A presentation made by a group of students towards acoustical studies in DPAC

1. A CASE STUDY ON
ACOUSTICAL DESIGN
(DPAC) Chai Phey Chiat
Chow Wei Qi
Goretty Lee Pey Shy
Joslyn Siew Zi Tong
Koh Jing Fan
Ong Yi Teng (Crystal)
Serene Lim Jia Yi
Toh Yi Lin
Yap Shu Won
0334480
0331447
0326837
0334488
0330792
0326486
0334258
0327984
0331392

2. INTRODUCTION
Name of Auditorium : Damansara Performing Arts
Centre
Address : H-01, DPAC, Empire
Damansara, Jalan PJU 8/8, Damansara Perdana,
47820 Petaling Jaya, Selangor, Malaysia.
Chosen Auditorium : Proscenium Theatre
Total seats : Max. 200 pax
Stage : 11.25m (width) x 7.25m
(depth)
2

3. INTRODUCTION
-
3
Empire
Damansar
a
Empire
City
LDPHighway
Metropolit
an Square
Condo
PJ Trade
Centre
DPAC
- Built in 2013.
- A platform to enable local dance
artists to have more engagement
with international artists.
- Located within Empire Damansara,
Damansara Perdana, a mixed
development that satisfies both
business and lifestyle needs.

4. 1.
CONSTRUCTION
MATERIALS USED
(Damansara Performing Arts Centre)
4

5. CEILING
Materials : Concrete Slab and Spray Foam
- Ability to reflect sound since it is a hard surface. Hence, a
layer of sound insulation must be applied to reduce the
resultant sound.
- Spray foam as a layer covering concrete slab to reduce
sound reflection.
- Spray foam absorb small amount of sound.
- Most of the sounds are dispersed out.
5

6. REFLECTOR PANELS
Materials : Plywood
- Panels that are hang up just below the ceiling.
- Reduce sound reflection.
- Spray foam only reduces part of the sound waves,
hence, reflector panels reduce sound reflection by
absorbing sound waves.
- Absorb only low frequency sound, while high frequency
sound bounce back.
- Direct sound can be heard clearer for audience sitting at
the back as mass reflection of sound can be reduced using
reflector panels.
6

7. ACOUSTIC TREATED WALLS
Materials : Fibre Board, Rockwool, Concrete
- Combination of materials produces sound insulating wall.
- Reflects and transmit part of the sound into the wall.
- Fibre board facing the interior of the auditorium,
rockwool as the middle component and concrete at the
other side of the wall.
7
Acoustic
Treated
Wall
Zig-Zag
Steel Panel
Fibre Board Rockwool

8. ZIG-ZAG STEEL PANELS
Materials : Steel
- Diffuse the sound as diffusion of sound minimizes the
coherent reflections that causes distinct echoes.
- It is also functioning as to make an enclosed space
sound larger.
8
Incident Sound
Diffused Sound
Diffused Sound
Diffused Sound
Diffused Sound

9. CYCLORAMA WALLS
Materials : Fibre Board, Steel Framing
- Located on the stage.
- Define boundary of stage.
- Act as a sound barrier to backstage or vice versa.
- Made of fibre board at both sides, and the steel framing
system which holds the fibre board.
- White colour of it’s surface creates reflection of light and
forms focus point to the audience.
9

10. FLOORING
Materials : Concrete and Plywood
- Concrete flooring.
- Plywood lied with vinyl sheet as stage to ensure safety
of performers.
- Sound waves bounce and reflect to the whole theatre
due to hard surfaces of concrete and plywood flooring.
- Reflection of sound is reduced with installation of
zig-zag steel panels which diffuse sound in auditorium
and the absorption of sound by audience.
10
Plywood flooring
Concrete
flooring

11. FLOORING
Dance Vinyl Flooring
- This type of flooring has a high slip-resisting property.
It is installed on the plywood flooring which is the stage
as to increase the performers safety. However, it does
not have any effect towards sound absorption.
11

12. STAIRCASE
Materials : Plywood and Metal Plate
- Both the materials have a flat and reflective
surface therefore the sound waves are not
absorbed by them.
- Plywood has a coated surface, which
reflects light to the audience for walking
safely in the auditorium.
- LED lighting hidden underneath the
concrete flooring.
12

