SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN BACHELOR OF SCIENCE (HONS) IN ARCHITECTURE
Building Science ll [BLD 61303] Project 1 Case Study on Acoustic Design
Prepared by: Melvyn Poh Ern Meng
0322653
Brian Koh Jun Yan
0322002
Hong Shi Lik
0322081
Kiu Ngin Pern
0322084
Muhammad A’ameer
0322891
Saw E Sean
0322003
Nhat Dinh
0313309
Chan Jing Jun
0326762 Tutor: Ar. Edwin Chan
1
TABLE OF CONTENT 1
2
3
4
Introduction of Shantanand Auditorium
3
1.1 1.2 1.3 1.4 1.5 1.6
4 4 5 6-7 8-9 10-11
Acoustics and Architecture
12
2.1 2.1.1 2.1.2 2.1.3 2.2
13-14
Literature Review Acoustics in Architecture Sound Intensity Level Reverberation, Attenuation, Echos and Sound Shadow Methodology
15-16
Acoustic Design Analysis
17
3.1 3.2 3.3 3.4 3.5 3.6 3.7
18-24 25-26 27 28-30 31-32 33-45 46-52
Sound reinforcement system Sound propagation and concentration Sound Shadow Sound reflection and diffusion Flutter echoes and sound delay Noise intrusion (Noise source) Construction of materials
Calculations 4.1 4.2 4.3 4.4
5
Aim and Objectives Site background Historical Background Sense of Place Architectural Drawings Auditorium design analysis
Area of floor Area of wall Area of other material Reverberation Time
53 54 55 56 57
Design Solution and Suggestion
58
5.1 5.2 5.3 5.4 5.5
59 60 61 62 63
Create a buffer zone Materiality for doors and walls in the buffer zone Increase the reverberation time in the auditorium Shaping a concave shape at the balcony parapet Increase the balcony height and tited ceiling
6
Conclusion
64-65
7
Reference Link
66-69
8
Peer Evaluation Form
70-78
2
1.
INTRODUCTION OF SHANTANAND AUDITORIUM
3
1.1 Aims & Objective In this projects objectives and aims are : 1. To produce an in-depth acoustic design analysis of our chosen auditorium and the effectiveness that contribute to the acoustic quality of Shantanand auditorium. 2. To study and analyse the characteristics of acoustic auditorium and suggest ways to improve the acoustic qualities with the space. 3. To generate documentation report based on the researched datas and on-site analysis is that are able to show the relationship between acoustical design with space.
1.2 Site Background
Name - Shantanand auditorium Location - 114-116, Jalan Berhala, Brickfields, Kuala Lumpur Type Of Auditorium - Community Auditorium Year of Completion - 2011 Total Volume - 4312 Total Seats - 618 Figure 1.2.1 Key Plan showing location of Temple of Fine Arts in Brickfields.
Temple of Fine Arts in Kuala Lumpur is famous for being the main centre for learning classical Indian music in Malaysia. Located at Brickfields also known as “Little India� of Kuala Lumpur. The building is well known as the cultural performance stage of Shantan auditorium. The auditorium has fulfilled the needs of acoustical design an treatment without significant live and dead spots. Thus is able to provide the best sound quality throughout the whole auditorium. The purpose of this auditorium are for musical production such as, dance drama, musical vocals, acting and etc.. The hall itself has an area of 8796 sqm. It can accommodate a total of 618 people within the main hall and the first floor balcony. The temple of Fine Arts location is surrounded by apartments, religious buildings as well as a cemetary across the river. This makes the overall noise level of the site very quiet thus the auditorium is not disturbed by exterior noise pollutions.
4
Figure 1.2.2 : 5-storey building “Temple of Fine Arts” at Jalan Brickfields
1.3 History Background The founder of the Temple of Arts, Swami Shantanand Sawaswathi, wanted to provide a centre for the Malaysian Youth to show their love towards cultural, artistic and spiritual wealth. His hope was to create an avenue possible for cross-cultural interactions for the many races of Malaysia. The auditorium was named after Swamiji signifying the presence and guidance of his Holiness Swami. The auditorium also name the “Heartspace for Creating Expression” was to promote the beauty of Indian arts and performances that allows the younger generation to appreciate. In 2011 the “Temple Of Fine Arts” finished construction and launched with the Prime Minister on the 4th of July 2011.
Figure 1.3.1 : Shantanand auditorium prime choice venue for performing arts.
5
1.4 Sense of Place
Figure 1.4.1 Stage curtains give a sense of mystery and curiosity to the coming performance for the audience
Figure 1.4.3. Auditorium has a sense of harmony from the color of walls to seating to the use of lighting
Figure 1.4.2. Stage in auditorium is made of timber with rubber finishing giving it an organic feel to it
Figure 1.4.4. Shantanand auditorium portrays a sense of classical elegance through lighting
6
Figure 1.4.5 Behind stage control room
Figure 1.4.6 Second Floor balcony seating
Figure 1.4.7 Backstage equipment and storage area.
Figure 1.4.8 View from scaffolding seeing seating area of auditorium
Figure 1.4.9 Lighting scaffolding walkway for maintenance workers and technicians
Figure 1.4.10 Backstage view out into auditorium during rehearsal
7
1.5 Architectural Drawing
A
A’
Figure 1.5.1 Ground Floor Plan Scale 1:200
A
A’
Figure 1.5.2 First Floor Plan Scale 1:200
8
A
A’ Figure 1.5.3 Reflected Ceiling Plan Scale 1:200
Figure 1.5.4 Section A - A’ Scale 1:100
9
1.6 Auditorium Design Analysis Shape and massing
Figure 1.6.1 Figure above shows second floor plan which the sound shadow was right under it and the shape of auditorium.
