The Acoustic Treatment & Speech Intelligibility Quality Analysis Of Masjid UTeM Using Advance Tool Simulation And Measurement.
i THE ACOUSTIC TREATMENT & SPEECH INTELLIGIBILITY QUALITY
ANALYSIS OF MASJID UTeM USING ADVANCE TOOL SIMULATION AND MEASUREMENT
Nurul Syaffinaz Binti Muttakal
This Report Is Submitted In Partial Fulfillment of Requirement For The Bachelor Degree of for Electronic Engineering (Computer Engineering)
Faculty of Faculty of Electronic and Computer Engineering Universiti Teknikal Malaysia Melaka
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UNIVERSTI TEKNIKAL MALAYSIA MELAKA
FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA II
Tajuk Projek :
THE ACOUSTIC TREATMENT & SPEECH INTELLIGIBILITY QUALITY ANALYSIS OF MASJID UTeM USING ADVANCE TOOL SIMULATION AND MEASUREMENT
Sesi
Pengajian : SESI 2012/2013
Saya NURUL SYAFFINAZ BINTI MUTTAKAL mengaku membenarkan Laporan Projek Sarjana Muda ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut: 1. Laporan adalah hakmilik Universiti Teknikal Malaysia Melaka.
2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3. Perpustakaan dibenarkan membuat salinan laporan ini sebagai bahan pertukaran antara institusi pengajian tinggi.
4. Sila tandakan ( √ ) :
SULIT*
*(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)
TERHAD** **(Mengandungi maklumat terhad yang telah ditentukan
oleh organisasi/badan di mana penyelidikan dijalankan)
TIDAK TERHAD
Disahkan oleh:
__________________________ ___________________________________
(NURUL SYAFFINAZ BINTI MUTTAKAL)
11 JUN 2013
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“I hereby declare that this report is the result of my own work except for quotes as
cited in the reference”
Signature : ………..
Author : NURUL SYAFFINAZ BINTI MUTTAKAL
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“I hereby declare that I have read this report and in my opinion this report is
sufficient in terms of the scope and quality for award of Bachelor of Electronic Engineering (Computer Engineering) with Honors”
Signature : ……….…
Supervisor’s Name : ENGR. MOHD MUZAFAR BIN ISMAIL
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I want to dedicate this to my family, especially my mother who always gives her support and understanding during my studies. A million thank you to my father for
his financial support mainly. Last but not least, to my colleagues and lecturers for their help and suggestion in order to fulfill this research
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ACKNOWLEDGEMENT
In the name of Allah s.w.t, the most merciful and gracious.
Alhamdulillah. Thanks to Allah, whom with His willingness to give me this blast opportunity to complete my final year project, as well as publishing this reports to be presented to the Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka (UTeM) Insha’Allah. The final year project program is the compulsory subject for future Bachelor Degree holder to fulfill the degree requirement.
I would like to express my outmost gratitude to those who gave me the possibility to complete this thesis especially my supervisor, Eng.Mohd Muzafar Bin Ismail for his useful guidance, constructive critics and invaluable advice throughout two semesters upon the completion of final year project.
I ought to acknowledge as well the many colleagues, students, lecturers, who assisted, advised, and supported my final year project over the years
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ABSTRACT
The final year project is a requisite subject for engineering students towards completing the Bachelor Degree program. The final year project is exposed to observe students what they have learned in four years at university, thus relates the theoretical and technical knowledge with the relevance in the final year project. Right through the final year project, students were projected to successfully enhancing their skills in technical, communication, management time, creativity as well as able to give personal ideas or opinions. For a mosque in UTeM, the acoustical requirements in terms of intelligibility and liveliness are dissimilar for the types of sounds-recitation and speech on religious subjects. To attain an overall satisfactory acoustical performance, it is significant to find an optimum Reverberation Time (RT) and the best directivity, which is the major factors affecting intelligibility and liveliness. Experiment is conducted to find the effect of RT by making it a variable, while keeping other factors as non-variable and fulfilling ideal conditions for maximum intelligibility. Bearing in mind, the acoustical problems always occurred in acoustical building. To improve the problem, this researched is come out with the new idea of solution by using biodegradable sound absorber materials which is the mixture of Dried Rice Straw and Kekabu. All the outputs is represent by using DPlot Simulation.