13. CURTAIN
Materials :
- There are three types of curtain found in DPAC.
Duvetyn, Bolton Twill fabric as well as Velvet fabric.
- The main function for these curtains are to hide the
lights from entering the auditorium.
- This is to prevent disturbance while the performance is
going on.
It can also absorb sound as well as decrease excessive
echo delay.
13
Duvetyn
Bolton Twill Fabric
Velvet Fabric

14. CURTAIN
Bolton Twill Fabric
- Used as a covering for the control space entrance.
- Cost friendly and durable.
- Reduce sound penetration and to avoid sound from
transferring through the structure.
14

15. CURTAIN
Velvet Fabric
- Placed at entrance of DPAC.
- Durable and reduce sound penetration.
- Avoid sound to transfer through the structure.
- Prevent lights from entering the theatre hence it does
not affect the quality of audience during the show.
15

16. CURTAIN
Duvetyne Fabric
- Placed at both sides of the stage as a stage skirting
- Fireproof
- Reduce reflection of lights and to prevent lights from
the backstage to penetrate to the audience or vice versa.
- Hide performers who are preparing for the show.
- High opacity, ideal for blocking out lights.
16

17. SEATINGS
Materials : Foam and Fabric cover, Plywood,
Steel
- Seatings made of foam and covered with
fabric maximize the sound absorption.
- As effective as the sound absorption of one
human being is equal to a seat.
- Steel stand supporting the seat.
- Air conditioning system in the steel stand
creates noises.
17

18. DOOR
Materials : Rockwool and Plywood
- Sound and noise control is in primary
concern.
- Sound waves can be reduced either from
the exterior to the interior of the auditorium
or vice versa.
- Audience will not be distracted as
minimal sound will transmit into the
theatre.
18
normal
door
normal
door
acoustic
door

19. SOUND LOCK
- To reduce the noise coming from the exterior of
auditorium.
- Sound is transmitted through the door into the “sound
lock” space.
- Sound has to transfer a distance of air to the acoustic
door, part of the sound waves have been turned into heat
energy and dissipates in the air.
- Acoustic door is installed with absorbing materials,
the sound is unable to transfer into the auditorium and
therefore the sound is greatly reduced.
19

20. 2.
SOUND SOURCE
(Damansara Performing Arts Centre)
20

21. 21
Sounds are vibrating waves that could be produced by musical instruments, human
vocal cord, running engine, vibrating loudspeaker diaphragm and so on. Sound can be
propagated through a medium such as air, water or even solid. Difference between
sound and noise is noise are unpleasant, loud and disturbing.
Sounds that can be found in DPAC :-
1. Speakers
2. Human Vocal Chord
3. Musical Instruments
What is Sound?

22. 22
Plan of DPAC
Locations of Speaker

23. 23
Locations of Speaker
Section of DPAC

24. 24
Plan of DPAC

25. 25
Section of DPAC

26. 26
Plan of DPAC

27. 27
Section of DPAC

28. 3.
SOUND PROPAGATION
(Damansara Performing Arts Centre)
28

29. SOUND REFLECTION
29
Seats are set back from the stage at a
distance to accommodate the shown
reflected sound without being interrupted
by the vertical reflective panel. The front
seats are strategically located to receive
the smallest angle of reflected sound from
the sound source.
Direct Sound
Reflected Sound
2100mm
Audience seating layout affected by sound reflection
Vertical reflective
panel

30. SOUND REFLECTION
30
Right side of the theatre has
more concentrated sound
distribution. However, the
reflected sound only reaches
a small range of audience
before it loses energy.
Left side of the theatre has a
wider reflected range due to
the angled walls.
Sound reflection analysis on plan

31. SOUND REFLECTION
31
Reflective ceiling plan
Suspended front
reflective panel
Suspended side
reflective panel
Vertical panel is placed attached to the ceiling in between the audience and stage to prevent
the stage lighting to affect the audience experience. This degrades the efficiency of sound
reflection.
Sound reflection analysis on section

32. SOUND REFLECTION
32
4790mm
3375mm
From the diagram on the left, the
suspended reflective steel panels
lengthens the range of useful ceiling
reflection, reaching a wider range of
audience.
Reflection panels

