Acoustics : sound fields, transducers and vibration

Acoustics sound fields, transducers and vibration

Acoustics: Sound Fields, Transducers and Vibration, Second Edition guides readers through the basics of sound fields, the laws governing sound generation, radiation, and propagation, and general terminology. Specific sections cover microphones (electromagnetic, electrostatic, and ribbon), earphones,...

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Detalles Bibliográficos
Otros Autores: Beranek, Leo L., author (author), Mellow, Tim J., author
Formato: Libro electrónico
Idioma:Inglés
Publicado: London, England : Academic Press [2019]
Edición:Second edition
Materias:
So > Enregistrament i reproducció
Electroacústica
Electro-acoustics.
Sound > Recording and reproducing.
Ver en Biblioteca Universitat Ramon Llull:https://discovery.url.edu/permalink/34CSUC_URL/1im36ta/alma991009630612306719
Tabla de Contenidos:
  • Front Cover
  • ACOUSTICS: SOUND FIELDS, TRANSDUCERS AND VIBRATION
  • Cover Details
  • ACOUSTICS: SOUND FIELDS, TRANSDUCERS AND VIBRATION
  • Copyright
  • CONTENTS
  • PREFACE TO THE SECOND EDITION
  • PREFACE TO THE FIRST EDITION
  • ACKNOWLEDGMENTS
  • One - Introduction and terminology
  • I: INTRODUCTION
  • 1.1 A LITTLE HISTORY
  • 1.2 WHAT IS SOUND?
  • 1.3 PROPAGATION OF SOUND THROUGH GAS
  • 1.4 MEASURABLE ASPECTS OF SOUND
  • PART II: TERMINOLOGY
  • 1.5 GENERAL
  • Acoustic
  • Acoustical
  • Imaginary unit
  • Harmonically varying quantity
  • Instantaneous value
  • Root mean square value
  • 1.6 STANDARD INTERNATIONAL (SI) UNITS
  • 1.7 PRESSURE AND DENSITY
  • Static pressure (P0)
  • Microbar (μbar)
  • Instantaneous sound pressure [p(t)]
  • Effective sound pressure (prms)
  • Density of air (ρ0)
  • 1.8 SPEED AND VELOCITY
  • Speed of sound (c)
  • Instantaneous particle velocity (particle velocity) [u(t)]
  • Effective particle velocity (urms)
  • Instantaneous volume velocity [U(t)]
  • 1.9 IMPEDANCE
  • Acoustic impedance (ZA) (American standard acoustic impedance)
  • Specific acoustic impedance (Zs)
  • Mechanical impedance (ZM)
  • Characteristic impedance (ρ0c)
  • 1.10 INTENSITY, ENERGY DENSITY, AND LEVELS
  • Sound intensity (I)
  • Sound energy density (D)
  • Electric power level or acoustic intensity level
  • Sound pressure level
  • Intensity level (IL)
  • Acoustic power level (PWL)
  • Sound level
  • Band power level (PWLn)
  • Band pressure level (BPLn)
  • Power spectrum level
  • Pressure spectrum level
  • NOTES
  • Two - The wave equation and solutions
  • III: THE WAVE EQUATION
  • 2.1 INTRODUCTION
  • 2.2 DERIVATION OF THE WAVE EQUATION
  • 2.2.1 The equation of motion
  • 2.2.2 The gas law
  • 2.2.3 The continuity equation
  • 2.2.4 The wave equation in rectangular coordinates
  • 2.2.5 The wave equation in cylindrical coordinates.
