BACHELOR OF SCIENCE (HONS) IN ARCHITECTURE
BUILDING SCIENCE II (BLD61303)
ASSIGNMENT 1 - AUDITORIUM : A CASE STUDY ON ACOUSTIC DESIGN SHANTANAND AUDITORIUM CHEONG YEN SIN
0328050
GRACE WONG LI XIN
0324575
HO PEI SAN
0332992
NG YU JIE FREDERICK
0327607
NG ZHIANG HAN
0331394
TERENCE THIA HOU YET
0327661
WESLEY WONG TECK WON
0330496
TUTOR : DR. SUJA
AUDITORIUM CASE STUDY
TABLE OF CONTENTS 3.6 Sound Reection and Sound Transmission 1.0 Introduction
3.7 Sound Defect
1.1 Introduction of Shantanand
3.8 Sound Delay
1.2 History of Shantanand Auditorium
3.9 Noise Intrusion
1.3 Site Location and Context
3.10 Materiality and Sound Absorption CoefďŹ cient
1.4 Drawings
3.11 Acoustical Treatment and Components
1.5 Photos of Shantanand
4.0 Reverberation Time 2.0 Methodology
4.1 Introduction
2.1 Measuring and Recording Equipment
4.2 Area of Floor Materials 4.3 Area of Wall Materials
3.0 Acoustical Design Analysis
4.4 Area of Other Materials
3.1 Auditorium Form and Shape
4.5 Volume of Auditorium
3.2 Leveling and Arrangement of Seats and Stage
4.6 Reverberation Time Calculation
3.3 Sound Reinforcement System
5.0 Conclusion 3.4 Sound Attenuation 5.1 Shantanand Auditorium
3.5 Sound Propagation 5.2 Design Considerations and Suggestions
6.0 References
LIST OF FIGURES Figure 1.1 The Temple of Fine Arts Figure 1.2 Swamiji Figure 1.3 Site Context of Shantanand auditorium Figure 1.4 Seatings of Shantanand auditorium Figure 1.5 Stage of Shantanand auditorium Figure 1.6 Equipments inside the control room Figure 1.7 Front view of Shantanand auditorium Figure 1.8 Backstage of Shantanand auditorium Figure 1.9 Backstage of Shantanand auditorium Figure 1.10 Side view of Shantanand auditorium Figure 1.11 Viewing from the first floor area Figure 2.1 Digital Sound Level Meter Figure 2.2 DSLR Digital Camera Figure 2.3 Smartphone Figure 2.4 Measuring Tape Figure 2.5 Laser Distance Meter
Figure 3.1.1 : Fan shaped and rectangular form of the auditorium. Figure 3.2.1 : Seating area seats arrangement is elevated. Figure 3.2.2 : Seating area seats are arranged in a single level. Figure 3.3.1 Array speaker. Figure 3.3.2 Placement of Array speaker. Figure 3.3.3 Stage monitor speaker. Figure 3.3.4 Placement of Stage monitor speaker. Figure 3.3.5 sensor control subwoofers. Figure 3.3.6 Placement of sensor control subwoofers. Figure 3.3.7 Single speaker cabinet. Figure 3.3.8 Placement of Single speaker cabinet. Figure 3.4.1: Sound attenuation of ground floor. Figure 3.4.2: Sound attenuation of first floor. Figure 3.5.1: Sound propagation of Ground Floor. Figure 3.5.2: Sound propagation of First Floor. Figure 3.6.1 Diagram showing the reflection of sound when it hit the wall. Figure 3.6.2 Diagram showing the sound reflection when it hit the ceiling. Figure 3.6.3 Diagram showing the sound dispersion when it hit the convex-surface ceiling . Figure 3.6.4 Diagram showing the glass blocks the sound and unnecessary sound reflection. Figure 3.7.1 Diagram shows the travel path of sound waves to the audience seatings. Figure 3.8.1 Diagrams indicate the sound reflections Figure 3.8.2 Diagrams indicate the sound reflections Figure 3.8.3 Diagrams indicate the sound reflections Figure 3.9.1 Diagrams show the interior noise intrusion. Figure 3.9.2 Internal noise source location (Reflected ceiling plan)
Figure 3.9.3 High ceiling round air-conditioning diffuser Figure 3.9.4 High ceiling square air-conditioning diffuser Figure 3.9.5 Linear air-conditioning diffuserFigure 3.11.1 Parquet Wood Flooring in Shantanand Auditorium Figure 3.11.2 Details of the acoustical floor carpet Figure.3.11.3 Parquet Wood Flooring location in Shantanand Auditorium Figure.3.11.4 Sound absorption on different floor surface Figure 3.11.5 Acoustical floor carpet in Shantanand Auditorium Figure 3.11.6 Acoustical floor carpet in Shantanand Auditorium Figure.3.11.7 Details of the acoustical floor carpet Figure 3.11.8 Acoustical floor carpet absorbs sound better than any hard surface flooring Figure 3.11.9 Pleated Velour curtain in Shantanand Auditorium Figure 3.11.10 Pleated Velour curtain location in Shantanand Auditorium Figure 3.11.11 Acoustic surfaces Figure 3.11.12 Seating area of the Shantanand Auditorium Figure 3.11.13 Seating area of the Shantanand Auditorium Figure 3.11.14 Close up look of the air diffuser pedestal Figure 3.11.15 Diffusion of sound towards Polyurethane Figure 3.11.16 Close up look of the air diffuser pedestal Figure 3.11.17 Gypsum plaster ceiling in Shantanand Auditorium Figure 3.11.18 Gypsum plaster ceiling location in Shantanand Auditorium Figure 3.11.19 Gypsum plaster ceiling detail Figure 3.11.20 Timber Acoustic panel in Shantanand Auditorium Figure 3.11.21 Timber Acoustic panel location in Shantanand Auditorium Figure 3.11.22 Timber Acoustic panel detail Figure 3.11.23 Hard acoustical wall in Shantanand Auditorium Figure 3.11.24 Location of Hard Acoustical wall in Shantanand Auditorium Figure 3.11.25 Fibreglass acoustic panels in Shantanand Auditorium Figure 3.11.26 Fibreglass acoustic panels location in Shantanand Auditorium Figure 3.11.27 Details of fibreglass acoustic panels
