Building Science 2 Report

Damansara Performing Arts Centre ARC 3413 Building Science II Auditorium: A Case Study on Acoustic Design Tutor: Ar. Edwin

Goh Jyia Whey Jordan Tok Wen Xuan Khoo Yung Keat Rudy Irawan Wong Lieng Kam Siti Nur Fatahiah

0324910 0327629 0324688 0328658 0323566 0320595

Content 1.0 Introduction 1.1 Aims & Objective 1.2 Site Background 1.3 History Background 1.4 Architectural Drawing 1.5 Auditorium Design Analysis

2.0 Acoustics & Architecture 2.1 Introduction to Acoustics 2.2.1 Acoustics in Architecture 2.2.2 Sound Intensity Level 2.2.3 Reverberation, Attenuation, Echoes & Sound Shadow 2.3 Methodology

3.0 Acoustic Design Analysis 3.1 Sound Reinforcement System 3.2 Sound Propagation and Sound Concentration 3.3 Sound Shadow 3.4 Sound Reflection and Diffusion 3.5 Flutter Echoes & Sound Delay 3.6 Noise Intrusion 3.7 Construction of Materials

4.0 Calculation 4.1 Area of Materials 4.2 Reverberation Time

5.0 Acoustical Defects & Design Issues Design Solution & Suggestion 5.1 Staircase Squeaky Noise caused by Occupant Activities 5.2 Unsuitable Material for Insulation 5.3 Placement of Loudspeakers 5.4 Concentration of Sound

6.0 Conclusion 7.0 Reference

Chapter 1

Introduction 1.0

1.1 Aims & Objective 1.2 Site Background 1.3 History Background 1.4 Architectural Drawing 1.5 Auditorium Design Analysis

1.0 Introduction 1.1 Aims & Objective 04

Figure 1: Interior of DPAC Auditorium

1.1.1 Introduction An auditorium is a venue used in which live performances, concerts, speeches, lectures and so on are held at whereby the sound quality and sound acoustics of the room is a major contributing factor to an outstanding performance. A desired auditorium where the acoustic design including the layout as well as absorption materials should preserve and enhance the desired sound but eliminate noise and unwanted sounds. In a group of six, we are required to conduct a case study on a local auditorium to observe and report. Our group has chosen Damansara Performing Arts Centre (DPAC). We need to understand the layout of the auditorium and sound absorption materials and from there conduct a sound analysis to determine sound absorption, sound reflection, sound diffusion and so on to analyse the overall sound phenomena happening in the auditorium. We have conducted a site visit to DPAC and acquired data in which will assist us throughout this assignment.

1.1.2 Aim and Objectives The aim of the project is to help students understand and analyse acoustic theories in an auditorium of our choosing. The learning outcomes of this project include: - To analyse the acoustic characteristics of an auditorium.

- To analyse the acoustic qualities of the auditorium and suggest ways to improve.

- To analyse and determine the sound absorption materials used in the auditorium

Introduction 1.2 Site Background 05

Name of Auditorium Damansara Performing Arts Centre (DPAC) Location H-01, DPAC, Empire Damansara, Jalan PJU 8/8, Damansara Perdana, 47820 Petaling Jaya, Selangor, Malaysia.

Type of Auditorium Multipurpose Auditorium Total Seats Maximum 200 seat capacity Stage Size 11.25m (width) x 7.25m (depth) Volume 4236 mÂł

Figure 2: Direction to DPAC

Diagram 1: Empire Damansara Floor Plan

Introduction 1.2 Site Background 06

Figure 3: DPAC Entrance

Damansara Performing Arts Centre is equipped with a proscenium theatre, a black box, an indoor theatre foyer and dance studios. The facilities that are provided in DPAC cater to professional practices of different forms for all performing arts practitioners.

Our main focus is the Proscenium Theatre, which is the main auditorium of DPAC with a stage size of 11.25m (width) x 7.25m (depth), the overall volume is 4236m³. The theatre is able to house 200 guests, equipped with 2 changing rooms, one backstage and one on the level above.

DPAC was designed to be fitted between the car park and office buildings in empire Damansara, not as a standalone theatre, in which modifications and changes had to be made to ensure the theatre’s layout was sufficient and does not affect the sound quality. A column blocking in the theatre had to be removed and replaced with metal trusses to accommodate more seating and to hold up the roof. Several spaces and parts in the room had to be extended to improve the sound insulation in the theatre. The theatre adapts to an industrial design concept as Empire Damansara has adapted the industrial design and with the theatre which is made up of metal containers and metal plates for the interior finish. This allows the theatre to blend in with it’s site and not clash with it’s context.

Introduction 1.3 History Background 07

In 2013, with the guidance of Artistic Director, Wong Jyh Shyonh, the establishment of Damansara Performing Arts Centre (DPAC) and DPAC Dance Company (DDC) was formed. The company’s aim was to present in-house dance productions with local artists and well as form collaborative projects with international artists. The theatre has then provided a space in Damansara district for the growing need of theatrical arts. DPAC promote the arts through learning and practising and appreciating arts in Malaysia through their strong establishment. They’ve hosted plenty of local and international acts and with that, they aim to open the eyes of the public about the enriched forms arts in our lives to shape today’s world.

Figure 4: Repertoires on stage in DPAC

Figure 5: Repertoires on stage in DPAC

Introduction 1.4 Architectural Drawing 08

1.4.1 Floor Plan Scale:150

27130

26130

Introduction 1.4 Architectural Drawing 09

1.4.2 Section A-A’

15264

Scale:150

27130

Introduction 1.4 Architectural Drawing 10

1.4.3 Ceiling Plan Scale:150

27130

26130

Introduction 1.5 Auditorium Design Analysis 11

1.5.1 Volume

Diagram 2: Section Showing Volume of DPAC

DPAC has the capacity to fit in medium crowd. Each individual could enjoy to the extent as the volume is small and the stage is near. The audience is close and tight to the stage so they can experience the immediacy of the performance. The overall physical volume and acoustics of a drama room are controlled so that the room supports the performance with little or no direct amplification.

1.5.2 Shape and Form The theatre is a basic rectangular shoe box shape with a slight angle inward to the stage. This direct-view orientation allows for the audience to be “in conversation� with the performance, making it easier to achieve suspension of disbelief and invest themselves in the performance.

Diagram 3: Plan Showing shape of DPAC

Introduction Auditorium Design Analysis 12

1.5.3 Leveling of Seats

Diagram 4: Section of DPAC showing Sound Waves

The seats of DPAC theatre are designed by raising the level of seats to allow the sound waves to be transferred clearly to the audience without it being blocked by the absorbers. Though the variation in floor elevations may seem insignificant, these “slight� dimensional shifts can make a significant cumulative difference of inches and feet by the last row of the auditorium.

