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to-BAND GRAPHIC EQUALIZER
FRANCIS ABLIGADO BUJET
Tesis Dikemukakan Kepada Fakulti Kejuruteraan, Universiti Malaysia Sarawak
Sebagai Memenuhi Sebahagian daripada Syarat Penganugerahan Sarjana Muda Kejuruteraan
Dengan Kepujian (Kejuruteraan Elektronik dan Telekomunikasi) 2000
, ..
to-BAND GRAPHIC EQUALIZER
FRANCIS ABLIGADO BUJET
Tesis Dikemukakan Kepada Fakulti Kejuruteraan, Universiti Malaysia Sarawak
Sebagai Memenuhi Sebahagian daripada Syarat Penganugerahan Sarjana Muda Kejuruteraan
Dengan Kepujian (Kejuruteraan Elektronik dan Telekomunikasi) 2000
In memory of my beloved father, Bujet ak Joub,
and, for my mom, my brothers and my sisters.
ii
In memory of my beloved father, Bujet ak Joub,
and, for my mom, my brothers and my sisters.
ii
ACKNOWLEDGEMENT
Thank you to Almighty God above for giving me the strength to finish my
final year thesis based on my final year project. Hereby I would like to give my
greatest gratitude and my warm love to those who have given me their support
together with their strength for the past three years time in UN1MAS.
First of all, I would like to give my deepest loves and my warm and tender
thanks to my mom, Milat ak Minjot, both my brothers; Awie and Nickey, and my
sisters; Kak Mala and Kak Janet, for their financial support, encouragement and
useful advice.
Special thanks go to Associate Professor Dr. Mohamad Kadim Suaidi, Dean,
Faculty of Engineering, UNIMAS for his support and concern. To my supervisor;
Miss Licha Mued and Mr. Ng Liang Yew, for their ideas and quidance throughout
this project. To En Thelaha Masri and En. Hushairi Zen, for their suggestions and
experiences in implementing and testing the project. To both Lab Administrator; En.
Zakaria and En. Wan Abu Bakar, for their assistant, cooperation and contribution in
preparing and providing experimental equipment to the project. To all my
coursemates and friends in Kolej Sri Muara (No. 72 & 73), for their assistant and
" support.
To those that I might forgot to mention, but not in my heart, thank you very
much.
iii
ACKNOWLEDGEMENT
Thank you to Almighty God above for giving me the strength to finish my
final year thesis based on my final year project. Hereby I would like to give my
greatest gratitude and my warm love to those who have given me their support
together with their strength for the past three years time in UN1MAS.
First of all, I would like to give my deepest loves and my warm and tender
thanks to my mom, Milat ak Minjot, both my brothers; Awie and Nickey, and my
sisters; Kak Mala and Kak Janet, for their financial support, encouragement and
useful advice.
Special thanks go to Associate Professor Dr. Mohamad Kadim Suaidi, Dean,
Faculty of Engineering, UNIMAS for his support and concern. To my supervisor;
Miss Licha Mued and Mr. Ng Liang Yew, for their ideas and quidance throughout
this project. To En Thelaha Masri and En. Hushairi Zen, for their suggestions and
experiences in implementing and testing the project. To both Lab Administrator; En.
Zakaria and En. Wan Abu Bakar, for their assistant, cooperation and contribution in
preparing and providing experimental equipment to the project. To all my
coursemates and friends in Kolej Sri Muara (No. 72 & 73), for their assistant and
" support.
To those that I might forgot to mention, but not in my heart, thank you very
much.
iii
ABSTRACT
Graphic Equalizer (EQ) is an electronic project that has help to overcome the
problem encountered by those who are interested to produce a better sound quality
from their sound system. EQ can help to tune more specifically so that we can get
the sound that we want. This report consists of the overview of a lO-band graphic
equalizer and also the literature review of it. This includes the basic condition of the
system used in graphic equalizer such as in cut or boost condition. The report is
quite general, as the reason is to give the overall idea and understanding regarding
the project. There are also evaluation of function of the component used for the
project such as the dual operational amplifier (op-amp) as the lCs and also the
filters function. Besides that there are also explanations on how the project are
being tested before being implemented on the printed circuit board (PCB). The
simulation and analysis done is to make sure that the project has been implemented
successfully as required in the objectives. Finally it is hope that readers would have
a better understanding regarding a lO-band Graphic Equalizer operation and the
effect it could gives in a sound system.
IV
ABSTRACT
Graphic Equalizer (EQ) is an electronic project that has help to overcome the
problem encountered by those who are interested to produce a better sound quality
from their sound system. EQ can help to tune more specifically so that we can get
the sound that we want. This report consists of the overview of a lO-band graphic
equalizer and also the literature review of it. This includes the basic condition of the
system used in graphic equalizer such as in cut or boost condition. The report is
quite general, as the reason is to give the overall idea and understanding regarding
the project. There are also evaluation of function of the component used for the
project such as the dual operational amplifier (op-amp) as the lCs and also the
filters function. Besides that there are also explanations on how the project are
being tested before being implemented on the printed circuit board (PCB). The
simulation and analysis done is to make sure that the project has been implemented
successfully as required in the objectives. Finally it is hope that readers would have
a better understanding regarding a lO-band Graphic Equalizer operation and the
effect it could gives in a sound system.