  • 2.2.6 The wave equation in spherical coordinates
  • 2.2.7 General one-dimensional wave equation (Webster's equation) [6]
  • IV: SOLUTIONS OF THE WAVE EQUATION IN ONE DIMENSION
  • 2.3 GENERAL SOLUTIONS OF THE ONE-DIMENSIONAL WAVE EQUATION
  • 2.3.1 General solution
  • 2.3.2 Steady-state solution
  • 2.4 SOLUTION OF WAVE EQUATION FOR AIR IN A TUBE TERMINATED BY AN IMPEDANCE
  • Particle velocity
  • Transmitted and reflected pressures
  • Impedance
  • Impedance measurement
  • Rigid termination (infinite impedance)
  • Sound pressure
  • Specific acoustic impedance
  • 2.5 IMPEDANCE OF A CLOSED TUBE USING THE INHOMOGENEOUS WAVE EQUATION
  • Boundary conditions
  • Solution of the inhomogeneous wave equation for a closed tube
  • Impedance of the closed tube
  • Expansions for cot and csc
  • 2.6 IMPEDANCE OF AN OPEN TUBE USING THE INHOMOGENEOUS WAVE EQUATION
  • Solution of the inhomogeneous wave equation for an open tube
  • Impedance of the open tube
  • Expansion for tan
  • 2.7 SOLUTION OF WAVE EQUATION FOR AIR IN A TUBE FILLED WITH ABSORBENT MATERIAL
  • 2.8 FREELY TRAVELING PLANE WAVE
  • Sound pressure
  • Particle velocity
  • Specific acoustic impedance
  • 2.9 FREELY TRAVELING CYLINDRICAL WAVE
  • Sound pressure
  • Particle velocity
  • Specific acoustic impedance
  • 2.10 FREELY TRAVELING SPHERICAL WAVE
  • Sound pressure
  • Particle velocity
  • Specific acoustic impedance
  • V: SOLUTIONS OF THE HELMHOLTZ WAVE EQUATION IN THREE DIMENSIONS
  • 2.11 RECTANGULAR COORDINATES
  • The plane wave equation in x
  • The plane wave equation in y
  • The plane wave equation in z
  • 2.12 CYLINDRICAL COORDINATES
  • The radial equation in w
  • The azimuthal equation in φ
  • The axial equation in z
  • 2.13 SPHERICAL COORDINATES
  • The radial equation in r
  • The inclination equation in θ
  • The azimuth equation in φ
  • NOTES
  • Three - Electromechanoacoustical circuits.
  • VI: MECHANICAL CIRCUITS
  • 3.1 INTRODUCTION
  • 3.2 PHYSICAL AND MATHEMATICAL MEANINGS OF CIRCUIT ELEMENTS
  • 3.3 MECHANICAL ELEMENTS
  • Mechanical impedance ZM and mechanical admittance YM
  • Mass MM
  • Mechanical compliance CM
  • Mechanical resistance RM and mechanical conductance GM
  • Mechanical generators
  • Levers
  • Simple lever
  • Floating lever
  • VII: ACOUSTICAL CIRCUITS
  • 3.4 ACOUSTICAL ELEMENTS
  • Acoustic mass MA
  • Acoustic compliance CA
  • Acoustic resistance RA and acoustic conductance GA
  • Acoustic generators
  • Mechanical rotational systems
  • VIII: TRANSDUCERS
  • 3.5 ELECTROMECHANICAL TRANSDUCERS
  • Electromagnetic-mechanical transducer
  • Electrostatic-mechanical transducer
  • 3.6 MECHANOACOUSTIC TRANSDUCER
  • 3.7 EXAMPLES OF TRANSDUCER CALCULATIONS
  • IX: CIRCUIT THEOREMS, ENERGY, AND POWER
  • 3.8 CONVERSION FROM ADMITTANCE-TYPE ANALOGIES TO IMPEDANCE-TYPE ANALOGIES
  • 3.9 THÉVENIN'S THEOREM
  • 3.10 TRANSDUCER IMPEDANCES
  • Transmission matrix for an electrical two-port network
  • Transmission matrix for an electromagnetic-mechanical transducer
  • Impedance matrix for an electromagnetic-mechanical transducer
  • Transmission matrix for an electrostatic-mechanical transducer
  • Impedance matrix for an electrostatic-mechanical transducer
  • Analogous circuits for the two-port network using z-parameters [12]
  • NOTES
  • Four - Acoustic components
  • 4.1 INTRODUCTION
  • X: ACOUSTIC ELEMENTS
  • 4.2 ACOUSTIC MASS (INERTANCE)
  • Tube of medium diameter
  • 4.3 ACOUSTIC COMPLIANCES
  • Limitations on an acoustic compliance
  • Series acoustic compliance
  • 4.4 ACOUSTIC RESISTANCES
  • Tube of small diameter [0.005&lt
  • l&lt
  • radius a (in meters)&lt
  • 0.002/f] [1]
  • Narrow slit [2] [t (in meters)&lt
  • 0.003/f]
  • 4.5 CAVITY WITH HOLES ON OPPOSITE SIDES-MIXED MASS-COMPLIANCE ELEMENT.