1.5.4 Arrangement of Seats

Sound Source

140 Degree

50 Degree

50 Degree

Sound Shadow

Diagram 5: Plan of DPAC showing arrangement of seats

15000

Vertical sightlines require the examination of line of sight in section view from every seated row of the theatre to common targets at the stage edge. Left and right chairs are arranged in 50 degree towards the stage to have an unobstructed view to the stage. The plan of DPAC (Figure) showing the seats arrangement, distance between sound source and sound receiver and seats orientation angle.

Chapter 2

Acoustics & Architecture 2.0

2.1 Introduction to Acoustics 2.2.1 Acoustics in Architecture 2.2.2 Sound Intensity Level 2.2.3 Reverberation, Attenuation, Echoes & Sound Shadow 2.3 Methodology

Acoustic & Architecture 14

2.1 Introduction to Acoustics Architectural acoustics is the relationship between sound produced in a space and its listeners, of particular concern in the design of auditoriums. Good acoustic design takes into account of issues such as reverberation time, sound attenuation, echoes, sound shadows, sound intimacy, finish materials, and external noise. Architectural modifications may act as a focusing elements to improve sound quality. All acoustical situations consist of three parts: source, path, and receiver.

2.2.1 Acoustics in Architecture Acoustics is related to recorded music, to speech and hearing, to the behavior of sound in concert halls and buildings, and to noise in our environment. Room acoustics are a significant part of the architectural atmosphere. Acoustics is known as the ‘science of sound.’ Sound is caused by vibrations which transmit through a medium such as air. It is the technology of designing spaces and systems that meet out auditory needs. Architectural acoustics tend to maintain the sound inside and block unwanted noise from outside. Good acoustical design ensures the efficient distribution of desirable sounds, as well as the exclusion of undesirable sound.

2.2.2 Sound Intensity Level Sound intensity level is known to be a unitless quantity informing us the level of the sound relative to a fixed standard, in where intensity is the power per unit area carried by a wave. Sound intensity have been used as a technique in consulting acoustics in general.The benefit of intensity measurement in architecture is principally in its ability to indicate the source direction. The current work in intensity is based on an interest in the performance of acoustical dividers and absorbers.

Sound intensity levels are quoted in decibels (dB), which is more often than sound intensities in watts per meter squared. The reasons for this choice of units are related to how we perceive sounds.

Figure 6: Formula of Sound dB

Acoustic & Architecture 15

2.2.3 Reverberation, Attenuation, Echoes, and Sound Shadow Reverberation is the persistence of sound after source of sound has ceased, resulting from repeated reflections. Reverberation time is perceived as the time for the sound to decrease after the sound source ceases, which also depends upon the intensity of the sound.

Reverberation affects the way a space sounds. A high reverberation time could make a room sound loud and noisy. A high reverberation time causes sound to sound muffled and muddy.

Rooms are then designed to typically have a low reverberation time: <1 second. A high reverberation time can enhance a music hall by adding richness, depth, and warmth to music. A higher level of reverberation within a concert hall is therefore critical.

To control reverberation time, acoustic absorption is used.

Figure 7: Reverberation Time for Type of Space

Attenuation is the acoustic measure of energy loss, which can be the results of sound absorption and sound scattering. The combined effect of both absorption and scattering causes attenuation.

Sound absorption is the incident of sound wave energy is absorbed into the material.

Echoes are the distinct repetition of original sound that could be clearly heard above the general reverberation. A reflected sound can be perceived as discrete echo if the reflected sound wave is heard after it was heard as a direct sound.

Sound shadow is an area in which sound waves fail to propagate due to physical obstructions or disruptions which send the sound waves off course. This creates an issue where the theatre is in need of sound reinforcement.

2.3 Methodology 16

Sound Level Meter In this assignment, 01dB A-scale sound level meter was used as the sound measurement instrument. The A-scale frequency weighting corresponds to the way the human ear responds to the loudness of sound and the weighted sound level value is read on the meter. Different sound frequency and type can be measured through the changing air pressure on air due to the sound waves such as sound concentration, sound shadow, and background sound.

Figure 8: Sound Level Meter

Measuring Tape Incomplete and missing measurement on the given architectural drawing are measured on site using the measuring tape. Small scale detail and distance in between object can be obtained through the utilization of this instrument which is important for the research and calculation purpose later.

Figure 9: Measuring Tape

Digital Single-Lens Reflex Camera Digital camera as documentation purpose which is a visual recorder during the site visit. Site acoustical design and fixtures are mainly recorded throughout the documentation by this instrument. In case of further analysis of the needed space, the image is used as the preference.

Figure 10: DSLR

Laser Measure Laser measure tools to determine the dimension in between unreachable object by measuring tape such as height of the ceiling and the width of the wide spaces. This instrument provides faster and time efficient measurement process without risking the safety.

Figure 11: Laser Measure

Portable Bluetooth Speaker This instrument was used to produce contrasting sound around the theatre in order to test the spaceâ&#x20AC;&#x2122;s acoustic performance.

Loud sound and high frequency produced from the portable speaker was played at various point of the hall.

Figure 12: Portable Bluetooth Speaker

Chapter 3

Acoustic Design Analysis 3.0

3.1 Sound Reinforcement System 3.2 Sound Propagation and Sound Concentration 3.3 Sound Shadow 3.4 Sound Reflection and Diffusion 3.5 Flutter Echoes & Sound Delay 3.6 Noise Intrusion 3.7 Construction of Materials

Acoustic Design Analysis 3.1 Sound Reinforcement System 18

Sound reinforcement system amplifies or enhances the clarity of the original sound as well as to add loudness and reverberation. This include the use of microphones, signal processors, amplifiers, and loudspeakers in the enclosure. It is a controlled system to distribute sounds to a larger or more distant audience. DPAC requires a sound reinforcement system that is pro acoustics and suitable for performances such as dance, music acts, and theatre work.

The system consists of four main stages: Input transducers > Mixing effects > Amplification > Output transducers Input Transducers: The first step of a sound system is to convert the source of sound to an electrical signal that can be fed to the rest of the system by using a microphone or playback device. The most common input devices are microphones and audio players.

Mixing Effects: Electrical audio signals from the input sources are then fed to a processor that mixes a variety of input sources to add effects. This stage consists of a mixing consoles for the audio engineers to use, as well as signal processors and equalizers.

Mixing Consoles: A device that the audio engineers use to mix multiple audio signals while adjusting their relative levels and independent sound quality. This shapes the sound and volume of all the sounds played in the theatre.

Monitor Speakers

Main Speakers

Mixing Consoles

The mixing consoles is located behind the seatings of theater. This allows the audio engineer to be aware of the acoustics in the hall as they are in the same space while being out of sight from the audience view.

Diagram 6: Location of the sound reinforcement system

Figure 13: Mixing Consoles Behind the Audience

Acoustic Design Analysis 3.1 Sound Reinforcement System 19

Amplification: The power amplifier mixs and processes audio signal to a level that is sufficient to drive the speaker system.The power amplifiers are often placed out of sight and easy to overlook, but are vital part of the overall system, which handles higher voltage and current than any of the other component.

