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Old 11th November 2013, 05:29 AM   #11
whgeiger is offline whgeiger  United States
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Quote:
Originally Posted by whgeiger View Post
... recommend Marshall Leach's Book

INTRODUCTION TO ELECTROACOUSTICS AND AUDIO AMPLIFIER DESIGN: Jr. W. Marshall Leach: 9780757503757: Amazon.com: Books

Regards,

WHG

P.S. The pricing at Amazon is absurd! Will find a seller elswhere or provide a free copy if you want it.
Buy Introduction To Electroacoustics and Audio Amplifier Design (9780757572869) @BiggerBooks.com

https://www.kendallhunt.com/store-product.aspx?id=68126
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Old 11th November 2013, 09:57 AM   #12
tvrgeek is offline tvrgeek  United States
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Leach is not a place to begin. D'Apolitto or Toole is. In the long term, yes understanding the amplifier is important as it is part of the system. Just not where you start.
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Old 11th November 2013, 12:28 PM   #13
forr is offline forr  France
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This is not really a technical book but it clarifies many ideas about what we can expect from music reproduction by loudspeakers (which is the prior question, isn't ?). It is easy to read :

Loudspeakers: For Music Recording and Reproduction - Philip Richard Newell, K. R. Holland - Google Livres
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Old 11th November 2013, 01:11 PM   #14
Brian77223 is offline Brian77223  United States
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Thanks for the replies, Now the hard part is deciding which one to start on!

-Brian
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Old 11th November 2013, 06:55 PM   #15
tvrgeek is offline tvrgeek  United States
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The free ones on the WEB while waiting for your copy of D'Apiltto.
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Old 11th November 2013, 10:13 PM   #16
whgeiger is offline whgeiger  United States
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Default Nonsense!

Quote:
Originally Posted by tvrgeek View Post
Leach is not a place to begin. D'Apolitto or Toole is. In the long term, yes understanding the amplifier is important as it is part of the system. Just not where you start.
Only the LAST of twelve chapters is devoted to the "amplifier".

Obviously, you have not read the book, yet you pass judgment on the recommendations of those that have.

I have provided the table of contents below, so that no doubt remains about Leach's comprehensive treatment of the subject of electro-acoustics.

WHG

Title: Introduction to Electroacoustics and Audio Amplifier Design, Third Edition.
Author: W. Marshall Leach, Jr.
Contents:

1 Basic Principles of Sound 1
1.1 Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Sources of Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Velocity of Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Frequency of Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.5 Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.6 Human Speech . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.7 Frequency Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.8 Audio Sub Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.9 Sound Pressure Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.10 Equal Loudness Contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.11 Loudness Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.12 Audio Test Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.13 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2 Fundamentals of Acoustics 15
2.1 Basic Equations of Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2 The AcousticWave Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.3 The PlaneWave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.4 Specific Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5 Acoustic Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.6 Acoustic Intensity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.7 Wavelength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.8 Particle Displacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.9 The Omni-Directional Spherical Wave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.10 Volume Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.11 The Simple Spherical Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.12 Acoustic Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.13 The Plane Circular Piston . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.14 The Pattern Beamwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.15 Fresnel Diffraction Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.16 Acoustic Reflections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.17 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

3 Analogous Circuits of Acoustical Systems 33
3.1 Acoustic Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.2 Acoustic Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.3 The PlaneWave Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.4 Acoustic Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.5 Acoustic Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.6 AcousticMass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.7 Acoustic Impedance on a Piston in a Baffle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.8 Acoustic Impedance on a Piston in a Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.9 Radiation Impedance on a Piston in Free Air . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.10 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

4 Analogous Circuits of Mechanical Systems 49
4.1 Mechanical Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.2 Mass, Compliance, and Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.3 Mechanical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.4 Moving-Coil Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.5 Crystal Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.6 Condenser Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.7 Mechano-Acoustic Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.8 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

