Audio Technology

ET 163 Audio Technology

I. CATALOG DESCRIPTION:

ET163 Audio Technology C 2, P 2, CR 3

Modern audio technology is introduced. Topics include basic acoustics, transducers such as microphones and loudspeakers, signal processing, and amplification systems. An introduction to digital audio is included as well as software/Internet applications.

Corequisites: ET152 Circuits 2 or ET102 Technical Electricity or permission of instructor.

II. MATERIALS:

Text: Handbook for Sound Engineers: The New Audio Cyclopedia 3E, Ballou, Butterworth-Heinemann

Tools: Scientific calculator, electronic hand tools and breadboard

III. STUDENT LEARNING OUTCOMES:

The student will demonstrate a working knowledge of audio systems, including input and output transducers, signal processing, and amplification schemes, along with the basics of digital audio.

The student will demonstrate a basic knowledge of the fundamentals of acoustics.

The student will demonstrate an ability to apply general electrical theory to solve problems in audio systems.

The student will use mathematical techniques to solve problems in audio and acoustics.

The student will demonstrate the ability to work effectively as part of a team in the laboratory.

The student will demonstrate the proper usage of audio test equipment through the laboratory.

Link to Course Assessment Standards

Background

Success in this course requires a good working knowledge of DC and AC circuit principles. You must be proficient in algebra. Also, it is helpful if you have taken at least one course covering linear semiconductor applications. For lab, you'll need the standard array of goodies as used in most other electrical courses (breadboard, DMM, small handtools, hook-up leads, etc.) Some lab work will be performed using digital audio software. A portion of the lab exercises require a non-formal report due no later than one week after the exercise. Late penalty is one letter grade for the first half week, two letter grades for the second half week. Reports are not accepted beyond two weeks and receive a grade of 0. Remember, plagiarism is grounds for failure. Please note that there is far more material in our text than we could ever hope to cover in a semester (or even two semesters). As this is an elective course, I am open to shifting emphasis to different topics than outlined here. Your in-class feedback will be most welcome.

Week-by-week progress and assignments
Links to lecture notes and labs at bottom of page

1
Introduction to course. Review of basic quantities such as voltage, current, impednace, power, decibels, frequency, and phase angle.

Reading: Begin chapter 1 and review first half of chapter 11 and also chapter 47. There's some good practical info on electrical components in chapter 11. Chapter 47 is filled with reference material.
Lab: Introduction: Lab procedures and safety, equipment usage.

2
This week we begin an introduction to basic acoustics. We include concepts such as propogation velocity, wavelength, standing waves, and dispersion. By week's end we'll discuss acoustic spaces. Concepts include reverberation, echo, absorption and diffusion.

Reading: Finish chapter 1 and read chapters 4 and 5.
Lab: Using decibel based measurements.

3
We finish acoustic spaces and examine human hearing. This will include frequency range, timbre, pitch, Fletcher-Munson curves, loudness, etc.

Reading: Finish chapters 4 and 5, and read chapter 2. We'll be skipping around a bit in here (none of the more arcane material).
Lab: Exploration of human hearing: frequency range and timbre.

4
We introduce input transducers this week (microphones).

Reading: Chapter 16.
Lab: Exploration of human voice and instrument characteristics (frequency spectra).

5
Output transducers are considered at week's end, and that means loudspeakers. We begin with the various basic types including dynamic moving coil, electrostatic, and piezo.

Reading: Begin chapter 17.
Lab: Measuring loudspeaker impedance.

6
This week we look at low frequency enclosures. These include sealed, vented, and labyrinth.

Reading: Finish chapter 17.
Lab: Measuring Thiele-Small parameters.

7
We complete the section on output transducers, finishing with line sources and horn loaded systems. We also have our first test.

Reading: Begin chapters 20 and 21.
Lab: Measuring frequency response.

8
We begin discussion of amplification including classes A, B, D, and G. Topics include distortion mechanisms and measurement.

Reading: Finish chapters 20 and 21.
Lab: Rise time and fall time.

9
This week we finish amplification and discuss high level usage such as active vs. passive crossovers, multi-amp systems, and self-powered systems.

Reading: Chapter 26. Again, we won't be hitting everything. Also, start chapter 25.
Lab: Measuring distortion: THD and slew limiting (power bandwidth).

10
This week we begin digital audio. We start with different ways of digitizing audio, focusing on linear PCM. This week's lab revolves around the Sample Wrench audio editor. This is very important as all of the labs for the remainder of the course will use this software.

Reading: Skim remainder of chapter 25.
Lab: Introduction to Sample Wrench audio editor/analyzer.

11
This week we discuss signal processing. This is a wide-ranging topic and covers a lot of ground. We begin with the basics such as equalization, compression, and limiting. We then pick up artificial ambience, namely reverb, echo, and doubling

Reading: Chapter 23.
Lab: Equalization and spectral analysis.

12
We continue signal processing and discuss pitch shifting and time compression. We conclude signal processing with a discussion of special effects such as flanging, chorusing, and distortion, as well as noise reduction and feedback supression.

Reading: Chapter 24.
Lab: Echo, reverb, delay, chorusing, flanging.

13
We finish digital audio and discuss concepts such as quality versus storage requirements/streaming bandwidth. We also talk about different audio file formats.

Reading: Begin chaper 30.
Lab: Special effects generation, part 1 (AM, FM, rectify, transfer function).