IV
ABSTRAK
Grafik Equaliser (EQ) merupakan satu projek elektronik yang telah berjaya
mengatasi masalah terutama kepada sesiapa yang berminat untuk menghasilkan
kualiti bunyi yang lebih baik terhadap sistem audio. EQ dapat membantu untuk
melaraskan nada bunyi dengan lebih spesifik supaya kita boleh memperolehi mutu
audio seperti yang kita ingini. Laporan ini mengandungi gambaran keseluruhan
tentang projek lO-band Graphic Equalizer saya dan juga kajian literaturnya. Ini
merangkumi keadaan asal grafik equalizer seperti semasa 'cut' atau 'boost'.
Kandungan laporan ini juga agak umum. Ini adalah bertujuan untuk memberi
gambaran dan kefahaman secara menyeluruh mengenai projek yang akan saya
laksanakan nanti. Laporan ini juga mengandungi penerangan tentang fungsi bagi
komponen yang digunakan untuk projek ini nanti seperti operational amplifier (op
amp) dan filters. Selain daripada itu laporan ini juga menyelitkan penerangan
tentang bagaimana projek ini diuji di atas breadboard terlebih dahulu untuk
memastikan bahawa ia dapt berfungsi sebelum di pasang di atas papan litar
bercetak (PCB). Projek simulasi dan data analisis yang dibuat bertujuan untuk
" memastikan bahawa projek ini adalah berjaya dan mencapai objektifnya. Akhir
sekali adalah diharap supaya para pembaca akan memperoleh pemahaman yang
lebih jelas mengenai operasi lO-band Graphic Equalizer dan kesan yang dapat
dihasilkan terhadap sebuah system audio.
v
"
ABSTRAK
Grafik Equaliser (EQ) merupakan satu projek elektronik yang telah berjaya
mengatasi masalah terutama kepada sesiapa yang berminat untuk menghasilkan
kualiti bunyi yang lebih baik terhadap sistem audio. EQ dapat membantu untuk
melaraskan nada bunyi dengan lebih spesifik supaya kita boleh memperolehi mutu
audio seperti yang kita ingini. Laporan ini mengandungi gambaran keseluruhan
tentang projek lO-band Graphic Equalizer saya dan juga kajian literaturnya. Ini
merangkumi keadaan asal grafik equalizer seperti semasa 'cut' atau 'boost'.
Kandungan laporan ini juga agak umum. Ini adalah bertujuan untuk memberi
gambaran dan kefahaman secara menyeluruh mengenai projek yang akan saya
laksanakan nanti. Laporan ini juga mengandungi penerangan tentang fungsi bagi
komponen yang digunakan untuk projek ini nanti seperti operational amplifier (op
amp) dan filters. Selain daripada itu laporan ini juga menyelitkan penerangan
tentang bagaimana projek ini diuji di atas breadboard terlebih dahulu untuk
memastikan bahawa ia dapt berfungsi sebelum di pasang di atas papan litar
bercetak (PCB). Projek simulasi dan data analisis yang dibuat bertujuan untuk
memastikan bahawa projek ini adalah berjaya dan mencapai objektifnya. Akhir
sekali adalah diharap supaya para pembaca akan memperoleh pemahaman yang
lebih jelas mengenai operasi lO-band Graphic Equalizer dan kesan yang dapat
dihasilkan terhadap sebuah system audio.
v
----~--... .. --...--....----- ... --
TABLE OF CONTENTS
Page
Dedication 11
Acknowledgement 111
Abstract IV
Abstrak V
Table of Content VI
List of Figures Xl
List of Tables xv
List ofAppendix xvi
CHAPTER 1 INTRODUCTION
1.1 Introduction 1
1.2 Objective 2
1.3 Project Overview 3
1.4 Why Use an Equalizer? 4
" 1.5 The Decibel (dB) 5
l.6 Project's Technical Data and Features 6
1.7 Report Overview 6
Vl
"
TABLE OF CONTENTS
Dedication
Acknow ledgement
Abstract
Abstrak
Table of Content
List of Figures
List of Tables
List of Appendix
CHAPTER 1 INTRODUCTION
1.1
1.2
1.3
1.4
1.5
Introduction
Objective
Project Overview
Why Use an Equalizer?
