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Last Modified : Sat, 28 Jan 17

ECE403-2016AudioEngineering-S17

  • Instructor: Jont Allen (jontalle@illinois.edu); Office hours: By Appointment
  • TA: Sarah Robinson (srrobin2@illinois.edu); Office hours: TBA & By Appointment (2137 Beckman Institute)
  • Class Time: 12:30 T/R (Tuesday/Thursday), Place: 3081-ECEB: ECE, UIUC, UI Calendar
  • Lectures will be presented on Tuesdays & Labs on most Thursdays (see schedule). Labs will be completed in small teams of 3-5 students.
  • Previous ECE 403 Websites: 2016, 2013, 2012, 2011, 2010, 2009, 2008
  • Text: Beranek & Mellow (2012) Buy; Browse; Reference text: Electroacoustics (pdf) TOC, Preface, Preface1
  • Topics: Transducer design & analysis: 2-port networks, loudspeakers, microphones; acoustic wave phenomena; acoustics of rooms and auditoriums; artificial reverberation and sound localization; Topics in digital audio.
  • Lab location: 5072 ECE (you have ICard access). Four network-analyzers (MU boxes) in cabinet on right
    NOTE: This lab is OCCUPIED Monday, Tuesday, Thursday & Friday 2-5pm by ECE 420 students, who have priority during these times.
  • Homeworks: There will be 5 homework assignments (a-e); Links to these assignments are available in the Daily Schedule below.
  • Software for Labs: G7-software (runs in Matlab or Octave; TA note: Octave graphics are slow for me)
  • Tools: MATLAB, Octave, Latex
  • Final Report: Format for final report pdf, LaTeX example: zip
  • This week's schedule

Spring 2017 Daily Schedule

If the LaTeX math in this table does not render properly, try a browser extension (e.g. google chrome)

L W D Date TOPIC
Part I: Basic Acoustics (Ch 1) (3 Lect)
M 1/16 MLK Day
1 3 T 1/17 *Lect: Introduction: We will study how loudspeakers work, both basic theory & hands-on lab experiments.
*Anatomy of a loudspeaker
*Review of Basic Acoustics (Pressure and Volume velocity, dB-SPL, etc.)
*Acoustic Intensity & Energy density, Level in Decibels [dB]
*Read Ch 1, p. 1-17
2 R 1/19 *Lect: Derivation of the wave equation & Webster Horn equation
*Applications of the Laplace transform {$h(t) \leftrightarrow H(s)$}: Fourier {$\cal F$} and Laplace {$\cal L$} Transforms;
[e.g.: {$\delta(t) \leftrightarrow 1$}, {$\delta(t-T) \leftrightarrow e^{-j\omega T}$}; {$1\leftrightarrow 2\pi\delta(\omega)$}, etc.]
*Notes on the Laplace {$\delta(t)$} function (i.e., is {$u(t) \equiv \int_{-\infty}^t\delta(t)dt$} a function? pdf)
*Impedance {$Z(s)$} and complex functions of complex frequency {$s$}; Example of a 1{$^{st}$}-order lowpass filter;
*Comparison of the step function {$u(t)$} for {$\cal F$} & {$\cal L$} transforms
*Read Ch 2, p. 21-29 (Wave Equation)
3 4 T 1/24 *Lect: Solutions of the wave equation
*Impedance boundary conditions {$Z(s)=N(s)/D(s)$}
*The Inverse Laplace transform; Convolution of vectors {$\leftrightarrow$} product of polynomials
*Read Ch 2, p. 37-48
*Homework A (Discuss on Lect 5; due on Tues 2/7 (Lect 7))
II: Circuit Analysis (Ch 3-4) (5 Lect, 1 Lab)
4 R 1/26 *Lect: Mechanical impedance {$Z_m(s)=$} Force/Velocity: Mass, stiffness, resistance
*Frequency vs. time domain impedance; Network Postulates:Causal; stable; stable inverse; Conservation of Energy ({$\Re Z \ge 0$})
*What is a Network analyizer? (MU box Demo)
*Read Ch 3, p. 65-84

