Electroacoustic transducers

We can all see how quickly electroacoustic transducers change, i.e. microphones, headphones, loudspeakers and loudspeakers. New technical and technological solutions are introduced that have an impact on the production, processing and reproduction of sound.
There is no position on the Polish market in which the current state of knowledge on electroacoustic processing technology will be thoroughly discussed. This book fills this gap. It provides general information about waves and acoustic systems as well as mechanical vibrations. The theory of modeling acoustic and mechanical systems is presented. The principles of operation of electromechanical and electroacoustic transducers, both reversible and irreversible, have been described. A lot of space was devoted to loudspeakers, headphones and microphones. The methodology for measuring electroacoustic transducers is also presented.
The book is intended for students and academics of such specialties as acoustics, telecommunications, radio communications, multimedia techniques, sound engineering and sound engineering. It will also be used by people looking for answers to many questions related to the use of electroacoustic systems and conditions for receiving sound effects. It will also be useful for the average users of increasingly sophisticated audiovisual equipment - be it a recording studio or a home cinema.

Table of Contents

From the author

List of important markings

1. Introduction

Literature

2. Waves and acoustic systems

2.1. Acoustic waves
2.2. Wave energy and sound intensity 2.3. Spherical wave and acoustic dipole
2.4. Source radiation
2.5. Deflection of the wave
2.6. waveguides
2.7. resonators
2.8. Acoustic systems with fixed constants
Literature

3. Vibration of mechanical systems

3.1. Introduction
3.2. A system with one degree of freedom
3.2.1. Free vibrations
3.2.2. Small damped vibrations
3.2.3. Vibrations forced
3.2.4. Non-linear vibrations
3.3. Systems with more degrees of freedom
3.4. Continuous systems
3.4.1. String
3.4.2. Rod
3.4.3. Beam
3.4.4. Membrane
3.4.5. Plate
3.4.6. Coatings
Literature

4. Modeling of electrical, mechanical and acoustic systems

4.l. Elements of modeling theory and basic knowledge from the theory of electrical circuits
4.2. filters
4.3. Electromechanical analogies
4.4. Electroacoustic analogies
4.5. Acoustic filters
4.6. Computer methods of modeling of mechanoacoustic systems
4.6.l. Finite element method
4.6.2. The method of boundary integrals
4.6.2.1. Integral formulas of sound radiation
4.6.2.2. Elements of Fredholm's theory of linear integral equations
4.6.2.3. Integral equations of the sound radiation theory
4.6.2.4. Methods for solving radiation problems
near the characteristic wave numbers
4.6.3. Coupling of vibrations and radiation
4.6.4. Examples of calculations
Literature

5. Operating principles of electromechanical converters

5.1. Introduction. Classification of electromechanical transducers
5.2. Theory of linear converters
5.3. Transducers of magnetic type
5.3.1. Magnetoelectric transducer
5.3.2. Electromagnetic transducer
5.3.3. Magnetostrictive (piezomagnetic) transducer
5.4. Electric type transducers
5.4.1. Electrostatic transducer
5.4.2. Piezoelectric transducer
5.5. Irreversible transducers
5.5.1. Piezoresistive transducers
5.5.2. Electronic transducers
5.5.3. Optomechanical transducers
5.5.4. Pneumatic transmitter
5.6. Direct electroacoustic processing
5.6.1. Introduction
5.6.2. Pickups with Dirichlet's surface condition
5.6.3. Volumetric transducers
5.6.3.1. Jonofony
5.6.3.2. Volumetric electrotherapeutic transducers
5.6.3.3. Volumetric magnetohydrodynamic transducers
5.6.3.4. Parametric antennas
Literature

6. Speakers and headphones

6.1. Introduction
6.2. Magnetoelectric coil loudspeaker open
6.2.l. Speaker construction
6.2.2. Speaker operation in the range of small and medium frequencies
6.2.2.1. Frequency characteristics of the loudspeaker
6.2.2.2. Optimization of loudspeaker reference efficiency
6.2.3. Speaker operation in the field of high frequencies
6.2.3.1. Impact of coil inductance
6.2.3.2. The effect of membrane non-planarity
6.2.3.3. Impact of membrane flexibility
6.2.4. Speaker operation with large signals
6.2.4.1. Thermal limitations of the loudspeaker power
6.2.4.2. Speaker power limitations
Nonlinear distortions
6.3. Ribbon speaker and isodynamic speaker
6.4. Magnetoelectric horn loudspeaker
6.4.l. The principle of work
6.4.2. Analysis of the properties of a horn magnetoelectric loudspeaker
6.4.3. Designing tubes for horn loudspeakers
6.5. Manger speaker and multimode speaker
6.5. Electrostatic speaker
6.7. Piezoelectric speaker
6.8. Headphones
Literature

7. Housings and loudspeaker sets

7.1. Introduction
7.2. The baffle is closed and the housing is open
7.3. The enclosure is closed
7.4. Housing with a hole
7.5. Housing with passive membrane
7.6. Housings with acoustic waveguide
7.6.l. Labyrinth housing
7.6.2. Horn housing
7.7. Bandpass enclosures
7.7.1. Introduction
7.7.2. Symmetrical fourth order bandpass device
7.7.3. Symmetrical sixth-order bandpass device
7.7.4. Unbalanced sixth-order bandpass device
7.7.5. Symmetrical eight-order bandpass device
7.8. Multi-speaker device. Speaker
7.9. Speaker sets and loudspeakers
Literature

8. Microphones

8.l. Introduction
8.2. Classification of microphones and shaping the characteristics of directionality and efficiency
8.3. Magnetoelectric microphones
8.4. Electrostatic microphones
8.5. Capacitive microphones with phase modulation
8.6. Microphones and piezoelectric hydrophones
8.7. Electromagnetic laryngofon
8.8. Distortion, noise and interference in microphones
8.9. Wireless microphones
Literature

9. Measurements of electroacoustic transducers properties

9. l. Introduction
9.2. Measurements of the properties of loudspeakers and loudspeakers
9.2.1. Introduction
9.2.2. Normalization of measurements of loudspeakers and loudspeakers
9.2.3. Classic methods for measuring speaker properties
9.2.3.1. Measurements of transfer characteristics
9.2.3.2. Measurements of directional characteristics and directional parameters
9.2.3.3. Measurements of impedance characteristics and derivative parameters
9.2.4. Speaker measurements using modern methods of signal transformation
9.2.4.1. Introduction
9.2.4.2. Impulse and correlation methods. MLS method
9.2.4.3. Delay spectrometry method
9.2.4.4. Time-frequency analysis
9.2.5. Measurements of nonlinear distortions
9.2.6. Vibration measurements of membranes
9.2.7. Subjective measurements regarding speakers
9.3. Measurements of the headphones properties
9.3. l. Normalization of headphone measurements
9.3.2. Measured quantities and methods of measuring them
9.4. Measurements of microphone properties
9.4.1. Normalization of measurements of the properties of microphones
9.4.2. Measurements regarding microphones for speech and music processing
9.4.2. l. Measurement conditions
9.4.2.2. Measurements of efficacy and frequency characteristics of efficacy
9.4.2.3. Measurements of directional characteristics and determination of directional parameters of microphones
9.4.2.4. Measurements of nonlinear distortions and "pop"
9.4.2.5. Microphone noise measurement
9.4.2.6. Measurement of the influence of external factors on the microphone
9.4.3. Calibration of measuring microphones
9.4.4. Measurements of hydrophone properties

Literature

Norms and normative documents

Index