33. SOUND DIFFUSION
33
Direct Sound Diffusion of Sound Sound source
1
33
4
11
3
3 1
4
4
Direct
sound
Diffused
sound
There are a few prominent “diffusers”
in DPAC:
1. Zig zag reflective steel panels
2. Lightings
3. Cornerings
4. Stairs

34. SOUND DELAY/ ECHO
34
D
R1
R2
R3
R4
Direct Sound
Sound SourceReflected Sound
Listener
R1 = 10.2m
R2 = 11.0m
R3 = 10.3m
R4 = 10.5m
D = 11.2m
Time Delay 1
= (R1 + R2 - D) / 0.34s
= (10.2 + 11.0 - 11.2) / 0.34
= 29.4msec
.. . No delay
Time Delay 2
= (R3 + R4 - D) / 0.34s
= (10.3 + 10.5 - 11.2) / 0.34
= 28.24msec
.. . No delay
Time delay = (R1 + R2 -D)/0.34
Time delay 30msec - Effective reflective sound
Time delay 40msec - Delay
D
R1
R2
R1 = 10.6m
R2 = 18.2m
D = 14.0m
Time Delay
= (R1 + R2 - D) / 0.34s
= (10.6 + 18.2 - 14.0) / 0.34
= 42.35msec
.. . Sound delay

35. 35
SOUND DELAY/ ECHO
D
R1
R2
Direct Sound
Sound SourceReflected Sound
Listener
R1 = 10.6m
R2 = 17.6m
D = 14.0m
Time Delay
= (R1 + R2 - D) / 0.34s
= (10.6 + 17.6 - 14.0) / 0.34
= 41.76msec
.. . Sound delay
D
R1
R2
R1 = 11.0m
R2 = 12.0m
D = 16.2m
Time Delay
= (R1 + R2 - D) / 0.34s
= (11.0 + 12.0 -16.2) / 0.34
= 20msec
.. . Effective

36. 36
SOUND DELAY/ ECHO
Reflective ceiling plan
D
R1
R2
R1 = 8.0m
R2 = 6.0m
D = 8.4m
Time Delay
= (R1 + R2 - D) / 0.34s
= (8.0 + 6.0 - 8.4) / 0.34
= 16.47msec
.. . Effective
D
R1
R2
R4
R3
R1 = 13.6m
R2 = 3.9m
R3 = 12.0m
R4 = 7.0m
D = 15.0m
Time Delay 1
= (R1 + R2 - D) / 0.34s
= (13.6 + 3.9 - 15.0) / 0.34
= 7.35msec
.. . Effective. Also shows that there’s no
sound shadow
Time Delay 2
= (R3 + R4 - D) / 0.34s
= (12.0 + 7.0 - 15.0) / 0.34
= 11.76msec
To conclude this topic, the back corner areas experiences the defects of delayed sound reflection

37. SOUND SHADOW
37
D 2H
D
H D = 2.0m
H = 3.2m
2H = 6.4m
Calculation
.. . No sound shadow
.. . D 2H
To achieve uniform quality of sound under the entire
seating area, balconies (projector’s space) did not
protrude too deeply into the air-space of the room .

38. ECHO FLUTTER
38
The walls on one side is
slightly slanted at an 5
degree angle, which
disrupts the originally
parallel walls on both
sides of the theatre.
Hence, flutter echo fails
to occur.
The distance from the
backdrop of the stage
towards the wall at the
back of the audience
that is supposingly
parallel are far enough
apart to minimise the
effect of echo flutter.
d = 17.2m

39. SOUND DISTRIBUTION
39
Sound distribution of Huawei
smartphone music with highest
volume in the seating area
34.5
33.2 35.5 35.2
34.0 35.8 35.3
Sound
source
Sound distribution of noise
(air-borne, structure-borne,
inside noise) in the seating area
32.0
30.531.630.1
30.430.9
30..1
Sound distribution of normal
speech level the seating area
taken from the stage
44.1
45.446.644.9
45.647.145.7
Sound
source The sound distribution
is considerably evenly
distributed and at the
same time shows that
the sound propagation
strategies applied is in
an acceptable range
with the potential for
better improvements.
Decibel(dB) reading on sound distribution

40. 4.
POTENTIAL OF NOISE
INTRUSION
(Damansara Performing Arts Centre)
40

41. 41
Noise is unwanted sound judged to be unpleasant, loud or disruptive to hearing.
There are two ways in which noise (or sound in general) can be transmitted in acoustics hall:
1. Air-borne Sound Transmission
The noise is transmitted through the air from its sources. Along the continues air paths
through opening,such as open doors, cracks around doors and electrical fixtures.
2. Structure-borne Sound Transmission
Sound energy from a sources sets into vibration solid parts of the building structure, it
is transmitted directly through the structure is radiated from building structure.
What is Noise?

