Building Science 2

1. BUILDING SCIENCE 2 (BLD
61303/ARC 3413)
PROJECT 1
AUDITORIUM: A CASE STUDY ON
ACOUSTIC DESIGN
PREPARED BY:
Leemul Dev Nathoo (0326878)
Low Chi Yin (0329147)
Nadrah Idrus (0323741)
Neville Geoffrey (0317780)
Ngu Xian Le (0323898)
Nurul Shahira (0326500)
Siti Nur Fatahiah (0320595)
Sharifah Sarah Yasmin (0331760)
Vincentia Mutiara Kartika (0303496)
Tutor: Mr Azim Sulaiman
1

2. CONTENTS
1.0 Introduction
1.1 Acknowledgement
1.2 Aim and Objectives
1.3 Background
1.4 Site Information
1.5 Drawings
3
2.0 Methodology
2.1 Measuring Instruments
2.2 Data Collection Methods
2.3 Sound Equipments
2.4 Equipments Specification
8
3.0 Acoustical Phenomena
3.1 Acoustic in Architecture
3.2 Sound Intensity
3.3 Reverberation, Attenuation, Echoes, and Sound Shadows
3.4 Issues of Acoustic Design Strategies
3.5 Acoustic Design for Auditorium
13
4.0 Acoustical Analysis
4.1 Auditorium Design Analysis
4.2 Material and Properties
43. Acoustic Treatment and Components
4.4 Sound Sources
4.5 Noise Sources
4.6 Sound Propagation and Related Phenomena
18
5.0 Reverberation Time 32
6.0 Observation, Recommendation and Conclusion 34
7.0 References 36

3. 1.0
INTRODUCTION

4. 1.1 Acknowledgement
1.2 Aim & Objectives
With great pleasure, we would like to express our utmost appreciation and
gratitude to our lecturers, Mr Azim and Mr Edwin, who has given us guidance and
supervision throughout this project.
We would also like to thank Chris, for helping us on arranging the site visit at
MAPKL and the friendly companion throughout the visiting period. With his help,
we were able to get more informations about this site.
The aim of the report is to document the research that had conducted on the
acoustical design of an auditorium in order to provide an insight into the intricacies
of acoustic modelling, design, and implementation.
The objectives of the report are as follows:
1. To analyze the relationship between acoustics and the materials, spatial
planning and context of an auditorium.
2. To study and develop an understanding of auditoriums through their design
layout and judge its influence on the effectiveness of the acoustical design for
its designated purpose.
3. To study the general acoustical characteristics of an auditorium hall and
develop a good understanding of the physics being their functions.
By observing and analyzing the types of acoustical design theories applied in
the auditorium, we are then able to develop a better understanding on the
characteristics of architectural space and how it affects the multiplicity of design
approaches that can be taken for the said space to be considered “acoustically
efficient”. It is also important to know how different types of designs and their
acoustical treatments influence the sound efficiency and the overall user experience.

5. 1.3 Background
MAP is an arts and cultural platform that serves as a catalyst to explore
contemporary ideas and provide opportunities for arts and cultural producers to
develop their ideas while promoting compelling encounters to a broad audience.
MAP’s main spaces include the White Box and Black Box. They are supplemented by
Publika's Art Row, Outdoor Stage at The Square, and The Boulevard. Its
management team and operating system promote the importance of openness,
flexibility, and ease of use. MAP and Publika has played host to a diverse range of
activities, including exhibitions, theatres, dance performances, fashion shows, music
gigs, corporate events, community bazaars, lectures, seminars, workshops, . It
encourages groups and organizers to use the space to achieve their goals toward a
more positive social and economic change.
1.4 Site Information
Name of auditorium: MAPKL Black Box
Location: Level G2, Block A5, Solaris Dutamas, No 1, Jalan Dutamas 1
Type of auditorium: Multi purpose auditorium
5,000 sq ft space with option for 250 tiered seating or 300 floor-level seating.
The space is sealed from daylight and equipped with lighting and AV system.