The Decibel (dB)
l.6
1.7
Project's Technical Data and Features
Report Overview
Vl
Page
11
111
IV
V
VI
Xl
xv
xvi
1
2
3
4
5
6
6
•
CHAPTER 2 LITERATURE REVIEW
2.1 The Concept of Equalization 7
2.1.1 Another Point of View on Equalization 7
2.1.2 What Equalization Can and Cannot Do 8
2.1.3 System Design Criteria for Equalization 9
2.1.4 System Equipment 9
2.2 Equalizers 10
2.2.1 Type of Equalizer 12
2.2.1.1 Graphic Equalizer 16
2.2.1.2 Band-Reject Equalizer 17
2.2.1.3 Cut-and-Boost Equalizer 17
2.2.1.4 The Boost-and-Cut versus Cut-only Equalizer 18
2.2.1.5 Synergistic Equalizer 19
2.2.1.6 Parametric Equalizer 20
2.2.1. 7 Shelving Equalizer 21
2.2.1.8 Programmable Equalizer 24
2.2.1.9 Adaptive Equalizer 25
2.2.1 Equalizers in Sound Reinforcement 26
2.3 Filters 28
" 2.3.1 Passive Filters 28
2.3.2 Active Filters 28
vii
"
CHAPTER 2 LITERATURE REVIEW
2.1 The Concept of Equalization
2.1.1 Another Point of View on Equalization
2.1.2 What Equalization Can and Cannot Do
2.1.3 System Design Criteria for Equalization
2.1.4 System Equipment
2.2 Equalizers
2.2.1 Type of Equalizer
2.2.1.1 Graphic Equalizer
2.2.1.2 Band-Reject Equalizer
2.2.1.3 Cut-and-Boost Equalizer
2.2.1.4 The Boost-and-Cut versus Cut-only Equalizer
2.2.1.5 Synergistic Equalizer
2.2.1.6 Parametric Equalizer
2.2.1. 7 Shelving Equalizer
2.2.1.8 Programmable Equalizer
2.2.1. 9 Adaptive Equalizer
2.2.1 Equalizers in Sound Reinforcement
2.3 Filters
2.3.1 Passive Filters
2.3.2 Active Filters
vii
7
7
8
9
9
10
12
16
17
17
18
19
20
21
24
25
26
28
28
28
2.4 Power Supply 29
2.4.1 Rectifiers 29
2.4.2 Simple DC Power Supply 30
2.4.3 One-Half Wave Supplies 32
2.4.4 Full-Wave Supplies 32
2.4.5 Filters in Power Supply 33
2.4.6 Capacitor Filters 33
CHAPTER 3 METODOLOGY
3.1 Introduction 35
3.2 Component of Project 35
3.2.1 Passive Components 36
3.2.2 Active Components 36
3.3 Testing the Components 36
3.3.1 Resistors 37
3.3.1.1 Fixed Resistors 37
3.3.1.2 Variable Resistors 40
3.3.2 Capacitors 42
3.3.3 IC AN6551 43
"3.3.4 Diodes 43
3.3.5 Zener Diodes 44
3.3.6 Bipolar Transistor 44
viii
2.4 Power Supply 29
2.4.1 Rectifiers 29
2.4.2 Simple DC Power Supply 30
2.4.3 One-Half Wave Supplies 32
2.4.4 Full-Wave Supplies 32
2.4.5 Filters in Power Supply 33
2.4.6 Capacitor Filters 33
CHAPTER 3 METODOLOGY
3.1 Introduction 35
3.2 Component of Project 35
3.2.1 Passive Components 36
3.2.2 Active Components 36
3.3 Testing the Components 36
3.3.1 Resistors 37
3.3.1.1 Fixed Resistors 37
3.3.1.2 Variable Resistors 40
3.3.2 Capacitors 42
3.3.3 IC AN6551 43
" 3.3.4 Diodes 43
3.3.5 Zener Diodes 44
3.3.6 Bipolar Transistor 44
viii
3.4 Project Implementation 44
3.4.1 Components Testing 45
3.4.2 Components Testing 45
3.4.3 Printed Circuit Board (PCB) 46
3.4.4 Etching 47
3.4.5 Drilling 47
3.4.6 Mounting and Soldering 48
CHAPTER 4 DESIGN SPECIFICATION
4.1 The Basic Equalizer Circuit 49
4.2 The System 51
4.3 The Control of Gain 53
4.4 Sounds Frequency Recognition 53
4.5 Frequency Controls Adjustment 53
4.6 Other Controller 55
4.7 The Power Supply Unit 55
CHAPTER 5 TESTING AND TROUBLESHOOTING
5.1 Power Supply and Voltage Regulator 57
5.2 Main Circuit 60" 5.2.1 Microphone 62
5.2.2 10-band Frequency Controller 64
I
IX
3.4 Project Implementation 44
3.4.1 Components Testing 45
3.4.2 Components Testing 45
3.4.3 Printed Circuit Board (PCB) 46
3.4.4 Etching 47
3.4.5 Drilling 47
3.4.6 Mounting and Soldering 48
CHAPTER 4 DESIGN SPECIFICATION
4.1 The Basic Equalizer Circuit 49
4.2 The System 51
4.3 The Control of Gain 53
4.4 Sounds Frequency Recognition 53
4.5 Frequency Controls Adjustment 53
4.6 Other Controller 55
4.7 The Power Supply Unit 55
CHAPTER 5 TESTING AND TROUBLESHOOTING
5.1 Power Supply and Voltage Regulator 57
" 5.2 Main Circuit 60
5.2.1 Microphone 62
5.2.2 10-band Frequency Controller 64
IX
CHAPTER 6 PROBLEM ENCOUNTERED AND FAULT 75
DIAGNOSIS
CHAPTER 7 DISCUSSION
7.1 Recommendation 78
7.2 Conclusion 80
REFERENCES 82
APPENDIX 84
x
CHAPTER 6 PROBLEM ENCOUNTERED AND FAULT
DIAGNOSIS
CHAPTER 7 DISCUSSION
7.1 Recommendation
7.2 Conclusion
REFERENCES
APPENDIX
x
75
78
80
82
84
LIST OF FIGURES
Page
Figure 1.1: Graphic Equalizer in an Audio System 3
Figure 1.2: Final End Project (Controller) 3
Figure 2.1: Basic Boost Filter Response 13
Figure 2.2: Constant-Q Boost Filter Response 13
Figure 2.3: Constant-Shape Boost Filter Response 13
