ARC 3413 A Case Study on Acoustic Design

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