SEM 5 : PROJECT 1 REPORT BUILDING SCIENCE 2

PANGGUNG BANDARAYA DBKL
DBKL CITY THEATRE

School of Architecture,Building and Design
Bachelor of Science (Hons) in Architecture
building science ii
arc3413/bld61303
PROJECT 1 :
Auditorium : A case Study on Acoustic Design
Tutor : Mr. Edwin
Aaron Tan Weng Ming
Arvindhan Balasingam
Darshiini Vig
Eddie Goh Poh King
Khor Hao Xiang
Loh Wei Shuen
Lovie Tey Yiqing
Schani Daniel Bharat
0322400
0319753
0319359
0322915
0318065
0317896
0318155
0318788

Building Science II PROJECT 1 : Auditorium : A case Study on Acoustic Design
1
CONTENTS
1.0 Introduction
1.1 Historical Background
1.2 Literature Review
1.2.1 Architectural Acoustics
1.2.2 Reverberation Time
2.0 Aim and Objective
3.0 Technical Drawings & Zonings
3.0 Ground Floor Plan
3.1 First Floor Plan
3.2 Sections
4.0 Observation and Analysis
4.1 Materiality
4.1.1 Identification of Materials
4.1.2 Sound Absorbent
4.1.3 Sound Reflector
4.2 Sound Source
4.2.1 Interior
4.2.2 Exterior
4.3 Sound Path
4.3.1 Sound Incident
4.3.2 Sound Reflection
4.3.3 Sound Concentration
4.3.4 Sound Diffusion
4.3.5 Sound Absorption
5.0 Noise
5.1 Noise control
6.0 Reverberation Time Calculation
7.0 Recommendation
8.0 References
02
04
05
08
25
28
29
32

2
Panggung Bandaraya DBKL (Malay for DBKL City Theatre) is a historical theatre hall located
across the Merdeka Square at the junction of Jalan Tun Perak and Jalan Raja, in Kuala Lumpur,
Malaysia Construction began in 1896 and was completely finished in 1904.The Panggung Bandaraya is
gazetted as a heritage building under the Antiquities Act, and its Moorish façade preserved.
The theatre formerly occupied the historic Old City Hall of Kuala Lumpur. The theatre and old
City Hall building were designed by colonial government architect, Arthur Benison Hubback, who was
also responsible for designing the Kuala Lumpur Railway Station, the Jamek Mosque and other colonial
structures throughout the Klang Valley.
A major fire in 1992 destroyed the entire interior of the theatre but City Hall's designers and
builders restored it soon after. The refurbishment that was undertaken had incorporated significant
modifications to the furnishing and the sound system, imbuing the interior with a sense of timeless
elegance. Architectural work on the exterior carefully preserved the theatre’s heritage.
With a 104-year old history, Panggung Bandaraya is a theatrical gem that is ideal for staging
productions from plays to musicals. The scene various successful productions throughout the years, the
old theatre holds many fond memories for performing arts enthusiasts in the city.
1.0 Introduction
1.1 Historical Background

1.2 Literature Review
1.2.1 Architectural Acoustics
Architectural acoustics is the science of planning and building a structure to maximise
sound flow and remain effective at extreme capacities. To retain audible comfort in a
building or space, architectural acoustics play a huge role.Certain measure of sound
intensity can be categorized as comfort levels for the users are applied here. The
architectural acoustics are affected by a few factors such as the building envelope design
from exterior to interior or vice versa and nature of material used in the interior design as
well as inter-space noise control. Sound source will be identified before the application of
architectural acoustics in a building.
1.2.2 Reverberation Time
In closed interiors of more or less substantial size, the listener does not only hear a direct
sound but a series of its delayed repetitions, that bounce off the confining surfaces.
Because the energy of sound waves is absorbed at every bounce during their travels,
these repetitions become weaker over time. When the source of sound is turned off, the
amount of reflected energy in the room decreases until it is entirely absorbed. This gradual
dying-out of sound is called reverberation
3

2.0 Aim and Objective
An auditorium is a special room built to enable an audience to hear and watch
performances at venues such as theatres. A successful auditorium design greatly depends
on its acoustic design which includes the auditorium layout and the absorption materials
used. It is essential to preserve and enhance the desired sound and to eliminate the
undesired sound.
From this project, we aim to understand the acoustic characteristic of the selected
site. The building that we had chosen for case study is the DBKL City Theatre. From the
case study, we are to study the materials used for sound absorption, sound source and
sound path of the auditorium as well as several calculations to prove the possibility of the
analysis.
4