Figure 2.4: Basic Cut Filter Response 15
Figure 2.5: Constant-Q Boost/Cut Filter Response 15
Figure 2.6: Reciprocal Peaking Filter Response 15
Figure 2.7: Subtractive Equalizer 17
Figure 2.8: Low-frequency Shelving Equalizer Response 23
Figure 2.9: High-frequency Shelving Equalizer Response 23
Figure 2.10: A Straight-line Approximation of the Shelving Equalizer 24
Response
Figure 2. 11A: Half-wave Transfomerless Power Supply 31
Figure 2.l1B: Half-wave Transformer-isolated Power Supply 31
, Figure 2.l1C: Output Waveform from Half-wave Power Supply 31
Figure 2.12: Capacitor Filter 33
Figure 3.1: Color-code Bands on a Resistor 37
Xl
LIST OF FIGURES
Figure 1.1: Graphic Equalizer in an Audio System
Figure 1.2: Final End Project (Controller)
Figure 2.1: Basic Boost Filter Response
Figure 2.2: Constant-Q Boost Filter Response
Figure 2.3: Constant-Shape Boost Filter Response
Figure 2.4: Basic Cut Filter Response
Figure 2.5: Constant-Q Boost/Cut Filter Response
Figure 2.6: Reciprocal Peaking Filter Response
Figure 2.7: Subtractive Equalizer
Figure 2.8: Low-frequency Shelving Equalizer Response
Figure 2.9: High-frequency Shelving Equalizer Response
Figure 2.10: A Straight-line Approximation of the Shelving Equalizer
Response
Figure 2. 11 A: Half-wave Transfomerless Power Supply
Figure 2.l1B: Half-wave Transformer-isolated Power Supply
, Figure 2.l1C: Output Waveform from Half-wave Power Supply
Figure 2.12: Capacitor Filter
Figure 3.1: Color-code Bands on a Resistor
Xl
Page
3
3
13
13
13
15
15
15
17
23
23
24
31
31
31
33
37
Figure 3.2: Example of Color Code Conversion 39
Figure 3.3(a): Potentiometer Symbol 40
Figure 3.3(b): Rheostat Symbol 40
Figure 3.3(c): Potentiometer connected as a Rheostat 40
Figure 3.4: Sliding Type Variable Resistor 41
Figure 3.5: Example of Capacitor Number Convercion 43
Figure 4.1: Schematic showing a Basic Equalizer 49
Figure 4.2: Schematic showing a Basic Tuned Circuit Type Equalizer 50
Figure 4.3: Basic Schematic of lO-band Graphic Equalizer 52
Figure 5. 1 (a): Output of Rectifier (+) 58
Figure 5.1(b): Output of Rectifier (-) 58
Figure 5.2(a); Output ofVoltage Regulator (+) 59
Figure 5.2(b): Output of Voltage Regulator (-) 59
Figure 5.3(a): Output at Pin (1I9)-IC1 61
Figure 5.3(b): Output at Pin (2/8)-IC2 61
Figure 5.3(c): Output at Pin (2/8)-IC3 61
Figure 5.4(a): Microphone Input Signal 63
Figure 5.4(b): Microphone Output at Capacitor, C1 63
Figure 5.4(c): Microphone Output at Capacitor, C2 63
" Figure 5.5(a): Input at Auxiliary (30 Hz) 65
Figure 5.5(b): Channel Output (30 Hz) 65
Figure 5.5(c); Output at Capacitor, C2 (30 Hz) 65
xu
Figure 3.2: Example of Color Code Conversion 39
Figure 3.3(a): Potentiometer Symbol 40
Figure 3.3(b): Rheostat Symbol 40
Figure 3.3(c): Potentiometer connected as a Rheostat 40
Figure 3.4: Sliding Type Variable Resistor 41
Figure 3.5: Example of Capacitor Number Convercion 43
Figure 4.1: Schematic showing a Basic Equalizer 49
Figure 4.2: Schematic showing a Basic Tuned Circuit Type Equalizer 50
Figure 4.3: Basic Schematic of lO-band Graphic Equalizer 52
Figure 5. 1 (a): Output of Rectifier (+) 58
Figure 5.1(b): Output of Rectifier (-) 58
Figure 5.2(a); Output of Voltage Regulator (+) 59
Figure 5.2(b): Output of Voltage Regulator (-) 59
Figure 5.3(a): Output at Pin (1I9)-IC1 61
Figure 5.3(b): Output at Pin (2/8)-IC2 61
Figure 5.3(c): Output at Pin (2/8)-IC3 61
Figure 5.4(a): Microphone Input Signal 63
Figure 5.4(b): Microphone Output at Capacitor, C1 63
Figure 5.4(c): Microphone Output at Capacitor, C2 63
" Figure 5.5(a): Input at Auxiliary (30 Hz) 65
Figure 5.5(b): Channel Output (30 Hz) 65
Figure 5.5(c); Output at Capacitor, C2 (30 Hz) 65
xu
Figure 5.6(a): Input at Auxiliary (60 Hz) 66
Figure 5.6(b): Channel Output (60 Hz) 66
Figure 5.6(c): Output at Capacitor, C2 (60 Hz) 66
Figure 5.7 (a): Input at Auxiliary (125 Hz) 67
Figure 5.7(b): Channel Output (125 Hz) 67
Figure 5.7(c): Output at Capacitor, C2 (125 Hz) 67
Figure 5.8(a): Input at Auxiliary (250 Hz) 68
Figure 5.8(b): Channel Output (250 Hz) 68
Figure 5.8(c): Output at Capacitor, C2 (250 Hz) 68
Figure 5.9(a): Input at Auxiliary (500 Hz) 69
Figure 5.9(b): Channel Output (500 Hz) 69
Figure 5.9(c): Output at Capacitor, C2 (500 Hz) 69
Figure 5.1O(a): Input at Auxiliary (1 kHz) 70
Figure 5.1O(b): Channel Output (1 kHz) 70
