arts Center (DPAC). It is
located inside the Uzma Tower, which is within Damansara Perdana, and is located right
beside an underground carpark. The area is occupied by residential blocks, office towers
and commercial blocks, which makes it a very busy area. Opposite the site, which is over
the Lebuhraya Damansara-Puchong (LDP), a construction work is going on which
produces noise. Besides, noise also comes from LDP as there are many cars pass by
every day. The underground parking area also produces noise as the air-conditioning
compressors are placed there.
Although there are several noise identified outside, the theater is relatively quiet.
Acoustic doors used at the front and rear of the theater have contributed well in
preventing noises from coming in. There are no echoes observed during our visit. As the
theater is not deep, we could clearly hear when the person in charge was explaining about
the acoustic design by talking normally without the aid of microphone.
There is also hardly any sound from the air-con because it is only situated at the front of
the audience seating area. A specially designed metal structure with openings placed
below the seat will instead delivers cold air from the FCU unit, at which the air duct/pipe
is applied with sound absorbent to reduce noise. However, the round and steps in the
theater is made up of concrete and plywood, which will reflects sound and produces loud
noise when people are stepping on it. This would lead to great noise disturbance when
audiences use the staircases when a show is being played.

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Figure: 3.2.1.1: Site located opposite highway and construction site.
Figure 3.2.1.2: Overview of the theater, showing the concrete ground, plywood steps and
high ceiling.

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3.2.2 Measuring Device
Sound Level Meter
Figure 3.2.2.1: Diagram shows the meter, Lutron S1-4023SD, and the meter’s
specification table.
Specification
Model KK Instruments
Lutron S1-4023SD
Range Auto range: 30-130dB
Manual range: 3
ranges
~ 30-80dB
~ 50-100dB
~ 80-130dB
Resolution 0.1dB
Accuracy Meet IEC 61672

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Digital Single-Lens Reflex (DSLR)
Figure 3.2.2.2: Diagram shows the model of the DSLR used, which is the Canon EOS
M2. The camera is used to capture and record the site condition, materiality, construction
and technical details at the site.
Measuring Tape
Figure 3.2.2.3: Measuring tape is brought along to measure the thickness of material and
doors.

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3.2.3 DATA COLLECTION METHOD
a) Preliminary studies on the theaters and halls available in the area. Choose Damansara
Performing Arts Center (DPAC) as our case study.
b) Emailed the person-in-charge of DPAC and arranged a suitable time for us to visit the
theater.
c) Normally the theater will be busier during the weekends and certain weekdays, thus we
consult the person-in-charge to let us visit the theater when it is not in use.
d) The drawings are obtained from the internet. The drawings are then being redrawn by
our team members, with the measurements already stated in the drawings. The drawings
included plans, elevation and section.
e) Once we reached the site, the person who walk us around, who is actually the designer
of the theater, explains the overall acoustics of the theater as well as his design intention.
He also explain about the issues they are facing previously and how they solve it. We
have obtained a lot of valuable information from him.
f) Some members started data collecting on site with the tools mentioned earlier.
g) The data is then being compiled and tabulated.
h) Members are divided to collect data and observe the theater according to the following
list:
- All finishing materials and their specifications for walls, floor, ceiling, seats and
curtains.

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- Details of acoustic wall paneling or wall treatment.
- Elements or details that disperse, reflect or absorb sound.
- Sound reflectors on ceiling or walls.
- Check for sound shadow areas.
- Briefly analyze the surrounds with respect to potential noise intrusion.
- Check if there’s adjacent plant rooms that could pose a noise problem.
- Take as many pictures as possible for identification and reference purposes.
i) By using the data collected on site, Sound Pressure Level (SPL), Reverberation Time
(RT), and Intensity Level (IL) can be calculated.
j) Further discussion between group members are then carried out to analyze the result of
the data.

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DATA COLLECTION PROCEDURE
a) Gridlines are drawn to the plan to divide the theater into few zones for easy and
consistent sound intensity collection.
b) The theater is divided into 2 zones, which is the stage and the audience seating area.
Figure 3.2.3.1: Zone 1 is the stage area whereas zone 2 is the audience seating area.
c) Photos and location of sound sources are noted before the start of data collecting
process.
d) One of the member moves through the intersection of grid from front to back. The
intensity of sound is collected using the sound level meter at 1m height. This is to ensure
the readings is consistent and accurate at each zones.

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Figure 3.2.3.2: Method used to measure the intensity of sound.
e) The measurements shown on the meter is noted down.
f) Surrounding site conditions at points with higher sound intensity are analyze and
recorded.
g) The data collected is tabulated when we got back from the site.
3.2.4 ACOUSTIC ANALYSIS CALCULATION METHOD
Sound Pressure Level (SPL)
Sound pressure is a measure of the pressure on the eardrum while sound power is the
total sound energy radiated by the sound sources. The actual intensity and the actual
pressure corresponds to a particular decibel level, but are different in magnitude and units.
Therefore, the sound intensity level and sound pressure level have been equalized and the
decibel values of the two can be used interchangeably. Below is the equation used to
measure the sound pressure level of a sound source:

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SIL = 10 log (I/Io)
Where,
I = Intensity (watts)
Io = base intensity (1 x 10-12
W/m2
, the threshold of hearing)
For the analysis, this equation is required to measure the combined sound pressure level,
so that the average sound level of the covered area can be calculated. Since decibels
cannot be added up by themselves, it is needed to convert decibels into sound intensity.
After adding all the sound intensity of that zone, the sound intensity value is then
converted into decibels again.
Sound Reduction Index (SRI)
Sound reduction index, also known as transmission loss (TL), is the ratio expressed in
decibels, of the acoustic energy reradiated by the barrier to the acoustic energy incident
on it. This number is important to the building designer as it shows the actual noise
reduction between two spaces separated by a barrier. SRI can be defined as the difference
between the sound intensity levels in two rooms.
SRI = 10 log (1/T)
Where,