5 Microphones 63
5.1 Classifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
5.2 Modeling Diaphragm Reflections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.3 DiaphragmBack Acoustical Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.4 DiaphragmMechanical Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
5.5 CondenserMicrophone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
5.6 CondenserMicrophone SPICE Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5.7 Condenser Microphone Buffer Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.8 DynamicMicrophone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.9 RibbonMicrophone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.10 Proximity Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5.11 CombinationMicrophone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.12 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

6 Moving-Coil Loudspeakers 85
6.1 Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
6.2 Analogous Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6.3 Combination Analogous Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.4 Infinite Baffle Analogous Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.5 Low-Frequency Solution for UD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
6.6 Low-Frequency Bode Plots for UD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
6.7 Small-Signal Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.8 High-Frequency Solution for UD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.9 On-Axis Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
6.10 Pressure Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
6.11 Bode Plots ofOn-Axis Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
6.12 Filter Theory Description of G (s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.13 Cutoff Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.14 Effect of Non-Zero Generator Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.15 Frequency of Peak Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
6.16 Voice-Coil Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
6.17 The Lossy Voice-Coil Inductance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
6.18 On-Axis Pressure Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
6.19 Acoustic Power Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
6.20 Reference Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
6.21 DiaphragmDisplacement Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
CONTENTS v
6.22 Voice-Coil Electrical Power Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
6.23 Displacement Limited Power Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
6.24 SPICEModels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
6.25 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

7 Closed-Box Loudspeaker Systems 113
7.1 Modeling the Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
7.2 The Analogous Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
7.3 The Volume Velocity Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
7.4 The On-Axis Pressure Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
7.5 Effect of the Box on the SystemResponse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
7.6 Sensitivity of the Lower Cutoff Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
7.7 SystemDesign with a Given Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
7.8 System Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
7.9 System Design From Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
7.10 A SPICE Simulation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
7.11 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

8 Vented-Box Loudspeaker Systems 127
8.1 Modeling the Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
8.2 Effect of the Vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
8.3 The On-Axis Pressure Transfer Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
8.4 Voice-Coil Impedance Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.5 TheMagnitude-Squared Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
8.6 The B4 Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
8.7 The QB3 Alignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
8.8 The Chebyshev Alignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
8.9 Example Pressure Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
8.10 Design with a Given Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
8.11 System Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
8.12 Design from Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
8.13 Vented-Box SPICE Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
8.14 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

9 AcousticHorns 147
9.1 TheWebster Horn Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
9.2 Salmon’s Family of Horns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
9.3 Finite Length Horn Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
9.4 AHorn Analogous Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
9.5 SPICE Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
9.6 Horn Driving Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
9.7 Mid-Frequency Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
9.8 Condition for Maximum PAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
9.9 The Horn Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
9.10 The Low-Frequency Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
9.11 The High-Frequency Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
9.12 Low-Frequency SystemDesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
9.12.1 Design with aGiven Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
9.12.2 System Design from Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
9.13 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

10 Crossover Networks 163
10.1 Role of Crossover Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
10.2 Passive Crossover Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
10.3 L-Pad Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
10.4 Effect of the Voice-Coil Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
10.5 Effect of the Driver Phase Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
10.6 Constant-Voltage and All-Pass Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
10.7 Active Crossover Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
10.8 A SPICEModeling Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
10.9 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

11 A Loudspeaker Potpourri 187
11.1 The Isobaric Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
11.1.1 The Acoustical Analogous Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
11.1.2 The Small-Signal Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
11.1.3 SPICE Simulation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
11.2 4th-Order Bandpass Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
11.2.1 System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
11.2.2 Output Volume Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
11.2.3 On-Axis Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
11.2.4 Fourth-Order Band-Pass Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
11.2.5 System Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
11.2.6 Design with aGivenDriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
11.3 6th-Order Bandpass Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
11.3.1 System Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
11.3.2 System Alignment Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
11.3.3 System Design from Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
11.3.4 Example SystemDesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
11.4 Passive Radiator Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
11.4.1 System Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
11.4.2 Example SystemDesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
11.5 Assisted Vented-Box Alignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
11.5.1 System Transfer Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
11.5.2 5th-Order Alignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
11.5.3 6th-Order Alignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
11.5.4 The Vented-Box SystemParameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
11.5.5 Example Design from Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
11.6 A Closed-Box System Equalizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
11.6.1 Equalizer Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
11.6.2 Equalizer Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
11.6.3 Example Realization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
11.7 Driver ParameterMeasurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
11.7.1 Basic Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
11.7.2 TheMeasurement Test Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
11.7.3 Measuring RE , fS , QMS , QES, and QT S . . . . . . . . . . . . . . . . . . . . . . . . . 210
11.7.4 Measuring VAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
11.7.5 Conversion to Infinite-Baffle Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 212
11.7.6 Measuring the Voice-Coil Inductance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
11.8 ParameterMeasurement Summary Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