Figure 4.2.1 Indicating different floor materials Figure 4.3.1 Indicating different wall materials Figure 4.4.1 Indicating different other materials Figure 4.4.2 Indicating different other materials Figure 4.4.3 Indicating different other materials Figure 4.5.1 Indicating the zones of estimated volume Figure 4.6.1 Optimum sound reverberation time for specific spaces Figure 5.2.1 Timber Flooring Figure 5.2.2 Glass railing at the upper balcony Figure 5.2.3 Door view from outside of Auditorium Figure 5.2.4 Door view from inside of the Auditorium
Introduction 1.1 Introduction of Shantanand 1.2 History of Shantanand 1.3 Site Location and Context 1.4 Drawings 1.5 Photos of Shantanand
introduction
1.3 History of Shantanand
His Holiness Swami Shantanand Saraswathi (Swamiji), the founder of Shantanand Auditorium, who established this auditorium in May 1991. The intention of this auditorium is to create awareness and appreciation for Indian classical and music, visioning to help the Malaysian youth to rediscover the cultural, artistic and spiritual wealth of their forefathers and to make it relevant for themselves and for future generations to come. Swamji believed that music and dance is the key essential to the holistic development of the child. Swamiji envisioned that The Temple of Fire Arts would be the place where a young child could learn music and dance from teachers who understood the true source of creativity and inspiration. Besides that, as a tribute to Swamiji being the inspiration and Founding Patron of the Temple of Fine Arts, this “heartspace for creative expression” – the auditorium, has aptly been named after Swamiji. It signifies the continuing presence, inspiration and guidance of Swamiji in upholding these noble ideals. Since its soft launch in January 2011, and later the official opening by The Honourable Prime Minister of Malaysia, Dato' Sri Mohd Najib bin Tun Abdul Razak on the 4th of July 2011, Shantanand Auditorium has become a venue of choice for artistic productions and corporate events in Kuala Lumpur. Figure 1.2 Swamiji
introduction
1.1 Introduction of Shantanand
Name
: Shantanand Auditorium
Location
: 114-116, Jalan Berhala, Brickfields, Kuala Lumpur 57000, Malaysia
Total fixed seats capacity : 618 Year of completion
: 2011
Built up area
: 8769 msq
Figure 1.1 The Temple of Fine Arts
The Shantanand Auditorium is a choice performance venue suited for cultural and artistic events. It has also served well as a venue for weddings, seminars, workshops and corporate events.The Temple of Fine Arts is located right in the centre of the crescent-shaped Jalan Berhala in Brickfields. The 5-storey building was designed with the needs of the institution such as music studios and dance studios. Shantanand Auditorium occupies the second and third floor of the Temple of Fine Arts.
introduction
1.4 Site Location and Context
Figure 1.3 Site Context of Shantanand auditorium (shantanand, 2011)
The Shantanand Auditorium is located near to the religious landmarks in Jalan Berhala, BickďŹ els, such as opposite of Buddhist Maha Vihara, and beside of Hindu temple (Kuil Thirumurugan). It is also surrounded by vegetation and the main entrance can be clearly seen from Jalan Berhad. The auditorium is also few steps away from the Global Indian International School, Kuala Lumpur.
introduction
1.5 Drawings
Ground Floor Plan Scale 1 : 200
introduction
1.5 Drawings
First Floor Plan Scale 1 : 200
introduction
1.5 Drawings
Ceiling Plan Scale 1 : 250
introduction
1.5 Drawings
Section A-A Scale 1 : 200’
introduction
1.6 Photos of Shantanand
Figure 1.4 Seatings of Shantanand auditorium
Figure 1.5 Stage of Shantanand auditorium
Figure 1.6 Equipments inside the control room
Figure 1.7 Front view of Shantanand auditorium
introduction
1.6 Photos of Shantanand
Figure 1.8 Backstage of Shantanand auditorium(Cheong,2019)
Figure 1.10 Side view of Shantanand auditorium(Cheong,2019)
Figure 1.9 Backstage of Shantanand auditorium(Cheong,2019)
Figure 1.11 Viewing from the first floor area(Cheong,2019)
Methodology 2.1 Measure and Recording Equipment
Methodology
2.1 Measuring and Recording Equipments
Digital Sound Level Meter The digital sound level meter used for acoustic measurement. The unit of measurement of sound intensity is in decibels (dBA) which used to measure sound intensity levels at various locations within the auditorium to measure the sound concentration and also the background noise levels.