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T = Transmitted sound energy/ incident sound energy (dB)
This equation is only for a component with single material. The following formula can be
used to calculate the overall transmitted sound energy for a composite material:
T0 = (T1 x A1) + (T2 x A2) + (T3 x A3)/ A1 + A2 + A3
Where,
T0 = overall transmission coefficient (of a composite wall)
T1 = transmission coefficient of one component (dB)
A1 = area of that component (m2
)
After calculating all these, the overall transmission is subbed into the SRI formula to find
the sound reduction index. The SRI equation is used to measure the insulation against
direct transmission of air-borne sound and then contribute to analyze the effectiveness of
a certain partition in terms of materials and its ability to reduce sound transmission.
Reverberation Time (RT)
Reverberation is the prolongation of sound as a result of successive reflections in an
enclosed space after the sound source is ceased. Reverberation time is defined as the time
required for the sound level to decrease 60dB after the source has stopped producing

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sound. It varies to the room volume, materials used in the room and also the sound source.
RT can only be measured in an enclosed space.
RT = 0.16 V/A
Where,
RT = Reverberation time (sec)
V = Volume of the room (m3
)
A = Total absorption of room surfaces
RT is controlled mainly by the acoustic absorption within the enclose space, since it’s the
only variable in the formula given above. Each material has its own absorption
coefficient, most of the values can be obtained from a table written with its specifications
and readings (refer to Appendix). The equation allows us to analyze on the effectiveness
of the absorption of materials used in the selected site.
Time Delay
Time delay, as discussed before, is the time of delay where the reflected sound reaches
the listener after they hear the direct sound from the source. If the time delay is relatively
short, the reflected sound can reinforce the direct sound. But if the time delay is longer,
echo can happen, which makes speeches less intelligible and make music sound ‘mussy’,

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which is an undesirable experience. To calculate the time delay, the formula stated below
is used:
Time delay = (R1 + R2 – D)/ 0.34
Where,
R1 = Incident ray of reflected sound (meters)
R2 = Reflected ray of reflected sound (meters)
D = Distance between sound source and recipient (meters)
The formula above is used to calculate the time of delay in DPAC. A section drawing
helps in the calculation in order to find out all the variables, including the distance and
length of each rays. Based on the result, we can determine whether echo could happen in
the theater and its expected performance.

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3.3 DATA COLLECTION
3.3.1 MATERIALS AND ABSORPTION COEFFICIENT
Wall
1. Acoustically treated wall
Materials Area covered Absorption coefficient
Concrete + Rock wool + Fibre board 363m2
0.55 (500Hz)
Figure 3.3.1.1: Area covered by acoustically treated wall and measurement taken
For a proscenium theatre which serves multipurpose, DPAC is acoustically designed for
its wall, which extends from the front stage towards the back wall of audience seatings.
The materials chosen for this theatre are efficient sound absorber which give a reading of
0.55 for its absorption coefficient, a moderate absorber suitable for proscenium.

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Figure 3.3.1.2: Sound wave travels through the wall and energy is absorbed
The 42cm acoustic wall is constructed by two-component insulation, which are rock wool
core and fibreboard insulation with 150mm thickness, followed by a 250mm thick
concrete plastered by cement. Rockwool is made by spinning molten rock in a rotating
wheel at a high speed. Thus the molten rock becomes a mass of intertwined fibres which
are very fine threads that are bound with each other with the help of starch. As this
process involves dust formation, oil is added in the procedure.

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Figure 3.3.1.3: Fiberboard and rock wool core
(Source: http://www.archiexpo.com/prod/celenit/product-55534-888376.html)
Rockwool is a soft layer, makes it a sound absorber. Placing fibreboard on it makes the
wall a more effective acoustic absorber as the board absorbs high frequencies that the
rock wool does not.
2. Zig Zag Steel Panels
Figure 3.3.1.4: Zig zag panel mounted on acoustic wall

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Steel 326.7m2
0.88 (500Hz)
On the acoustic wall, multiples steel panel is placed in irregular arrangement to serve as
aesthetic purpose and to hide the lighting systems and wires based on the designer. The
zig zag pattern of the metal panels could cause sound diffusion which could lead to
unwanted sound in the theatre.
3. Cyclorama (Front stage Back Panel)
Plywood 85m2
0.05 (500Hz)
Figure 3.3.1.5: Area covered by cyclorama and picture taken from site

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Cyclorama, usually shortened to just ‘cyc” (pronounced sike) is a plain cloth or plastered
wall filling the rear of the stage. It is often used as the main backing for a dance piece etc.
In DPAC proscenium stage, the cyclorama is made by a plain flat white plywood. It
covers the entire back of stage with 13m length, 6m height and 150mm thick.
Figure 3.3.1.6: Diagram shows the sound reflection on cyclorama and ceiling reflectors
This white panel is functioned as a sound reflector during performances for sound travel
towards the audiences. Hard flat surface of plywood and white colour of it enhance the
sound reflection, along with the set of plywood reflectors installed on the ceiling above
the audience seats.

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Ceiling
1. Concrete Slab and Spray Foam
Concrete slab + spray foam 324.5m2
0.15 (500Hz)
Figure 3.3.1.7: Area covered by concrete slab with spray foam and picture taken from site
When designing the ceiling for the theatre in DPAC, sound absorption has come into
consideration. The concrete slab constructed could result in excessive reflection of sound
because of its hard surface, which would then produce unnecessary noise in the theatre.
Hence, a layer of 0.5 inches thick spray foam has been applied on the ceiling surface as
its acoustic finish.