Figure 5. 10(c): Output at Capacitor, C2 (1 kHz) 70
Figure 5. 11(a): Input at Auxiliary (2 kHz) 71
Figure 5. 11(b): Channel Output (2 kHz) 71
Figure 5. 11(c): Output at Capacitor, C2 (2 kHz) 71
Figure 5. 12(a); Input at Auxiliary (4 kHz) 72
)-igure 5.12(b): Channel Output (4 kHz) 72
Figure 5. 12(c): Output at Capacitor, C2 (4 kHz) 72
xiii
Figure 5.6(a): Input at Auxiliary (60 Hz) 66
Figure 5.6(b): Channel Output (60 Hz) 66
Figure 5.6(c): Output at Capacitor, C2 (60 Hz) 66
Figure 5. 7 (a): Input at Auxiliary (125 Hz) 67
Figure 5.7(b): Channel Output (125 Hz) 67
Figure 5.7(c): Output at Capacitor, C2 (125 Hz) 67
Figure 5.8(a): Input at Auxiliary (250 Hz) 68
Figure 5.8(b): Channel Output (250 Hz) 68
Figure 5.8(c): Output at Capacitor, C2 (250 Hz) 68
Figure 5.9(a): Input at Auxiliary (500 Hz) 69
Figure 5.9(b): Channel Output (500 Hz) 69
Figure 5.9(c): Output at Capacitor, C2 (500 Hz) 69
Figure 5.1O(a); Input at Auxiliary (1 kHz) 70
Figure 5.1O(b): Channel Output (1 kHz) 70
Figure 5. 10 (c): Output at Capacitor, C2 (1 kHz) 70
Figure 5. 11 (a); Input at Auxiliary (2 kHz) 71
Figure 5. 11 (b): Channel Output (2 kHz) 71
Figure 5. 11 (c): Output at Capacitor, C2 (2 kHz) 71
Figure 5. 12(a); Input at Auxiliary (4 kHz) 72
)igure 5.12(b): Channel Output (4 kHz) 72
Figure 5. 12(c); Output at Capacitor, C2 (4 kHz) 72
xiii
---.--.~----------------
Figure 5. 13(a): Input at Auxiliary (8 kHz) 73
Figure 5. 13(b): Channel Output (8 kHz) 73
Figure 5. 13(c): Output at Capacitor, C2 (8 kHz) 73
Figure 5. 14(a): Input at Auxiliary (16 kHz) 74
Figure 5. 14(b): Channel Output (16 kHz) 74
Figure 5. 14(c): Output at Capacitor, C2 (16 kHz) 74
xiv
Figure 5. 13(a): Input at Auxiliary (8 kHz) 73
Figure 5. 13(b): Channel Output (8 kHz) 73
Figure 5. 13(c): Output at Capacitor, C2 (8 kHz) 73
Figure 5. 14(a): Input at Auxiliary (16 kHz) 74
Figure 5. 14(b): Channel Output (16 kHz) 74
Figure 5. 14(c): Output at Capacitor, C2 (16 kHz) 74
xiv
LIST OF TABLES
Page
Table 3.1: Resistor Color Conversion Table 38
Table 3.2: Capacitor Number Conversion Table 42
Table 4.1: Capacitors for each Frequency Channel 52
Table 4.1: Five main Groups of Sound Frequency Range 54
xv
Table 3.1:
Table 3.2:
Table 4.1:
Table 4.1:
LIST OF TABLES
Resistor Color Conversion Table
Capacitor Number Conversion Table
Capacitors for each Frequency Channel
Five main Groups of Sound Frequency Range
xv
Page
38
42
52
54
LIST OF APPENDIX.
Appendix A: Schematic Diagram of lO-Band Graphic Equalizer
Page
84
Appendix B: Schematic Diagram of Power Supply 85
Appendix C: List of Components 86
Appendix D: Project being Test on the Testboard(Breadboard) 88
Appendix E: lO-Band Graphic Equalizer and Power Supply 90
Appendix F: PCB as Viewed from Bottom 91
XVI
LIST OF APPENDIX.
Appendix A: Schematic Diagram of lO-Band Graphic Equalizer
Appendix B: Schematic Diagram of Power Supply
Appendix C: List of Components
Appendix D: Project being Test on the Testboard(Breadboard)
Appendix E: lO-Band Graphic Equalizer and Power Supply
Appendix F: PCB as Viewed from Bottom
XVI
Page
84
85
86
88
90
91
CHAPTER 1
INTRODUCTION
1.1 Introduction
Equalizer (EQ) a class of electronic fllters designed to modify or adjust
electronic or acoustic systems (3]. Equalizers can be fixed or adjustable. In the
early years of telephony and cinema, the first equalizers were fixed units
designed to correct for losses in the transmission and recording of audio signals.
Audio systems have also used some form of equalizer technology since 25 years
ago. Since then, the equalizer has been used to correct and enhance sound. It has
also formed the basis for many of the sophisticated automatic audio-processing
systems in use today. Perhaps as time goes by, equalizer are considered as some
of the most overused and misunderstood devices in the field of sound.
Hence, the term equalizer described electronic circuits that corrected
these losses and made the output equal to the input. Equalizers commonly
modifY the frequency response of the signal passing through them; that is, they
modifY the amplitude versus frequency characteristics. There are also fixed
equalizers that modifY the phase response of the transmitted signals without
disturbing the frequency content. These are referred to as all-pass, phase-delay,
or signal-delay equalizers.