The shape of the auditorium is a mixture of rectangular and shoe-box design whereby the stage is located at the narrower section of the auditorium. The seats located under the upper balcony experience sound shadow, an occurrence when sound does not reach as effectively as it should. Arrangement of seats
Figure 1.6. 2 Figure above shows the efficiency of seats arrangement in aspect dimension and position
The arrangement plan of seats in Shantanand was done in a way where sound is transmitted all throughout the auditorium. The distance between the sound source from the stage and the back seats are within the scope of 15.2m, an ideal range for the human voice to be heard clearly. Other than that, the auditorium seats are placed within 140 degree of sound projection. This permits the obervation of high recurrence sounds. The line of the seats along the edge of the auditorium are oriented towards the stage to provide proper views as well as acoustical thought as the sound travels in a circular order. 10
Leveling of seats
Figure 1.6.3 Figure above show the seating area seats are arranged in single level
To ensure that the sound waves are properly distributed throughout the auditorium as well as the assurance of unobstructed views, the seats were designed to be sloped. 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 1.6.4 Figure above show the seating area seats arrangement is elevated
By raising the level of seats, the audience would be able to receive direct sound without obstruction from absorbers.
11
2. ACOUSTICS AND ARCHITECTURE
12
2.1 Literature Review 2.1.1 Acoustic In Architecture Acoustics is defined as the science behind the production,reception and effects of sound. Sound can be defined as vibrations that travel through mediums such as gas, liquids and solids and return back to the initial point from deflection. Sound can be reflected, absorbed, transmitted and diffracted. A sound wave is a longitudinal wave where particles of the medium are temporarily displaced in a direction parallel to the energy travelling and returned to its original position. The vibration in a medium produces alternative waves of relatively dense and sparse particles which are called compression and rarefaction respectively. Acoustics in the built environment is normally evaluated on noise curve and reverberation time (RT). By employing sound absorption materials as wall and ceiling cladding, the desired RT’s can be achieved. The sound absorption materials are rated with sound absorption coefficient. The absorption and transmission loss are dependent on the fiber or material size, volume of fiber,porosity, airflow resistance, thickness, density, compressions and position of materials. Fiber or material size, porosity, thickness and density are the major factors for sound absorption within an interior space. Sound absorption however are inversely proportional to the diameter or width of the fibre. 2.1.2. Sound Intensity Level (SIL) Sound energy is conveyed to our ears or instruments by means of a wave motion though some elastic medium (gas, liquid or solid). At any given point in the medium, the energy content of the wave disturbance varies as well as the square of the amplitude of the wave motion. That said, if the amplitude of the oscillation is doubled, the energy of the wave motion is quadrupled. Sound intensity also known as acoustic intensity is defined as the power carried per unit area. The SI unit of intensity, which includes sound intensity, is the watt per square meter (W/㎡). One application is the noise measurement of sound intensity in the air at a listener’s location as a sound energy quantity. Normally sound intensity is measured as a relative ratio to some standard intensity. The response of the human ear to sound waves closely follows a logarithmic function of the form “R = k log l”, where “R” is the response to a sound that has an intensity of “l”, and “k” is the constant of proportionality. Thus,
we
define
the
relative
sound
intensity
level
as
SL (dB)= 10log l l0 The unit of SL is called a “decibel” (abbreviated as dB). “I” is the intensity of sound expressed in watts per meter and the “ l0” Is the reference intensity defined to be 10-12 W/㎡. This value of “l0” is the threshold (minimum sound intensity) of hearing at 1kHz, for a young person under the best circumstances. Note that “I/l0” is a unitless ratio, the intensities need only to be expressed in the same units.
13
2.1.3 REVERBERATION, ATTENUATION, ECHOS AND SOUND SHADOW Sound reverberation is the persistence of sound reflection after the source of the sound has ceased. Reverberation of the sound that persists in an enclosed space due to multiple reflections. Even after the source of the sound has stopped. Reverberation is an important parameter for describing speech intelligibility and the perception of music and is used to correct or normalise sound insulation and sound power measurements. For example, specifying highly reflective ceiling panels directly above the stage area in the auditorium will help direct the sound towards specific seating area, thus enhancing the room’s acoustical performance. However, the same reflective performance will become a negative factor, if said highly reflective walls and ceiling materials are installed in the rear auditorium. This is because the sound of reflections from the rear of the room takes too long to reach the audience, resulting in a distracting echo effect. When sound travels through a medium, its intensity diminishes proportionally with the distance traveled. In idealized materials, sound pressure (signal amplitude) is only reduced by the spreading of the wave. Natural materials, however, all produce an effect which further weakens the sound. This further weakens the results from scattering and absorption. Scattering is the reflection of sound is directions other than its original direction of propagation. Absorption is the conversion of the sound energy to other forms of energy. The combined effect of scattering and absorption is called attenuation. An acoustic shadow or sound shadow is an area through which sound waves fail to propagate, due to topographical obstruction or disruption of the waves via phenomenon such as wind currents, buildings or sound barriers. A short distance acoustic shadow occurs behind a building or sound barrier. The sound from a source is shielded by the obstruction. Due to diffraction around the object, it will not be completely silent in the sound shadow. The amplitude of the sounds can be reduced considerably however, depending on the additional distance the sound has to travel between the source and receiver. Sound reflection occurs when sound waves bounce off smooth, hard wall, ceiling and floor surfaces. Concave surfaces tend to concentrate or focus reflected sound in one area. Convex surfaces do just the opposite, they disperse found in multiple directions
14
2.2 Methodology The sound level meter is used to measure and record noise levels precisely. It calculates the pressure caused by sound waves travelling through the air from noise sources. The unit of measurement of sound intensity in decibels (dBA) which reflects the frequency-dependent nature of human hearing at low sound levels.
Figure 2.2.1 Sound Level Meter
Sound (dB)
Musical noise
60 dB
Regular piano practise
70 dB
Fortissimo singer at 3ft. (1m)
75-85 dB
Chamber music in small auditorium
84-103 dB
Violin
85-111 dB
Flute
106 dB
Timpani & bass drum rolls
120-137 dB
Symphonic music peak
120 dB
Amplified rock music 5ft. (1.5m)
150 dB
Rock music peak close to speakers
Figure 2.2.2 Loudness of musical noise
15
Digital Camera Digital camera were used to capture photos of the existing context within our auditorium in order for us to refer back and analyze the noise intrusions, acoustics finishing used to absorb unwanted sound, reflection sound concentration, sound absorption, sound reverberation time and etc.