Figure 2.1 Digital Sound Level Meter
DSLR Digital Camera The DSLR digital camera was used to capture photographs for our data collection such as photographs of building materials, and the surrounding condition of the auditorium .
Figure 2.2 DSLR Digital Camera
Methodology
Smartphone Smartphones were used as a secondary equipment for capturing photographs of the auditorium. It is also used as a operator to produce single frequency sound on stage for the reading of the sound meter to be taken at different location point in auditorium. Figure 2.3 Smartphone
Measuring Tape The measuring tape was used to measure the distance and dimension of the auditorium for drawing purposes. It also help to measure the distance from the position of sound meter readings taken to the stage. Figure 2.4 Measuring Tape
Laser Distance Meter The laser measuring tool was used to measure the distances that measuring tape couldn’t reach, mainly distances beyond 5.5m in the auditorium. Ceiling height and angle of ceiling also measured by the laser distance meter. Figure 2.5 Laser Distance Meter
Acoustic Design Analysis 3.1 Auditorium Form and Shape 3.2 Leveling and Arrangement of Seats and Stage 3.3 Sound Reinforcement System 3.4 Sound Attenuation 3.5 Sound Propagation 3.6 Sound Reection and Transmission 3.7 Sound Defect 3.8 Sound Delay 3.9 Noise Intrusion 3.10 Materiality and Sound Absorption CoefďŹ cient 3.11 Acoustical Treatment and Components
Acoustic Design Analysis
3.1 Auditorium Form and Shape
Fan shape
Rectangular
The form of the auditorium is designed as a fan shape which is a mixture of rectangular/ shoe-box and fan shape design whereby the stage is located at the narrower section of the auditorium bringing out distant spectators to the performers. Nevertheless, the arrangement plan of Shantanand Auditorium is perfectly in within the 130° maximum limit for the wide fan arrangement to make sure that sounds can be clearly heard throughout the auditorium.
Figure 3.1.1 : Fan shaped and rectangular form of the auditorium.
3.2 Levelling and Arrangement of Seats and Stage
Acoustic Design Analysis
The seats were designed to be sloped to ensure that the sound waves are properly distributed throughout the auditorium as well as the assurance of unobstructed views. Figure 3.2.1 : Seating area seats arrangement is elevated.
In the case where the seats are arranged in a single level, sound waves travelling to the furthermost seat would be disrupted as it would have to pass through several absorbers such as padded seats and individuals.
Figure 3.2.2 : Seating area seats are arranged in a single level.
3.3 Sound Reinforcement System
Acoustic Design Analysis
Introduction The distance from the centre of the stage until the edges or the end of the auditorium is about 17 m long. Therefore, the auditorium need to be supported by sound reinforcement equipment to help amplify and deliver the sound from performers during the performance on the stage because 15m is the maximum distance for auditorium to function without the sound reinforcement system.
The type of sound reinforcement system typically in this auditorium can be classify into into 4 categories : Sound reinforcement equipment 1. LINE ARRAY SPEAKERS 2. STAGE MONITOR SPEAKERS 3. SENSOR CONTROL SUBWOOFERS 4. SINGLE SPEAKER CABINET
1.
Acoustic Design Analysis
LINE ARRAY SPEAKERS Placement : Hanging above the stage Quantity : 2
Figure 3.3.1 Array speaker
Figure 3.3.2 Placement of Array speaker
Array speakers is a loudspeaker system that is consist of a number of identical loudspeaker element mounted in a line and fed in phase, to create a near-line source of sound. Array speakers have slanted angled down at bottom half part to provide extra coverage at location close to the front stage. The top half will be angled upward to facing the audience at the ďŹ rst oor of the auditorium. This speaker are placed above on a hanging position.
Acoustic Design Analysis
2. STAGE MONITOR SPEAKERS Placement : corners side of the stage Quantity : 2
Figure 3.3.3 Stage monitor speaker
Figure 3.3.4 Placement of Stage monitor speaker
The foldback system, stage monitor speakers`main function is to directly project sound towards the stage. This type of speakers are commonly used to amplify sound when acoustics instruments or vocals are utilised while performers performing on the stage. It helps to maintain the quality of sound during the performance, allowing performers to notice their sound themselves., preventing them to hear reverberated sound reection bouncing from the rear wall.
Acoustic Design Analysis
3. SENSOR CONTROL SUBWOOFERS Placement :side of below the stage Quantity : 2
Figure 3.3.5 sensor control subwoofers
Figure 3.3.6 Placement of sensor control subwoofers
Sensor control subwoofers are use to provide better sound quality for low frequency. It reinforces low pitched audio frequency such as bass and sub-bass from 20Hz to 80Hz. This sensor- controlled technology is self optimising. It allows slower sound attenuation and ease sound travel to the audience. Both speakers are located at each side of the stage to provide wider and equally sound wave in the auditorium.
Acoustic Design Analysis
4. SINGLE SPEAKER CABINET Placement :side of the stage Quantity : 2
Figure 3.3.7 Single speaker cabinet Figure 3.3.8 Placement of Single speaker cabinet
Single speaker cabinet generally reproduces tone as sound waves in the air. Its function is similar with studio microphone as well. The auditorium selectively use the single speaker cabinet depending on the performance.
3.4 Sound Attenuation
Acoustic Design Analysis
Sound attenuation is a measure of the energy loss of sound propagation in media.