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Figure 3.3.1.8: Diagram shows application of spray foam below concrete slab
(Source: http://www.webstersinsulation.com/wp-
content/uploads/2014/05/concreteinsulation-300x167.jpg)
Spray foam is a sound insulation that virtually eliminates airborne sounds such as music,
telephones, conversations and all mid to high range frequency noise. The execution of
spray foam is started with:
1. Examination of surfaces condition to verify and determine if sealing is required to
ensure bonding.
2. Then, it is followed by the preparation by providing coverings for surfaces that are not
to receive insulation to prevent over-spray.
3. Installation of spray foam and curing material with continuous natural or mechanical
ventilation.
4. Over spray is removed and protection of spray foam is done.
As a result, spray foam has increased the absorption coefficient of the ceiling from 0.05
(without spray foam) to 0.15 (with spray foam) in 500Hz.

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2. Reflector Panel
Plywood 20.5m2
0.05 (500Hz)
Figure 3.3.1.9: Area covered by reflected panel indicated on ceiling plan and picture
taken from site
In a theatre, sound travels through the space towards audiences by direct sound path and
reflective sound path. The front seatings are able to receive direct sound. However, when
the direct sound travels to the middle and back seatings, sound energy loss occurs. Hence,
wall and ceiling need to be carefully designed to aid in the sound reflection to allow
sound travel to all the audiences.
Beneath the ceiling, multiple plywood reflector panel are installed, hanged by steel
attached to the concrete slab. This is to allow sound to be reflected to audiences mainly at
the middle and back seatings. The panels are located in rows at the front and both sides of
the theatre. It covers only partially of the ceiling to avoid redundant sound reflection.

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Floor
1. Audience seating area
Concrete 190 m2
0.05 (500Hz)
Plywood 20.5m2
0.05 (500Hz)
Figure 3.3.1.10: Floor area covered by plywood and concrete respectively
For the flooring in DPAC, concrete is mostly used while plywood is used particularly for
the stage, which is called deck. The reason they used plywood for the deck is because it is
better to deal with abuse compare to other wood, so it is has more durability and
economical.
Plywood
Concrete

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Figure 3.3.1.11: Installation of Rosco Adagio in roll
(Source: http://cartwheelfactory.com/imagesjpg/rosco-subfloor.jpg)
The plywood floor is finished with vinyl sheet called Rosco Adagio to increase slip
resistances for the performers and it is suitable in multi-purpose show including ballet,
modern, tap etc. Concrete and plywood are both hard solid surfaces that allow sound
reflection thus sound could reach all of the audiences during performances and shows.
Stage is made by plywood and uplifted 185mm to create void underneath that could help
increasing the bouncy of performers and to avoid the injuries of performers as it disperses
some of the forces associated with dance, particularly in jumping and landing. The black

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colour of Rosco Adagio serves as a background that allows the audiences to have better
focus view on the performers during the show.
2. Staircase
Plywood 12.5m2
0.05 (500Hz)
Steel (side surface) 28m2
0.08 (500Hz)
There are two rows of staircases between the audience seats to allow easy access for the
audiences, the material used are plywood and metal. There are 12VDC SMD 5050 LED
strips placed under the plywood to lead the way to the audience seats.

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Figure 3.3.1.12: Elevation diagram showing the components of staircases
The purpose of using plywood is to serve as aesthetic purpose which also allow the
staircase to be more noticeable when the audiences are entering or leaving the theatre.
The hard surface of the staircase also reflect the sound and this might cause disturbance
when audiences walk out or into the theatre when the show is playing. The metal plate
located at the riser below the plywood tread also function as sound reflector in the
audience seatings.

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Seating
Cushion (Foam inner + fabric cover) 485m2
0.05 (500Hz)
Plywood (back, side armrest) 146.5m2
0.08 (500Hz)
Steel (stand) 40.6 0.08 (500Hz)
Figure 3.3.1.13: Area covered by cushion and plywood on audience seatings
The seats in DPAC are using the very common theatre seats which are made by plywood
and red cushion with a metal stand below. It makes the whole theatre looks more
colourful and it also provide comfort seating to audiences to enjoy the show.
Cushion
Plywood

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The metal stand also incorporates air conditional openings for every seats. The cushion
which covers a relatively large area of the theatre facing the stage act as sound absorber,
while the plywood placed at the back and side of the cushion has hard surface that reflect
sound.
Door
1. Plywood (normal door) 1.84m2
0.05 (500Hz)
2. Plywood + rockwool + metal
doorlock (acoustic door)
6m2
0.1 (500Hz)

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Figure 3.3.1.14: Indication of normal and acoustic door
In a proscenium theatre, the usage of acoustic door is crucial in bocking the noise from its
exterior through the openings. All of the openings are treated well, with acoustic doors on
the audience entrance and loading bay entrance in the backstage.
Figure 3.3.1.15: Section showing acoustic door material layers with 3D illustration

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Acoustic doors in DPAC are constructed by plywood with rock wool insulation in
between. Similar to the acoustic wall, the function of rock wool infill is to absorb
unnecessary sound. The absorption coefficient of normal plywood door could be
enhanced from 0.05 to 0.1 for 500Hz.
To reduce noise when closing the doors, a strip of rubber is applied on the edge of both
acoustic and normal doors in DPAC to minimize friction between plywood door panels.
Double door system is applied at the entrance by installing two doors, which is an
acoustic door and a normal timber door. The door facing the exterior is unnecessary made
into acoustic door as the space between both doors has provided a sound lock generating