Figure 2.2.3 : Digital Camera
Measuring Devices Measuring tapes and laser distance measurer was used to measure and record the reading of the dimension of our auditorium for drawings and calculation purposes. It was used to measure the distance of the sound level meter from the sound source when taking the sound levels.
Figure 2.2.4 : Measuring Tape Figure 2.2.5 : Laser Distance Measurer
Bluetooth Speaker Is used to present the acoustic performance of the auditorium. A constant sound in terms of volume and frequency at a single point was released as sound energy level and the readings were taken from various distances.
Figure 2.2.6 : Bluetooth Speaker
Data Collection Method There was a rehearsal going on during our site visit. Therefore, we analysed the acoustic performance of the auditorium during this rehearsal. By using the equipment above, we have recorded every necessarily detail of the auditorium which includes its layout and form, sound sources, types of furniture, finishings, materials and etc. All the readings were taken for drawing and calculation purposes. On-site sketches for the floor plans and sections were also taken for further analysis on acoustic 16 performance of this auditorium.
3. ACOUSTICS DESIGN ANALYSIS
17
3.1 Sound reinforcement system The type of speakers typically used in auditorium can be classify into 3 different categories. 1. Sensor controlled subwoofer 2. Compact 3 way symmetrical line array module speakers 3. Two way compact versatile full range system speaker
Figure 3.1.1 : Sensor controlled subwoofer
Sensor controlled subwoofer is designed to produce low frequency sounds, typically from 40Hz up to 500 Hz. It helps to achieve a better sound quality for low frequency.
Figure 3.1.2 : Compact 3 way symmetrical line array module speakers
It function is to provide additional sound pressure and further dispersion option. It also provides a point source with a flexible coverage of sound.
Figure 3.1.3 : 2 way compact versatile full range system speaker
Usually located on the central part of the theatre or auditorium. It helps to achieve the balance and quality of sound throughout the space of the theatre. 18
Sound Reinforcement use in Shantanand Auditorium - Single speaker cabinet
Figure 3.1.4: Single speaker cabinet
Figure 3.1.5 : Placement of single speaker cabinet below the stage
Single speaker cabinet are used to reproduce tone as sound wave generated from the performance stage and then transmit it to the audience. 2 speakers are located below the stage. However, the speakers are sometimes placed on top of the stage platform so that the high frequencies can be project over to the nearest audience facing the stage. Both speakers are placed on each side of the stage to distribute wider and equally sound wave in the auditorium.
19
- Stage monitor speaker
Figure 3.1.6 : Stage monitor speaker
Figure 3.1.7 : Stage monitor speaker
Figure 3.1.8 : Placement of stage monitor speaker located on the stage facing the performers
Stage monitor speaker are also used commonly on the stage. It is essential for the performers as it helps to amplify sound when acoustics instruments or vocals are utilised, it functions as a monitoring device for the performers in order for them to keep track and maintain their quality of their sound.
20
-Array speakers
Figure 3.1.9 : Array speaker
Figure 3.1.10 :Placement of array speaker on top of the columns
A line array is a loudspeaker system that is consists of a number of identical loudspeaker elements mounted in a line and fed in phase, to create a near-line source of sound. The distance between adjacent drivers is close in between that they constructively interfere with each other to transmit sound waves farther than traditional horn-loaded loudspeakers, and with a more evenly distributed sound output pattern. The speakers are placed above on a hanging position. The left and right placing of the speakers are slanted angled down to provide extra coverage to the nearest front of the stage, while the top half will be angled upward facing the mezzanine floor of the auditorium.
21
-Conventional sound reinforcement system
Figure 3.1.11 : The conventional equipment used in the auditorium which consists of the microphone,signal processor amplifiers and portable loudspeaker
Commonly used sound reinforcement system may include the combination of microphones, signal processor amplifiers and portable loudspeaker. These conventional system are also used as a sound and volume enhances to distribute wider coverage to the whole auditorium.
22
Figure 3.1.12 : Indication of speakers in section
There are approximately 8 permanent speakers used in the auditorium. The type of speaker system used in the Shantanand Auditorium is mainly on distributed system. A distributed speaker system is where a number of overhead loudspeakers being installed in the auditorium. Distributed speaker system is used to overflow sound to the audience in the auditorium. A distributed speaker system is effective to majority of the audience to gain adequate sound quality.Besides that, there are some landed speakers on the stage and floor also contributes to the adequate of sound quality.
Advantages of using sound reinforcement systems -The use of digital speaker sound system will allow the users to adjust and modify sound frequencies and sound intensity. -Speakers are used as sound amplification to reinforce sound levels when sound quality is weak. -Speaker systems also function to provide artificial reverberation in rooms to produce satisfactory sounds for listening.
23
Disadvantages of using sound reinforcement system
Figure 3.1.13 : Sound distribution uneven for middle audience
-The placement of the reinforcement systems are mainly focused on the left and right side of the stage.This might cause an unbalance sound distribution from both sides and the middle. - Reinforcement systems are not the solution to prolong the reverberation times of standing sound waves. Standing sound waves are low frequency resonances that take place between two parallel reflecting surfaces -The originality sound of the performers are not clearly heard as the audience would hear the same sounds arriving at two separates times. The ideal difference should not be more than 1/30 seconds. This causes the disturbance in harmony of the original sound. - When placement of the speaker is halfway down or is facing directly towards the front of the stage, the audience might hear the sound from the loudspeaker first, followed by the direct sound as a faint echo. However, this problem can be solved by adding a delayed mechanism in the loudspeaker that balance the direct sound. - If the distance of the speaker is far away from the audience, sound attenuation might occur, where the sound path is affected which reduces the intelligibility. - Need maintenance and proper storage care for the speakers. - If the speakers malfunction during the performance, it will cause a disturbance in the sound distribution. - Inefficient because the performers must tune or adjust the speakers according to its suitable outcome. It is also troublesome for them to carry in and out for different type of stage shows.