Output Transducers: The last stage in the sound system consists of the speakers that convert the amplified electrical output from the power amp back into the acoustic sound we are able to hear. Main output transducers are the main loudspeakers and monitor loudspeakers.

Main Loudspeakers: They are placed on both sides of the stage, facing towards the audience to enhance the sound of performance.

Diagram 7: Section View of Main Speaker Placement

Figure 14: Main Loudspeakers Placement

The main loudspeakers are placed on both the left and right side of the theatre, facing the audience.

However, this is a disadvantage, due to: 1.

2.

Diagram 8: Plan View of Main Speaker Placement

Audience would hear two sound sources at the same time.

Placed on the both left and right of the stage, instead of middle of the stage to signify original source of sound.

Acoustic Design Analysis 3.1 Sound Reinforcement System 20

Monitor Loudspeakers: They are pointed towards the onstage performers in aid of hearing their performances. However, using monitor speakers instead of ear monitors would results in an increase of stage volume, which can lead to more feedback issues and hearing damage for the performers that in front of them.

Diagram 9: Location of the Monitor Loudspeakers in Floor Plan View.

Figure 15: Monitor Loudspeakers

The monitor speakers are placed on the left and right side of the stage, pointing towards the performers which helps cue the performances. They are hidden behind the curtains to keep them away from the audienceâ&#x20AC;&#x2122;s eye of sight. However, being hidden behind the curtains causes the sound waves to be absorbed.

Acoustic Design Analysis 3.2 Sound Propagation & Sound Concentration 21

Sound propagates through air as a longitudinal wave. The speed of sound is determined by the properties of the air and not by the frequency or amplitude of the sound. Sound waves, as well as most other types of waves, can be described in terms of the following basic wave phenomena.

Figure 16: Basic Wave Phenomena

The reading of sound is taken from different position of the theatre as the sound propagation are varied. The readings taken show that the layout and the use of material of DPAC are inappropriate such as: 1.

2.

It produce uncomfortable sound at certain area Sound are distributed unevenly throughout the theatre

87 dB

SIL Reading Location 88 dB

86 dB

88 dB

Sound Source Direct Sound

79 dB

Area

Diagram 10: SIL Reading of The Theatre

Acoustic Design Analysis 3.2 Sound Propagation & Sound Concentration 22

Sound concentration occurs when there is a concave reflecting surfaces where it can concentrate the reflected sound. The sound is concentrated at the center back seats which is the VIP seats of the theatre due to excessive diffusion and reflective of the material.

Sound Concentration

Diagram 11: Concentration of Sound in Theatre

Acoustic Design Analysis 3.3 Sound Reflection & Diffusion 23

In motive to keep any sound contained within the theatre, smooth and hard surfaces were used in components of the hall such as the floor, stage as well as the walls.

The zig-zag steel panels that attached on the acoustic treated wall are used for diffusing the sound source all over the theatre without the use of speakers.

Flat ceiling reflector are slightly tilted to project sound energy towards the rear seatings of the gallery and distribute across a wide range of frequencies evenly.

Diagram 12: The Sound Propagation from the Centre of Stage

Diagram 13: The Sound Propagation from the Back of the Stage The reflective sound also failed to convey uniformly to all of the audience as it concentrated at the VIP seats. It is due to the flat ceiling reflective panel that are ineffective and not well configured.

Sound Source Direct Sound

Reflected Sound Diffusion of Sound

Flat Ceiling Reflector

Acoustic Design Analysis 3.3 Sound Reflection & Diffusion 24

Sound Diffusion, a sound is said to be homogeneous when sound pressure is equal in all part of an theatre. Diffuser which scatter sound are critical in acoustical theatre design to improve the sound quality in frequencies throughout the middle and high range of the spectrum.

The purpose of sound diffusion is to promote uniform sound distribution and to prevent the occurrence of undesirable defects such as echo. It keeps sound waves from grouping, so there are no hot spots or nulls in a room, making the instrumental or any sound source sounds more natural as the human ear is used to reflections and reverb trails from a single sound source arriving at the inner ear at multiple intervals.

Diagram 14: Corrugated Surface of The Steel Panel Diffuse The Sound Evenly to The Audience

Sound Source Direct Sound Reflected Sound Diffusion of Sound Diagram 15: Floor Plan of DPAC

Acoustic Design Analysis 3.4 Sound Reflection & Diffusion 25

The sound diffusion method being used in DPAC is the steel panel with irregular surface, zig-zag steel panel are placed around total 90% over the wall of the theatre. For the materiality aspect, the acoustic wall surface area are covered by various sized steel panel with a thickness of 0.1 inch (3mm) steel panel. Its absorption coefficient is around 0.08 under 500 Hz, which mean most of the sound energy get reflected when it strikes on the surface.

The reason of the steel panel covers all the surrounding walls is to further enhance the diffusion of sound where audience can receive a natural quality of sound and there wonâ&#x20AC;&#x2122;t be any hard reflection which gives a sound illusion of two sound source, which is called echo or delay reflection.

Figure 18: Sharp Edge Service Room Table

Figure 19: Sharp Edge Staircase

Besides zig-zag steel panels, there has a lot of sharp edged element at there that can bing minimal diffusion, such as edge of staircase, edge of table at service room and so on.

Figure 17: Zig-zag Steel Panel

Figure 20: Zig-zag Steel Panel

Acoustic Design Analysis 3.3 Sound Reflection & Diffusion 26

Diagram 16: Sound Diffusion to Front Rows

The placement of the Zig-zag steel panel and sound absorption of the drapery at front stage causes the front row of the theatre receive more direct sound from the sound source in front and some from diffusion.

Diagram 17: Sound Diffusion to Centre Rows

Diffusion Sound

Direct Sound

Zig-zag Reflective Panel

Reflected Sound

Drapery

Acoustic Design Analysis 3.3 Sound Reflection & Diffusion 27

Diagram 18: Sound Diffusion to Back Rows

Seats located nearer to steel panels would receive more diffusion of sound. Therefore, the diagrams above well explained why the SIL reading at centre-front of the theatre are relatively lower than other zone of the theatre.

Diffusion Sound

Direct Sound

Zig-zag Reflective Panel

Reflected Sound

Drapery

Acoustic Design Analysis 3.4 Sound Shadow 28

Sound Shadow effect occurs due to obstructed sound wave by an object in its path, causing sound wave fail to propagate in an certain area. The sound shadow effect causes different sound level intensity such as reduction in noise volume which minimizes the audienceâ&#x20AC;&#x2122;s experience in the theatre.

In DPAC, sound shadow defect can be found in the space underneath the overhang stage nearby the entrance, where the overhang obstruction affects the sound intensity level around that area, thus sound waves least propagates to. The sound intensity level dropped from the middle part of the theatre which is 86 dB to 79 dB under the overhanging stage, thus affect the last row audiences during the performance. Therefore, sound shadow effect in DPAC is tackled by utilizing diffusion through zig zag panels in order to increase the sound quality and sound intensity level in the sound shadow area.