12 Audio Power Amplifiers 217
12.1 Power Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
12.2 Effects of Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
12.2.1 Feedback Amplifier Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
12.2.2 Effect of Feedback on Distortion and Noise . . . . . . . . . . . . . . . . . . . . . . . . 220
12.2.3 Effect of Feedback on Output Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . 220
12.3 AmplifierModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
12.3.1 Open-Loop Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
12.3.2 Gain Bandwidth Product . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
12.3.3 Slew Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
12.3.4 Relations between SlewRate and Gain-Bandwidth Product . . . . . . . . . . . . . . . 224
12.3.5 Closed-Loop Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
12.3.6 Transient Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
12.3.7 Input Stage Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
12.3.8 Full Power Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
12.3.9 Effect of an Input Low-Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
12.3.10 JFET Diff Amp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
12.3.11 Diff Amp with Current-Mirror Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
12.4 Signal Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
12.5 The Stability Criterion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
12.5.1 The Bode Stability Theorem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
12.5.2 Single-Pole Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
12.5.3 Two-Pole Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
12.5.4 An Alternate Stability Criterion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
12.6 Techniques for Compensating Feedback Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . 242
12.6.1 Gain Constant Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
12.6.2 First Pole Lag Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
12.6.3 Second Pole Lead Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
12.6.4 Feedforward Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
12.7 Output Stage Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
12.7.1 Common-Collector Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
12.7.2 Common-Emitter Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
12.7.3 Quasi-ComplementaryOutput Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
12.7.4 MOSFET Output Stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
12.8 Voltage Gain Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
12.9 Input Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
12.10 Completed Amplifier Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
12.11 Protection Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
12.11.1 BJT Protection Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
12.11.2 MOSFET Protection Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
12.12 Power Supply Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
12.13 Decoupling and Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
12.14 Power Dissipation and Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
12.15 The Class-D Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
12.16 AmplifierMeasurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
12.17 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
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Old 12th November 2013, 07:24 PM   #17
tvrgeek is offline tvrgeek  United States
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Join Date: Dec 2009
Location: North Carolinia/Piedmont
WHG,
"Not a place to start"

http://www.amazon.com/INTRODUCTION-E...Marshall+Leach
is why I have only skimmed it in a library. $1800

Last edited by tvrgeek; 12th November 2013 at 07:30 PM.
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Old 13th November 2013, 01:23 AM   #18
whgeiger is offline whgeiger  United States
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Join Date: May 2004
Location: Pensacola, Florida
Default Disinformation

Quote:
Originally Posted by tvrgeek View Post
WHG,
"Not a place to start"

INTRODUCTION TO ELECTROACOUSTICS AND AUDIO AMPLIFIER DESIGN: Jr. W. Marshall Leach: 9780757503757: Amazon.com: Books
is why I have only skimmed it in a library. $1800
.. will not 'save the day' for you. You parrot an URL link already provided and characterized by me as "absurd". The works of d'Apolito & Toole which I have read and studied as well, are certainly not works for beginners. The work of Leach is succinct and embodies and distills that presented earlier by Olson, Beranek, Thiel & Small as well as others. The only requirement is that the reader have a minimum mathematical skill of a high school student who has passed an advanced algebra course. Bottom line: you have not read the book that you say is “not a place to start”. That dog is not hunting well here for you.