Figure 3.4.1: Sound attenuation of ground floor
By playing music using speakers we brought, the measure of the Sound Intensity Level (SIL) in Shantanand Auditorium conveys a distinct concentrated sound attenuation at the center of the auditorium. The sound intensity decreases towards the end of auditorium. Thus,we learnt that the energy loss of sound propagation in Shantanand is low due to the shallow depth of the auditorium.
Figure 3.4.2: Sound attenuation of first floor
3.5 Sound Propagation
Acoustic Design Analysis
Sound propagates from a point source, travels outwards in circular waves motions and its intensity spread out via the inverse square law (the intensity is proportional to 1/(distance squared).
Figure 3.5.1: Sound propagation of Ground Floor
By using the sound meter and speaker we brought to the auditorium, we recorded the sound intensity level in different seats at constant amplitude and frequency. From the information we gathered, we can know the reduction of propagation in sound energy at different seating zone. It is separated into 4 levels of intensity, it is not equal and consistent throughout each level. According to the collection of data, there are a difference of 3-4 decibel. The sound is concentrated in the middle seat in which it got the highest reading as compared to other sides. As for the back part of ground oor, the sound intensity is lower as the upper balcony blocks the dispersion of sound wave.
Figure 3.5.2: Sound propagation of First Floor
Acoustic Design Analysis
3.6 Sound Reflection and Transmission
Reflected sound Direct sound Concentrate area
Geometry and Form (wall) Reflection Sound reflection is the return of sound wave travels through air from a surface. It usually occurs on flat, rigid surfaces like concrete or brick walls. It will also be affected by the geometry and built form of an auditorium. It can help increase the efficiency of th sound propagation to the audience. Shantanand Auditorium is having a fan shape floor plan, both side of the angled wall and straight wall reflect the sound to every seating even corners of the auditorium evenly. Another reason that sound reflection works well here because it is a shoe-boxed shape which means placing the stages in the narrow end of auditorium.
Figure 3.6.1 Diagram showing the reflection of sound when it hit the wall
Acoustic Design Analysis Flat surface ceiling
Tilted ceiling
Convex-surface ceiling Direct sound Reflected sound
Ceiling Reflection
Figure 3.6.2 Diagram showing the sound reflection when it hit the ceiling.
The Shantanand Auditorium initially was designed to serve as a multipurpose hall. Then it was renovated as an performance theatre where all the musical performances, indian dance and other events were mostly held at here by the Indian community. The efforts were done to fulfill the acoustic requirements of music performances spaces. They lowered the ceilings height with additional ceilings like flat surface ceiling, tilted ceiling and convex-surface ceiling. This ceilings functions as an useful sound reflections towards the seating area. The flat surface ceiling and tilted ceiling retain the sound as it reach to the audiences. While the convex-surface ceiling causes dispersion of sound to the upper balcony seats, enhancing sound diffusion across wide range of frequency.
Figure 3.6.3 Diagram showing the sound dispersion when it hit the convex-surface ceiling .
Acoustic Design Analysis
Direct sound Subwoofer sound Glass Reflection
Glass Reflection From the diagrams, it shows that the glass railings blocks sound from the lower level to reach the upper balcony(first level), in fact it reflects the sound away. The speakers are added hanging above the stage to ensure that the sound wave to reach the upper balcony.
Unnecessary Sound Reflection
Figure 3.6.4 Diagram showing the glass blocks the sound and unnecessary sound reflection.
The subwoofer that placed at the lower level emits lower frequency sounds that are less prone to suffer from diffraction after striking a surface of small architectural elements. Therefore the sharp edges of the upper balcony would not separate the low frequency sounds produced by the sub-woofers, repealing unnecessary sound reflection into the performance space.
Acoustic Design Analysis
3.7 Sound Defects Sound defects also known as acoustical defects in an enclosed space such as sound shadow.
Sound Shadow It is also known as acoustic shadow where the regions which the frequency of sounds are altered as sound waves undergoes diffraction effects around large pillars, corners or underneath a low balcony. When a sound source is produced from the stage, sound waves travels towards the nearest audience before reaching further. 78dB
The effectiveness of sound waves is at optimum until it reaches the middle part of the seating where it is guided by side wall panel and ceiling to transfer the sound to a further range. Figure 3.7.1 Diagram shows the travel path of sound waves to the audience seatings.
Sound shadow does not occur as the seatings under the balcony are within the acceptable range of sound propagation. (78dB)
Acoustic Design Analysis
3.8 Sound Delay
5.2m
6.5m
3.6m
Figure 3.8.1 Diagrams indicate the sound reflections
Reflected Sound 1
Reflected Sound 2
Time delay = R1+R2-D / 0.34 = (6.5+5.2-3.6) / 0.34 = 23.8 msec (<30msec) There is no sound delay at this seating. No echo is heard.
Direct Sound
Acoustic Design Analysis
7.2m
5.8m 9.1m
Figure 3.8.2 Diagrams indicate the sound reflections
Reflected Sound 1
Reflected Sound 2
Time delay = R1+R2-D / 0.34 = (5.8+7.2-9.1) / 0.34 =11.47 msec (<30msec)
There is no sound delay at this seating. No echo is heard.
Direct Sound
Acoustic Design Analysis
10.5m 15.2m
11.8m
Figure 3.8.3 Diagrams indicate the sound reflections
Reflected Sound 1
Reflected Sound 2
Time delay = R1+R2-D / 0.34 = (10.5+9.8-15.2) / 0.34 =15msec (<30msec) There is a no sound delay at this seating. No echo is heard.