6. 1.4 Drawings
Ground Floor Plan

7. Section A-A
Section B-B

8. 2.0
METHODOLOGY

9. 2.1 Measuring Instruments
Digital sound level meter
A device used measure sound that travels through air at a particular point in
the auditorium,its unit is decibel.It is commonly a hand-held instrument with a
microphone. The diaphragm of the microphone responds to changes in air pressure
caused by sound waves.
Measuring Devices
These devices are used to obtain measurements of our auditorium for
drawing and calculation purposes. They were also used to measure the distance
of the sound level meter from the sound source when sound levels were taken.
Speaker
The speaker was used to play music in the auditorium that act as a
sound source at a single point.

10. Digital Camera
A digital camera is used to capture images of the existing context within our
auditorium. These images would later be used as evidence to our analysis on how
such components contribute to external noise, such as the finishing materials
(including walls, floor, ceiling etc.), details of acoustic wall panelling or wall
treatment, position of sound source (including speakers, poorly designed air
conditioning or lighting systems etc.), occupancy level and activities carried out
within the auditorium.
2.2 Data Collection Methods
In order to achieve first hand experience, formal arrangements were made
prior to the visit ensuring that the auditorium would be unoccupied and allowing us
to conduct a thorough investigation without disturbance. With the help of all
preceding tools mentioned, we noted down as many details within our ability and
constraints, including the auditorium’s layout & form, noise sources, furniture,
materials and notable acoustic components. Measurements of the auditorium were
also taken for drawing and calculation purposes, along with on-site sketches of the
floor plans and sections for supporting any analysis.

11. 2.3 Sound Equipments
The surround system that Black Box used is stereo system that allow panning
and it adds depth to the acoustic image. This system is perfect to greatly enhance
live music on the site.
The speakers located at the highest position in the site surround the area to
spread the sound uniformly to the whole area.
The subwoofer located at both side of the stage. They are placed on the
ground as opposed to being ceiling mounted, to ease relocated to serve different
purpose of the event.

12. 2.4 Equipments Specification
Product Brand
Dimension
Power Consumption
Weight
Frequency
Sound Level
Behringer
640 * 400
300W
55.2lbs
55Hz-18kHz

13. 3.0
ACOUSTICAL
PHENOMENA

14. 3.1 Acoustics in Architecture
In today’s architectural environment, good acoustical design is a necessity.
Acoustics in Architecture is concerned with the propagation of sound within a
building, from the exterior of the building to the interior and vice versa. In other
words, acoustics in buildings concerns the prevention of sound transmission in order
to avoid unnecessary acoustic disturbances.
The type of building or function of a room affects the level of acoustics
required for hearing and understanding to take place properly. For example,
acoustic feedback of an interior for speech or music is essential in a music hall or
lecture room; infiltrating noise is from the outside is disturbing – and can even be
unhealthy.
Technically, sound is defined as a vibration in an elastic medium. An elastic
medium is any material (air, water, physical object, etc.) that has the ability to return
to its normal state after being deflected by an outside force such as a sound
vibration. The more elastic a substance, the better it is able to conduct sound waves.
3.2 Sound Intensity
Sound Intensity Level is defined as the sound power per unit area
(watts/m2).
Sound power ( W ) describes the strength at the source , and sound intensity (
I ) or sound pressure ( P ) describes the strength at the receiver , accounting for
distance, room surface sound absorption, room geometry, and other environmental
effects.

15. 3.3 Reverberation, Attenuation, Echoes and Sound Shadows
Reverberation
As sound ricochets inside an enclosed space, and reflections bring about
reflections‐of‐reflections, sound seems to linger. The persistence of sound in a room
after the sound source is suddenly stopped is dubbed reverberation. Reverberation
is the collection of reflected sounds from the surfaces in an enclosure like an
auditorium. It is a desirable property of auditoriums to the extent that it helps to
overcome the inverse square law dropoff of sound intensity in the enclosure.
However, if it is excessive, it makes the sounds run together with loss of articulation -
the sound becomes muddy, garbled. To quantitatively characterize the
reverberation, the parameter called the reverberation time is used.
Attenuation
When sound travels through a medium, its intensity diminishes with distance.
In idealized materials, sound pressure (signal amplitude) is only reduced by the
spreading of the wave. Natural materials, however, all produce an effect which
further weakens the sound. This further weakening results from scattering and
absorption. Scattering is the reflection of the sound in directions other than its
original direction of propagation. Absorption is the conversion of the sound energy
to other forms of energy. The combined effect of scattering and absorption is called
attenuation.
Echoes
Echo is a reflection of sound that arrives at the listener with a delay after the
direct sound. The delay is proportional to the distance of the reflecting surface from
the source and the listener.
Sound Shadows
Sound Shadows is a phenomenon caused by the absorption or obstruction of
a sound wave by an object in its path. The effect produced is perceived as a
reduction in loudness depending on the observer's position with respect to the
sound source and obstructing object and is greatest when the three are aligned.