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ABSTRAK
Projek tahun akhir merupakan salah satu mata pelajaran wajib bagi pelajar kejuruteraan untuk melengkapkan program Ijazah Sarjana Muda. Projek tahun akhir menentukan dan memastikan pelajar apa yang telah mereka pelajari dalam tempoh empat tahun di universiti, sekali gus mengaitkan pengetahuan teori dan teknikal dengan permohonan dalam projek tahun akhir. Melalui projek tahun akhir, pelajar dijangka berjaya meningkatkan kemahiran mereka dalam bidang teknikal, komunikasi, pengurusan masa, kreativiti, serta mampu untuk memberi idea atau pendapat peribadi. Melalui kajian di masjid UteM, keperluan akustik dari segi kejelasan dan keberkesanan adalah berbeza bagi jenis bacaan, ucapan tazkirah mahupun azan. Untuk memastikan prestasi akustik memuaskan, adalah penting untuk mengenalpasti RT yang paling optimum dan keberkesan pembesar suara yang terbaik, ini kerana kedua dua aspek ini yang merupakan faktor utama yang mempengaruhi kejelasan dan keberkesanan sesuatu bunyi. Eksperimen dijalankan untuk mengkaji kesan RT dengan menitikberat faktor luaran demi mendapatkan kejelasan bunyi yang paling maksimum. Setiap bangunan tidak pernah terlepas dengan masalah akustik. Untuk mengatasi masalah ini, kajian ini telah menggunakan idea baru bagi penyelesaian masalah akustik tersebut iaitu dengan menggunakan bahan-bahan mesra alam sebagai penyerap bunyi seperti campuran Jerami Padi dan Kekabu. Semua hasil dapatan kajian di nyatakan dan diilustrasikan dalam simulasi DPlot.
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ix TABLE OF CONTENT
CHAPTER TOPIC PAGES
PROJECT TITLE i
REPORT VERIFICATION STATUS FORM ii
DECLARATION iii
SUPERVISOR DECLARATION iv
DEDICATION v
ACKNOWLEDGEMENT vi
ABSTRACT vii
ABSTRAK viii
TABLE OF CONTENT ix-xi
LIST OF FIGURES xii-xiii
LIST OF TABLES xiv
LIST OF ABBREVIATIONS xv
1 INTRODUCTION
1.1 Background Study 1 - 2
1.2 Objectives of the Study 2
1.3 Problem Statement 3
1.4 Scope of Project 3
1.5 Project Methodology 4-5
1.6 Report Outline 6
2 LITERATURE REVIEW
2.1 Directivity of Acoustic 7 - 9
2.2 Directivity of loudspeaker 9 - 10
2.3 Measurement of directivity 10-11
2.3.1 Speech Transmission Index (STI) 11-13 2.3.2 Articulation Loss for Consonant 13-14
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2.4 Speech Intelligibility 14-15
2.4.1 Signal to noise ratio (SNR) 15 2.4.2 Reverberation Time (RT) 15-16 2.4.3 Critical Distance (Dc) 17-18 2.5 Sound Absorption in Enclosed Rooms 18-20
3 METHODOLOGY
3.1 Specification of project 21
3.2 Project flow chart 22
3.3 Design of experimentation 21-22
3.3.1 Selection of room sample 23
3.3.2 Measurement positions and points 24 3.3.3 Monopole sound source illustration 25-26 at various locations
3.4 Acoustics measurement 26-27
3.5 Software Simulation 27-29
3.6 Project Experiment 30-32
4 RESULTS & DISCUSSION
4.1 The RT60 Calculation 33
4.1.1 Volume and surface area calculation for
First Floor praying area. 34-35
4.2 SPL and %Alcons 35
4.2.1 SPL and %Alcons calculation for First
Floor praying area. 36-43 4.2.2 SPL and %Alcons calculation for
Second Floor muslimah praying room 44-49 4.3 The correlation between SPL and %Alcons 50-51 4.4 SPL % RT60 Using New Sound Absorber 52
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4.5 Discussion 53-54
5 CONCLUSION
5.1 Conclusions 55
5.2 Recommendation for future work 56
5.3 Benefit of the Project 56
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xii
LIST OF FIGURE
NO TITLE PAGE
1.1 The overall process of project 4
1.2 PSM 1 Gantt Chart 5
1.3 PSM 2 Gantt Chart 5
2.1 The reverberation time (Tontechnik-Rechner) 16
2.2 The graph of critical distance 17
2.3 An illustration of sound reflection in enclosed room 19 2.4 The illustration of reflection, absorption and transmission 20
3.1 The research flow chart for overall process 22
