PANGGUNG BANDARAYA DBKL DBKL CITY THEATRE
School of Architecture,Building and Design Bachelor of Science (Hons) in Architecture
building science ii arc 3413 / bld 61303
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
CONTENTS 02
1.0
PROJECT 1 : Auditorium : A case Study on Acoustic Design
Introduction 1.1
Historical Background
1.2
Literature Review 1.2.1 Architectural Acoustics 1.2.2 Reverberation Time
04 05
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2.0
Aim and Objective
3.0
Technical Drawings & Zonings
4.0
3.0
Ground Floor Plan
3.1
First Floor Plan
3.2
Sections
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
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5.0
Noise 5.1
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Noise control
6.0
Reverberation Time Calculation
7.0
Recommendation
8.0
References
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
1.0 Introduction 1.1 Historical Background 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.
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Building Science II
1.2
PROJECT 1 : Auditorium : A case Study on Acoustic Design
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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
3.0 Technical Drawings and Zonings 3.1 Ground Floor Plan
Fan-shaped auditorium
Splayed wall
Scale 1: 175 Figure 1.1 Ground Floor Plan
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
3.2 First Floor Plan
Concave timber finishes
Convex timber finishes
Concave timber finishes Splayed wall
Scale 1: 175 Figure 1.2 First Floor Plan
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Slopping floor & raised stage
Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
3.3 Sections
Concave Ceiling Concave ceiling
Convex timber Convex timber finishes finishes Scale 1: 200
Scale 1: 100 Figure 1.3 Section X-X
Coffered ceiling
Concave ceiling
Slopping floor & raised stage Scale 1: 175
Concave ceiling
Figure 1.4 Section Y-Y
7 Convex timber
PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
4.0 Observation and Analysis 4.1 Materiality 4.1.1 Identification of Materials in Auditorium
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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
4.1.2 Sound Absorbent
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 Sound Absorption Coefficient : 0.15 The concave plaster ceiling mainly helps to concentrate the sound to the center with its low sound absorption rate
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
Carpet Sound Absorption Coefficient : 0.40 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 Sound Absorption Coefficient : 0.40 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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
4.1.3 Sound Reflector
Timber Panel Sound Absorption Coefficient : 0.10 Timber Panel channels sound reflection, to the seatings.
Wooden Doors Sound Absorption Coefficient : 0.07 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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
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
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
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PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
Figure 2.4 Functioning Speakers
Primary Sound Source 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.
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 2.5 Secondary Sound Source : Backstage and Air-Con vent
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
Secondary Sound Source 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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
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
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PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
4.2.2 Exterior Sound Source
Figure 2.8 Primary Sound Source : Construction Site
Primary Sound Source 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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
Secondary Sound Source 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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
4.3 Sound Path
Figure 2.10 Sound Path of Speakers
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
4.3.1 Sound Incident ( Direct Sound )
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
4.3.2 Sound Reflection
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.
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PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
Figure 2.11 Sound Reflection on Ground Floor
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 2.12 Sound Reflection on Ground Floor
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PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
4.3.3 Sound Concentration
Figure 2.13 Sound Concentration through Section X-X
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. 4.3.4
Sound Diffusion
Figure 2.14 Sound Diffusion through Section X-X
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
4.3.5 Sound Absorption
Fabric wrapped panels and curtains along the walls at both sides of the auditorium help absorb the excessive sound.
Figure 2.15 Sound Absorption on Ground Floor
Fabric wrapped panels along the back of the auditorium’s first floor walls absorb excessive sound to prevent echoes.
Figure 2.16 Sound Absorption on Ground Floor
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
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.
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PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
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.
Backstage
Washroom
Foyer Figure 3.1 Noise
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PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
5.1
Noise Control
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
6.0 Reverberation Time Calculation Reverberation time based on 1000Hz 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 = 0.16v = 0.16 x 1758.26 A 326.26 = 0.86s 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.
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PROJECT 1 : Auditorium : A case Study on Acoustic Design
Building Science II
7.0 Recommendations
Figure 4.1 Toilet Relocation
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
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
Figure 4.2 Door Replacement
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
Figure 4.3 Sound Lock Efficiency
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.
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Building Science II
PROJECT 1 : Auditorium : A case Study on Acoustic Design
8.0 References Absorption Coefficient Chart. (n.d.). Retrieved April 29, 2017, from http://www.acousticsupplies.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.
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