79 dB 86 dB

Diagram 19: Section of DPAC Showing Sound Shadow Sound Shadow Reflected Sound

Figure 21: Sound Shadow Area in DPAC

Figure 22: Zig-Zag Panel at Sound Shadow Area

Acoustic Design Analysis 3.5 Flutter Echoes & Sound Delay 29

Echo and reverberation are two different thing.

Echo is a reflection of sound that arrives at the listener with a delay after the direct sound.

Different functions of the spaces have different sound delay period, thus different perceptions of echo. A space that having speech the time delay is 40 msec whereas space for music is 100 msec perceived as a sound distinct from that travelling directly from source to listener is deemed as an echo.

Methodology: Identification of occurence of echoes using formula below: Reflected Sound 1 + Reflected Sound 2 - Direct Sound â&#x2030;Ľ 34 m R1 + R2 - D â&#x2030;Ľ 34 m

A sound delay of 40 msec is acceptable for an art performing theatre (Diagram 20)

10m

11.9m

15.5m

Listener 1

Sound Source Direct Sound Reflected Sound Diagram 20: Floor Plan Showing Sound Delay From Listener 1

Time Delay = (R1 + R2 - D) / 0.34s = (10 m + 15.5m - 11.9 m) / 0.34 s = 13.6 m / 0.34 s = 40 msec

Acoustic Design Analysis 3.5 Flutter Echoes & Sound Delay 30

A sound delay of 29.1 msec is slightly acceptable for an art performing theatre (Diagram 21)

7.7m 12.5m

14.7m Listener 2

Sound Source Direct Sound Reflected Sound

Diagram 21: Floor Plan Showing Sound Delay From Listener 2

Time Delay = (R1 + R2 - D) / 0.34s = (7.7 m + 14.7m - 12.5 m) / 0.34 s = 9.9 m / 0.34 s = 29.1 msec

Acoustic Design Analysis 3.5 Flutter Echoes & Sound Delay 31

A sound delay of 11.2 msec and 8.8 msec are quite short for an art performing theatre (Diagram 22)

9.9m 10.5m 11.1m

5m

3.6m

Listener 3

Sound Source Direct Sound Reflected Sound

Diagram 22: Floor Plan Showing Sound Delay From Listener 3

Time Delay = (R1 + R2 - D) / 0.34s = (9.9 m + 5m - 11.1 m) / 0.34 s = 3.8 m / 0.34 s = 11.2 msec

Time Delay = (R1 + R2 - D) / 0.34s = (10.5 m + 3.6m - 11.1 m) / 0.34s = 3.8 m / 0.34 s = 8.8 msec

Acoustic Design Analysis 3.5 Flutter Echoes & Sound Delay 32

8.4m Listener 1

8.8m

2.6m

Diagram 23: Section Showing Sound Delay From Listener 1

Time Delay = (R1 + R2 - D) / 0.34s = (8.4 m + 8.8m - 2.6 m) / 0.34 s = 14.6 m / 0.34 s = 43 msec

Sound Source Direct Sound Reflected Sound

A sound delay of 43 msec is acceptable for an art performing theatre (Diagram 23) and a sound delay of 14.7 msec is quite low for an art performing theatre (Diagram 24)

Listener 2

7.5m

10.1m

Diagram 24: Section Showing Sound Delay From Listener 2

Time Delay = (R1 + R2 - D) / 0.34s = (10.1 m + 7.5 m - 12.6 m) / 0.34 s = 5 m / 0.34 s = 14.7 msec

Sound Source Direct Sound Reflected Sound

Based on the formula and calculation, we concluded that there is no echo in the Damansara Performing Art Centre theatre as it is relatively small space for performance purpose. It is because the sound are being absorbed quicker by the environment due to the close proximity of the walls as the size of the theatre is too small for an echo to occur.

Acoustic Design Analysis 3.5 Flutter Echoes & Sound Delay 33

Flutter Echo consists of a rapid succession of noticeable small echoes. It is observed when a short burst of sound is produced between between parallel sound-reflective surfaces. Flutter echoes may still occur between non-parallel surfaces or between absorbent non-parallel surfaces.

DPAC did not create flutter echo as the walls of the theatre is not parallel to each other. Besides, the zig-zag steel panels diffuse the sound, so it doesnâ&#x20AC;&#x2122;t lead to flutter echo.

Sound Source Direct Sound Diffused Sound Diagram 25: Floor Plan of DPAC

Acoustic Design Analysis 3.6 Noise Intrusion 34

Any sound judged as undesirable by the recipient is considered to be noise. Noise is unwanted sound. Noise can be distracting, annoying, or harmful to everyday activities (work, rest, entertainment, or study). Whether or not a sound is considered undesirable will depend not content and origin of the sound and recipientâ&#x20AC;&#x2122;s state of mind and temperament. As a rule, noises of mechanical / electrical origin ( fan, motors, pumps,etc) are more disturbing than those of natural origin (wind, waterfall, rain, etc). Only on the loudness of the sound but on its frequency, continuity, time of occurrence, place and activity being carried out, information. High-frequency noises are also more disturbing than low-frequency noises. The acceptable level of noise depends not only on objective, physical factors but also on subjective, psychological factors. Whenever a noise is disturbing or not depends on the state of mind or expectation of the listener.

Example: In a sleeper train, the monotonous noise, even at 70 to 80 dBA will not be disturbing, but in a quiet home, if the listener is badly 'tuned', even the ticking of a clock at 20 dBA may cause great annoyance.

Detrimental Effects of Noise on the Listener or Environment: 1. Excessive noise can adversely impact the health of building occupants such as sleep disturbance or sleep deprivation and increased stress.

2. In educational settings, noisy environments hinders concentration and knowledge retention.

3. In healthcare facilities, noisy environments can prolong recuperation time.

4. Distraction from a particular task can cause inefficiency, inattention and errors with detrimental effect on working efficiency and production.

5. Quality of life in general decreases in noisy environment.

6. Loss of hearing can occur over prolonged exposure to excessive noise levels.

7. Interference with desirable sounds such as music or speech can be annoying and in some situations dangerous.

8. Expenses are incurred by the measures needed to try and combat noise.

Levels of Noises Produce Both Psychological and Physiological Effects: 65 dBA: up to this level of noise may create annoyance, but its result is only physiological (bodily fatigue). Above this level, psychological effects such as mental and nervous effects, may occur.

90 dBA: many years of exposure to such noise levels would normally cause permanent hearing loss.

100 dBA: with short period of exposure to this level, the aural acuity may be impaired temporarily, and prolonged exposure is likely to cause irreparable damage to the auditory organ.

120 dBA: causes pain.

150 dBA: causes instantaneous loss of hearing (deafness).

Acoustic Design Analysis 3.6 Noise Intrusion (Exterior Noise) 35

1. Environmental Sound from Exterior Vehicular Noise from Lebuhraya Damansara - Puchong & Jalan PJU 8/8 Facing to the northwest of a large contour area of vegetation, DPAC is located in Empire Damansara, Petaling Jaya of more than a 150 meters from Lebuhraya Damansara - Puchong and at the roadside of Jalan PJU 8/8.