3.2 Sample of plan layout 23
3.3 Sample of parameters points. 24
3.4 (a) Loudspeaker between Floor and Wall, (b) Loudspeaker between
Floor and Ceiling, and (c) Loudspeaker at flat surface ceiling-wall
junction 25
3.5 The sample of unfinished contour plot 27
3.6 Step to changing the contour level 28
3.7 Step to set intervals 28
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3.9 Shaded band in planar form 29
3.10 The experiment process flow 30
3.11 The dimension of modified anechoic chamber 31
3.12 The process flow implementation new sound absorber 32 4.1 (a) SPL simulation at First Floor for Q=1 (b) SPL simulation at First Floor for Q=2 (c) SPL simulation at First Floor for Q=4 39-40 4.2 (a) %Alcons simulation at First Floor for Q=1 (b) %Alcons simulation at First Floor for Q=2 (c) %Alcons simulation at First Floor for Q=4 41-42 4.3 (a) SPL simulation at Second Floor for Q=1 (b) SPL simulation at
Second Floor for Q=2 (c) SPL simulation at Second Floor for Q=4 46-47
4.4 (a) %Alcons simulation at Second Floor for Q=1 (b) %Alcons simulation at Second Floor for Q=2 (c) %Alcons simulation at
Second Floor for Q=4 48-49
4.5 The relationship between SPL and %Alcons at Q=1 50
4.6 The relationship between SPL and %Alcons at Q=2 50
4.7 The relationship between SPL and %Alcons at Q=4 51 4.8 The SPL and RT60 by using dried rice straw and kekabu 52
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LIST OF TABLES
NO TITLE PAGE
2.1 Monopole sound source Q and d at various locations
(Rossing et al., 2002) 8
2.2 Methods used in Speech Intelligibility Predictor (Paulraj et al., 2010). 11 2.3 Classification of quality of Speech Intelligibility Score (Ballou, 2008) 13
4.1 Volume and surface area calculation 34
4.2 Parameter for RT60 34
4.3 Summarized calculation for RT60 and Dc 35
4.4 Distance between loudspeaker and microphone at First Floor of Masjid 36 4.6 %Alcons values according critical distance at First Floor of Masjid 38 4.7 The distance between loudspeaker and listener at Second Floor
of Masjid 43
4.8 Sound pressure level according critical distance at Second Floor
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4.9 %Alcons values according critical distance at Second Floor
of Masjid 45
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1
CHAPTER 1
INTRODUCTION
Praying and lecturing, this both activities are mainly related to the speech which is important part of services in Mosque. However, an acoustical problem in the intelligibility of speech is the general rule in this type of building that may isolate our ability to recognize speech. Therefore, the purpose of this paper is to study the acoustical treatment and speech intelligibility quality analysis of Masjid UTeM using advance tool simulation and measurement.
1.1Background study
The concept idea of the acoustic treatment & speech intelligibility quality analysis in different dimension rooms in Masjid UTeM are a eminence of sound distribution. The importance of loudspeaker directivity in respect of speech intelligibility will represent.
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There are several numbers of acoustical parameters that can gauge the quality of sound. In a very limited budget, one of the parameter where practically used is loudspeaker. The arrangements of loudspeaker affect the sound distribution. This can be interpreted in terms of directivity factor. The propagation of sound also varied accordingly to room shape and the volume of room. For that reason, the relations between loudspeaker and sound propagation can be quantified in terms of directivity. The other way to get a good sound production is sound absorber. In this project, the Dried Rice Straw (jerami padi) & Kekabu are used to find out either both material is a good sound absorber or not.