16. 3.4 Issues of acoustic design strategies
Exterior to Interior noise Transmission
As was the case for room to room transmission loss, exterior to interior noise
transmission depends on the weakest link in the chain, which in most cases is either
the windows or the doors. Where a site is located in a noisy area and a quiet interior
noise environment is desired, windows and doors that have a high transmission loss
values are critical. Thus the doors, both wood and glass, and windows are the main
transmission path.
When choosing a suitable location for a building in which artistic
performances will take place, the exposure to exterior noise must be investigated so
that the necessary noise control and sound insulation measures can be estimated
and later designed.
Like windows, exterior and interior doors are a major source of sound leakage
in critical applications. Unlike windows, doors are frequently opened and closed and
it is the gaps at the joints and at the threshold that present the greatest problem in
controlling noise.
Protecting against noise and vibrations from various Systems
Occupied spaces need the continuous delivery of the requirements for the
human habitat— air, water, power, a controlled thermal environment— and the
return of the waste products back to the surroundings in the form of carbon dioxide,
waste water, sewage, refuse, and heat. To carry out these functions specialized
machines are included in every building. Noise and vibration are often the
byproducts of these mechanical processes.
One of the most important quality attributes in rooms for sound is their ability
to facilitate silence. This is the only way to ensure that the quietest passages of music
or text are not lost in the background noise. In acoustically demanding venues, it is
normal to specify a maximum of 25 dB(A) for disturbing background noise;
requirements are also placed on the spectral composition of the disturbing noise
level.
Achieving a low level for any disturbing background noise calls for careful
planning, which begins with the choice of location for the building and the design of
the internal layout and continues right up to the specifications for passive noise
control measures and building services.

17. 3.5 Acoustic design for auditorium
Aims:
● Preservation of sound intensity
● Clearly in sound delivery
● Reasonably reduce noise, echoes
● Optimize reverberant sound
Considerations:
Selections of Site
The proposed site should be far away from possible noise like railway station,
industrial area, construction site, highway and etc for an excellent acoustical quality
of the auditorium hall.
Shape and Form
For greater seating capacity, the side walls should be splayed from the stage.
The splayed side walls allow greater seating area that is relatively close to the stage.,
a greater ratio of reverberant sound is desirable.
Small general-purpose auditorium are typically rectangular, with the walls near the
front of the room angled out from the stage. For lecture halls more of a fan shape is
preferred, with the maximum angle between opposing walls no more than 140 ◦ . In
the case of mixed use spaces the included angle falls between 40 ◦ and 80 ◦ , with
smaller values being best for music.
Materials
Apart from the seating, all the other surfaces in a concert hall for classical
music are generally acoustically reflective. This means that solid surfaces with a high
weight per unit area are required in order to achieve good reflection of the sound,
also for low frequencies.
Volume
Volume influences both the reverberation time and room gain. At low
capacities a high volume per seat is necessary to control excessive loudness. At
higher capacities a low volume per seat helps preserve acoustical energy.

18. 4.0
ACOUSTICAL
ANALYSIS

19. 4.1 Auditorium Design Analysis
4.1.1 Shape of Auditorium
The auditorium is configured in a more intimate space such as to
bring the audience closer to the speaker. Due to the proximity of the
audience to the speaker, the sound from the speakers is loud and more
audible. Therefore in turn improving the listening condition for the
audience.
However, the arrangement, which is on the front and the two sides,
that is 180o
exceeds the maximum limit of 130o
for a wide fan arrangement.
This affects the audience situated beyond the suggested limit, and they
would have to put up with a poor sound quality.