Direct Sound
Acoustic Design Analysis
10.5m 15.2m
11.8m
Figure 3.8.3 Diagrams indicate the sound reflections
Reflected Sound 1
Reflected Sound 2
Time delay = R1+R2-D / 0.34 = (10.5+9.8-15.2) / 0.34 =15msec (<30msec) There is a no sound delay at this seating. No echo is heard.
Direct Sound
Acoustic Design Analysis
3.9 Noise Intrusion Noise is an unwanted sound judged to be unpleasant, loud or disruptive to hearing from the perspective of an recipient. Noise can be categorized to variable, continuous, impulsive and intermittent which depends the changes over time.
1 3
3 1
3
3 1. Performers stepping on the stage
2
4.Anti slip metal stair nosing
4
2.Timber flooring
5
5 5.Opening and closing of wooden doors at entrance
5 Figure 3.9.1 Diagrams show the interior noise intrusion.
Affected seating area
Noise
3.Opening and closing of wooden doors at entrance
Acoustic Design Analysis
Low frequency noise will be produced from the air flow inside the diffusers. Although there is noise produced but it might not affect the audience sitting near the stage because the distance between the diffuser and sitting is far. However, the audience who seats at the first floor might be affected due to the closer distance compare to ground floor seating.
High ceiling round air-conditioning diffuser Figure 3.9.3 High ceiling round air-conditioning diffuser
High ceiling square air-conditioning diffuser Figure 3.9.4 High ceiling square air-conditioning diffuser
Linear air-conditioning diffuser
Figure 3.9.2 Internal noise source location (Reflected ceiling plan)
Figure 3.9.5 Linear air-conditioning diffuser
Acoustic Design Analysis
3.10 Materiality and Sound Absorption Coefficient
The different types of materiality used in different parts of the auditorium have different absorption coefficient value. The following table showcase the different material used in different area.
Absorption Coefficient Area
Component
Materials 125 HZ
500 HZ
1000 HZ
0.30
0.50
0.80
0.18
0.42
0.59
0.15
0.75
0.80
0.15
0.10
0.07
Acoustic rough plaster
Timber acoustic panel
Wall Seating
Fiberglass absorption panel
Timber floor on joist
Flooring
Acoustic Design Analysis
Absorption CoefďŹ cient Area
Component
Materials 125 HZ
500 HZ
1000 HZ
0.03
0.25
0.31
0.15
0.04
0.04
0.14
0.06
0.08
0.13
0.08
0.09
Pile carpet bounded to closed cell from underlay
Flooring
Gypsum board
Ceiling
Seating Solid timber door
Door
Steel Railing
Railing
Acoustic Design Analysis
Absorption CoefďŹ cient Area
Component
Materials 125 HZ
500 HZ
1000 HZ
0.11
0.06
0.05
0.10
0.04
0.03
0.13
0.42
0.59
0.37
0.69
0.73
Steel railing with glass panel
Railing 6mmm glass railing
Seating Fabric upholstered tip-up seats unoccupied
Furniture
Fabric upholstered tip-up seats occupied
Acoustic Design Analysis
Absorption Coefficient Area
Component
Materials 125 HZ
500 HZ
1000 HZ
0.05
0.13
0.22
0.01
0.01
0.02
0.14
0.05
0.08
0.30
0.50
0.80
Pleated medium velour curtain
Seating
Drapery
Painted smooth concrete
Wall
Glass window with blackout window film
Stage
Window
Acoustic absorption panel
Absorption Panel
Acoustic Design Analysis
Absorption CoefďŹ cient Area
Component
Materials 125 HZ
500 HZ
1000 HZ
0.01
0.15
0.25
0.20
0.30
0.30
0.01
0.01
0.02
0.07
0.49
0.75
Rubber sheet on timber ďŹ&#x201A;oor
Carpet, thin over thin felt on timber foldable stage
Floor
Stage
Painted smooth concrete
Pleated medium valour
Drapery
Acoustic Design Analysis
Absorption CoefďŹ cient Area
Component
Materials 125 HZ
500 HZ
1000 HZ
0.13
0.08
0.09
0.40
0.20
0.15
0.14
0.06
0.08
0.60
0.60
0.60
Steel Decking
Stage Deck
Plywood Battens
Stage Sidewalk
Timber panel with timber frame
Control Room
Deck Opening
Per metre square
Seating and Stage
Ventilation Grille
3.11 Acoustical Treatment and Components
Acoustic Design Analysis
Acoustic treatment is an important hall construction, it can affect the sound surrounding by adding difference acoustic elements on different surface. A good design can equally distribute sounds to all the seats, which depends on proper shaping and ďŹ nishes on the interior surface. A standard acoustic treatment should meet following requirement : 1 Freedom from the acoustical faults of echoes, ďŹ&#x201A;utter and focus 2 Freedom from disturbing noises produced by construction materials 3 Proper room volume and shape to control the environment sounds transmission
1.
Acoustic Design Analysis
Timber Floor Joist
Timber Floor Joist greatly improves the impact sound insulation due to the usage of acoustic joist strips which are an economical way of reducing impact noise through conventional timber joist ďŹ&#x201A;oors. The strips supplied in 20m self adhesive rolls are easily placed on the top of the joist.