42. 42
AIR-BORNE SOUND
TRANSMISSION
TNB
DPAC
JALAN PJU 8/8
VEHICLES
- DPAC is located in Empire
Damansara, Petaling Jaya
- At the roadside of Jalan PJU 8/8
- TNB Station generates mechanical
systems that brings a source of noise
and sound pollution.

43. 43
AIR-BORNE SOUND
TRANSMISSION
Audience Entrance Door
- Sound intrusion could be identified when
there is an opening and closing the door
or human chatter and human noise
outside the entrance door.
Backstage Entrance Door
- Acts as an entrance for the performers
which also leads to a basement parking
lots or loading bay, which sound
intrusion could be identified.

44. AIR-BORNE SOUND
TRANSMISSION
Lighting Fixtures
- LED strip are kept in the internal steel panel where occupant could
be heard when sitting right next to or near to the steel panel.
- Sound intrusion could be identified from the buzzing noise of
lighting fixture.
44

45. AIR-BORNE SOUND
TRANSMISSION
Ducting & Diffuser
- Ducting and diffuser supply positive pressure
distribution systems and negative pressure
ducting for exhausting air from rooms.
- It is one type of sound intrusion that could be
identified due to the high pressure of air
distribution.
45

46. STRUCTURE-BORNE
SOUND TRANSMISSION
Fan Coil Unit (FCU)
- Opening slab metal stand were
designed beneath the seats
incorporates air conditioning on
every seats
- The sound transmitted through
structural-borne in which sound is
vibrating on the solid surface of the
AHU duct which causes a noise
issue to the interior
46

47. STRUCTURAL-BORNE
SOUND TRANSMISSION
Squeaky Staircase
- staircase treads is made by plywood, which
sound intrusion could be identified when
occupants are stepping on the staircases due
to structural borne transmission
47

48. STRUCTURAL-BORNE
SOUND TRANSMISSION
Performance stage flooring
- The stage is made of
plywood, it has sound
control which bounces
high frequencies,
resonating better sound
quality, and absorbing bass
energy
- the stage floor is covered
with vinyl sheet to
increase slip resistance
and reduce the noise.
48
Stage
Apron
Audience
seat

49. 5.
CALCULATIONS
(Damansara Performing Arts Centre)
49

50. REVERBERATION TIME
Reverberation time is defined as the time for the sound pressure level in a room to decrease by 60dB
from its original level after the sound is stopped. The reverberant sound in a room will fade away due to
the sound energy bouncing off. This often caused by absorption by multiple reflections between the
surfaces of a room.
It is dependent upon the following variables:
1. The volume of the enclosure (distance)
2. The total surface area
3. The absorption coefficients of the surfaces
50

51. REVERBERATION TIME
Hence, reverberation time can be calculated by the Sabine Formula:
Where:
RT = reverberation time (sec)
V = volume of the room (cu.m)
A = total absorption of room surfaces (sq.m sabins)
51

52. Estimated Floor Area (m²)
A : 173.46
B : 160.70
C : 29.61
Estimated Volume (m²)
A : 1243.88
B : 1854.64
C : 87.50
Total Volume of Auditorium (m3)
= 3186.02
Reverberation Time Calculation
Volume of Auditorium
A
B
C AB
C
52

53. Surface Material Area 500Hz
Absorption
coefficient
Abs.
units (m²
sabins)
Flooring
( Stage )
Plywood 128.21 0.05 6.41
Flooring
( Audience )
Concrete 106 0.02 2.12
Staircase Plywood 7.828 0.05 0.40
Staircase
(Metal Plate)
Steel 8.71 0.08 0.70
Human / Seat Cushion 169 0.042 7.10
Total Absorption (A) 16.73
A
B
C
E
A
B
C
D
E