24
3.2 Sound concentration and propagation Sound Propagation
Figure 3.2.2 : Figure above show the wide shallow concave shape of the Shantanand Auditorium that helps spread sound evenly
Figure 3.2.1 : Figure above show sound distribution in the seating area taken from the sound source of the stage
From a point source the sound waves will be circular, and intensity of sound will be surmised the Inverse Square Law. After we gathered the information of the sound intensity level utilizing sound level meter from the performers amid their practice, we plotted out the sound dispersion all through the seating and discovered that energy loss of sound propagation in Shantanand Auditorium is low a direct result of its wide shallow arrangement. The separation from the stage to the end is just 14.9m long due to its sunken plan of seating generally near the stage. The stage as the propagation area changed, outputting consistent sound from the performers. The discoveries demonstrate that the design and the utilization of material of Shantanand Auditorium are not proper as it produce unpleasant sound at certain area and uneven sound distribution.
Figure 3.2.3 : Figure above shows SIL readings of the auditorium 25
Sound Concentration
Figure 3.2.4 : Figure above show sound distribution in the seating area taken from the sound source of the stage
The shape and composition of the auditorium reflects sound to the center of the auditorium. This concentration of sound makes the highlighted area the best spot in the auditorium.
26
3.3 Sound Shadow
Figure 3.3.1 : Sectional Drawing showing the dimension of the sound shadow area and differences of sound intensity level
Sound shadow imperfection can be resolved when the sound wave neglected to propagate because of the exhibition obstruction. After we gathered the information of sound intensity level from the performers, we discovered there is intermediate sound shadow under the gallery as the sound intensity level dropped from 65 dB to 55 dB when we were moving from the front seating to the seating under the overhang. The display overhang depth ought to be not as much as double the height of the exhibition underside, however Shantanand Auditorium has moderately low floor to ceiling height of 2.38m with 4.76m depth under the balcony. The ratio of the ceiling height and depth is precisely 1:2 which implies the occurrence of a sound shadow. Consequently, the side wall of Shantanand Auditorium is made of timber board to reflect sound into the sound shadow area.
27
3.4 Sound Reflection and Diffusion Auditorium halls vary in both shapes and sizes, depending on the purpose and budget. Of the abundance of shapes, the two most common shapes used would be the the rectangular or shoe-boxed geometry halls. The Shantanand auditorium is shoe-boxed, where the stage is placed at the narrow end of the hall. This is usually done to maximise the seating area while maintaining relatively close distance between the seats and stage.
Figure 3.4.1 indicates how the composition of the auditorium reflects sound throughout the space. The walls reflect sound towards the center of the auditorium, reaching the seats located at the sides as well.
28
The Shantanand auditorium was initially designed as a multi-purpose hall. It was later redesigned into a performance theatre where musical performances from the Indian community were held. The area was renovated in order to fulfil the acoustic requirements of a musical performance hall. One of the many renovations included the change in ceiling, whereby they lowered the floor to ceiling heights and included several additional elements such as a tilted ceiling surface as well as a convex-surfaced ceiling. These can be seen in Figure 3.4.2. The tilted ceiling allows for sound from the performers to reach the audience in the upper balcony area as shown in Figure 3.4.2. The convex-surface ceiling also disperses sound to the upper balcony seats.
Figure 3.4.2 shows the reflection and dispersion of sound from a performer through a sectional cut of the auditorium.
29
Figure 3.4.3 shows how the glass railing blocks direct sound from the performer from reaching the audience in the upper balcony.
It can be seen in Figure 3.4.3 that the upper balcony areas do not receive direct sound as the glass railing obstructs sound from reaching. Due to this, sound reinforcement was added in the form of array speakers, shown in Figure 3.4.4, that are hung closer to the ceiling. This inclusion allows for the upper balcony area to receive direct sounds.
Figure 3.4.4 shows reflection made from the sound reinforcement
It can be seen in Figure 3.4.3 that the upper balcony areas do not receive direct sound as the glass railing obstructs sound from reaching. Due to this, sound reinforcement was added in the form of array speakers, shown in Figure 3.4.4, that are hung closer to the ceiling. This inclusion allows for the upper balcony area to receive direct sounds. The sub-woofers are places on floor level as lower frequency sounds are less prone to suffer from diffraction due to small architectural elements. Therefore, sharp cornices as displayed in Figure 3.4.4 would not scatter the low frequency sounds produced by the sub-woofers, negating unnecessary sound reflections.
30
3.5 Flutter echoes and sound delay Echoes are deemed to be one of the more serious acoustical defects. Different occurrences would consider different values for a sound reflection to be considered an echo. 40 milliseconds is considered an echo for speech whereas musical performances only consider 100 milliseconds as an echo.
Echo =
(R1 + R2) - D 0.32
=
(15.9m + 16.4m) - 13.6m 0.32
=
58.4 msec
Figure 3.5.1
Echo =
(R1 + R2) - D 0.32
=
(4.6m + 5.5m) - 3.6m 0.32
=
20.3 msec
Figure 3.5.2 31
Echo =
(R1 + R2) - D 0.32
=
(9.3m + 3.8m) - 12.8m 0.32
=
0.9 msec
Figure 3.5.3
In Figure 3.5.4, it shows that the upper balcony does not receive echo without sound reinforcement because the area does not receive direct sound as it is blocked by the glass railing
Figure 3.5.4
The shathanand auditorium does not have any flutter echoes due to the absence of parallel walls where sound is prominent. Though the rear and entrance walls are parallel, the walls along the entrance are of sound absorbent material, negating the reflection patterns that would cause echo flutters.
To conclude the analysis of sound echo, the Shantanand auditorium has acceptable sound delay for its purpose for musical performances as all values for sound delay are below 100 milliseconds.
