The document discusses the acoustic design of the MBSA Auditorium located in Wisma MBSA, Shah Alam. Key aspects of the design include the reversed fan shape of the auditorium which helps diffuse sound to audiences. Materials like timber and carpet are used to absorb and diffuse sound. The seating arrangement is raked at a shallow angle to avoid direct sound towards audiences. The design aims to distribute sound evenly without concentrations and uses sound reinforcement systems. Reverberation time calculations show the design meets standards.

1. Building Science II (BLD 61303)
Project 1
A Case Study in Acoustic Design
(MBSA Auditorium)
Group Members
Chow Su Ling 0325020
Lim Peidi 0324272
Ng Lek Yuen 0324010
Ng Pui Yan 0324785
Sarah Esa 0324805
Tan Yang 0328025

2. Introduction

3. Wisma MBSA
The aim is to build a new civic center for
the new town in Shah Alam. The civic
center comprises of an administration
building, a town hall, an auditorium, a
small theater, a library and a museum.
Location : Wisma MBSA, Persiaran
Perbandaran, Seksyen 14, Shah
Alam
Architect : Baharudin Abu Kassim
Client : Majlis Bandaraya Shah Alam

4. MBSA Auditorium
Talk Events Performances

5. Level 3 Floor Plan
55000
55100
A
A’

6. Level 4 Floor Plan
55000
55100
A
A’

7. Level 5 Floor Plan
55000
55100
A
A’

8. Section A-A’

9. Auditorium Design Analysis
Shape & Massing . Seating Arrangement

10. Shape & Massing
The shape of the auditorium implements the reversed fan shape where the
sound can be reflected throughout the auditorium

11. Shape & Massing
Helps to diffuse sound
to the audience
Convex Ceiling Flat Ceiling
Helps to reflect sound
direct to the speaker
Reflected Sound Sound Shadow

12. Seating Arrangement
Raking of seat to a level that is not too
steep to avoid too much direct sound
towards the audience
Seating arrangement layout

13. Acoustics Design Analysis
Materiality . Propagation & Concentration . Sound Shadow . Reflection . Sound Delay . Noise Source . Sound Lock .
Sound Reinforcement

14. Materiality
Timber
Sound
Diffuser
Timber
Wall
Panel
Carpet
Floorin
g
Acoustic
al Plaster
Ceiling
Retractabl
e Seats

15. Sound Propagation
The materials and propagation areas has allowed consistent sound to be
propagated throughout the auditorium which demonstrates that the designated
utilization of material at MBSA auditorium are proper as it produces pleasant
sound, distributed consistently to every area

16. Sound Concentration
There is no specific concentration of sound in an area due to well distributed
sound within the auditorium because of its shape. The even distribution of
sound allows audiences to receive equal amounts of sound from every
seating position in the auditorium.

17. Sound Shadow
The depth of the balcony exceeds the height of the
gallery which creates an acoustical shadow beneath
H ≥ D
3.2 ≥ 5.2

18. Sound Shadow
Sound energy that enters does not leave strong as balcony is too deep with
the angle view of less than 45 degrees

19. Reflection Towards Front Rows
Sound Reflection Direct Sound
Weak sound reflection. Shorter distance in between allows direct sound
towards audiences

20. Reflection Towards Back Rows
Sound Reflection Direct Sound
Direct sound get weaker to the end. Reflected sound blocked by gallery
Sound
Reinforcement
Direct Sound
Sound reinforcement added to provide direct sound

21. Reflection Towards Gallery
Sound Reflection Direct Sound
Sounds get weaker due to long distance towards the gallery
Sound
Reinforcement
Direct Sound
Sound reinforcement provides direct sound

22. Sound Diffusion
Timber diffuser allows
high frequency sound to
be diffused as they have
shorter wave length

23. Sound Delay
12.5m
9.5m
11.2m
17.7m7.1m
20.1m
Time Delay
= (R1 + R2 – D)/0.34
= (11.2 + 12.5 – 9.5) /0.34
= 41.8 msec
Time Delay
= (R1 + R2 – D)/0.34
= (17.7 + 7.1 – 20.1) /0.34
= 13.8 msec
Acceptable sound delay as sound delay are below 100msec and
around 40msec

24. Interior Noise Source
Foot Steps
Ballast in
Lights
Squeaking
Sound of
Chairs
Air Con
Diffuser
Chit
Chat
65dB
32dB
24dB
28dB
38dB

25. Exterior Noise Source
Mosque
51dB
65dB
67dB
50dB
68dB
Chit Chat
Highways
AHU Room
Opening &
Closing Doors

26. Sound Lock
Level
3
Level
4
Sectio
n

27. Sound Reinforcement System in MBSA
Array
Speaker
Stage Monitor
Speaker
Single Speaker
Cabinet

28. Indication of Speakers in Sections
Distributed speaker system is used to overflow sound to the audience in the
auditorium. A distributed speaker system is effective to majority of the
audience to gain adequate sound quality. Besides that, there are some landed
speakers on the stage and floor also contributes to the adequate of sound
quality.

29. SABINE FORMULA : RT = 0.16V / A
Where,
RT : Reverberation Time (Sec)
V : Volume of the Room
A : Total Absorption of Room Surface
= 1.25s
= 1.25s(0.16) 7545m3
964.71m2
The volume of MBSA auditorium is
approximately 7545 m3, with a
reverberation time of 1.25 seconds.
Reverberation Time

30. Designed with in-depth acoustic to cater speech events
Conclusion
Dedicated for speech only but with the sound reinforcement system,
MBSA Auditorium provides efficiency for performances
Equipped with systems to ensure the audience have best experience
- Sound evenly distributed without sound concentration
- Materials that diffuse & reflects sound to audience while
absorbing excessive sound
Auditorium cannot designed to cater all events as every event has
different acoustics requirements

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