By using the Sound Level Meter, the result is measured by 72 dB. Unpleasant or disturbance noise caused by heavy traffic are created and could be heard during a peak hour. Effectively, minimal noise intrusion could be identified from the surrounding context.

Jalan PJU 8/8

ya

ara ns ma a D

-P

H ng ho

wa igh

y

uc

hra

bu Le

Diagram 26: Site Plan of Empire Damansara

Vegetation

Acoustic Design Analysis 3.6 Noise Intrusion (Exterior Noise) 36

2. TNB Station Mechanical Noise from TNB Station Above the backstage of theatre, sound intrusion could be identified as TNB Station generates mechanical systems that brings a source of noise and sound pollution. Despite that, it does not bring issues to the interior.

TNB Station

Diagram 27: Floor Plan of Empire Damansara

TNB Station

Acoustic Design Analysis 3.6 Noise Intrusion (Exterior Noise) 37

3. Car Park & Audience Entrance Door Vehicular Noise from Car Park Parking lot is located at the exterior of DPAC, which sound intrusion could be identified due to the movement of vehicular engine. By using the Sound Level Meter, the result is measured by 75 dB. Despite that, the acoustic door of the theatre is carefully designed with fibrous materials, using 25mm Rockwool core infill which absorbed and minimize the sound to obstruct both vehicular noise from entering to the theatre. Whereas, the performing stage and backstage, which is close to the car park uses Plywood surface creating a great reflection of sound or noises from entering the backstage.

Parking lot

Diagram 28: Floor Plan of Empire Damansara

Damansara Performing Art Centre (DPAC)

Performing Stage Backstage Damansara Performing Art Centre (DPAC)

Acoustic Design Analysis Noise Intrusion (Interior Noise) 38

Human Noise from Audience Entrance Door (Structural Borne Noise) Sound intrusion could be identified when there is an opening and closing the door or human chatter and human noise outside the entrance door. However, sound lock is placed at the double door system, the acoustic door (inner door) prevents the noise from interfering the audience seats near to the door and it serves as a function to isolate the sound waves in sound lock with the outer door.

As a result to bring down the noise level down to 40 dB from 72 dB serve as a great sound insulation. In addition, Velvet curtains are added to enhance and absorb the amount of sound and noise.

Theatre of Damansara Performing Art Centre (DPAC) 40 dB

Figure 23: Double Door System

Lobby of Damansara Performing Art Centre (DPAC) 72 dB

Sound Lock

Noise

Normal Door Acoustic Door

Diagram 29: Floor Plan of DPAC

Velvet Curtains

Figure 24: Velvet Curtains

Acoustic Design Analysis Noise Intrusion (Interior Noise) 39

Human Noise from Backstage Entrance Door (Structural Borne Noise) Backstage entrance door acts as an entrance for the performers which also leads to a basement parking lots or loading bay, which sound intrusion could be identified. Despite that, the acoustic door of the theatre is carefully designed with fibrous materials, using 25mm Rockwool core infill which absorb and minimize the sound to obstruct both vehicular noise from entering to the theatre. It is one of the most effective acoustic insulation solution as it provides airborne sound absorption which can dramatically improve the acoustics which due to its high density, non directional fibres that trap the sound waves and absorb vibration (Industrial Noise Control, Inc, 2007). Whereas, the performing stage and backstage, which is close to the car park uses Plywood surface creating a great reflection of sound or noises from entering the backstage.

Basement Parking & Loading Bay Theatre of Damansara Performing Art Centre (DPAC) 40 dB

Sound Lock

Lobby of DPAC 72 dB

Diagram 30: Floor Plan of Damansara Performing Art Centre (DPAC)

Figure 25: Backstage Entrance Door

Acoustic Design Analysis Noise Intrusion (Interior Noise) 40

4. Internal Noise Operates by Building M&E Service and Machinery Ducting & Diffuser (Structural Borne Noise) Ducting and diffuser supply positive pressure distribution systems and negative pressure ducting for exhausting air from rooms. It is one type of sound intrusion that could be identified due to the high pressure of air distribution.

In DPAC, Centralized Air Conditioning with delivery ducts is used, such as Fan Coil Unit, diffuser and ducting.

Figure 26: Backstage Ducting

Fan Coil Unit is the selection of fan with low noise and it might require acoustics box up if its installed within a sensitive room such as the theater to reduce noise (Building Designs Ltd, 2018).

Diffuser is the selection of diffuser with low regeneration noise. Excessive air or high velocity of air flows thru diffusers blades with generate noise. Air speed and volume per diffuser are essential (Building Designs Ltd, 2018).

Figure 27: Performing Stage Diffuser

Ducting with internal lining of rockwool and thermalrock with tissue facing or GI sheet ensuring acceptable indoor air quality as well as thermal comfort.

Figure 28: Seating Area Ducting & Diffuser

Acoustic Design Analysis Noise Intrusion (Interior Noise) 41

Fan Coil Unit (FCU) (Structural Borne Noise) Temperature is one of the element that could affect on designing a comfortable theatre to provide comfort to building occupants. It feels cold in an empty room, but it can quickly heats up when itâ&#x20AC;&#x2122;s fill up with people. Hence, the opening slab metal stand were designed beneath the seats incorporates air conditioning on every seats, which is a more convenient way to control the temperature of the interior. The noise functioning of an air-conditioning unit is unavoidable. The sound transmitted through structural borne in which sound is vibrating on the solid surface of the AHU duct which causes a noise issue to the interior. By minimizing the noise of air flow in the audience seating area, it is under controlled by putting a layer of foam that wraps around the AHU duct to minimize the air friction. To achieve such result, it requires a Centralised Air-Conditioning with delivery ducts. A Fan Coil Unit (FCU) is a very simple and flexible device that consist a heating and cooling heat exchanger. Itâ&#x20AC;&#x2122;s is a part of an HVAC system which has a low noise unit. The noise output level can be as low as NR25 (Designing Buildings Ltd, 2018).

AHU Duct FCU Air Conditioning

Foam Layer reducing air friction and absorb sound from FCU Unit

Diagram 31: Section of DPAC

Figure 29: Openings Slab Metal Stand

Figure 30: Ducting with Foam

Acoustic Design Analysis Noise Intrusion (Interior Noise) 42

Table 1: Maximum Noise Rating Level on Application

Air Conditioning Unit (Structural Borne Noise) Air Conditioning Unit, a structural borne sound path, is installed beneath the ceiling of the performing stage. However, minimal noise are produced which would not affect during the performance.

Diagram 32: Section of DPAC

Acoustic Design Analysis Noise Intrusion (Interior Noise) 43

Projector Cooling Fan Mounted to the Wall of Audience Seats (Airborne Borne Noise) Projectorâ&#x20AC;&#x2122;s cooling fan, an airborne sound transmission, is one type of sound intrusion that could be identified. It is placed to the wall, behind the audience seatings as noise could be heard throughout the performance. This is one of the common issue faced by most of the theatre, therefore, there is a need to reduce the noise by an acoustic design.