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a very high acoustic insulation. Curtains are installed at the doors for further sound
absorption, which will be described in the following sections.
Elements on Front Stage
Figure 3.3.1.16: Components on a typical proscenium stage
(Source: https://www.austheatre.com.au/img/3dstagecurtains.jpg)
In typical proscenium stage, there are layers of curtains hanging on the stage, each for
different purposes. The diagram above shows the general curtains set up on a stage,
including house curtains behind the proscenium frame, side legs, borders, mid stage
curtain and backdrop curtain.
1. Proscenium frame
Plywood 47.3m2
0.05 (500Hz)

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Figure 3.3.1.17: Proscenium frame location in a theatre stage
(Source: https://s-media-cache-
ak0.pinimg.com/originals/e5/e4/99/e5e499ab7ca3c762b097b8837ffc8dd0.gif)
In a proscenium theatre or stage, there is a frame or arch separating the stage from the
auditorium, through which the action of a play is viewed. It simplifies the hiding and
obscuring of objects from the audience's view such as sets, performers not currently
performing, and theatre technology.
Figure 3.3.1.18: Area covered by proscenium frame and picture taken from site

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The frame in DPAC proscenium stage is 2.5m deep from the ceiling and 2.5m offset from
both the left and right side of the stage. It is made by plywood, painted in black as a
picture frame to focus audiences’ view and for minimal sound reflection.
2. Curtains on stage
Duvetyn 188m2
0.2 (500Hz)
Figure 3.3.1.19: Area covered by curtains on the stage
In DPAC, the curtains used on stage are the house curtain, 3 side legs fixed on both the
left and right of the front stage as well as the backdrop curtain. The house curtain is
opened at the beginning of a performance to reveal the stage set and closed during
intermissions and at the end of a performance. While the side legs to give depth to the
stage and sometimes to mask stage equipment. Backdrop curtain hangs in the back of the
stage to indicate scenery.

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These four layers of curtains used Duvetyn as material. Its black colour creates a
background and gives depth to the stage and thus create a focus of the stage when
performances are viewed. It also help to hide preformers who are preparing for the next
change for the show. Despite the soft surface of the heavy curtains which could absorb
sound, the black colour is also to minimize reflection of sound during a play.
Curtains at Audience Entrance
Velvet 16.8m2
0.25 (500Hz)
Figure 3.3.1.20: Area covered by curtains at the entrance
The red thick velvet curtain located at the front entrance is to serve the purpose of
covering the entrance to avoid the sound spreading towards the exterior and also to
reduce any noise from the exterior. This is due to the soft surface of curtain which could
absorb a little amount of sound. It also act as a welcoming element at the entrance of
theatre.

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3.3.2 IDENTIFICATION OF EXISTING ACOUSTIC/ SOUND SOURCE
Environmental Sound from Exterior
1. Vehicular noise from Lebuhraya Damansara-Puchong
Figure 3.3.2.1: Distance of DPAC to highway and surrounding context
Damansara Performing Art Centre (DPAC) is located in Empire Damansara, Petaling
Jaya, which is to the east of a large contour area of vegetation. Damansara-Puchong
highway is located more than 150 meters from the site. Hence, there is minimal noise
intrusion could be identified from the surrounding context.

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2. Car Park and Audience Entrance
Figure 3.3.2.2: Position of the acoustic door facing the underground carpark
There is an underground car park on the exterior of the theatre hall, which could be
identified as one of the sound intrusion. However, the carefully designed acoustic door
with rock wool core infill has obstructed the vehicular noise from entering the theatre hall.
Figure 3.3.2.3: Sound absorption shown in section of door and double door system
Plywood surface close to the carpark has greatly reflected the sound or noises from
entering the theatre backstage. Besides, the 25mm rock wool infill further absorbed the

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sound and minimize the sound that pass through the interior. Behind the acoustic door is
another door which the two combined to become a double door system, which create a
sound lock which serve as a great sound insulation.
Figure 3.3.2.3: Double door system in DPAC entrance
(normal door on the left, acoustic door on the right)
The similar door system is applied at the entrance for the audiences. At the entrance,
other than just the double doors, velvet curtains are added as it can absorb a little amount
of sound.

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3. TNB Station
Figure 3.3.2.4: Location of TNB station in relation with backstage of DPAC
Above the backstage of theatre hall, there is a TNB substation which could be a source of
noise and sound pollution. However, it does not bring effects to the interior of the main
area of the theatre, which are the front stage and audience seats.
Interior sound source
The interior sound source of the theatre hall comes mainly from the air conditioners,
projector fans and human activities. Initiatives have been taken to reduce the noise
produced from these elements during performances.

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Operation of Building M&E services and Machinery
1. Air conditioning system (Structural Borne Sound Path)
Figure 3.3.2.5: FCU air-conditioning system below the theatre audience seating area
In any indoor room, the noise of a functioning air-conditioning unit is inevitable. It is the
type of sound transmitted through structural borne in which sound is vibrating on the
solid surface of the AHU duct. This issue also occurs in DPAC. There are initiatives
taken which has minimize the sound of air flow in the audience seating area.

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Figure 3.3.2.6: Diagram showing the foam applied in air duct as sound absorbent for the
air-conditioning system
Figure 3.3.2.7: Air conditioning openings under seats (left); Treated AHU duct (right)
The noise of the fan coil unit (FCU) used in DPAC is controlled by putting a layer of
foam in the AHU duct to reduce air speed, thus minimize the air friction that produce
noise. The air duct is connected to the specially designed openings underneath the
audience seating.
Figure 3.3.2.8: Location of air conditioning on front stage
For the front stage, air conditioning unit is installed beneath the ceiling. However, there
are minimal noise which would not bring effects to the performance.

