Under the semester system, this course is now ECE 4445.

EE 4026 Audio Engineering (3D)

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Credit: 3-0-3

Prerequisite: EE 3280

Course Objectives: Introductory acoustics, electroacoustic modeling, microphones, loudspeakers, crossover networks, and audio amplifiers.

Text: Leach, Introduction to Electroacoustics and Audio Amplifier Design

TOPICAL OUTLINE

Basic Principles of Sound

Sound, Sources of Sound, Velocity of Sound, Frequency of Sound, Pitch, Human Speech, Audio Frequency Bandwidths, Audible Characteristics of Different Frequencies, Sound Pressure Level, Equal Loudness Contours, Loudness Levels, Audio Test Signals

Fundamentals of Acoustics

The Acoustic Wave Equation, The Plane Wave, Specific Impedance, Acoustic Intensity, Wavelength of Sound, Particle Displacement, The Simple Spherical Wave, Volume Velocity, Power Radiated in a Simple Spherical Wave, Acoustical Images, The Directivity Pattern, The Plane Circular Piston in an Infinite Baffle, The Pattern Beamwidth, Fresnel Diffraction Effects, Acoustical Reflections

Electro Acoustical Analogous Circuits

Acoustic Sources, Acoustic Impedance, The Plane Wave Tube, Acoustic Resistance, Acoustic Compliance, Acoustic Mass, Acoustic Radiation Impedance on a Circular Piston in an Infinite Baffle, Acoustic Radiation Impedance on a Circular Piston in a Long Tube, Acoustic Radiation Impedance on a Circular Piston in Free Air

Electro Mechanical Analogous Circuits

Mechanical Sources, Mechanical Mass, Compliance and Resistance, Mechanical Systems, The Electromagnetic Mechanical Transducer, The Crystal Electrostatic Mechanical Transducer, The Condenser Electrostatic Mechanical Transducer, The Mechano Acoustic Transducer

Microphones

Classification of Microphones, Modeling Reflections at the Microphone Diaphragm, Modeling the Acoustical Load on the Back of the Diaphragm, Modeling the Diaphragm Mechanical System, The Condenser Microphone, An Example SPICE Simulation of the Condenser Microphone, Condenser Microphone Buffer Amplifiers, The Dynamic Microphone, The Ribbon Microphone, The

Moving Coil Loudspeaker Drivers

Construction, The Analogous Circuits, The Combination Acoustical Analogous Circuits, The Infinite Baffle Analogous Circuit, The Low Frequency Volume Velocity Transfer Function, The Infinite Baffle Resonance Frequency and Total Quality Factor, Bode Plots for the Low Frequency Volume Velocity Transfer Function, The Low Frequency Small Signal Parameters, The High Frequency Volume Velocity Transfer Function, Definition of the Normalized On Axis Pressure, The Infinite Baffle Pressure Transfer Function, Filter Theory Description of G(s), Effect of Non Zero Generator Resistance on Driver Parameters, The Lower Half Power Cutoff Frequency, Frequency of Peak Response, Bode Phase Plot of the On Axis Pressure Transfer Function, The On Axis Reference Pressure Sensitivity, The Voice Coil Impedance Function, The Voice Coil Equivalent Circuit, The Acoustic Power Response, The Reference Efficiency, The Diaphragm Displacement Function, The Voice Coil Electrical Power Rating, The Displacement Limited Acoustic Power Rating, Example Loudspeaker Analyses with SPICE, The Isobaric Connection

Loudspeaker Driver Parameter Measurements

Basic Theory for Measuring the Small Signal Parameters, The Small Signal Parameter Test Set, Measurement of the Voice Coil Resistance, the Fundamental Resonance Frequency and the Three Quality Factors, Measurement of the Volume Compliance, Conversion to the Infinite Baffle Parameters, Measurement of the Voice Coil Inductance

Closed Box Loudspeaker Systems

Modeling the Effects of the Box, The System Analogous Circuits, The Low Frequency Volume Velocity Transfer Function, The Closed Box On Axis Pressure Transfer Function, Effect of the Box Volume of the System Response, Sensitivity of the Lower Cutoff Frequency, System Design with a Given Driver, System Design from Specifications, A Closed Box SPICE Simulation Example

Vented Box Loudspeaker Systems

Modeling the Enclosure, Effect of the Vent, The On Axis Pressure Transfer Function, The Voice Coil Impedance Transfer Function, The Butterworth Alignment, The Quasi Butterworth Third Order Alignments, The Chebyshev Alignments, The On Axis Pressure Bode Magnitude Plots, Design with a Given Driver, A Vented Box SPICE Simulation Example, The 4th Order Bandpass Systems

Crossover Networks

Role of the Crossover Network, First Order Crossover Networks, Second Order Crossover Networks, Third Order Crossover Networks, Effect of the Voice Coil Impedance, Measuring the Voice Coil Impedance, Effect of the Driver Phase Response, Effect of Driver Offset, Active Crossover Networks, SPICE Modeling Example, The System Group Delay

Audio Power Amplifiers

Amplifier Power Specifications, The Gain of a Feedback Amplifier, Effect of Feedback on Distortion and Noise, Effect of Feedback on Output Impedance, The Amplifier Stability Criterion, The Single Pole Amplifier, The Two Pole Amplifier, The Alternate Stability Criterion, Techniques for Compensating Feedback Amplifiers, Signal Tracing, Power Supply Design, Power Amplifier Circuit Topologies, Gain Bandwidth Product and Slew Rate, Power Supply Decoupling and Grounding, Amplifier Protection Circuits, Amplifier Measurements