1.2 Objectives of the Study
The objectives of the project are as following:
i. To study the effect of directivity on speech intelligibility with respect to room sizes and loudspeaker configuration.
ii. To find out the correlation between sound pressure level (SPL) and reverberation time (RT) due to directivity configuration of speech intelligibility.
iii. To observe the absorption coefficients of two sound absorber which is Dried Rice Straw(jerami padi) and Kekabu
1.3 Problem Statement
This project is proposed to overcome the production of echoes that occur in entire room of Masjid UTeM. Due to that, the listeners cannot reach the maximum accuracy of speech while being in the mosque. The production of high sound
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pressure level in acoustic wave makes it possible to achieve good speech intelligibility. Hence, this project wished for conquer the production of high sound pressure level.
Nowadays, the used of synthetic materials as sound absorber is still applied extensively. The used of the synthetic material also known as non-biodegradable material may cause pollution to the environment. Therefore, the researcher studies on the problems and came out with the idea using waste materials, dried rice straw (jerami padi) and kekabu which much cheaper as sound absorber.
1.4 Scope of project
The scopes of the project are as follows:
i. Rectangular room is used for experimentation in two different volumes and dimension.
ii. Directivity is investigated by three directivity configuration on Sound Pressure Level (SPL) and Reverberation Time (RT). Three loudspeaker directivity configuration.
iii. There are few points in room’s dimension is chosen to identify SPL and RT
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4 1.5 Project Methodology
This part will cover five main things to fulfil this research which are description of methodology, step of measurements, room’s layout and software simulation.
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Figure 1.2: PSM 1 Gantt Chart
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6 1.6 Report Outline
This report consists of three chapters, which describe the entire process of the research work. The outlines of the report are as follows:
Chapter 1 reviews the background of the research, objectives, problem statement and followed by scopes of work and report outline.
Chapter 2 highlights the details of the project comprises literature review and theory pertaining to the reason of idea outcome of the project.
Chapter 3 discussed the research methodology and the measurement processes that have been made of the study.
Chapter 4 summarized the result findings and discussed for every results due to objectives.
Chapter 5 conclude the overall process of researched and points out the objectives of the researched are achieved or not.
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CHAPTER 2
LITERATURE REVIEW
There are several criteria we need to consider in order to produce good intelligibility of speech. In any room, acoustics awareness is the needs to better perception of speech. Therefore, in this chapter we discuss the aspects of acoustic in production of high quality of speech.
2.1 Directivity of Acoustic
The ability to transmit or receive sound waves is more strongly in some directions than in others. The directivity is determined by the interference of coherent sound vibrations that arrive at some point of the medium from individual sections. In this study, the directivity is caused by the interference of pressures on the surface of the receiver.
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Speech sounds do not have a same potency in all directions (Everest, 2001). Mouth is one of the paradigms of speech sources. Mouth is a continuous source of speech sound. The sound source can be characterized by their power and directivity. Frequency is an essential of speech intelligibility and this should be scattered in the same way in form of directions of all the listeners (Esterhuizen, 2007).
The important of the directivity is to signify the direction of the sound generated by voice in the direction we want it to go. There are three directivity configurations which is directivity factor, directivity index and directivity of loudspeaker. Refer to Rossing et al. (2002), the directivity factor, Q is defined as the ratio of the sound intensity at the distance, r in front of a source to the sound intensity averaged over all directions.
Table 2.1: Monopole sound source Q and d at various locations (Rossing et al., 2002)
Source Location Directivity factor, Q Directivity Index, d (dB)
Between floor and ceiling 1 0
Flat Surface 2 3
Intersection of floor and wall 4 6
Corner of room three plane 8 9
Directivity factor, D or Q factor :
D =
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9
Directivity Index, d :
d
=(2.2)
Where :
I = Sound Intensity measured at distance, r
Io= Comparison sound intensity at distance, r
Io=
W= Energy produced by respected sound source
Table 2.1 shows the indicator of directivity factor and directivity index due to different locations. Refer to equation (2.1), the directivity index is obtained in unit decibel (dB). The mathematical expression of directivity factor relies on the directionality of sound source. The sound that radiates equally in all directions (a spherical source) has a directivity factor Q which is equal to 1. This theory shows that the sound is well distributed and maybe the production of the echoes happens here. Based on the table 2.1 the hypothesis can be made, the larger value of directivity factor the higher the directional sources.