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2. Projector Fans (Airborne sound path)
Figure 3.3.2.8: Location of projector and fans in the theatre
Figure 3.3.2.9: Projector (left); Projector fans (right)
(Source:
http://www.gadgetreview.com/wp-content/uploads/2016/02/Epson-Home-Cinema-1440-
Best-Projector-2016.jpg
https://www.dhresource.com/0x0/f2/albu/g4/M00/DA/F4/rBVaEFehmjWAHwAvAAloy
nfe7bk843.jpg)

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In DPAC, one of the noise that could be identified is the sound produced by the cooling
fans of projector, which is also another airborne sound transmission. The location of
projector which is mounted to the wall near the back audience seatings causes the sound
obviously heard in the theatre during performances as the fans are functioning throughout
the play. This is an issue faced by most of the theatres, thus an acoustic design on
reducing the projector fans need to be made to solve the problem.
Figure 3.3.2.10: An example of indoor hush box
(Source: https://www.projectorenclosure.com/wp-content/uploads/indoor-hush-boxes-
projector-enclousres.jpg)
There is an existing design solution mainly for home usage, which could also be
considered to locate in a theatre. A hush box is designed as a projector enclosure which is
used to silence or hush a projector or other electronic devices that generate noise from the
cooling fan system or the electronics. It is done by drawing fresh air from the room itself.
Factors need to be considered are methods of bringing fresh air into the box and expel air
out of the box as well as air filtration to filter dust in the room.

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Occupant Activities
1. Staircase (Structural-borne sound path)
Figure 3.3.2.11: Noise produced by structural-borne sound path on the plywood staircase
when audiences steps on it
The staircase treads in DPAC is made by plywood, which causes noises when occupants
are stepping on the staircases. This could be a disturbance of noise when occupants are
entering and leaving the theatre particularly when a show is being played. The sound is
transmitted through structural-borne, where sound vibrates on the solid hard surface of
the plywood. In order to reduce the noise, softer material such as carpeted staircase thread
is more suitable to be used in a theatre.

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3.4 ANALYSIS AND CALCULATION
3.4.1 SOUND REFLECTION
In DPAC theatre hall which is mainly used for art performances, several aspects such as
the sound reflection were taken into consideration for a better acoustical performance.
This analysis will check to see if these additions are beneficial to the room acoustics, and
will make suggestions for changes if problems are found regarding the acoustics of this
space.
The reflection of sound follows the same laws as reflection of light
• angle of incidence (i) = angle of reflection (r)
• the incident wave, the reflected wave and the normal lay in the same plane.

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Figure 3.4.1.1: Acoustic Reflected Ray Floor Plan
S: Sound source; L1: Listener; D1: Direct sound; R1, R3, R5: Incident sound wave; R2,
R4, R6: Reflected sound wave

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Figure 3.4.1.2: Acoustic Reflected Ray Section
S: Sound source; L1: Listener; D1: Direct sound; R1, R3, R5, R7: Incident sound wave;
R2, R4, R6: Reflected sound wave; R8: Partially absorbed reflected sound wave
The amount of waves reflected depends on the smoothness, size, and softness of the
materials. To keep the sound inside the hall, a lot of components such as the wall, floor,
and stage are made out of smooth and hard surfaces which reflect almost all incident
sound energy striking them significantly. Smooth surfaces produce strong reflected sound
waves when sound waves hit them following the rule that the angle of incidence is equal
to the angle of reflection. The reflection of sound happens everywhere inside the room,
avoiding unnecessary usage of speakers which can save cost and energy during the
performance, making the hall livelier acoustically. Hence, the audience are able to enjoy
and witness the originality of the pure melody from the performers.

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S: Sound source; L1, L2, L3: Listener; R1, R3, R5: Incident sound wave; R2, R4, R6:
Reflected sound wave
In order to reflect sound effectively to the audience, sound reflecting panels are placed
suspended from the ceiling in this space. This analysis will check whether or not these
sound reflecting panels are effective.
Areas distinguished by blue are “live” areas, while seats marked in red indicate “dead”
areas. This shows that the sound reflecting panels are inefficiently designed to spread
sound to all areas of the theater. This might be unfair for some of the audience as they are
not able to receive the sound thoroughly during performance. Hence, solution will be
provided for this case.

70
S: Sound source; L1, L2: Listener; R1, R3: Incident sound wave; R2: Reflected sound
wave; R4: Partially absorbed reflected sound wave
As shown in figure above, some of the reflected sound wave is being absorbed by the
acoustic spray foam attached to the ceiling, making the spreading of reflected sound wave
throughout the hall inefficient. In contrast, as the sound reflecting panels suspended from
the ceiling is located near the stage, the audience of the front rows receive more of the
reflected sound ray than the rows behind. Therefore, we will try to find some solutions to
solve this problem, allowing the sound to be reflected to all areas of the audience.

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3.4.2 SOUND ABSORPTION
Sound absorption effect in DPAC is barely acceptable because of its function as a theatre
mainly for art performance, as they need reflection to enhance or amplify the sound.
Sound absorption is the change in sound energy when it passes through a material or
strikes on a surface. Majority of sound absorption is provided by the audience, therefore,
in this case, the room surface can be relatively reflective.
Beneficially, a reflective front stage area provides strong early reflections that is
integrated with the direct sound and enhance it. On the contrary, strong late reflection and
reverberation, such as from the rear walls, would not be integrated and may produce
echoes. To accommodate this, the stage area and front of the hall are made reflective and
absorption is placed in the seating area and rear of the hall.
Table below shows Sound absorption coefficient (α) of every material that is available in
the auditorium. Based on the absorption coefficient calculate the quantifying sound
absorption, which mean the effective absorption of a particular surface depends on the
area as well as on the absorption coefficient of the material. As for quantifying total room
absorption, it is basically a sum of every absorption of surface (AS), to get a total
absorption (AT).