20. 4.1 Auditorium Design Analysis
4.1.2 Levelling of Seats
The levelling of the seating area is of the utmost importance to ensure
that sound waves reach the ears of all the people in the audience clearly.
There are two types of seat in the auditorium, the fixed and the movable
seats. The movable seats are normally used to accomodate more people and
are placed on the ground, whereas the fixed seats are placed at level terraces
of three levels.
At the ground floor pit, the sound attenuation problem is not
resolved as the seats are located at same level. The intensity of sound is
decreased over time to reach the furthermost seat as sound is absorbed in
part

21. The seats at the terrace on the ground floor are elevated from the
ground floor pit and are evenly allocated. The terrace seats are in the
most effective arrangement as they are arranged in a staggered manner.
Adequate sound diffusion is achieved to promote uniform distribution of
sound and accentuates the natural qualities of speech.

22. 4.1.3 Sound shadow
Sound shadow defect can be determined when the sound waves
failed to propagate due to the obstructions and attenuation. After we
collected the data of sound intensity level, we found out that there is no
sound shadow at auditorium. The sound intensity was constantly at 65 dB.
Sound source
Blocked

23. 4.2 Material and Properties
AREA COMPONENT MATERIALS SURFACE
FINISH
COEFFICIENT
MATERIAL DESCRIPTION 125HZ 500Hz 2000
Hz
AUDITORIUM WALL CONCRETE Smooth painted
concrete, 150mm
thick
Paint 0.01 o.o1 0.02
FLYTOWER STEEL STEEL
JOISTS/FRAMING
CURTAIN HEAVY
CLOTH
Medium velour,
50% gather, over
solid backing
0.05 0.40 0.60
FLOORING CONCRETE Smooth painted
concrete slab
Paint 0.01 0.01 0.02
DOORS 1.STEEL
2.TIMBER
Steel double sheet
skin door
Solid timber single
door.
Paint 0.35
0.30
0.44
0.10
0.54
0.05
STAGE FLOORING TIMBER
PLYWOOD
Wooden floor on joist paint 0.15 0.10 0.06
WINDOWS GLASS Glass panels 6mm 0.10 0.04 0.02
CEILING PLASTER Gypsum plaster 0.45 0.80 0.65
CONCRETE PADDED CHAIR HEAVY CURTAIN PLYWOOD

24. 4.3 Acoustic Treatment and Components
Musika has not undergone much acoustic treatments due to the its small
size and volume. However some of these features have been observed during the
visits.
VELOUR CURTAINS
These are heavy sound absorbing curtains that are placed in strategic
locations of the auditorium in order to dampen sound efficiently. Curtains are
located at 2 types of areas; openings and glass panels.
Curtains are found at access points in order to diminish sound coming from the
opening and closing of the doors as people walk in and out of the auditorium,
and also to stop sound from escaping the auditorium.

25. CEILING
Suspended Acoustic Ceiling
Suspended ceiling with rockwool hung above the perforated ceiling tile helps to
improve the sound insulation system in this tight space. it is suspended quite a
distance away from the actual plaster ceiling to absorb both way of sound
reflection, from top and below to prevent echo which can reduce the acoustical
quality in the space. .
WALL
Curved Wall Surface
Curved wall (outwards) has tendency to disperse sound that is reflected to it.
With the big curve, sound is dispersed throughout the space in different
directions.

26. 4.4 Sound Sources
The auditorium is design to produce and contain sound within its enclosed
space via the Audio Visual A.V. system installed. The control room for the AV
system is located perpendicular of the performance stage for optimal sound
monitoring. The sound produced in the auditorium is contained via sound
absorbing walls and ceiling, sound absorbing curtains, and functional room buffer
that minimizes sound leakages to the outside, whilst also keeping external noises
at a minimum.
4.4.1 Internal sound system
The internal sound system, comprising of the input and output components. The
input component would include microphones, condenser microphones and
electromagnetic guitar pickup, depending what event will be held there. Output
component would be their amplifiers and 10 in house speaker including ceiling
mounted speakers and bass speakers. The sound produce are then monitored
and controlled by the sound engineer in the sound booth.
Main Speakers
These are the speakers that deliver most of the sound to the audience or listeners.
In the auditorium, 8 individual speakers can be found mounted to the ceiling and
is arrange for total dispersion of sound for better acoustic.