32
3.6 Noise intrusion (Noise source) Sound & Noise sources Noise is generally defined as an undesirable sound that is determined by the attitude of the occupants toward the noise source. Noise can be categorized as continuous, variable, impulsive or intermittent depending on how it changes over time. In addition, continuous noise is noise that remains constant and stable over given time period. Different operations or different noise sources can also cause the sound to change. Noise is intermittent if there is a mix of relatively quiet and noisy time periods. Impulsive or impact noise is a very short burst of loud noise which lasts for less than a second. Although the Shantanand Auditorium is designed based on the acoustic architecture and filled with acoustic equipment yet there are still some internal and external noises that cause a disturbance within the auditorium.
33
External Noise Sources There are multiple noise source created at the outside of the hall. Opening and closing of the door, human chatters and human noise. On the outside of the hall where the lobby is just situated next to the door, the conversation of the people will enter the auditorium through the main entrance which just shows that there is no buffer zone between the area and the door lacks of sound treatment. Besides, before entering the hall, peoples required to take off their shoes, this helps to avoiding the sound produce by human walking which affect the performance and overall sound distribution inside the hall. There is a corridor beside the auditorium that is use as a passageway for the crew and workers to get into the front and back of the auditorium without the occupants. However, the seats near the doors and passageway will get noise disturbance if people using the passageway due to lack of buffer zone and noise insulation around the wall.
Figure 3.6.1 Shoes need to be taken off before entering through the door. This act may cause some noise intrusion
Figure 3.6.3 The distance between the walkway and seats are near which create unwanted sound disturbance when people using it
Figure 3.6.2 No buffer zone that separate between the walkway and the main door
Figure 3.6.4 Noise can be heard from the side of the room if there are functions going on.
34
2
1 Figure 3.6.5
-Corridor The high concentration of people gather at the corridor area increases the noise level that affecting the audience inside.
-Side Room Noise produced by opening and shutting of the doors.
35
Internal Noise Sources The most disturbance sound among the multiple noise sources in the hall are came from the electrical appliances. Besides that, sound produce by human chatting, foot stepping on the timber floor and the doors opening and closing. The air flowing through the air conditioning diffuser creates low frequency noise. Audience who seats at the gallery and under the gallery will directly facing disturbance due to the close proximity of the seat. The door located at the entrance and passageway create noise while people using it. There is no buffer zone surrounding the area where the door is situated too near the seats which in some circumstances where the technicians or stuff using it. However the additional curtain in front of the door helps reducing the noise created by the people at the entrance. The floor between the stage and audience are timber floor which resulted foot stepping noises when people walks through. The stage uses timber flooring which covered with rubber sheet but it does not reduced the noise created by the stepping of the performers. In the audience area, the timber floor is covered by soft pile carpet which avoid the creation of foot step and absorb the noise created by the people.
Figure 3.6.6 Curtains create an informal buffer zone which help absorb the noise
Figure 3.6.7 The door is located too near to the seat which noise from the outside will disturb the audience hearing experience
Figure 3.6.8 The air conditioning diffuser create low frequency noise as the proximity within the seat and ceiling too near
36
1
2
Figure 3.6.9
-Air Conditioning Diffuser Continuous noise produced by the air passing through air conditioning diffuser.
-Footstep Impulsives noise generated by the footsteps as people walking around.
37
Internal Noise Sources Location (Floor Plan)
STAGE Foot stepping on stage
Figure 3.6.10 Ground Floor Plan (NTS)
ENTRANCE(G FLOOR) Timber door open & closing
Figure 3.6.11 First Floor Plan (NTS)
DOORS TO PASSAGEWAYS Timber door open & closing
AREA IN FRONT OF THE STAGE Foot stepping on timber floor
AUDIENCE AREA Human sounds & chatters
ENTRANCE (1ST FLOOR) Timber door open & closing 38
Internal Noise Sources Location (Reflected Ceiling Plan)
Figure 3.6.12 Reflected Ceiling Plan GF (NTS)
GALLERY AREA High ceiling square air-conditioning diffuser
AUDIENCE AREA High ceiling round air-conditioning diffuser
CORRIDOR Linear air-conditioning diffuser
Figure 3.6.13 Reflected Ceiling Plan 1st (NTS)
39
Materiality and Sound Absorption Coefficient
GROUND FLOOR PLAN INTERIOR: SEATING
GROUND FLOOR PLAN INTERIOR: STAGE
FIRST FLOOR PLAN INTERIOR: SEATING
FIRST FLOOR PLAN INTERIOR: CONTROL ROOM
40
Table of Materiality and Sound Absorption Coefficient
ABSORPTION COEFFICIENT(⍺) AREA
SEATING
COMPONENT
MATERIAL 125 Hz
500 Hz
1000 Hz
0.13
0.59
0.58
0.37
0.68
0.73
0.15
0.10
0.07
0.30
0.25
0.31
FURNITURE
FABRIC UPHOLSTERED TIP-UP SEATS (UNOCCUPIED)
FABRIC UPHOLSTERED TIP-UP SEATS(OCCUPIED)
FLOOR
WOODEN FLOOR
PILE CARPET BOUNDED TO CLOSED-CELL UNDERLAY
41
ABSORPTION COEFFICIENT(⍺) AREA
SEATING
COMPONENT
MATERIAL 125 Hz
500 Hz
1000 Hz
0.15
0.04
0.04
0.05
0.13
0.22
0.13
0.08
0.09
0.10
0.04
0.03
CEILING
GYPSUM BOARD WITH CEILING GRID
CURTAIN
PLEATED MEDIUM VELOUR CURTAINS
RAILING
STEEL RAILING (G FLOOR)
6 mm Glass Railing (1st Floor)
42
ABSORPTION COEFFICIENT(⍺) AREA
SEATING
COMPONENT
MATERIAL 125 Hz
500 Hz
1000 Hz
0.15
0.75
0.80
0.30
0.50
0.80
0.18
0.42
0.59
0.14
0.06
0.08
WALLS
FIBERGLASS ABSORPTION PANEL
ACOUSTIC ROUGH PLASTER TO SOLID BACK
TIMBER ACOUSTIC PANEL
DOOR
SOLID TIMBER DOOR
43
ABSORPTION COEFFICIENT(⍺) AREA
STAGE