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Drawings below show the types of material used and their location on plan, section and
ceiling plan.
Figure 3.4.2.1: Floor plan

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Figure 3.4.2.2: Reflected ceiling plan

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Methodology:
Absorption of a surface = Surface area (m2
) x Absorption coefficient (α) of surface
AS = S1 x αS
Total Absorption = ∑ (Area x Absorption Coefficient)
Surface Material Area
(m2
)
Absorption
Coefficient
Absorption of
a surface area
(m2
sabins)
Wall (Acoustic
wall)
Concrete with
fibreboard & rock
wool
363 0.55 199.65
Wall (Front
Stage)
Plywood 85 0.05 4.25
Wall (Zig-zag
steel panel)
Steel 326.7 0.08 26.136
Ceiling (Acoustic
ceiling)
Concrete with spray
foam
324.5 0.15 48.675
Ceiling (Reflector
panel)
Plywood 20.5 0.05 1.025
Floor (Audience) Concrete with spray
foam
190 0.05 9.5
Floor (Front
Stage)
Plywood 147 0.05 7.35
Staircase Plywood 12.5 0.05 0.625
Floor with stair
side surface
Steel 28 0.08 2.24
Seating cushion Foam inner with
fabric cover
485 0.46 223.1
Seating back,
side, armrest
Plywood 146.5 0.08 11.72
Seating stand Steel 40.6 0.08 3.248
Curtain
(Entrance)
Velvet 16.8 0.25 4.2
Curtain (Side
legs)
Duvetyn 188.5 0.2 37.7
Acoustic door Plywood with metal
door lobe and rock
wool
6 0.1 0.6
Proscenium frame Plywood 47.3 0.05 2.365
Normal door Plywood 1.84 0.05 0.092

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AT = (S2 x α2) + (S2 x α2) … + (Sn x αn)
Table 3.4.2.1: Total Absorption (A) of surfaces
Line Chart 3.4.2.: Absorption of a Surface
Based on the chart, most of the sound absorption happen in the wall, curtain, ceiling, and
also seating, which represents a person. Porous material is being used on all these places
such as rock wool, fibreboard and foam spray.
199.65
4.25
26.136
48.675
1.025
9.5
7.35
0.625
2.24
223.1
11.72
3.248
4.2
37.7
0.6
2.365
0.092
0 50 100 150 200 250
Wall (Acoustic wall)
Wall (Front stage)
Wall (Zig-zag steel panel)
Ceiling
Ceiling (Reflector panel)
Floor (Audience)
Floor (front stage)
Staircase
Floor with stair side surface
Seatings cushion + people
Seatings back, side, armrest
Seating stand
Curtain (Entrance)
Curtain (Side legs)
Acoustic door
Procenium frame
Normal door (Electrical room)
Absorption of a surface area (m2sabins)
typeofSurface
ABSORPTION OF A SURFACE
(Electrical room)
Total Absorption (A) 582.476

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Figure 3.2.4.4: Seat with cushion
For seating, it must represent a person when it is not being seated, so the absorption is the
highest among all other surface. Primarily the absorption happens in the seat cushion,
where the fabric and foam acts as a porous material which absorb most of the sound
energy.
Figure 3.2.4.5: Zig-zag steel panel
For the acoustic wall, it is a porous absorber, where rock wool and fibreboard does most
of the absorption of energy. The layer of wall consists 250mm thick concrete wall,

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150mm think rock wool and 10mm think of fibreboard. In this particular case, when
sound wave strikes the wall, first the energy will be absorbed. When it reaches concrete
wall, it is being reflected back and it then passes through the rock wool layer again, this
creates a double absorption of sound energy which is very efficient.
Figure 3.2.4.6: Acoustic spray foam on ceiling
Same apply to the ceiling, which consists of 15mm thick of spray foam and 300mm thick
concrete slab. Because of the spray foam thickness, it greatly affect the absorption
coefficient.

79
Figure 3.4.2.7: Floor Plan shows Reflection
R1: Incident sound wave; R2: Reflected sound wave

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Figure 3.4.2.8: Section shows Reflection
D: Direct sound; R1, R3: Incident sound wave; R2, R4: Reflected sound wave
Figure 3..4.2.9: Wall details
R1: Incident sound wave; R2: Reflected sound wave
Figure 3.1 shows when a sound wave strike on the wall, it gets double absorption by the
rock wool and fibreboard. Hence the sound energy gets lesser compared with the incident
sound wave, this helps prevents any echo or unwanted delay sound.

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3.4.3 SOUND DIFFUSION
Diffusion of sound in another term is the scattering of sound energy. The purpose of
sound diffusion is to promote uniform sound districution and to prevent the occurrence of
undesirable acoustical defects such as echo.
There is only one sound diffusion method being used in DPAC is the steel panel with
irregular surface, in which it is designed in a zig-zag pattern. In materiality aspect, these
steel panel come with various sizes and have a thickness of 0.1inch (3mm-), its
absorption coefficient is around 0.08 under 500Hz, which mean most of the sound energy
get reflected when it strikes on the surface.
The coverage of this steel panel is around 90% of the total acoustic wall surface area,
which contributed to a huge impact on diffusing sound. These steel panels covers all the
surrounding walls shown in figure 1, the reason of this is to further enhance the diffusion
of sound where audience can receive a natural quality of sound and there won’t be any
hard reflection which gives a sound illusion of two sound source, which is called echo or
delay reflection.