Figure 3.11.1 Parquet Wood Flooring in Shantanand Auditorium
Figure 3.11.3 Parquet Wood Flooring location in Shantanand Auditorium
Figure 3.11.2 Details of the acoustical floor carpet
Figure.3.11.4 Sound absorption on different floor surface
2. Pile carpet bounded to closed- cell foam underlay
Acoustic Design Analysis
Pile carpet are common material used for auditoriums. While carpets reduce noise transmission through ďŹ&#x201A;oor in multi-storied buildings, the degree of actual noise reduction, as well as the people perception of it, are dependent on the frequency distribution of the sound. Carpets are extremely effective sound absorbers because the individual ďŹ bres, pile tufts and underlay have different resonant frequencies at which they absorb sound.
Figure 3.11.6 Acoustical floor carpet in Shantanand Auditorium Figure 3.11.5 Acoustical floor carpet in Shantanand Auditorium
Figure.3.11.7 Details of the acoustical floor carpet
Figure 3.11.8 Acoustical floor carpet absorbs sound better than any hard surface flooring
Acoustic Design Analysis
3. Stage curtain ( Pleated Velour Curtain )
Acoustic curtains are designed to improve sound quality and reverberation levels within the room that they are installed. Velour curtains can dramatically reduce high frequency echo and excessive reverb in a room as it is thick and highly porous. These pores acts as thousands of tiny sound traps, capturing the energy and turning into heat. The pleated curtain expose more surface area for sound absorption to occur, hence providing better acoustic performance. The thicker the velour curtains, the more effective it will be against longer wavelength( low frequency)sound. However, a thickness of 20mm to 50mm is needed to be effective to absorb low frequency sounds.
Figure 3.11.9 Pleated Velour curtain in Shantanand Auditorium
Figure 3.11.11 Acoustic surfaces
Figure 3.11.10 Pleated Velour curtain location in Shantanand Auditorium
Acoustic Design Analysis
4. Seating
Figure 3.11.13 Seating area of the Shantanand Auditorium
To maximise the sound absorption in the auditorium, polyurethane foam with a high porosity allows effective sound absorption coefficient.
Figure 3.11.14 Close up look of the air diffuser pedestal
The auditorium chairs with air diffuser pedestal at beneath help to absorb the sound and noises efficiently.
Figure 3.11.12 Seating area of the Shantanand Auditorium
Gravity seating mechanism ensures that the seat will always quietly return to a consistent vertical position.
Figure 3.11.15 Diffusion of sound towards Polyurethane
Figure 3.11.16 Close up look of the air diffuser pedestal
Acoustic Design Analysis
5. Ceiling
In Shantanand Auditorium, gypsum board is used as the ceiling material. The gypsum board used in auditoriums usually have a thickness of 1 ½ to 2 inches because the stiffness and mass is necessary to resist panel vibration which causes low frequency absorption and to achieve good reďŹ&#x201A;ections at all frequencies. The height of the auditorium is around 9m, which hardly transmits sound. Therefore the suspended ceiling effectively helps to control sound transmission and lower down the volume of the auditorium. Besides the angle of the ceiling helps to reďŹ&#x201A;ect sounds to the seating area and avoid room echos.
Figure 3.11.17 Gypsum plaster ceiling in Shantanand Auditorium
Figure 3.11.19 Gypsum plaster ceiling detail
Figure 3.11.18 Gypsum plaster ceiling location in Shantanand Auditorium
Acoustic Design Analysis
6. Hard acoustical wall ( Timber acoustic panel)
Timber acoustic panels provide a great sound absorbing surface which are installed not only for aesthetic purposes. The distance between the grooves can be altered with smaller widths generally increasing acoustic performance. Besides, there are air gap in between each panel to absorb redundant low frequency through panel vibration. The solid back of the timber acoustic panel is smooth plaster as for a standard acoustic panel the back solid structure, plaster or gypsum board must be used as base.
Figure 3.11.20 Timber Acoustic panel in Shantanand Auditorium
Figure 3.11.22 Timber Acoustic panel detail
Figure 3.11.21 Timber Acoustic panel location in Shantanand Auditorium
7. Hard acoustical wall ( Rough Plaster)
Acoustic Design Analysis
In Shantanand Auditorium, rough plaster is used as finish for 6 columns in the auditorium. The rough plaster allows for many internal reflection, resulting in more absorption and less reflection. Besides, rough plaster are layered above smooth concrete solid back to prevent vibration and reflect sound effectively with the six columns in this auditorium.
Figure 3.11.23 Hard acoustical wall in Shantanand Auditorium Figure 3.11.24 Location of Hard Acoustical wall in Shantanand Auditorium
Acoustic Design Analysis
8. Soft acoustical wall ( Fibreglass acoustic panel)
Fiberglass acoustic panels are often used in auditorium wall surface. Fiberglass acoustic panels are sealed airtight with high sound absorption coefďŹ cient in a wide range of frequencies, they have excellent performance when attaching it directly against the rear surface. The acoustic panel function as controlling echos, and sound foci from the rear wall and balcony faces. The reverberation time in the room is related directly directly to the volume of the room and, inversely, to the total sound absorption of the auditorium. A good placement of soft acoustic panel can achieve proper sound distribution diffusion, envelopment, intimacy and reverberation.