1
CHAPTER 1
INTRODUCTION
1.1 Introduction
Equalizer (EQ) a class of electronic fllters designed to modify or adjust
electronic or acoustic systems (3]. Equalizers can be fixed or adjustable. In the
early years of telephony and cinema, the first equalizers were fixed units
designed to correct for losses in the transmission and recording of audio signals.
Audio systems have also used some form of equalizer technology since 25 years
ago. Since then, the equalizer has been used to correct and enhance sound. It has
also formed the basis for many of the sophisticated automatic audio-processing
systems in use today. Perhaps as time goes by, equalizer are considered as some
of the most overused and misunderstood devices in the field of sound.
Hence, the term equalizer described electronic circuits that corrected
these losses and made the output equal to the input. Equalizers commonly
modifY the frequency response of the signal passing through them; that is, they
modifY the amplitude versus frequency characteristics. There are also fixed
equalizers that modifY the phase response of the transmitted signals without
disturbing the frequency content. These are referred to as all-pass, phase-delay,
or signal-delay equalizers.
1
Lower frequencies (bass) are the left half of the sliders, while higher
frequencies (treble) are on the right section of the equalizer. Each slider affects a
slighter higher tone than the one before it when going from left to right. The
volume of any given range can be increased by dragging a slider up and decrease
it by dragging the slider down. The center position effectively leaves the incoming
frequency unchanged.
1.2 Objective
The main objective of this project is to produce a successful lO-band
Graphic Equalizer for a sound system. Graphic equalizer is a kind or an audio
equalizer used necessary to produce a quality output from a sound system. Audio
equalizer separates a range of selective audio frequencies and this enable listener
or operator to select which frequencies to amplified or attenuate and therefore
produce quality sound without significance loss in treble, bass or mid-range audio
frequency. This 10-band Graphic Equalizer also known as First Octave Equalizer
will enable a range of audio frequencies to be equalized at a low cost. There are
lO-channel controls for the different frequencies of the first octave equalizer.
Each channel controls have a definite relationship with each other. This could be
done by observing the numerical values of the frequency for which the controls
are provided: 30Hz, 60Hz, 125Hz, 250Hz, 500Hz, 1kHz, 2kHz, 4kHz, 8kHz,
16kHz. A better understanding of an equalizer basic concept is also needed so
that any modification could be done if it is necessary. This project also required
" the author to have a better overview on how does each circuit actually works and
the relationship between each other to perform an equalizer system.
2
"
Lower frequencies (bass) are the left half of the sliders, while higher
frequencies (treble) are on the right section of the equalizer. Each slider affects a
slighter higher tone than the one before it when going from left to right. The
volume of any given range can be increased by dragging a slider up and decrease
it by dragging the slider down. The center position effectively leaves the incoming
frequency unchanged.
1.2 Objective
The main objective of this project is to produce a successful lO-band
Graphic Equalizer for a sound system. Graphic equalizer is a kind or an audio
equalizer used necessary to produce a quality output from a sound system. Audio
equalizer separates a range of selective audio frequencies and this enable listener
or operator to select which frequencies to amplified or attenuate and therefore
produce quality sound without significance loss in treble, bass or mid-range audio
frequency. This 10-band Graphic Equalizer also known as First Octave Equalizer
will enable a range of audio frequencies to be equalized at a low cost. There are
lO-channel controls for the different frequencies of the first octave equalizer.
Each channel controls have a definite relationship with each other. This could be
done by observing the numerical values of the frequency for which the controls
are provided: 30Hz, 60Hz, 125Hz, 250Hz, 500Hz, 1kHz, 2kHz, 4kHz, 8kHz,
16kHz. A better understanding of an equalizer basic concept is also needed so
that any modification could be done if it is necessary. This project also required
the author to have a better overview on how does each circuit actually works and
the relationship between each other to perform an equalizer system.
2
1.3 Project Overview
A graphic equalizer is an electronic project that consist of a 10-band
frequency channel controller, line-in and line out channel, an on/off button,
volume controller, balance controller and a 17 V regulated on board power
supply for supplying power to the equalizer main circuit. A basic idea of the
equalizer application is shown in Figure 1.1 and the expected output (casing) of
the project is shown in Figure 1.2.
AUDIO --... PRE ... GRAPHIC ... AUDIO .... OUTPUTI SPEAKERINPUT ~ AMP ~
EQUALIZER ~ AMPLIFIER ~
Figure 1.1: Graphic Equalizer in an Audio system
30 Hz 60 Hz 1211 Hz 2110 Hz IlOO Hz 1 kHz 2 kHz 4 kHz 8 kHz 16 kHz Vol. Bal. Mic.
Ig~ I LINE IN
o tttt++tttttttLINE OUT
o
Figure 1.2 Final End Project (controller)
3
1.3 Project Overview
A graphic equalizer is an electronic project that consist of a 10-band
frequency channel controller, line-in and line out channel, an on/off button,
volume controller, balance controller and a 17 V regulated on board power
supply for supplying power to the equalizer main circuit. A basic idea of the
equalizer application is shown in Figure 1.1 and the expected output (casing) of
the project is shown in Figure 1.2.