A hush box is designed as a projector enclosure to silence or decrease the noise that generate noise from the cooling fan system or the electronics. It is done by drawing fresh air from the room itself. Factors need to be considered are methods of bringing fresh air into the box and expel air out of the box as well as air filtration to filter dust in the room (Projector Enclosure, 2017).

Theatre of Damansara Performing Art Centre (DPAC)

Figure 30: Hust Box

Lobby of Damansara Performing Art Centre (DPAC)

Diagram 33: Floor Plan of DPAC

Figure 31: Cooling Fan

Acoustic Design Analysis Noise Intrusion (Interior Noise) 44

Staircase Squeaky Noise caused by Occupant Activities (Structural Borne Noise) In DPAC, staircase treads is made by plywood, which sound intrusion could be identified when occupants are stepping on the staircases due to structural borne transmission. Occupant entering or leaving the theatre causes a noise disturbance especially during a show is being played. The sound is transmitted through structural-borne, resulting from an impact or the vibration against it, where sound vibrates on the solid hard surface of the plywood (Design Buildings Ltd, 2018).

Theatre of Damansara Performing Art Centre (DPAC)

Figure 32: Plywood Staircase

Lobby of Damansara Performing Art Centre (DPAC)

Diagram 34: Floor Plan of Damansara Performing Art Centre (DPAC)

Acoustic Design Analysis Noise Intrusion (Interior Noise) 45

Performing Stage Flooring System (Structural Borne Noise) DPAC mainly serve for a small scale dance, drama and musical production. Possibility of sprung floor is advisable as it provided some degree of bounce and flex under impact. Performers need it to absorb shock to protect their joints from a nonsensical remark or action particularly during performance that requires jump. It is a great choice to choose plywood as it has sound control which it bounces high frequencies, resonating better sound quality, and absorbing bass energy.

Due to the limitation of space, it was built with a shallow apron where the stage is close to the audience seats. Hence,, the performing stage is covered with Vinyl Sheet (Rosco Adagio) to mainly increase the slip resistance and both reduces the noise.

Audience Seatings

Apron

Performing Stage

Diagram 35: Section of DPAC

Performing Stage Apron Audience Seatings

Vinyl Sheet (Rosco Adagio)

Plywood Dual density shock dampening elastomer blocks at predetermined interval.

Figure 33: Limited of Space

Diagram 36: Vinyl Sheet (Rosco Adagio)

Acoustic Design Analysis Noise Intrusion (Interior Noise) 46

Lighting Fixtures (Airborne Noise) Improper dimming or electromagnetic interference from other devices causes vibrations in the light bulb which sound intrusion could be identified from the buzzing noise of lighting fixture. LED strip are kept in the internal steel panel where occupant could be heard when sitting right next to or near to the steel panel.

By fixing the dimmer that is compatible with the LEDs to reduce the noise and ensure there's no humming sound.

Figure 34: Steel Panel

Auditorium of Damansara Performing Art Centre (DPAC)

Lobby of Damansara Performing Art Centre (DPAC)

Diagram 37: Floor Plan of DPAC

Figure 35: Steel Panel

Acoustic Design Analysis 3.7 Construction of Materials 47

3.7.1 Ceiling Material: Concrete Slab + Spray Foam In DPAC, concrete slab is used for ceiling which produces a high reflection and unnecessary noise as it is a hard surface material. Thus, a layer of spray foam has been applied on the surface of concrete slab as an acoustic finishes to reduce the sound reflection.

Spray foam can create a seamless air barrier that can block the transmission of sound from one area to another. By spraying a layer of foam onto the hard surface, it reduces the echo, thereby reducing the sound.

Figure 36: Concrete slabs for ceiling

Diagram 38: Area of Concrete Slabs for Ceiling

Acoustic Design Analysis Construction of Materials 48

Reflector Panel Material: Plywood In DPAC, the sound travels to the audience seatings by direct sound and reflective sound. Direct sound could be heard clearer to the front seating than the back. Thus, plywood reflector panels were installed in order to distribute sound evenly to the audience seatings.

Multiple plywood reflector panels can increase redundant sound reflection. Thus, plywood reflector panels were installed at the sides of the audience seatings to get reflected sound evenly.

Figure 37: Plywood Reflector Panels

Diagram 39: Location of Plywood Reflector Panels

Acoustic Design Analysis Construction of Materials 49

3.7.2 Acoustic Treated Wall Material: Concrete, Rockwool, Fibre Board Sound reflection and diffusion are frequently take place in DPAC. Therefore, acoustic treated wall is required in order to reduce the cause of unwanted sound. The acoustic treated wall consists of 3 layers which are concrete, rockwool and fibre board which is undeniably a good sound insulation barrier.

Diagram: Construction Detail of Acoustic Treated Wall

Diagram 40: Location of Acoustic Treated Wall

Figure 39: Rockwool

Rockwool is an excellent acoustic barrier that effectively absorbs sound, especially for low frequency (bass) ranges as it consists of higher density batts that can more effectively reduce airflow and decrease sound transmission.

Figure 38: Acoustic Treated Wall Materials

Figure 40: Fibre Board

Fibre board acts as an absorption material especially for the high frequency ranges.

Besides, it decreases the airborne noise and sound transmission from interior and exterior.

Acoustic Design Analysis Construction of Materials 50

Zig-Zag Steel Panels Material: Steel Zig-zag steel panels are placed in an irregular arrangement to serve an acoustical and aesthetic purpose to hide the lighting system. Zig-zag steel panels interrupt discrete echoes by scattering or diffusing sound energy over a wide area without removing it from the theater. This maintain sound clarity and improves speech intelligibility.

Figure 41: Zig-Zag Steel Panel

Diagram 42: Location of Zig-zag steel panels

Acoustic Design Analysis Construction of Materials 51

Cyclorama Wall (Front Stage Back Panel) Material: Plywood A cyclorama is a large curtain or wall that positioned at the back of the stage to blur the boundary and create an unlimited space.

Whereby for Damansara Performing Arts Center (DPAC), the cyclorama wall was built to define the boundary of stage, create a barrier with backstage and reflect the sound to the installed reflector panels on ceiling evenly for a better sound transmission. Besides, it also provides certain light reflection to create a focus point for audience.

Figure 42: Cyclorama Wall

Diagram 43: Location of cyclorama wall

Acoustic Design Analysis Construction of Materials 52

3.7.3 Flooring Material: Concrete, Plywood As DPAC is a multipurpose theatre, it serves other purposes such as movie screening, drama and small scale dance. Thus, acoustic performance and slip resistance is important for the audience’s experience and performer’s safety.

Plywood Concrete

Figure 43: Material of floor

Plywood

Concrete Diagram 44: Floor Plan of DPAC

In DPAC, concrete were used for the apron flooring and plywood with vinyl sheet (Rosco Adagio) are being used for the stage. Due to the hard surface of concrete and plywood, the sound might bounces and reflect to the whole theatre.