3.0 Technical Drawings and Zonings
3.1 Ground Floor Plan 
5
Fan-shaped
auditorium
Splayed wall
Scale 1: 175
Figure 1.1 Ground Floor Plan

3.2 First Floor Plan 
6
Concave timber
finishes
Splayed wall
Concave timber
finishes
Convex timber
finishes
Scale 1: 175
Figure 1.2 First Floor Plan

3.3 Sections
7
Scale 1: 175
Slopping floor & raised
stage
Coffered
ceiling
Concave ceiling
Concave ceiling
Convex timber
Scale 1: 200
Slopping floor & raised
stage
Concave ceiling
Convex timber
finishes
Scale 1: 100
Concave Ceiling
Convex timber
ﬁnishes
Figure 1.3 Section X-X
Figure 1.4 Section Y-Y

4.0 Observation and Analysis
4.1 Materiality
4.1.1 Identiﬁcation of Materials in Auditorium
8
Figure 2.1 Materials that can be found in the auditorium on ﬂoor plan
Figure 2.2 Materials that can be found in the auditorium in section

4.1.2 Sound Absorbent
9
Fabric Wrapped Panels
Sound Absorption Coefficient : 0.70
Consist of glass fibre acoustic panels with
acoustically transparent fabric, it helps to
absorb and reflect sound to archive sound
intelligibility.
Fabric Upholstered Seats
Sound Absorption Coefficient :
Wood : 0.07
Cushion Seats and Backs : 0.44
The empty seat is representing one
person’s sound absorption during an
ongoing performance. It helps to absorb the
emitting sound and minimise the sound
reverberation to prevent interruption. Hence
there is not much difference of sound
quality during an empty hall and occupied
hall.
Plastered Ceiling
The concave plaster ceiling mainly helps to
concentrate the sound to the center with its
low sound absorption rate

10
Carpet
Besides acting as a sound absorber, the
soft carpet flooring reduces walking noise
which does not interrupt the performance,
psychological feeling of warmth.
Velour Drapes
Velour fabrics being applied in the curtain
and the reflective panels in the auditorium.
The drapes acts act a reverberation control.
Sound Absorption Coefficient per person is 0.45

4.1.3 Sound Reflector 
11
Timber Panel
Timber Panel channels sound reflection, to
the seatings.
Wooden Doors
The wooden door uses to prevent the sound
escaping from and going into the
auditorium. Rubber stripes is added at the
door slits to minimize the airborne.
Sound Absorption Coefficient per person is 0.45

4.2 Sound Source
Sound source, or source origin, is simply the epicenter from which a noise or vibration is
produced from. Sound is transmitted from various elements, and therefore a
categorisation of internal and externally produced sounds can be categorised by its
origins.
4.2.1 Interior Sound Source
12
Primary Sound Source
Speakers located at the front emit
majority of the noise during
performances. The orientation of the
porches that hold the speakers are
angled to reduce deﬂection and noise
overlapping.
Figure 2.3 Primary Sound Source : Speakers

 
13
Secondary Sound Source
Sound originating from the backstage theatre,
resonates and reﬂects the most, due to the lack
of absorbents, causing high noise level that
move outward to the audience area. The sound
from the lateral AC vents on either side emit a
low blowing sound that isn't distracting unless
the room is empty. This sound source mostly
diffuses with distance away from the vents.
Figure 2.4 Functioning Speakers
They're a total of 8 speakers in the hall, but only having 2 functioning and the other 6
too old to use. Another issue is that they're located behind a sound proof cloth, to hide
them, again reducing the potential sound.The over acoustics of the theatre is now at an
inefﬁcient level or and possibly deviated from the original noise distribution.
Figure 2.5 Secondary Sound Source : Backstage
and Air-Con vent

14
Toilets located on opposite sides
of the auditorium, act as a
secondary sound source, there is
no door and only a heavy velour
curtain acting as the door, which is
inefﬁcient as there is high noise
levels that can be omitted during a
show with the use of the toilets.
Figure 2.6 Secondary Sound Source : Toilet

15
Tertiary Sound Source
Tertiary sound that originates from
people themselves, whispers,
adjustments of seats and seating
positions as well as ﬁddling.
Figure 2.7 Tertiary Sound Source : Audience