  • 4.6 INTERMEDIATE-SIZED DUCTS-MIXED MASS-RESISTANCE ELEMENTS
  • Medium tube [a (in meters) 0.01/f and a &lt
  • 10/f] [3,4]
  • Medium slit [t (in meters) 0.02/f and t&lt
  • 20/f] [5]
  • 4.7 PERFORATED SHEET-MIXED MASS-RESISTANCE ELEMENT [A (IN METERS) 0.01/F AND A&lt
  • 10/F] [3,4]
  • Definition of Q
  • 4.8 ACOUSTIC TRANSFORMERS
  • Junction of two pipes of different areas
  • Two pipes of different areas joined by an exponential connector [6]
  • XI: ELEMENTARY REFLECTION AND RADIATION OF SOUND
  • 4.9 REFLECTION OF A PLANE WAVE FROM A PLANE
  • 4.10 RADIATION FROM A PULSATING SPHERE
  • Radiation impedance
  • 4.11 RADIATION FROM A MONOPOLE POINT SOURCE (SIMPLE SOURCE)
  • Pressure and particle velocity
  • Strength of a point source [6]
  • Intensity at distance r
  • 4.12 COMBINATION OF POINT SOURCES
  • Two point sources
  • Linear array of point sources
  • 4.13 STEERED BEAM-FORMING ARRAY OF POINT SOURCES
  • 4.14 DIPOLE POINT SOURCE (DOUBLET)
  • Near-field and far-field
  • 4.15 RADIATION FROM AN OSCILLATING SPHERE
  • Near-field pressure
  • Far-field pressure
  • Radiation impedance
  • XII: DIRECTIVITY INDEX
  • 4.16 DIRECTIVITY INDEX AND DIRECTIVITY FACTOR
  • Directivity factor [Q(f)]
  • Directivity index [DI(f)]
  • Calculation of Q(f) and DI(f)
  • XIII: RADIATION IMPEDANCES
  • 4.17 PULSATING SPHERE
  • 4.18 OSCILLATING SPHERE
  • 4.19 PLANE CIRCULAR PISTON IN INFINITE BAFFLE
  • Approximate analogous circuits
  • Low- and high-frequency approximations
  • 4.20 PLANE CIRCULAR FREE DISK
  • 4.21 PLANE CIRCULAR PISTON RADIATING FROM ONE SIDE ONLY IN FREE SPACE
  • XIV: VISCOUS AND THERMAL LOSSES
  • 4.22 SOUND IN LOSSY TUBES
  • 4.23 WAVE EQUATION FOR AN INFINITE LOSSY TUBE
  • Assumptions
  • Categories
  • The momentum conservation equation
  • Thermal conduction (entropy) and the gas law
  • Solution of the velocity and temperature radial equations.
  • Mass conservation and Helmholtz wave equation
  • Dynamic density
  • Dynamic compressibility
  • Wave number and characteristic impedance
  • 4.24 FINITE LOSSY TUBES
  • A two-port network for a finite tube of any length [13]
  • A two-port network for a short finite tube
  • A two-port network for a short finite tube using approximate discrete elements
  • Regimes for an open-ended tube
  • Ultra-narrow tube
  • REFERENCES
  • Five - Microphones
  • XV: GENERAL CHARACTERISTICS OF MICROPHONES
  • 5.1 PRESSURE MICROPHONES
  • 5.2 PRESSURE-GRADIENT MICROPHONES
  • 5.3 COMBINATION OF PRESSURE AND PRESSURE-GRADIENT MICROPHONES
  • XVI: PRESSURE MICROPHONES
  • 5.4 ELECTROMAGNETIC MOVING-COIL MICROPHONE (DYNAMIC MICROPHONE)
  • General features
  • Construction
  • Electro-mechano-acoustical relations
  • Performance
  • 5.5 ELECTROSTATIC MICROPHONE (CAPACITOR MICROPHONE)
  • General features
  • Construction
  • Electromechanical relations
  • Analogous circuits
  • Acoustical relations
  • Performance
  • XVII: PRESSURE-GRADIENT MICROPHONES
  • 5.6 ELECTROMAGNETIC RIBBON MICROPHONES
  • General features
  • Construction
  • Analogous circuit
  • Performance
  • XVIII: COMBINATION MICROPHONES
  • 5.7 ELECTRICAL COMBINATION OF PRESSURE AND PRESSURE-GRADIENT TRANSDUCERS
  • 5.8 ACOUSTICAL COMBINATION OF PRESSURE AND PRESSURE-GRADIENT MICROPHONES
  • 5.9 DUAL-DIAPHRAGM COMBINATION OF PRESSURE AND PRESSURE-GRADIENT MICROPHONES
  • Omnidirectional performance
  • Bidirectional performance
  • Unidirectional performance
  • Condition for equal sensitivity in all three switch positions
  • Condition for stability
  • NOTES
  • Six - Electrodynamic loudspeakers
  • XIX: BASIC THEORY OF ELECTRODYNAMIC LOUDSPEAKERS
  • 6.1 INTRODUCTION
  • 6.2 CONSTRUCTION [2]
  • 6.3 ELECTRO-MECHANO-ACOUSTICAL CIRCUIT
  • Voice-coil velocity at medium and low frequencies
  • Voice-coil velocity at low frequencies.
  • 6.4 POWER OUTPUT.

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