27. 4.4 Sound Sources
Subwoofer
Responsible in the reproduction of low-pitched audio frequencies known as bass.
These bass speakers are placed one on each side of the stage. TO compensate the
main speakers, these bass speakers are larger and is place on the ground as
opposed to being ceiling mounted. Which means they can be easily relocated if
the current event has no function for it.

28. 4.5 Noise Sources
Noise can be defined as sound that is unpleasant to the listener. Both
sound and noise are ‘decibel-independent’. Low dB is considered as noise
whereas high dB is considered sound. Both external and internal noises are to be
considered when attempting noise suppression in designing of an auditorium.
External noise are noise originates from outside of the auditorium and internal
noise are noise produce within the auditorium.
4.5.1 External Noise
Majority of the external noise comes from the street just outside the
auditorium on the secondary entrance with approximately 70dB. On the
adjacent, there is another exit leading out to a hallway measuring
approximately 60dB. However, the external noise coming from these
entrance is significantly reduced when the door is completely shut.
Vehicle route

29. The reception/ticket booth acts as a noise buffer between the main
entrance door to the inside auditorium as there are two doors, one
entering the reception and another entering the auditorium from the
booth.
4.5 Noise Sources

30. 4.5 Noise Sources
4.5.2. Internal Noise
Internal noise in the auditorium are mostly contributed by the sound of
electrical equipment such as minor static noise from AV system and
sound generated from the turn on air conditioner.
Other internal noise that can be found in the auditorium hall can also be
generated from human activities for instance, walking on the timber
flooring, opening and closing of the doors and friction noise from
relocation of the folding chair.

31. 4.6 Sound Propagation and Related Phenomena
The measurement takes place during the speaker is turned to maximum
volume playing sound from 500 - 800 Hz . We measured multiple times at one
spot and takes the average reading.
1. The hall sound is about the same in all seatings areas .
2. The space near the stage receives the loudest sound .
3. There are severals area in the hall receives less sounds .
The diagram shows that the areas which have the highest and lowest
sound intensity in the hall . the placement of the speaker makes the sound
intensity level in the seatings almost even , but somewhere far away from the
seats does not receive the same sound intensity level as the seats area .

32. 5.0
REVERBERATION
TIME

33. 5.0 Reverberation Time
Surface Absorption At 500 Hz
Padded Chair
96.8m2
X 0.40
= 38.72 Sabins
Curtain
500m2
X 0.40
=200 Sabins
Wood Flooring
421m2
X 0.05
=21.05 Sabins
Brick Wall (uncovered)
224m2
X 0.42
=94.08 Sabins
Total Absorbtion Of Room
Surface
= 38.72 + 21.05 + 200 + 94.08
= 353.85 Sabins
Reverberation Time
= 0.16(2947) / 353.85 Sabins
= 1.33 Seconds

34. 6.0
OBSERVATION
& CONCLUSION

35. 6.1 Observation, Recommendation and Conclusion
After experiencing and studying the acoustic system in MAPKL, we found out
that this space has an almost uniform sound volume throughout the space. A good
auditorium design is where the acoustic system is uniform throughout the space as
the main function of this space itself is to deliver sound and acoustics to people.
Sound treatment system is one of the most important thing in this system as
it serves the prevention of sound shadows and echoes produced by an overly
reflected noise and sounds by the solid elements in the surrounding. Without these
treatments, the space’s acoustic quality will be really poor and this can lead to
uncontrolled sound pollution from in and outside of the building.
Balancing the acoustic will be better without being fully dependance on the
audio system. As an architect, the design should be depending more on the passive
side where installments are the second choice in making a space better.
Based on the analysis and calculation, Black Box auditorium had 1.33 Seconds
reverbnation time. Overall this site has a good acoustic system for a small event and
programs.

36. 7.0
REFERENCES

37. 7.0 References
Absorbtion Coeficient. (n.d.). Retrieved May 07 2018, Available at
http://www.acoustic.ua/st/web_absorption_data_eng.pdf
Reverberating Time, Reverberating Sound. Retrieved May 03 2018, Available at
http://hyperphysics.phy-astr.gsu.edu/hbase/Acoustic/revtim.html
Reverberating Time,, Echoes, Retrieved May 03 2018. Available at
https://www.dkfindout.com/us/science/sound/echoes/.