54. Surface Material Area 500Hz
Absorption
coefficient
Abs. units
(m²sabins)
A Door Plywood +
Rockwool
6.00 0.10 0.60
B Transition Curtain Velvet Fabric 16.80 0.25 4.20
C Interior Curtain Bolton Twill
Fabric
4.00 0.10 0.40
D Zig-zag steel panel Steel 215.35 0.88 189.51
E Stage Curtain Duvetyn, 101.00 0.20 40.96
F Acoustic Treated
Wall
Fibre Board,
Rockwool,
Concrete
358.92 0.75 269.19
G Cyclorama Wall Fibre Board, Steel
Framing
85.00 0.30 25.50
Total Absorption (A) 530.36
A
B
C
D
E
F
G
A B
C D
E F G

55. Surface Material Area 500Hz
Absorption
coefficient
Abs.
units
(m²
sabins)
Ceiling Concrete
Slab + Spray
Foam
363.70 0.15 54.56
Reflector
Panel
Plywood 21.86 0.05 1.09
Total Absorption (A) 55.65
B
A
A
B
55

56. Total Abs Unit
= 16.73 + 530.36 + 55.56
= 602.65m² sabins
Total Volume of the Theatre
= 3186.02m
REVERBERATION TIME
= 0.16V / A
= 0.16(3186.02) / 602.65
= 0.85sec
3
56
The reverberation time for auditorium is 0.85sec with 3186.02m
which falls within the average range of recommended reverberation
time. This shows that the materials used compromise with volume of
the theatre to achieve an adequate reverberation time. The theatre
accommodate both speeches and musical events, therefore the
reverberation time is balanced in between to suit both the function.
3
DPAC

57. 6.
SOUND DEFECTS &
DESIGN ISSUES &
SOLUTIONS
(Damansara Performing Arts Centre)
57

58. 58
STAIRCASE SQUEAKY NOISE
Sound Defects & Design Issue
Footsteps on the plywood staircase creates low
frequency vibrations that is transmitted through
structure-borne which tend to vibrate throughout the
whole structure thus producing unpleasing squeaky
noises.
Design Solution
- thick carpeted flooring for the staircase that acts
as an outstanding sound absorber
- Shock absorbing underlayment (rubber)
Carpet
Rubber
Plywood

59. 59
POOR SOUND ISOLATION
Sound Defects & Design Issue
I. Ducting and Diffusers
Excessive high velocity of air that flows
through the diffusers blades generates noise
that penetrates into the theatre.
Design Solution
Ducting and diffusers should be covered by the ceiling
and not exposed within the theatre.

60. 60
POOR SOUND ISOLATION
Sound Defects & Design Issue
I. Light Fixtures
The light fixtures behind the zig-zag steel panels
produce a buzzing and flickering sound generated
by the ballast.
Design Solution
Lighting should undergo frequent inspection and
maintenance to ensure it does not produce internal noise
that would affect the acoustic quality of the theatre.

61. 61
MECHANISM NOISE
Sound Defects & Design Issue
FCU Air Conditioning System machines are placed below
the seats, generating mechanical noises through
discharging low velocity air supply from the openings
below the seats
Design Solution
Avoid placing openings below the seats to avoid
penetration of air flow that generates noises.

62. 62
REFLECTION
Design Suggestion
The ceiling has a larger surface area of concrete slab with spray
foam which reduces the reflected sound intensity, therefore,
several reflecting panels should be added to the highlighted
spaced to allow better sound spreading to all the areas within
the theatre. This is to ensure that the reflected sound towards
the back are better reinforced.
Additional Reflecting Panel
Existing Reflecting Panel
Direct Sound
Reflected Sound

63. 7.
CONCLUSION
(Damansara Performing Arts Centre)
63

64. 64
● Besides rules and regulations on designing an auditorium,
there is a need for an architect to design a space with
materials that can tackle with the sound effects and issues
in an auditorium that can serve a good acoustic
performance to the audiences.
● The DPAC is installed with building materials that can solve
the issues of most of the acoustical problems
● Also, the analysing of several factors which include material
properties and etc. as the good quality of sound can be
delivered to the audience.

65. THE END
Thank you.
65