Besides, a layer of Rosco Adagio consist of slip resistance to ensure the performer’s safety. The controlled slip vinyl surface makes it equally successful as a ballet, modern and jazz floor.

Figure 44: Vinyl Sheet (Rosco Adagio)

Acoustic Design Analysis Construction of Materials 53

3.7.4 Staircase Material: Plywood, Metal Plate In DPAC, plywood is used for the tread of staircase in contrasting with the concrete floor, to let the audience notice. Besides, it also serves for an aesthetic purpose where LED strips are hide underneath the treads to leads audience to their seat.

Metal plate can be seen from the nose of riser, which it reflects the sound due to the hard surface, meanwhile, the vibration to the metal creating unwanted noise when audience stepping on the plywood staircase.

Plywood Tread

Metal Plate Riser

Figure 45: Staircase

Staircase

Diagram 45: Floor Plan of DPAC

Diagram 46: Section Staircase of DPAC

Acoustic Design Analysis Construction of Materials 54

3.7.5 Curtain Types: Duvetyn, Velvet Fabric, Bolton Twill Fabric In DPAC, there are 3 types of curtain that can be identified, which are Duvetyn, Velvet fabric and Bolton Twill fabric. These curtain are used to absorb sound, control the reverberation time and decrease excessive echo delay.

Duvetyn Bolton Twill Fabric Velvet Fabric

Diagram 47: Floor Plan of DPAC

Bolton Twill Fabric In DPAC, Bolton Twill Fabric is used as a covering for the service room entrance. The pattern of diagonal ribs creates a complex pattern which can help to hide the surface dust and dirt.

Figure 46: Bolton Twill Fabric

Acoustic Design Analysis Construction of Materials 55

Duvetyn Duvetyn is one of most economical masking fabrics employed by stage scenarists. Due to its matte finish and high opacity, it is ideal for blocking out unwanted light are typically used for stage skirting or as a black background.

In DPAC, Duvetyn is used at both sides of the stage to absorb sound and hide the performers who are preparing for the show. Besides, the colour of Duvetyn; black, helps to reduce the reflection of light.

Figure 47: Duvetyn

Diagram 48: Sound Absorption of Duvetyn

Diagram 49: HIgh Opacity of Duvetyn

Acoustic Design Analysis Construction of Materials 56

Velvet Fabric To reduce the sound that comes from exterior and interior, it is recommended to install velvet curtain on the entrance as Velvet curtain can improve the sound quality of the theatre. Heavy velvet can absorbs sound very well. In addition, it can absorb any sound wave impinging on the walls significantly.

In DPAC, it consists of an acoustic treated wall, acoustic door and sound lock to separate the noise, therefore, it absorbs sound but it doesnâ&#x20AC;&#x2122;t affect the overall effect that much. Thus, the main purpose of using Velvet curtains is to minimize the light penetration when people slip in.

Figure 48: Velvet Fabric

Theatre

Diagram 50: Floor plan shows decreased light interruption

Acoustic Design Analysis Construction of Materials 57

3.7.6 Seat Material: Foam Inner + Fabric Cover, Plywood, Steel In DPAC, fabric for cushion, plywood for armrests and steel stand are used for the seats. Fabric cushion is used to provide certain sound absorption, red colour is used to let audience feel elegant and create a sense of vibrant. Plywood armrests provide some sound reflection due to its hard surface.

Steel stand is built to support the seat and it also functions as an air conditional opening to ventilate the air movement, but it also creates certain noise.

Figure 49: Steel Stand

Seat

Diagram 51: Floor Plan of Damansara Performing Art Centre (DPAC)

Figure 50: Seat

Acoustic Design Analysis Construction of Materials 58

3.7.7 Door Material: Plywood, Rockwool In DPAC, there are 2 types of door which are acoustic door and normal door. Acoustic door is made by plywood with rockwool in inside as insulation to absorb noise and blocking unnecessary sound. Normal door is just a normal door that constructed by plywood, due to its hard surface, it acts as a sound reflector.

Normal Door

Theatre of Damansara Performing Art Centre (DPAC) 40 dB

Acoustic Door

Noise

Normal Door Sound Lock

Figure 51: Normal Door

Lobby of Damansara Performing Art Centre (DPAC) 72 dB

Diagram 52: Floor Plan of DPAC Acoustic Door Theatre Acoustic Door Sound Lock Sound Lock

Outside Normal Door Diagram 53: Floor Plan of DPAC

Sound Lock

Figure 52: Acoustic Door

Before the audiences go in the theatre there is a space that separates the theatre and outside, it is considered as sound lock. Sound lock is defined by at least 2 doors with an intermediate air space between them to prevent sound from escaping and entering.

Chapter 4

Calculation

4.1 Area of Materials 4.2 Reverberation Time

Calculation 4.1 Area of Floor and Ceiling Materials 60

M1

M2

M3

Diagram 54: Floor Plan with Flooring Material Indication

Diagram 55: Ceiling Plan with Material Indication

M4

M2

M1

Figure 53: Stage’s Floor

Diagram 56: Ceiling Plan with Reflector Ceiling Panel

M4

M3

Figure 54: Concrete Floor

Figure 56: Reflector Ceiling Panel

Figure 55: Ceiling

Legend

Component

Material

Surface Finishes

Area (m²)

Coefficient (500 Hz)

Absorption Unit (m² Sabins)

M1

Flooring (Stage)

Plywood and Vinyl Sheet

Uneven

147

0.03

4.41

M2

Flooring (Audience)

Concrete Slab

Smooth

190

0.05

9.5

M3

Ceiling

Concrete Slab + Spray Foam

Rough

324.5

0.15

48.675

M4

Reflector Ceiling Panel

Plywood

Smooth

20.5

0.05

1.025

Total Absorption (A)

63.61

Calculation 4.1 Area of Wall and Staircase Materials 61

M6 M5 M 8

M 9 M7

Diagram 58: Section with Wall Materials Indication

Diagram 57: Floor Plan with Stairs Material Indication M5

M6

Figure 57: Acoustic Wall

Figure 58: Zig Zag Steel Panel

M8

M9

Figure 60: Plywood Staircase

Figure 61: Metal Plate Staircase

M7

Figure 59: Cyclorama

Area (m²)

Coefficient (500 Hz)

Absorption Unit (m² Sabins)

Legend

Component

Material

Surface Finishes

M5

Acoustic Treated Wall

Concrete, Rock Wool, Fibre Board

Smooth

363

0.55

199.65

M6

Zig-zag Steel Panel

Steel

Polished

326.7

0.08

26.136

M7

Cyclorama (Front stage back panel)

Plywood

Smooth

85

0.05

4.25

M8

Staircase

Plywood

Smooth

12.5

0.05

0.625

M9

Staircase

Metal Plate

Smooth

28

0.08

2.24

Total Absorption (A)