WHG

Here is what Leach has to say about the purpose of this work:

Preface
This book is an outgrowth of a senior level elective course in audio engineering that I have taught to
electrical engineering students at the Georgia Institute of Technology. The first part of the book covers basic
acoustics. The emphasis is on that part of acoustics that pertains to the field of audio engineering. Most
of the remainder of the book concerns the application of the tools of electroacoustics to the analysis and
synthesis of microphones, loudspeakers, crossover networks, and acoustic horns. The book also concludes
with a chapter that covers the basic theory of audio amplifier design.
Electroacoustics is that part of acoustics that pertains to the modeling of acoustical systems with electrical
circuits. Because most acoustical devices have a mechanical part, the modeling of mechanical systems with
electrical circuits is a basic part of electroacoustics. Separate chapters in the book are devoted to analogous
circuits of mechanical systems and to analogous circuits of acoustical systems. The traditional approach in
these circuits has been to use transformers to model the coupling between the electrical, the mechanical, and
the acoustical parts. A major departure in this book is the use of controlled sources to model the coupling.
An advantage of this approach is that it avoids the need for mobility analogs. In addition, I have found that
students have much less difficulty with the approach. Perhaps this is because the controlled-source circuits
are more intuitive than the transformer circuits. The circuits can be easily analyzed with circuit simulation
software such as SPICE.
Electroacoustic models are developed for the more common microphone types and for the moving-coil
loudspeaker driver. Separate chapters cover closed-box and vented-box loudspeaker systems. Although
the emphasis is on basic system theory, practical methods of design are also presented. Because crossover
networks are such an important part of loudspeaker systems, a chapter is devoted to crossover networks.
Acoustic horns are a vital component in public address systems. A chapter is devoted to horn models.
A chapter entitled “A Loudspeaker Potpourri” covers topics such as the isobaric loudspeaker connection,
band-pass systems, passive-radiator systems, equalized systems, and loudspeaker parameter measurements.
In all cases, SPICE simulation examples are presented where appropriate.
One might ask why a chapter on audio amplifiers is included in a book that is primarily concerned with
electroacoustics. Without a power amplifier, a loudspeaker could not make sound. Therefore, one might
say that the role of an amplifier in a system is just as important as the role of a loudspeaker. The chapter
on amplifiers is not intended to be an in-depth chapter on electronic theory. Instead, it addresses the more
important aspects of amplifier design with an emphasis on the basic operation of the circuits. Practical
examples are presented that illustrate how some of the pitfalls of amplifier design can be avoided.
>snip<
An errata and updates can be found at An Introduction to Electroacoustics and Audio Amplifier Design.
W. Marshall Leach, Jr.
April 2003
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Old 13th November 2013, 07:57 PM   #19
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: North Carolinia/Piedmont
WHG, chill! I am not trying to gore your favorite book, just suggest that starting with the quality online sources is a better place to start, and my experience is that really understanding what you are measuring is very important or you won't be able to put to use everything else you learn.

As the OP is an engineer, he will have no trouble with D'Apolitto, and probably no trouble with Linkwitz or any of the ASE papers as we don't need to explain imaginary numbers to him.
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Old 13th November 2013, 09:28 PM   #20
whgeiger is offline whgeiger  United States
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Join Date: May 2004
Location: Pensacola, Florida
Default Beranek's "Acoustics", Revised

Has anyone here read this book?
If so, comments please.
Regards,
WHG

Title: Acoustics: Sound Fields and Transducers
Author (1): Lep L. Beranek
Author (2): Tim Mellow
Date: October 4, 2012
ISBN-10: 0123914213 |
ISBN-13: 978-0123914217
Edition: 1
Abstract: A thoroughly updated version of Leo Beranek's classic 1954 book that retains and expands on the original's detailed acoustical fundamentals while adding practical formulas and simulation methods.
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