AUDIO --.. PRE- ... GRAPHIC ... AUDIO ... OUTPUTI INPUT ~ AMP r'
EQUALIZER r' AMPLIFIER ~ SPEAKER
Figure 1.1: Graphic Equalizer in an Audio system
I g~ I LINE IN
o LINE OUT
30 Hz 60 Hz 1211 Hz 2110 Hz IlOO Hz 1 kHz 2 kHz 4 kHz 8 kHz 16 kHz Vol. Bal. Mic.
tttt++ttttttt o
Figure 1.2 Final End Project (controller)
3
.-.~.~.------------------------------
1.4 Why use an Equalizer?
Equalization allows the user to differentiate the tone characteristics of the
signal being reproduced in an Audio chain or system. This can be for a variety of
reasons. These include:
• In Live Sound Systems (both fixed installation and portableltouring) to
correct for the frequency response of the environment in which the system is
being used in order to reduce feedback rings and howl round, to correct for
irregular room frequency response, to correct loudspeaker amplitude
response.
• In frxed installations equalizers can be used to tailor the frequency response
of the system. For example background music needs a smooth mellow
unobtrusive sound, and therefore less low and high frequency energy, while
paging systems require high articulation for airports halls shopping centers,
and therefore more midrange energy.
• In Studio use to correct for the acoustics of the control room, equalize
instruments vocals etc. In Studio used for FilmNideo production equalizers
can be used to compensate for screen loss, reducing air-conditioning rumble
and other unwanted noise on soundtracks.
• In Broadcast applications most of the above are applicable,
equalizing landlines and satellite up links and down links.
as well as
4
1.4 Why use an Equalizer?
Equalization allows the user to differentiate the tone characteristics of the
signal being reproduced in an Audio chain or system. This can be for a variety of
reasons. These include:
• In Live Sound Systems (both fixed installation and portableltouring) to
correct for the frequency response of the environment in which the system is
being used in order to reduce feedback rings and howl round, to correct for
irregular room frequency response, to correct loudspeaker amplitude
response.
• In frxed installations equalizers can be used to tailor the frequency response
of the system. For example background music needs a smooth mellow
unobtrusive sound, and therefore less low and high frequency energy, while
paging systems require high articulation for airports halls shopping centers,
and therefore more midrange energy.
• In Studio use to correct for the acoustics of the control room, equalize
instruments vocals etc. In Studio used for FilmNideo production equalizers
can be used to compensate for screen loss, reducing air-conditioning rumble
and other unwanted noise on soundtracks.
• In Broadcast applications most of the above are applicable, as well as
equalizing landlines and satellite up links and down links.
4
1.5 The Decibel (dB)
The unit of decibel is used widely in sound engineering, often in
preference to other units such as volts, watts, or other units, since it is a
convenient way representing the ratio of one signal's amplitude to another [9]. It
is based on the logarithm of the ratio between two numbers. It also describes how
much larger or smaller one value is than the other one. If the reference value is
fIxed and known it can also be used as an absolute unit of measurement. In
different fields of sound engineering some standardized references have been
established for decibel scales.
The decibel is ten times the logarithm to the base ten of the ratio between
the power of two signal [10]:
The relationship to signal power must be taken into account if the decibel is used
to compare values other than signal powers. From Ohm's law it is known that
voltage has a square relationship to power [10]:
W=V'2/ R
Thus, to compare two voltages:
dB =10 log (V12/V:?) or
10 log (VJlV2)2 or
20 log (VI/ V2)
5
1.5 The Decibel (dB)
The unit of decibel is used widely in sound engineering, often in
preference to other units such as volts, watts, or other units, since it is a
convenient way representing the ratio of one signal's amplitude to another [9]. It
is based on the logarithm of the ratio between two numbers. It also describes how
much larger or smaller one value is than the other one. If the reference value is
fIxed and known it can also be used as an absolute unit of measurement. In
different fields of sound engineering some standardized references have been
established for decibel scales.
The decibel is ten times the logarithm to the base ten of the ratio between
the power of two signal [10]:
The relationship to signal power must be taken into account if the decibel is used
to compare values other than signal powers. From Ohm's law it is known that
voltage has a square relationship to power [10]:
W=V'2/ R
Thus, to compare two voltages:
dB = 10 log (V12/V:?) or
10 log (VJlV2)2 or
20 log (VI/ V2)
5
1.6 Project's Technical Data and Features
The technical data and features of this project is given as follows:
Input sensitivity: Auxiliary 1OOmV, Mic 1mV (maximum 10 mV) •
• Output level: Normal 2 V (maximum 5V)
• Power supply: +1- 18 to 50 V dc less than 100rnA (typical 50 rnA)
• Frequency response: +1- 0.2 dB (20-20kHz) to +1- 1 dB (20-20kHz)
• Frequency control: +1- at 30 Hz, 60 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz,
2 kHz, 4 kHz, 8 kHz and 16 kHz.
• 10 separated frequency controls with +1- 12 dB boosting or cutting effect
covering the whole audio range from 20 Hz to 20 kHz.
1.7 Report Overview
This report will cover 8 chapter which are summarized below:
• CHAPTER 2 will include the theory and concept apply in this project
• CHAPTER 3 will explain the components used for project implementation
and also the step required in implementing the project.
• CHAPTER 4 includes the project design of a 1O-band Graphic Equalizer.
• CHAPTER 5 consist of the troubleshooting done at the earlier stage to test
the circuit on the breadboard and later the circuit analysis of the project.
This chapter also gives detail explanation of how each part of the circuit
really work to produce an equalization effect.
• CHAPTER 6 is the list of problems encountered during the process of
" implementing the project and how they were solve in order to overcome
them.
• CHAPTER 7 are the recommendation given for future improvement and
finally the conclusion for the whole report and project implementation.