Figure 3.11.25 Fibreglass acoustic panels in Shantanand Auditorium
Figure 3.11.27 Details of fibreglass acoustic panels Figure 3.11.26 Fibreglass acoustic panels location in Shantanand Auditorium
Reverberation Time 4.1 Introduction 4.2 Area of Floor Materials 4.3 Area of Wall Materials 4.4 Area of Other Materials 4.5 Volume of Shantanand Auditorium 4.6 Reverberation Time calculation
4.1 Introduction The reverberant sound in a space will mitigate as sound energy bouncing off and being absorbed by multiple surface in the space. Reverberation time can be defined as the time for the sound pressure level in a space to decrease by 60dB from its original level after the sound stops. 500 Hz is the standard reference of measurement as this auditorium allows musical performances to fall under this category of frequency as a performing art space. Reverberation time depends on the following variables : 1. 2. 3.
The volume of the enclosure (distance) The total surface area The absorption coefficients of the surfaces
Thus, calculation of the reverberation time using Sabine Formula is, RT
=
0.16
V
A where,
RT
= A
=
V Total
Reverberation = Volume of absorption of room
time (s) the room (m³ ) surfaces (m² sabins)
Reverberation Time
4.2 Area of Floor Material
F1 F2 F3 F4
F5
F5 Figure 4.2.1 Indicating different floor materials
No
Surface /Finishes
Surface Area/m²
500 Hz
Absorption Coefficient
Abs Units (m² sabins)
F1
Painted smooth concrete floor
50.70
0.01
0.51
F2
Rubber sheet on timber floor
58.00
0.15
8.70
F3
Carpet on timber foldable stage
26.35
0.30
7.91
F4
Timber floor on joist
121.90
0.10
12.19
F5
Pile carpet bounded to closed-cell foam underlay
460.50
0.25
115.13
Total
144.44
Reverberation Time
4.3 Area of Wall Material
W1
W2
W2 W3
W4
W3
W5
W3
Figure 4.3.1 Indicating different wall materials No
Surface /Finishes
Surface Area/m²
500 Hz
Absorption Coefficient W1
Painted smooth concrete wall
W2
Timber acoustic panel
W3
Acoustic absorption panel
W4
W5
Abs Units (m² sabins)
307.2
0.01
3.07
128.55
0.42
53.99
58.00
0.75
43.50
Acoustic rough plaster
121.90
0.50
60.95
Stage timber sidewall
17.00
0.20
3.40
Total
164.91
Reverberation Time
4.4 Area of Other Materials
M1 M2 M5 M3 M4
M4 M4 M3
M1
Figure 4.4.1 Indicating different other materials No
Surface /Finishes
Surface Area/m²
500 Hz
Absorption Coefficient
Abs Units (m² sabins)
M1
6 Glass windows with window film
50.00
0.06
3.00
M2
18 Acoustic absorption panels
55.57
0.15
8.34
M3
10 Timber doors
22.50
0.06
1.35
M4
618 Unoccupied Seats
285.70
0.59
168.56
M5
Gypsum board ceiling
335.75
0.04
13.43
Total
194.68
Reverberation Time
M6
M8
M10 M9 M7 Figure 4.4.2 Indicating different other materials No
Surface /Finishes
Surface Area/m²
500 Hz
Absorption Coefficient
Abs Units (m² sabins)
M6
Steel railing (GF)
32.50
0.08
2.60
M7
Steel railing with glass panels (GF)
15.00
0.06
0.90
M8
6mm Glass railing (1F)
30.00
0.04
1.20
M9
100% Pleated medium velour curtain
20.50
0.13
2.67
M10
Acoustic rough plaster
125.75
0.01
1.26
Total
8.63
Reverberation Time
M11 M12 M14 M13
M11
Figure 4.4.3 Indicating different other materials No
Surface /Finishes
Surface Area/m²
500 Hz
Absorption Coefficient M11
50% Pleated medium velour curtain
M12
Abs Units (m² sabins)
135.23
0.49
66.26
Steel decking
55.53
0.08
4.44
M13
Timber panel with timber frame
10.50
0.06
0.63
M14
Ventilation grille
12.00
0.60
7.20
Total
78.53
Reverberation Time
4.5 Volume of Shantanand Auditorium A B C D
E Figure 4.5.1 Indicating the zones of estimated volume
No
Estimated Volume (mÂł)
A
496.86
B
568.40
C
258.23
D
1194.62
E
4512.90
Total
7031.00
Reverberation Time
4.6 Reverberation Time Calculation Using the Sabine Formula, RT
=
0.16
V
A where,
RT
= V
Reverberation = Volume of
the
time room
(m³
(s) )
A = Total absorption of room surfaces (m² sabins) Volume = 7031m³
∴
Total abs units = 144.44 + 164.91 + 194.68 + 8.63 + 78.53 =591.19 m² sabins RT
=
0.16
(7031) 591.19
=1.9 s As Shantanand auditorium functions as mainly music and dance performance hall, the ideal reverberation time will be 1.5 - 2.0s. The reverberation time for Shantanand auditorium is 1.9s, proving that it has successfully served its function as a performing art theatre in a medium room. (volume 750 -7500 m³ ). The table on the left shows the auditorium lies in the optimum reverberation time of its purpose served. High reverberation time is influenced by large volume of the space. However, it is not conducive for good speech intelligibility (SI) as the reverberation time needs to be below 1.5s. (more absorption surfaces required)
Figure 4.6.1 Optimum sound reverberation time for specific spaces
Conclusion 5.1 Shantanand Auditorium 5.2 Design Considerations and Suggestions
Conclusion
5.1 Shantanand Auditorium
Uses
Small Room (750m³)
Medium Room (750-7500m³)
Large Room (750-7500m³)
Speech
0.75
0.75-1.00
1.00
Multi-purpose
1.00
1.00-1.25
1.00-2.00
Music
1.50
1.50-2.00
2.00 or more