COMPONENT
MATERIAL 125 Hz
500 Hz
1000 Hz
0.01
0.01
0.02
0.15
0.75
0.80
0.14
0.53
0.75
0.13
0.08
0.09
WALLS
SMOOTH PAINTED CONCRETE
ACOUSTIC ABSORPTION PANEL
CURTAIN
50% PLEATED MEDIUM VELOUR CURTAINS
STAGE DECK
STEEL DECKING (FLY TOWER)
44
ABSORPTION COEFFICIENT(⍺) AREA
STAGE
COMPONENT
MATERIAL 125 Hz
500 Hz
1000 Hz
0.01
0.02
0.02
0.01
0.15
0.25
0.60
0.60
0.60
0.14
0.06
0.08
FLOOR
PAINTED SMOOTH CONCRETE
RUBBER SHEET, OVER TIMBER FLOOR
STAGE & SEATING
VENTILATION GRILLE
PER METER SQUARE
CONTR0L ROOM
DECK OPENING
TIMBER PANELS WITH TIMBER FRAME
45
3.7 Construction of Materials Ceiling -Gypsum Plaster with Ceiling Grid *Acoustic treatment is a crucial and amazing result of acoustical design elements to dampen and diffuse sound waves inside of a room to minimize constructive and deconstructive interference, thereby increasing the quality of the mental imaging of the sound field. It enhances a room to be designed to equally absorb sound waves to all the materials, which depends on the proper shapes and finishes on the surface. Figure 3.7.2 Image from site
Figure 3.7.1 Gypsum plaster ceiling
Figure 3.7.3 Gypsum plaster ceiling construction
Acoustic treatment Gypsum plaster is used as the ceiling in the auditorium. It is a common material that uses in most of the design of auditorium. With the proper angle on the ceiling panels, it also provides a good sound reflection to the seating area and minimizes the echo that is created. Materiality The gypsum board comes with extra thickness in 1 1/2 inch to resist panel vibration, due to its mass it can lower the absorption frequency and higher the reflections frequency. The height of the auditorium is around 9m, which hardly transmit sound. therefore the suspended ceiling provide short delayed of sound transmitting and lower down the volume of the auditorium.
46
Hard Acoustical Wall (Timber Acoustic Panel)
Figure 3.7.5 Timber panel walls on site
Figure 3.7.6 Timber acoustic panel construction
Acoustic Treatment Timber acoustic panel is installed at two sides of the stage. It is used not only for aesthetic purpose, it is also designed to absorb the sound energy in the space. To absorb unnecessary sound waves, it is designed with gap between each panel. For the base to support the timber acoustic panel, plaster or gypsum board is used for the basic requirement of standard acoustic panel.
47
Soft Acoustical (Fiberglass Acoustic Panel)
Figure 3.7.8 : The texture of the Fiberglass Acoustic Panel
Figure 3.7.9 : Sectional detail
Acoustic Treatment From the seating area, the wall is designed to place fiberglass acoustic wall as the surface of interior auditorium. It is used to control the echo from the rear wall and balcony faces. The reverberation time in the auditorium is directly proportional to the volume of the space and is inversely proportional to the total sound absorption within the room. With an optimized location and position for the installation of soft acoustical panel, it achieves a proper sound distribution diffuse and reverberation.
48
Parquet Wooden Flooring (Wooden Floor on Floor joist)
Figure 3.7.10 : The photo above shows the wooden flooring of the seating floor area.
Figure 3.7.11 :The wooden floor is nailing into the decking with allow sound to mechanically transfer through the nail into the deck negating the top soundproofing.
Materiality Acoustic joist strips are a practical method for diminishing effect commotion through regular timber joist floors. The strip is provided in 20m self cement rolls that are effortlessly put on the highest point of the joists. It incredibly decrease the effect sound protection. Likewise, it enhances the acoustic execution and in this manner decrease the effect sound level.
49
Seating Flooring (Pile Carpet Bounded to Closed-cell Underlay)
Figure 3.7.12 : Carpets absorb sounds up to ten times better than hard flooring
Figure 3.7.13 :Construction detail of acoustical floor carpet
Acoustic Treatment While rugs commotion transmission through floor in multi-structures, the level of real clamor diminishment, and also individuals' impression of it, are subject to the recurrence Conveyance of the sound. Floor coverings are greatly powerful stable safeguards in light of the fact that the individual strands, heap tufts and underlay have diverse resounding frequencies at which they assimilate sound.
50
Stage curtain (Pleated Medium Velour Curtain)
All of the sound wave bounces off
Figure 3.7.14 : Photo of the curtain behind the stage of the auditorium.
Acoustically reflective surface (wallboard, wood)
Some of the sound wave is absorbed
Acoustically Absorbent surface (Curtains, Carpet)
Figure 3.7.15 :The curtain make an acoustically excellent finish that fully preserves the absorptivity of the substrate.
Acoustic Treatment The pleated medium curtain plays a role as private-public space divider but also functions as a reverberation and echo reducer in the auditorium. It also reduces the interference from outside noise. It uses sound blocking lining that provides maximum sound protection from inner and outer area. As the thicker the curtain, the more effective the function to block longer wavelength of sound. Materiality
The curtain used behind the stage in the auditorium will reduce reverberation and echo in a large room, as well as reduce interference from outside noise. Also, it uses a powerful sound blocking lining to provide maximum sound protection. The acoustic curtain is thick and highly porous. The thicker the absorption material, the more effective it will be against a longer wavelength (lower frequency) of sound.
51
Seating Furniture
Figure 3.7.17 : Auditorium seats
Figure 3.7.16 : Floor plan that indicate the seating furniture
Figure 3.7.18 :Materials for upholstered tip-up seats
Acoustic Treatment Polyurethane froth with a high porosity permits compelling sound assimilation coefficient. It has a cell structure which permits wind current, the assimilated sound vitality is then changed over into warm vitality. The geometry example of these sorts of safeguards will influence the dissipating of the sound.