2.2 Directivity of loudspeaker
As discussed in 2.1 the definition of directivity elsewhere in general terms. In loudspeaker system, the directivity is the characteristic of how a loudspeaker distributes sounds in different directions. It also an indication of how directional the loudspeaker is. Loudspeaker with wide bandwidth, flat and smooth magnitude and uniformly wide directivity are more preferred as to direct sound to the target point (Olive, 2003). Bass frequencies have very long wavelengths which make it difficult to control the direction they travel.
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1.5 Project Methodology
This part will cover five main things to fulfil this research which are description of methodology, step of measurements, room’s layout and software simulation.
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Figure 1.2: PSM 1 Gantt Chart
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1.6 Report Outline
This report consists of three chapters, which describe the entire process of the research work. The outlines of the report are as follows:
Chapter 1 reviews the background of the research, objectives, problem statement and followed by scopes of work and report outline.
Chapter 2 highlights the details of the project comprises literature review and theory pertaining to the reason of idea outcome of the project.
Chapter 3 discussed the research methodology and the measurement processes that have been made of the study.
Chapter 4 summarized the result findings and discussed for every results due to objectives.
Chapter 5 conclude the overall process of researched and points out the objectives of the researched are achieved or not.
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CHAPTER 2
LITERATURE REVIEW
There are several criteria we need to consider in order to produce good intelligibility of speech. In any room, acoustics awareness is the needs to better perception of speech. Therefore, in this chapter we discuss the aspects of acoustic in production of high quality of speech.
2.1 Directivity of Acoustic
The ability to transmit or receive sound waves is more strongly in some directions than in others. The directivity is determined by the interference of coherent sound vibrations that arrive at some point of the medium from individual sections. In this study, the directivity is caused by the interference of pressures on the surface of the receiver.
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Speech sounds do not have a same potency in all directions (Everest, 2001). Mouth is one of the paradigms of speech sources. Mouth is a continuous source of speech sound. The sound source can be characterized by their power and directivity. Frequency is an essential of speech intelligibility and this should be scattered in the same way in form of directions of all the listeners (Esterhuizen, 2007).
The important of the directivity is to signify the direction of the sound generated by voice in the direction we want it to go. There are three directivity configurations which is directivity factor, directivity index and directivity of loudspeaker. Refer to Rossing et al. (2002), the directivity factor, Q is defined as the ratio of the sound intensity at the distance, r in front of a source to the sound intensity averaged over all directions.
Table 2.1: Monopole sound source Q and d at various locations (Rossing et al., 2002)
Source Location Directivity factor, Q Directivity Index, d
(dB)
Between floor and ceiling 1 0
Flat Surface 2 3
Intersection of floor and wall 4 6
Corner of room three plane 8 9
Directivity factor, D or Q factor :
D =
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Directivity Index, d :
d
=(2.2)
Where :
I = Sound Intensity measured at distance, r
Io= Comparison sound intensity at distance, r
Io=
W= Energy produced by respected sound source
Table 2.1 shows the indicator of directivity factor and directivity index due to different locations. Refer to equation (2.1), the directivity index is obtained in unit decibel (dB). The mathematical expression of directivity factor relies on the directionality of sound source. The sound that radiates equally in all directions (a spherical source) has a directivity factor Q which is equal to 1. This theory shows that the sound is well distributed and maybe the production of the echoes happens here. Based on the table 2.1 the hypothesis can be made, the larger value of directivity factor the higher the directional sources.
2.2 Directivity of loudspeaker
As discussed in 2.1 the definition of directivity elsewhere in general terms. In loudspeaker system, the directivity is the characteristic of how a loudspeaker distributes sounds in different directions. It also an indication of how directional the loudspeaker is. Loudspeaker with wide bandwidth, flat and smooth magnitude and uniformly wide directivity are more preferred as to direct sound to the target point (Olive, 2003). Bass frequencies have very long wavelengths which make it difficult to control the direction they travel.