82
Based on the diagram shown above, sound diffusion plays a major role in this auditorium.
The setup of zig-zag steel panel is pretty much workable but the down-side of it is that
the position and properties of steel panels, it is placed before the acoustic wall which
mean most of the sound energy will be diffused first before it is being absorbed, which
can lead to a situation where unwanted sound may be heard although the sound is being
scattered.
Figure 3.4.3.1: Detail 2, Diffusion on steel panel

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Figure 3.4.3.2: Floor plan shows diffusion
D: Direct sound; R1: Incident sound wave; R2: Reflected sound wave

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3.4.4 SOUND ECHO
Echoes are distinct repetition of the original sound. Ray diagrams are a method for
analyzing whether or not reflected sounds would cause annoying echoes. If the sound
path of the reflected sound is more than 34m longer than the direct sound path, the
listener will perceive a noticeable and annoying echo. Reflected sound can come from
either the ceiling or the walls, and both will be analyzed.
Methodology:
Identification of occurrence of echoes using formula below:
Reflected sound1 + Reflected sound2 – Direct sound ≥ 34m
R1 + R2 – D ≥ 34m

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Figure 3.4.4.1: Acoustic Reflected Ray Floor Plan
S: Sound source; L1, L2: Listener; Da: Direct sound; R1a, R2b: Incident sound wave;
R2a, R2b: Reflected sound wave

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Calculation:
R1a + R2a – Da = 10.8m + 8.8m – 8.8m = 10.8m (≤34m)
R1b + R2b – Db = 18.0m + 9.3m – 8.9m = 18.4m (≤34m)
Based on the formula and calculation, we concluded that there’s no echo in our hall as it
is relatively small space for performance purpose. This is because they are being
absorbed quicker by the environment because of the close proximity of the walls as the
size of the space is too small for an echo. In our hall, due to small distance between the
audience and the reflecting surface, the sound reflects and reaches the audience so fast
that it is not perceived as an echo but as one sound.

87
3.4.5 REVERBERATION TIME (RT)
Component Materials Surface area
(m2)
Absorption
Coefficient
(500Hz)
Sound
Absorption
(m2sabins)
Floor Concrete
(Audience zone)
190 0.05 9.5
Plywood (Front stage) 147 0.05 7.35
Staircase Plywood 12.5 0.05 0.625
Steel (side surface) 28 0.08 2.24
Seating +
people
Foam inner + Fabric
cover
485 0.46 223.1
Plywood
(back,side,armrest)
146.5 0.08 11.72
Steel (stand) 40.6 0.08 3.248
Curtain Velvet (Entrance) 16.8 0.25 4.2
Duvetyn 188 0.2 37.7
Ground Floor Plan Section A-A’

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Door Plywood + metal
doorlock + rockwool
(Acoustic door)
6 0.1 0.6
Plywood
(Normal door)
1.84 0.05 0.092
Proscenium
Frame
Plywood 47.3 0.05 2.365
Wall 250mm concrete +
150mm fibrebaord &
rockwool
363 0.55 199.65
Zig Zag Steel Panel 326.7 0.08 26.136
White panel Plywood
(Front stage)
85 0.05 4.25
Ceiling Concrete + Spray Foam 324.5 0.15 48.675
Plywood
(Reflector Panel)
20.5 0.05 1.025
Total Absorption (A) : 582.48
Total Sound Absorption = 582.48m2
sabins
Total Volume of the space = 4368m3
Reverberation Time = 0.16V/A
= 0.16 (4368) / 582.48
= 1.2s

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The recommended reverberation time for a multipurpose medium size hall is between 1s
to 1.25s. From the data above, the reverberation time of the theatre is 1.2s which fall
within the range of it. Thus, the theatre has a good reverberation without the need of
further sound absorber materials to be added.

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3.5 SOLUTIONS
1. Structure-borne sound
One of the materials that will lead to structure-borne sound in this theatre is the staircase
that is made up of plywood. It leads to impact noise when people step on it while going
up and down the staircase as the sound is generated from a vibrating source. In order to
overcome this problem, a layer of carpet can be added to the top of the plywood which
act as sound insulator to reduce sound impact level.
Plywood
Figure 3.5.1: Energy transmitted through
solid

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Figure 3.5.2: Reduction of impact noise
The energy transmitted through the carpet will be reduced and impact sound will be
absorbed by the carpet too as carpet has a higher absorption coefficient.
As carpet has a higher absorption coefficient which is 0.50 for 500Hz, it will definitely
affect the reverberation of this theatre if it is installed on the flooring. Below is the new
calculation for the reverberation time of the theatre:
Original Total Sound Absorption + Sound Absorption of Carpet
= 582.48m2
sabins + (12.5 x 0.5)
=588.73m2
sabins
Impact noise

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RT = 0.16V/A
= 0.16 (4368) / 588.73
= 1.18s
It still falls within the average range of the recommended reverberation time with is
between 1s - 1.25s. We can concluded that this suggestion is able to help to solve the
problem of structure-borne noise without interfering the reverberation time.
2. Reflection
Figure 3.5.3: Acoustic Reflected Ray Section
S: Sound source; L1, L2, L3, L4, L5, L6, L7, L8, L9, L10: Listener; D1, D2: Direct
sound; R1, R3, R5, R7, R9, R11, R13, R15: Incident sound wave; R2, R4, R6, R8, R10,
R12, R14, R16: Reflected sound wave

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To allow efficient sound spreading to all areas of the theater and to avoid “dead” areas,
several sound reflecting panels were added to the space for better acoustical performance.
The panels were positioned so that sound would be reflected to the rows behind to
enhance the listening experience. The sound ray analysis will check to see if these
additions are beneficial to the room acoustics. The first and second row seats are nearer to
the sound source. Direct sound from the sound source is loud and clear, making
enhancement by reflection unnecessary. Several sound reflecting panels are added to the
ceiling of the theatre. The size and position is made to suit the reflection of sound waves
from the stage, enhancing the listening experience of the audience seated in the back.