52
4. CALCULATION
53
4.1 Area of Floor Materials F1
F2
SABINE FORMULA : RT = 0.16V / A Where, RT : Reverberation Time (Sec) V : Volume of the Room A : Total Absorption of Room Surface
F3 Ground Floor Plan (N.T.S) F4
*The concert hall is currently used to house musical performances and etc.. 500 Hz was used as the standard of measurement as musical performances regularly fall into this category of frequency.
First Floor Plan (N.T.S) Figure 4.1.1 Floor Plan to indicate the floor materials Legend F1
Stage rubber sheet over timber floor
F2
Wooden Floor On Joist
F3
Pile Carpet Bounded to Closed-cell Underlay
F4
Pile Carpet Bounded to Closed-cell Underlay
Surface
Area (m2)
500 Hz Absorption Coefficient (α)
Abs.units (m2 sabins)
F1
81.20
0.15
12.18
F2
150.15
0.10
15.02
F3
310.20
0.25
77.55
F4
161.43
0.25
40.36
TOTAL (∑FAα)
145.11
54
4.2 Area of Wall Materials W1 W2 W3
SABINE FORMULA : RT = 0.16V / A Where, RT : Reverberation Time (Sec) V : Volume of the Room A : Total Absorption of Room Surface
Ground Floor Plan (N.T.S)
W4
W5 *The concert hall is currently used to house musical performances and etc.. 500 Hz was used as the standard of measurement as musical performances regularly fall into this category of frequency.
W3
Section (N.T.S) Figure 4.2.1 Drawing to indicate the wall materials Legend W1
Stage Smooth Painted Concrete Wall
W2
Acoustics Absorption Panel
W3
Timber Acoustic Panel
W4
Acoustic Absorption Panel
W5
Timber Panel with Timber Frame
Surface
Area (m2)
500 Hz Absorption Coefficient (α)
Abs.units (m2 sabins)
W1
178.34
0.01
1.78
W2
56.24
0.75
42.18
W3
141.54
0.42
59.45
W4
147.40
0.75
110.55
W5
9.30
0.06
0.56
TOTAL (∑WAα)
214.52 55
4.3 Area of Other Materials SABINE FORMULA : RT = 0.16V / A
M3 M7 M1
Where, RT : Reverberation Time (Sec) V : Volume of the Room A : Total Absorption of Room Surface
M4 M6 M2 M5
Section (N.T.S) Figure 4.3.1 Drawing to indicate other materials
*The concert hall is currently used to house musical performances and etc.. 500 Hz was used as the standard of measurement as musical performances regularly fall into this category of frequency.
Legend M1
Pleated Medium Velour Curtains
M2
618 Seats -Unoccupied
M3
Gypsum Board With Ceiling Grid
M4
6mm Glass Railing
M5
Doors
M6
Acoustic Rough Plaster To Solid Back
M7
Ventilation Grille
Surface
Area (m2)
500 Hz Absorption Coefficient (α)
Abs.units (m2 sabins)
M1
134.40
0.13
17.47
M2
290.46
0.59
171.37
M3
338.53
0.04
13.54
M4
30.40
0.04
1.22
M5
13.23
0.06
0.79
M6
32.23
0.50
16.12
M7
26.88
0.60
16.13
TOTAL (∑MAα)
236.64
56
4.4 Reverberation Time SABINE FORMULA : RT = 0.16V / A Where, RT : Reverberation Time (Sec) V : Volume of the Room A : Total Absorption of Room Surface
Note A : Area Α : Absorption Coefficient Aα : Absorption Surface
V = 4312.59 m3 A = ∑FA + WA + MA = 145.11 + 214.52 + 236.64 = 596.27 m2
α
α
α
RT= 0.16(4312.59)/596.27) = 1.16 sec
Figure 4.4.1 “Ideal” average reverberation time versus room volume for several basic types of room.
Edwin, C. (2018). Lecture 2 Room Acoustic [PDF slides].
The volume of Shantanand Auditorium is approximately 4312 m 3, with a reverberation time of 1.16 seconds. From the figure above we can conclude that the reverberation time is slightly off the recommended range for the auditorium to function as a concert hall. Replacing certain materials with harder surfaces might improve the rate of reflection, allowing for a better reverberation time.
57
5. DESIGN SOLUTION AND SUGGESTION
58
5.1 Create a buffer zone
Figure 5.1.1: The extension of the buffer zone are added in the ground floor plan
Shantanand auditorium is only accessible through one entrance and one exit of the solid timber door. However the sound absorption coefficient of the solid timber door is only 0.06. Its low value will cause external sound intrusion to the auditorium. By creating a buffer zone before the entrance to the auditorium, it enables the sound transmission to be trapped between door to door and is absorbed by additional acoustic wall panels at both sides of the wall. The noises created by the open and closing of the doors can be sealed within the buffer zone.
59
5.2 Materiality for doors and walls in the buffer zone
Figure 5.2.1 : The figure show the additional material apply in the buffer zone to trap sound
Figure 5.2.2 : The components of the acoustic wooden door (Soundproofing door)
The materials used for the doors and walls in the buffer zone area are essential in trapping sound due to its absorption and reflection ability. An acoustic timber door should be introduced to Shantanand auditorium as it has better sound proofing quality to reduce the sound being transmitted through the door. Furthermore, acoustical timber doors should come with proper intumescent seals at both sides as well as the bottom. Threshold plates provide an optimum seal surface for the bottom of door. 60
5.3 Increase the reverberation time in the auditorium
Figure 5.3.1 : The suggestion method to increase its reverberation time
Currently, the Shantanand auditorium uses carpet flooring and gypsum boards as the ceiling. Though the current materials contribute to the reflection and transmission of sound, replacing these materials would add to the reverberation time. A suggestion would be to use timber seating and replace the flooring material with teak wood. The current reverberation time is 1.16 seconds, well below the values required for a concert hall. If the suggested materials were to replace the current ones, the reverberation times, as shown in the figure above, would increase to 1.73 seconds, bringing the auditorium to be within the range a concert hall’s recommended reverberation time.