4.2.2 Exterior Sound Source 
16
Being located right by a main road,
the sound source from trafﬁc as well
as on coming vehicles, affects the
reverberation effect on the spaces
within the theatre. As well as noise
that has been developed from
ongoing construction just by the
entrance also greatly increases
reverberation
Figure 2.8 Primary Sound Source : Construction Site

17
The noise from the main
foyer, resonates and by the
time it reaches airlock,
which acts as a transitional
space. It begins to diffuse
due to the sound absorbing
wall. The sound source from
the foyer is most generated
from people, conversations
and people ordering food
from the counters.
Figure 2.9 Secondary Sound Source : Foyer

4.3 Sound Path 
18
Sound from the speakers are more intense at the direction they are pointing at. As a
result, sound from the four speakers will each cover an area and these areas will
intersect with each other as they are all pointed towards the seats. This causes the
audiences sitting at the darker area on the diagram to receive a higher sound amplitude
as the sound paths overlap with each others at that particular area.
Figure 2.10 Sound Path of Speakers

4.3.1 Sound Incident ( Direct Sound )
19
Audience sitting at the front row will receive the highest incident sound
amplitude and it is louder as they are nearer to the sound source.
Audience sitting at the middle row will receive a moderate incident sound
amplitude from the sound source.
Audience sitting at the back row are actually in the sound shadow where
incident cannot reach so there will be only diffracted sound reaching them.
Audiences sitting at the ﬁrst ﬂoor seats will receive the lowest incident sound
amplitude because they are the furthest from the sound source.

4.3.2 Sound Reflection  
20
Reflected sound at the audiences sitting at the front row are not significant as
they are very near with the sound source.
Audiences sitting at the middle row will receive reflected sound from the back
of the stage and the back of the auditorium. Concave ceiling of the auditorium
also helps to reflect and concentrate the sound.
Audiences sitting at the first floor seats will receive reflected sound from the
concave ceiling, a part of the sound will absorbed by the coffered ceiling on
the first floor.

21
Wooden railings on ground floor reflect and diffuse the sound from the sound source.
Wooden railings on first floor reflect and diffuse the
sound from the sound source.
Figure 2.11 Sound Reflection on Ground Floor
Figure 2.12 Sound Reflection on Ground Floor

4.3.3 Sound Concentration
22
The large concave ceiling of the auditorium does not just contribute to the aesthetics.
It also act as a reflecting surface which concentrate the sound to the audience seats
below it. As a result, the sound reverberates within the auditorium and enhance the
sound quality.
The convex wooden railings on the first floor act as sound diffusers which reflect
sound from the sound source to different directions. As a result, the sound is
distributed more evenly to the whole auditorium.
4.3.4 Sound Diffusion
Figure 2.13 Sound Concentration through Section X-X
Figure 2.14 Sound Diffusion through Section X-X

4.3.5 Sound Absorption 
23
Fabric wrapped panels and curtains along the walls at
both sides of the auditorium help absorb the excessive
sound.
Fabric wrapped panels along the back of the auditorium’s
ﬁrst ﬂoor walls absorb excessive sound to prevent echoes.
Figure 2.15 Sound Absorption on Ground Floor
Figure 2.16 Sound Absorption on Ground Floor

24
Figure 2.17 Coffered Ceiling Details
( Not to Scale )
Figure 2.18 Long Section
( Not to Scale )
Coffered Ceiling
Coffered ceiling in the auditorium work
as sound absorbers. similar to a cavity
absorber (helmholtz resonators), it allows
sound to enter the concaved block and
reﬂect multiple times inside before
coming back out. As a result the sound is
weakened. As the coffered ceiling is
located at the back of the auditorium, it
helps prevent echoes which is one of the
most drastic defects.

5.0 Noise
Noise is a form of unwanted sound, usually judged as undesirable by recipients. Noise
distracting, annoying, or harmful to everyday activity. to determine whether a sound is
undesirable or not depends on loudness of sound, frequency, continuity, time of
occurence, place and activity being carried out, information content and origin of the
sound.
25
Washroom
Foyer
Backstage
Figure 3.1 Noise

5.1 Noise Control
26
The existing door have a little feature that reduces air borne
leakage by attaching rubber around the gaps between door
and door frame, which helps in reducing noise penetration.
Velour drapes helps a little in noise
control as they have the function of
controlling reverberation in a enclosed
space, attenuate chatter and also
eliminate sound reﬂections. Yet, it
doesnt affect the noise to much as they
are not as efﬁcient to reduce excessive
noise from penetrating.