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4.0 CONCLUSION
Throughout the findings and analysis on Damansara Performing Art Centre (DPAC), we
have developed an in depth study and gained knowledge on acoustic design specifically
for a auditoriums, theatres and music halls. In our case, the analysis on a proscenium
theatre allows us to be exposed to the rules and requirements that serve a good acoustic
performance to the audiences.
Materials selection of all componenets in a proscenium theatre must be carefully taken
into consideraion by determing several factors including the material properties,
absorption coefficient, sound reflection, absorption, diffusion and echo caused by the
design and arrangement of the materials. A slight change in the thickness, arrangement
and shape of the materials can greatly influence the acoustic performance of the theatre.
To have a more accurate and reliable analysis on the acoustics, data and readings come
into use for the calculation of sound pressure level and reverberation time (RT) to
determine the overall performance of the theatre. For a multi-purpose theatre as DPAC,
an RT between 1s to 1.25s is the most efficient. Our calculation showing an RT of 1.2s
proved DPAC theatre has been well-designed. However, we had also come up with some
solutions to further improve the acoustics of the theatre which are proved applicable by
another new set of calculation. Solution provided could reduce the noise of occupant
activities during performance, hence providing a better watching experience.

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6.0 REFERENCES
INTRODUCTION
Damansara Performing Arts Centre. (2016). Retrieved 29 April 2017 from
http://www.dpac.com.my/content/73/Venue%20-%20Theatre%20Foyer%20DPAC.html
TECHNICAL DRAWINGS
Malaysia Convention and Exhibition Bureau. (2017). Retrieved 29 April 2017 from
http://venue.myceb.com.my/floor-plan/damansara-performing-arts-centre-floor-plan
LITERATURE REVIEW & RESEARCH METHOLOGY
Barron, M., 2009. Auditorium acoustics and architectural design, 2nd edition. Spon Press.
Walter, G., Alison, K. (2014). Mechanical and Electrical Equipment for Buildings
(12th ed.).
Albano. J. (2015). Studio Acoustics, Part 4: Reflections II: Flutter Echoes &
Ambience. Retrieved 29 April 2017, from
https://ask.audio/articles/studio-acoustics- part-4- reflections-ii- flutter-echoes- ambience/
Hoboken, N.J.: John Wiley & Sons.
R. Nave. (n.d.). Early First-Reflected Sound. Retrieved 28 April 2017, from
http://hyperphysics.phy-astr.gsu.edu/hbase/Acoustic/refdel.html
Staab, W. (2016). Hearing Aid Echo – Part 2. Retrieved 29 April 2017, from
http://hearinghealthmatters.org/waynesworld/2016/echo-has- the-last- word-part- 2/

99
DATA COLLECTION
Walter, G., Alison, K. (2014). Mechanical and Electrical Equipment for Buildings (12th
ed.).
akuTEK. (n.d.). Stage Acoustics- Literature Review. Retrieved 29 April 2017 from
http://www.akutek.info/Papers/JJD_stage_acoustics.pdf
Encyclopedia Britannica. (2008). Proscenium. Retrieved 29 April 2017 from
https://global.britannica.com/art/proscenium
Flashcard Machine. (2017). Parts of The Theatre. Retrieved 29 April 2017 from
http://www.flashcardmachine.com/parts-of-thetheatre.html
US National Library of Medicine. (2013). Preventing dance injuries: current perspectives.
Retrieved 29 April 2017 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3871955/
ANALYSIS & CALCULATION
Walter, G., Alison, K. (2014). Mechanical and Electrical Equipment for Buildings (12th
ed.).
Acoustic impact noise absorbing replacement carpet underlay.
(2017). Soundservice.co.uk. Retrieved 27 April 2017, from
http://www.soundservice.co.uk/Acousticunderlay.htm
Airborne noise vs. Structure-borne noise. (2017).聽 Residential Acoustics. Retrieved 28
April 2017, from https://residential-acoustics.com/airborne-noise-vs-structure-borne-
noise/
Farrar. J (2015, August 10). The Science of Auditorium Design. Retrieved April
22, 2017, from https://www.ethos3.com/2015/08/the-science-of-auditorium-
design/
Hosting.co.uk, J. (2017). Acoustic Insulation Materials for Soundproofing | Noise
Stop. Noisestopsystems.co.uk. Retrieved 29 April 2017, from
http://www.noisestopsystems.co.uk/acoustic-insulation

100
Noise: Building Acoustics: Reverberation Time. (2017). Noisenet.org. Retrieved
29 April 2017, from
http://www.noisenet.org/Noise_Room%20Acoustics_Reverb.htm
Noxon, A. (2002, August). Auditorium Acoustics 102: Reflections Make All the
Difference. Retrieved April 24, 2017, from
http://www.acousticsciences.com/media/articles/auditorium-acoustics-102-reflections-
make-all-difference
Shams, A (2012, September). The Acoustical Design of the New Lecture
Auditorium, Faculty of Law, Ain Shams University. Retrieved April 22, 2017,
from http://www.sciencedirect.com/science/article/pii/S2090447912000317
The Development and Production of a guide for noise Control from Laminate and
Wooden Flooring. (2017). Gov.scot. Retrieved 29 April 2017, from
http://www.gov.scot/Publications/2005/03/20901/55206
Tucker, B. (2016, November 2). Acoustic Physics in the Theater. Retrieved April
19, 2017, from https://www.octaneseating.com/acoustic-physics-in-the-theater

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