The case study opens our eyes and minds on the importance and application of acoustics in architecture for a building to be able to perform its served function. Every surface in the auditorium play vital role in the sound propagation and thus construction details should be considered and conscious design strategy should be implemented to create a fully functioning auditorium. In conclusion, through our findings and observations, the requirement of Shantanand Auditorium as a performing arts centre and music hall is within the sufficient range based on its acoustical design and optimum reverberation time of 1.9 s. It is a functional medium-sized auditorium for instrumental,dance or orchestra performance. Nonetheless, the auditorium is not suitable for speech related event according to the overall considerations as the sound absorption consideration is not suitably applied, in which, reducing echoes and allowing clarity of speech delivered. However, there are still some shortcomings in the auditorium that decreases its quality of acoustical experiential. Further implementation can be taken to enhance the direct sound, reduce noise intrusion and increase reverberation time in the auditorium. In addition, we have discovered how the layout and massing of the auditorium is able to affect the effectiveness of public address in the Shantanand Auditorium. We have also identified the properties of different acoustic materials used and how it control the desired sound. Moreover, we have also discovered the unwanted noise caused by several noise sources. The materials used influence the absorption, reflection, diffusion, dispersion and refraction of sound, which causes it to affect the overall experience in the auditorium. We have learnt the reverberation time calculation that is used to determine the time taken for sounds to decay in an enclosed space which is vital for us to find out the acoustical properties of an enclosed space.
Conclusion
5.2 Design Considerations and Suggestions
Figure 5.2.1 Timber Flooring
1 Change of material The timber flooring at the front part of seating will cause stepping noise by audiences walking over there and hence a change the timber flooring into carpet flooring or marmoleum vinyl sheet to reduce noise. Alternatively, additional unattached seats can be placed to avoid the noise intrusion that reduces the acoustical experience of the audience.
Figure 5.2.2 First floor Glass Railing
2 Replacing glass railing The glass railings become a blockage that obstruct the sound reaching to the audience sitting at the front in the first floor(a balcony). It reflects the sound away and reduce the sound intensity in first floor. Glass railing can be replaced with steel railings with gaps to allow sound propagation to the audience
Conclusion
5.2 Design Considerations and Suggestions
Figure 5.2.3 Door view from outside of Auditorium
Figure 5.2.4 Door view from inside of the Auditorium
3 Addition of extended corridor and sound lock The space leading to the auditorium is a open lobby with limited corridors. This causes external noise to diffuse into the auditorium and become background noise in the auditorium. Corridor should be added or extended outside the auditorium that leads the audience to enter the hall to block exterior noise at the same time retain the quality of music and sound inside the auditorium. Sound lock can also be added to prevent leakages of sound in or out from the auditorium.
References
References
Acoustic and Viewing Angle Analysis Of an Auditorium Building Saleh Ahmed - Retrieved from https://www.slideshare.net/SalehAhmed65/acoustic-and-viewing-angle-analysis-of-an-auditorium-building Auditorium Acoustics 1. Sound Propagation (free Field) - Ppt Download- Retrieved from https://slideplayer.com/slide/4350233/ Artsites.ucsc.edu. (2013). Sound Propagation. - Retrieved from http://artsites.ucsc.edu/EMS/music/tech_background/TE-01/teces_01.html Auditorium Seating Layout & Dimensions – The Complete Guide - Retrieved from http://www.theatresolutions.net/auditorium-seating-layout/ Audio Academy. (2017). Sound Reinforcement Systems - Audio Academy. - Retrieved from https://audioacademy.in/821-2/ Echocardiographer.org. (2012). Sound Striking An Interface: Reflection, Transmission, Refraction. Retrieved from http://echocardiographer.org/Echo%20Physics/Sound%20Striking%20An%20Interface.html Mathworks.com. (2019). Delay signal by variable time value - Simulink. Retrieved from https://www.mathworks.com/help/physmod/sps/powersys/ref/discretevariabletimedelay.htm Nde-ed.org. (1998). Attenuation of Sound Waves. - Retrieved from https://www.nde-ed.org/EducationResources/CommunityCollege/Ultrasonics/Physics/attenuation.htm Published Articles (2002) - Retrieved from https://www.acousticsciences.com/media/articles/auditorium-acoustics-102-reflections-make-all-difference
References
Published Articles - Retrieved from https://www.acousticsciences.com/media/articles/auditorium-acoustics-104 Reflection, Refraction, and Diffraction Retrieved from https://www.physicsclassroom.com/class/sound/Lesson-3/Reflection,-Refraction,-and-Diffraction Shantanand-adt.org. (2019). Home - Retrieved from http://shantanand-adt.org/ Standard.wellcertified.com. (2019). Exterior noise intrusion | WELL Standard. [online] - Retrieved from https://standard.wellcertified.com/comfort/exterior-noise-intrusion Shantanand-adt.org. (2019). Home - Retrieved from http://shantanand-adt.org/ YouTube. (2019). Why do we hear echoes? - Retrieved from https://www.youtube.com/watch?v=xQJ1JCpmS2I