27
The entranceway right after
the foyer acts as a sound lock
room, which have the function
of reducing transmission of
noise into an auditorium.
Coffered ceilings are also seen on
certain parts of the auditorium.
These coffered ceilings function as
sound diffusion by trapping sounds
in the sunken features.

6.0 Reverberation Time Calculation
Reverberation time based on 1000Hz 
28
As (chair) =
{ [ (8x0.12) + (4x0.02) + (4x0.04) + (2x0.17) ] x 0.07 } + { [2x0.17) + (4x0.19) +
(4x0.02) ] x 0.44}
= 0.1078 + 0.5192
= 0.627
∑ As (chair) = 280 x 0.627
= 175.56 sabins
As (floor) = (251.18 x 0.4) = 100.472 ≈≈ 100.47 sabins
As (wall Y) = (88.93 x 0.1) = 8.898
∑ As (wall Y) = 2 x 8.898
= 17.796 ≈≈ 17.8 sabins
As (wall X) = (98.23 x 0.1) = 9.823 ≈≈ 9.82 sabins
As (ceiling) = (150.71 x 0.15) = 22.6065 ≈≈ 22.61 sabins
AT = As (chair) + As (floor) + As (wall Y) + As (wall X) + As (ceiling)
= 326.26 sabins
V = 251.18 x 7
= 1758.26 m3
RT = =
= 0.86s
0.16v
A
0.16 x 1758.26
326.26
Conclusion:
According to the calculations, the reverberation time of the auditorium is 0.86s which is
more suitable for speech instead of musical performance. At the volume of XXX, the
recommended reverberation time for musical performance is 1.5-2s.

7.0 Recommendations
29
Toilet relocation
The locations of male and female toilets are at both sides of the front stage; therefore it is
a noise source. Hence, relocation of toilets are strongly recommended as toilets are a
frequently visited space that produces noise such as ﬂushing, door opening and closing
and so on that will interrupt the acoustics while the play is ongoing.
Recommendation
Shifting the toilets into the back of the auditorium as they are further away from the stage
to reduce noise interruption during the play
Figure 4.1 Toilet Relocation

30
Door Replacement
The doors that are present at the auditorium are made from solid timber that act as
another form of noise source due to the frequent opening and shutting of doors.
Recommendation
Acoustic doors should be used in the auditorium as they have features such as seals to
stop sound penetration around the door edges preventing noise from outside to
penetrate in. Other than that, acoustic doors are also silent when door is shutting or
opening so unnecessary noise will not affect the ongoing performance in the auditorium.
Figure 4.2 Door Replacement

31
Inefficient Sound Lock
Sound lock is technically an entranceway that has high absorptive walls and ceilings with
carpeted floor, used to reduce transmission of noise into an auditorium. As for the site,
there is an entranceway before the door into the auditorium which unintentionally acts as
a sound lock. But, it is not as effective because of its large volume, therefore sound or
noise is still able to transmit into the auditorium.
Recommendation
The sound lock efficiency can be increased by reducing the size of the entranceway, and
also creating two other sound locks of each sides of the entrance. This can be done by
adding another door and wall to create a small entranceway before entering the
auditorium.
Figure 4.3 Sound Lock Efficiency

8.0 References
Absorption Coefﬁcient Chart. (n.d.). Retrieved April 29, 2017, from http://www.acoustic-
supplies.com/absorption-coefﬁcient-chart/
Grondzik, W.T. & Kwok, A.G. (2015). Mechanical and electrical equipment for buildings.
New Jersey: John Wiley & Sons
McMullan, R.(2012). Environmental science in building. 7th. Ed. Basingstoke: McMillan.
Templeton, Duncan (1993). Acoustics in the Built Environment: Advice for the Design
Team. Architectural Press
Szokolay, S.V., (2004), Introduction to Architectural Science, Architectural Press,
Burlington.
Cavanaugh, W.J. & Wilkes, J.A.(1999). Architectural Acoustics – principles and Practice.
John Wiley & Sons, Inc. New York.
32

SEM 5 : PROJECT 1 REPORT BUILDING SCIENCE 2

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SEM 5 : PROJECT 1 REPORT BUILDING SCIENCE 2