francis abligado bujet graphic... · 2014-05-20 · to-band graphic equalizer . francis abligado...

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


3.4.3 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



3.4.3 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(c); Output at Capacitor, C2 (30 Hz) 65

xu

Figure 5.6(a): Input at Auxiliary (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 5.1O(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. 12(a); Input at Auxiliary (4 kHz) 72

)-igure 5.12(b): Channel Output (4 kHz) 72


xiii




Figure 5. 7 (a): Input at Auxiliary (125 Hz) 67









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

---.--.~----------------







xiv







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


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


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.


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.


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

francis abligado bujet graphic... · 2014-05-20 · to-band graphic equalizer . francis abligado...

Documents