6
1.6 Project's Technical Data and Features
•
•
•
The technical data and features of this project is given as follows:
Input sensitivity:
Output level:
Power supply:
Auxiliary 1OOmV, Mic 1mV (maximum 10 mV)
Normal 2 V (maximum 5V)
+1- 18 to 50 V dc less than 100rnA (typical 50 rnA)
• Frequency response: +1- 0.2 dB (20-20kHz) to +1- 1 dB (20-20kHz)
• Frequency control: +1- at 30 Hz, 60 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz,
2 kHz, 4 kHz, 8 kHz and 16 kHz.
• 10 separated frequency controls with +1- 12 dB boosting or cutting effect
covering the whole audio range from 20 Hz to 20 kHz.
1.7 Report Overview
This report will cover 8 chapter which are summarized below:
• CHAPTER 2 will include the theory and concept apply in this project
• CHAPTER 3 will explain the components used for project implementation
and also the step required in implementing the project.
• CHAPTER 4 includes the project design of a 1O-band Graphic Equalizer.
• CHAPTER 5 consist of the troubleshooting done at the earlier stage to test
the circuit on the breadboard and later the circuit analysis of the project.
This chapter also gives detail explanation of how each part of the circuit
really work to produce an equalization effect.
• CHAPTER 6 is the list of problems encountered during the process of
" implementing the project and how they were solve in order to overcome
them.
• CHAPTER 7 are the recommendation given for future improvement and
finally the conclusion for the whole report and project implementation.
6
CHAPTER 2
PROJECT THEORY AND CONCEPT
2.1 The Concept of Equalization
Sound system equalization is a process of adjusting the electronic
frequency response of a system to compensate for the response of an odd
loudspeaker and room acoustic. The goals of equalization are to provide a natural
sounding system with a good sound quality and to minimize feedback that might
be caused by peaks in the frequency response. In entertainment sound
reinforcement systems, equalization may also be used to enhance the sound
quality, for example, a nasal-sounding performer's voice. This use of equalization
is very different from the other uses and, in general, it is better to avoid using the
same equalizer to both equalize the overall system and provide enhancement of
an individual performer.
2.1.1 Anothe.t !toint of View on Equalization
A number of sound system designers now believe that the primary
purpose of equalization should be to remove frequency-response peaks from the
system loudspeakers. A secondary purpose, according to this viewpoint, is to roll
off the low and high frequency response to make the system subjectively sounds
better [7]. The high-frequency roll-off is used, if needed, to reduce an overly
sibilant sound quality. The low-frequency roll-off is used, if needed, to reduce the
boom sound quality in rooms with long RT60 at low frequencies.
7
CHAPTER 2
PROJECT THEORY AND CONCEPT
2.1 The Concept of Equalization
Sound system equalization is a process of adjusting the electronic
frequency response of a system to compensate for the response of an odd
loudspeaker and room acoustic. The goals of equalization are to provide a natural
sounding system with a good sound quality and to minimize feedback that might
be caused by peaks in the frequency response. In entertainment sound
reinforcement systems, equalization may also be used to enhance the sound
quality, for example, a nasal-sounding performer's voice. This use of equalization
is very different from the other uses and, in general, it is better to avoid using the
same equalizer to both equalize the overall system and provide enhancement of
an individual performer.
2.1.1 Anothe.t !toint of View on Equalization
A number of sound system designers now believe that the primary
purpose of equalization should be to remove frequency-response peaks from the
system loudspeakers. A secondary purpose, according to this viewpoint, is to roll
off the low and high frequency response to make the system subjectively sounds
better [7]. The high-frequency roll-off is used, if needed, to reduce an overly
sibilant sound quality. The low-frequency roll-off is used, if needed, to reduce the
boom sound quality in rooms with long RT60 at low frequencies.
7
In other words, by this philosophy, equalization has little to do with the
room and a flat-response loudspeaker system will eliminate the need for
extensive equalization in many cases.
2.1.2 What Equalization Can and Cannot Do
Equalization can make a well-designed sound system to become better. It
can improve sound quality by smoothing the frequency response or by
deliberately peaking response in the intelligibility frequencies (approximately
1500 to 5000 Hz) [7], Equalization can also help minimize the feedback caused by
frequency response irregularities.
Equalization cannot make a poorly designed system sound good.
Equalization cannot significantly improve the sound quality of low cost paging
type drivers or to make any other poor-sounding loudspeaker sound significantly
better. Equalization also cannot affect the reverberation time in a room in any
other way.
Equalization cannot significantly improve a feedback problem in a room
where the potential acoustic gain (FAG) is unacceptable. And, equalization
cannot solve system response problems when those problems are caused by signal
alignment irregularities.
8
In other words, by this philosophy, equalization has little to do with the
room and a flat-response loudspeaker system will eliminate the need for
extensive equalization in many cases.
2.1.2 What Equalization Can and Cannot Do
Equalization can make a well-designed sound system to become better. It
can improve sound quality by smoothing the frequency response or by
deliberately peaking response in the intelligibility frequencies (approximately
1500 to 5000 Hz) [7], Equalization can also help minimize the feedback caused by
frequency response irregularities.
Equalization cannot make a poorly designed system sound good.
Equalization cannot significantly improve the sound quality of low cost paging
type drivers or to make any other poor-sounding loudspeaker sound significantly
better. Equalization also cannot affect the reverberation time in a room in any
other way.
Equalization cannot significantly improve a feedback problem in a room
where the potential acoustic gain (FAG) is unacceptable. And, equalization
cannot solve system response problems when those problems are caused by signal
alignment irregularities.
8