232.901

Calculation 4.1 Area of Other Materials 62

M11

M12

M14

M13

Diagram 60: Section with Seat’s Component Materials Indication M10

Diagram 59: Floor Plan with Doors Material Indication

M10

Figure 62: Normal Door

M13

M11

M12

Figure 63: Acoustic Door

Figure 64: Seating Cushion

M14

Figure 65: Seat’s Plywood

Figure 66: Seating Stand

Area (m²)

Coefficient (500 Hz)

Absorption Unit (m² Sabins)

Legend

Component

Material

Surface Finishes

M10

Normal Door

Plywood

Smooth

1.84

0.05

0.092

M11

Acoustic Door

Plywood, Rockwool, Metal

Smooth

6

0.1

0.6

M12

Seating Cushion

Foam with Fabric Cover

Soft

485

0.46

223.1

M13

Seating Back, Side, Armrest

Plywood

smooth

146.5

0.05

7.325

M14

Seating Stand

Steel

Smooth

40.6

0.08

3.248

Total Absorption (A)

234.365

Calculation 4.1 Area of Other Materials 63

M16

M16

M17

M15

Diagram 62: Section with Curtains Material Indication M17

M15

Diagram 61: Floor Plan with Curtains Material Indication

M15

M16

M17

Figure 67: Duvetyn Curtain on Stage

Figure 68: Velvet Curtain at Entrance

Figure 69: Bolton Twill Fabric at Service Area

Legend

Component

Material

Surface Finishes

Area (m²)

Coefficient (500 Hz)

Absorption Unit (m² Sabins)

M15

Side Curtain

Duvetyn

Soft

188.5

0.2

37.7

M16

Entrance Curtain

Velvet

Soft

16.8

0.25

4.2

M17

Service Curtain

Bolton Twill Fabric

Soft

14

0.1

1.4

Total Absorption (A)

43.3

Calculation 4.2 Reverberation Time 64

Total Sound Absorption

= 63.61 + 232.091 + 234.365 + 43.3 = 573.366 m²sabins

Total Volume of the Theatre

= 4236 m³

Reverberation Time

= 0.16V / A = 0.16 x 4236 / 573.366 = 1.18 s

Diagram 63: Reverberation Time in Second

The volume of Damansara Performing Art Center (DPAC) is approximately 4236 m³ with reverberation time around 1.18 seconds. As an multipurpose medium size art center that conducts variety of activities such as dancing, movie screening and theatre, DPAC fulfils and comply to the reverberation time requirement of medium size hall which falls within the range of 1 to 1.25 seconds as shown in diagram above. Thus, DPAC has a good reverberation time as an multipurpose size hall even without any additional sound absorber material needed to be added in the future.

Chapter 5

Acoustical Defects & Design Issues Design Solution & Suggestion

5.1 Staircase Squeaky Noise caused by Occupant Activities 5.2 Unsuitable Material for Insulation 5.3 Placement of Loudspeakers 5.4 Concentration of Sound

Acoustical Defects and Design Issues 5.1 Staircase Squeaky Noise caused by Occupant Activities 66

Acoustical Defects & Design Issues Plywood or wood-base materials frequently are used as interior finish in buildings where sound absorption reduction of the level of sound generated in a room, within that room. In Damansara Performing Art Centre (DPAC), the sound of plywood staircase is transmitted through structural-borne, resulting from an impact or the vibration against it, where sound vibrates on the solid hard surface of the plywood (Design Buildings Ltd, 2018).

Design Solution & Suggestion To reduce the noise, softer material could be applied such as carpeted staircase thread as carpet has a higher absorption coefficient of a 0.5 for 500 Hz and surely will give an impact for the reverberation if carpet is placed.

Theatre of Damansara Performing Art Centre (DPAC)

Plywood Staircase

Figure 70: Plywood Staircase

Diagram 64: Floor Plan of DPAC

Acoustical Defects and Design Issues 5.2 Unsuitable Material for Insulation 67

Acoustical Defects & Design Issues Rockwool is a good material to block and isolate the sound, by installing it in inside of cavity absorbers to confine the sound in it, decrease the sound energy eventually and absorb noise efficiently.

But for DPAC, the fibre board is already considered as acoustic wall and it doesnâ&#x20AC;&#x2122;t have cavity absorbers for Rockwool to further absorb the noise. Besides, the concrete is blocking the noise from outside effectively, so it is not necessary to have rockwool inside the acoustic wall.

Figure 71: Wall Without Cavity Absorbers

Figure 72: Cavity Absorber

Diagram 65: Wall Section

Figure 73: Component of Cavity Absorber

Acoustical Defects and Design Issues 5.3 Placement of Loudspeakers 68

Acoustical Defects & Design Issues The main loudspeakers are placed on both the left and right side of the theatre, facing the audience. This is a disadvantage, due to: 1.

2.

Audience would be hearing two sound sources at the same time.

Placed on the both left and right of the stage, instead of middle of the stage to signify original source of sound.

Design Solution & Suggestion Loudspeakers are placed more in the center of the theatre, in a widespread manner. This would help the audience in navigating the original source of the sound, while the sound wave is then traveling to more people in the audience. This would improve the overall sound in the theatre.

Diagram 66: Original Placement of the Main Loudspeaker

Diagram 67: Suggestion of new Loudspeakers Placement

Acoustical Defects and Design Issues 5.4 Concentration of Sound 69

Acoustical Defects & Design Issues The sound is concentrated at the center back seats which are the VIP seats of the theatre due to excessive diffusion and reflective of the material. This causes the sound distributed unevenly throughout.

Design Solution & Suggestion Remove some of the zig-zag steel panel at the VIP seats to allow evenly distributed sound around the theatre.

Sound Concentration Sound Concentration

Diagram 68: Original Location of Sound Concentration

Diagram 69: Suggestion of Sound Concentration

Chapter 6

Conclusion

Conclusion 71

In our conclusion from our accumulated findings and in depth subsequent analysis of the acoustic design in Damansara Arts Performing Centre (DPAC), we have found DPAC and its design have achieved the goal to properly balance absorption and reflection to provide a favourable acoustical environment. Through our calculations, DPAC has a reverberation time of 1.18 seconds for its volume of approximately 4236 mÂł. It has fulfilled and complied to the reverberation time requirement of a medium sized hall, which must fall within the range of 1 and 1.25 seconds. This shows adequate reverberation time for its size without the need of additional absorber material in the future. However, this is mostly from the aid of additional finishes as the theatre itself on its own is not up to its most potential design efficiency. This is due to its poor choice of materials and design placements, which is evident as the theatre needs assistance in amplifying the sound acoustic. The theatre design was meant to be of multipurpose use, though it is not optimal for all purposes as it has its shortcomings that affect potential of the space. The theater is more fitting for a smaller performance as the design itself is unsuitable for larger production.

DPAC has room for improvements to enhance the acoustics to be more effective in multi-utilization. Careful consideration must be taken into account as it affects the overall sound acoustic inside the theatre. Throughout this project, we have learnt how different form, usage of materials, and element placements make many differences in the effect of acoustic.

Chapter 7

References

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