61
5.4 Shaping a concave shape at the balcony parapet
Figure 5.4.1 : The additional of concave shape at the balcony parapet
The additional concave shape parapet allowed direct and reflected sound to increase its concentration at the underside of the balcony. Sound will then transmit into the balcony underneath for the audiences to receive a clearer sound without flutter echoes.
62
5.5 Increase the balcony height and tited ceiling
Figure 5.5.1 : The escalated balcony height and tilted ceiling at the ground floor
The dimension of the floor to ceiling for the space below the upper balcony area can be increased in order to resolve the issue of a sound shadow. The dimension should not be less than the depth of the balcony. By doing so, sounds reaching the furthermost depths of the lower floor would be clearer.
63
6. CONCLUSION
64
In conclusion, this auditorium case study project has taught us a lot as a group, such as how acoustic design works better depending on the functions of the auditorium,as well as to suite the comforts of the user. The auditorium layout and the materials chosen on the structure as well as furnitures such as the walls, floors, chairs, curtains, etc.. can affect the acoustics inside the auditorium hall and even the effect external sounds from the auditorium hall. An uditorium is uniques as it is built to enable an audience to perceive and witness a performances as well as be used for recitals, presentations and performing arts. Apart from entertainment, an auditorium is also used for public speaking or talks such as lectures and workshops. A successful design of an auditorium depends on the acoustic design such as the layout as well as the absorption coefficient of materials used to encapsulate the desired tones and block out the unwanted. The volume of Shantanand Auditorium is approximately 4312 m3, with a reverberation time of 1.16 seconds. Hence the need for the auditorium to have additional sound reinforcement to compensate for the low reverberation time. From the figure above we can conclude that the reverberation time is slightly off the recommended range for the auditorium to function as a concert hall. Replacing certain materials with harder surfaces might improve the rate of reflection, allowing for a better reverberation time.
65
7. REFERENCE LINK
66
1. Absorption Coefficient Chart. (n.d.). Retrieved May 7, 2018, from http://www.acoustic-supplies.com/absorption-coefficient-chart/
2. Acoustic Damping using Polyurethane/Polymer Composites. (n.d.). Retrieved May 2, 2018, from http://www.appropedia.org/Acoustic_Damping_using_Polyurethane/Polymer_Composites
3.
Attenuation of Sound Waves. (n.d.). Retrieved May 6, 2018, from
https://www.ndeed.org/EducationResources/CommunityCollege/Ultrasonics/ Physics/attenuation.htm
4.
Auditorium Acoustics and Architectural Design. (n.d.). Retrieved on May 4th 2018 from
https://books.google.com.my/books
5.
Auditorium noise isolation and acoustical design principals. (n.d.). Retrieved on May 4th 2018 from
https://www.abdengineering.com/blog/auditorium-noise-isolation/
6.
Decibels dBA. (n.d.). Retrieved May 1, 2018, from
https://silentpc.com/cgi-bin/e/decibels.html
7. Dulari, H. R. (2002, May/June). The Temple of Fine Arts Kuala Lumpur Malaysia | Sanctuary of Arts for Dance and Music. Retrieved on April 15, 2018, from http://www.tfa.org.my/#!about us/building
67
8..
Edwin, C. (2018). Lecture 2 Room Acoustic [PDF slides]. Retrieve on May 4th 2018 from
https://lookaside.fbsbx.com/file/Lecture%202-%20Room%20Acoustic%20March%202018%20Edwin.p df?token=AWycuTZ2Fsd3QGrD84dvo0lrnpBJxPpUpkAPkFScbFehAHqLwE74MU4mwfPY_vHpkRxEFw u0CVCH0WNmsddBwvW_HvZnOU9o6vAvut2S2QbViHvQxLbY1Y9r7wHVpjcW017pl9z_cHU4KpZTij_v0 TdL8bFwuZXVhtYiU__zK7QYVgf
9.
Facilities. (n.d.). Retrieved May 02, 2018, from
http://shantanand-adt.org/index.php/facilities#seating
10. Farhis, M. N. (2007, November 5). The Temple of Fine Arts. Retrieved on March 15, 2018, from http://www.visitkl.gov.my/visitklv2/index.php?r=column/cthree&id=63&place_id=896
11.
How to Prevent Hearing Damage When Using Headphones. (n.d.). Retrieved May 3, 2018, from
https://headphonesaddict.com/safe-headphone-use/
12..
Littlefield, D. (2012). Metric handbook: planning and design data. London: Routledge.
13.
Network, D. (2015, March 16). Soundproofing a Floor. Retrieved May 2, 2018, from
http://www.diynetwork.com/how-to/rooms-and-spaces/floors/soundproofing- a-floor
14. Network, W. (n.d.). Acoustics Doors, Acoustic Sliding Doors, Sound profing doors. Retrieved May 02, 2018, from http://www.earconsacoustic.com/ acoustic-doors.html 60
15. Room Acoustics. (2014, January 25). Retrieved May 02, 2018, from https://www.soundandvision.com/content/room-acoustics
68
16.
Sound Intensity. (n.d.). Retrieved May 4, 2018, from
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/intens.html
17. Soundproofing floors and noise absorption. (n.d.). Retrieved May 5, 2018, from http://www.carpetyourlife.com/en/about-carpet/advantages/soundproofing-floors
18. The acoustical design of the new lecture auditorium, Faculty of Law, Ain Shams University. (2012, June 29). Retrieved on May 4th 2018 from https://www.sciencedirect.com/science/article/pii/S2090447912000317
19. The Acoustic Treatment Guide for Panels & Foam | LN. (2018, January 12). Retrieved on May 4th 2018 from https://ledgernote.com/columns/studio-recording/acoustic-treatment-guide-for-panels-and-foam/
20.
The Temple of Fine Arts. (n.d.). Retrieved May 4, 2018, from
http://www.visitkl.gov.my/visitklv2/index.php?r=column%2Fcthree&id=63&place_id=896
69
8. PEER EVALUATION FORM
70