14
Time for our second test. This covers amplification, digital audio and signal processing.

Reading: Finish chapter 30.
Lab: Special effects generation, part 2 (noise reduction, convolution, spectral warp).

15
We finish the course with a discussion of MIDI and Internet audio including perceptual coding, MP3, and copyright issues.

Reading: Chapter 29 and beginning of chapter 39.
Lab: Course review.

Resources

Lecture Notes:
Notes 1: Basic Acoustics
Notes 2: Acoustics and Hearing
Notes 3: Listening Spaces
Notes 4: Microphones
Notes 5: Loudspeakers, Part I
Notes 6: Loudspeakers, Part II
Notes 7: Amplifiers
Notes 8: Digital Audio
Notes 9: Signal Processing, Part I
Notes 10: Signal Processing, Part II
Notes 11: Signal Processing, Part III
Notes 12: File Formats, the Internet, and More

Labs:
Week 1: If Web-based, obtain appropriate equipment and parts
Week 2: dB and AC Measurements
Week 3: Hearing Range and Timbre
Week 4: Microphones
Week 5: Loudspeaker Impedance
Week 6: Measuring Thiele-Small Parameters
Week 7: Frequency Response Measurement
Week 8: Rise and Fall Times
Week 9: Distortion
Week 10: Digital Audio Editor Intro
Week 11: EQ and Spectral Analysis
Week 12: Time Delay Effects
Week 13: Assorted Special Effects
Week 14: The Return of the Son of Special Effects
Week 15: Course review for final exam

Suggested References:
Audio Engineer's Reference Book 2E, M. Talbot-Smith, Ed., Focal Press, ISBN 0-240-516850
Music, Physics, and Engineering 2E, H. F. Olson, Dover, ISBN 0-486-21769-8
Sound System Engineering 2E, D. & C. Davis, Sams, ISBN 0-672-21857-7
Op Amps and Linear Integrated Circuits, J. M. Fiore, Delmar, ISBN 07668-1793-8

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1	Introduction to course. Review of basic quantities such as voltage, current, impednace, power, decibels, frequency, and phase angle. Reading: Begin chapter 1 and review first half of chapter 11 and also chapter 47. There's some good practical info on electrical components in chapter 11. Chapter 47 is filled with reference material. Lab: Introduction: Lab procedures and safety, equipment usage.
2	This week we begin an introduction to basic acoustics. We include concepts such as propogation velocity, wavelength, standing waves, and dispersion. By week's end we'll discuss acoustic spaces. Concepts include reverberation, echo, absorption and diffusion. Reading: Finish chapter 1 and read chapters 4 and 5. Lab: Using decibel based measurements.
3	We finish acoustic spaces and examine human hearing. This will include frequency range, timbre, pitch, Fletcher-Munson curves, loudness, etc. Reading: Finish chapters 4 and 5, and read chapter 2. We'll be skipping around a bit in here (none of the more arcane material). Lab: Exploration of human hearing: frequency range and timbre.
4	We introduce input transducers this week (microphones). Reading: Chapter 16. Lab: Exploration of human voice and instrument characteristics (frequency spectra).
5	Output transducers are considered at week's end, and that means loudspeakers. We begin with the various basic types including dynamic moving coil, electrostatic, and piezo. Reading: Begin chapter 17. Lab: Measuring loudspeaker impedance.
6	This week we look at low frequency enclosures. These include sealed, vented, and labyrinth. Reading: Finish chapter 17. Lab: Measuring Thiele-Small parameters.
7	We complete the section on output transducers, finishing with line sources and horn loaded systems. We also have our first test. Reading: Begin chapters 20 and 21. Lab: Measuring frequency response.
8	We begin discussion of amplification including classes A, B, D, and G. Topics include distortion mechanisms and measurement. Reading: Finish chapters 20 and 21. Lab: Rise time and fall time.
9	This week we finish amplification and discuss high level usage such as active vs. passive crossovers, multi-amp systems, and self-powered systems. Reading: Chapter 26. Again, we won't be hitting everything. Also, start chapter 25. Lab: Measuring distortion: THD and slew limiting (power bandwidth).
10	This week we begin digital audio. We start with different ways of digitizing audio, focusing on linear PCM. This week's lab revolves around the Sample Wrench audio editor. This is very important as all of the labs for the remainder of the course will use this software. Reading: Skim remainder of chapter 25. Lab: Introduction to Sample Wrench audio editor/analyzer.
11	This week we discuss signal processing. This is a wide-ranging topic and covers a lot of ground. We begin with the basics such as equalization, compression, and limiting. We then pick up artificial ambience, namely reverb, echo, and doubling Reading: Chapter 23. Lab: Equalization and spectral analysis.
12	We continue signal processing and discuss pitch shifting and time compression. We conclude signal processing with a discussion of special effects such as flanging, chorusing, and distortion, as well as noise reduction and feedback supression. Reading: Chapter 24. Lab: Echo, reverb, delay, chorusing, flanging.
13	We finish digital audio and discuss concepts such as quality versus storage requirements/streaming bandwidth. We also talk about different audio file formats. Reading: Begin chaper 30. Lab: Special effects generation, part 1 (AM, FM, rectify, transfer function).
14	Time for our second test. This covers amplification, digital audio and signal processing. Reading: Finish chapter 30. Lab: Special effects generation, part 2 (noise reduction, convolution, spectral warp).
15	We finish the course with a discussion of MIDI and Internet audio including perceptual coding, MP3, and copyright issues. Reading: Chapter 29 and beginning of chapter 39. Lab: Course review.