5 5 T 1/31 *Lect: Acoustic Impedance Postulates: {$Z_a(s)=$}Pressure/volume-velocity
*Minimum phase (MP), positive real (PR)
*Transfer functions: all-pole (IIR), all-zero (FIR) and all-pass (pol-zero) functions
*Residue expansions and Inverse Laplace Transforms
*Inverse Laplace Transform {${\cal L}^{-1}$} definition: Residue Thm
*Discuss HW-A
*Read Ch 3, p. 84-94
6
0 		R 2/2 *Lect: Electrical impedance {$Z_e(s)=$}Voltage/Current
*2-port Transmission Matrix {${\bf T}(s)$} (ABCD) & Complex Functions of a complex variable
*Definition of, and conversion between, Transmission {${\bf T}(s)$} & Impedance {${\bf Z}(s)$} matrix
*Lab 0 (3081 ECEB): Define Lab partners
*Read Ch 3, p. ??; Network Postulates: Kim et al, Carlin; Transmission Matrix conversion tables: VanValkenburg-Pipes)
7 6 T 2/7 *Lect: Lumped approximations of Transmission lines and the {${\bf T}(s)$} (ABCD) method
*Thevenin and Norton equivalence representation
*HW-A DUE
*Homework B: You will need Ref. 1 (Discuss on Lect 9; due on Tues 2/21 (Lect 11))
*Read Ch 3, p.106-118
8
1 		R 2/9 *Lab 1 (5072 ECEB): Setup of hardware; Learn how to make impedance measurements: Circuit Schematic
*Install g7play software package
  • Construct circuit board to measure loudspeaker impedance, and debug it.
III: EM & PST motor: Ch 5 (6 Lect, 2 Labs)
9 7 T 2/14 *Lect: Hunt's 2-port impedance model of the loudspeaker
*2-port networks: Transformer, Gyrator and transmission lines
*Motional impedance (Hunt Chap. 2, pdf)
*Discuss HW-B\Lab exercise (Due Feb 21, in 1 week)
*Read Ch 4, p. 119-128
10
2 		R 2/16 *Lab 2 (5072 ECEB):
*Measurement of 2-port RC (example from HWb)
*Read Ch 3, p. ??
11 8 T 2/21 *Lect: Moving coil vs. Balanced armature Loudspeaker
*Faraday's Law of Induction: differential & integral form; Ampere's Law & Ampere's Force Law
*Reciprocity: PZT, Capacitance & Electrodynamic microphones
*HW-B DUE
*Homework C (Discuss on Lect 13; due on Thurs 3/2 (Lect 14))
*Read Ch 3, p. 94-96
12
3 		R 2/23 *Lab 3 (5072 ECEB): Measure Mass-loaded speaker impedance {$Z_e(f)$}
*Speaker Faced-Up vs. Faced-Down; {$Z_{mot}$}
*First measurement of a loudspeaker input impedance
*Read ??
13 9 T 2/28 *Lect: Reciprocal and reversible 2-port networks (T and Z forms)
*The Reciprocal calibrationmethod (i.e., cascaded loudspeakers)
*Forward, backward and reflected traveling waves
*Uniform Transmission lines & reflections at junctions
*Discuss Homework C (Due 3/2)
*Read ??
14 R 3/2 *Lect: Thevenin & Norton parameters of a loudspeaker: {$P_0(f), U_0(f), Z_0(s)$}
*Review for Exam I, which covers Lectures 1-12, HW-A,B,C
*HW-C DUE
*Read ??

15 10 T 3/7 NO class: Exam I Tuesday March 7, @ 7-9PM Room: 3081 ECEB
IV: Horns with Viscous & Thermal loss; Reciprocity (6 Lect, 2 Labs)
16 R 3/9 *Lect: Acoustic transmission lines
*Homework D: Acoustics & Transmission Lines (Discuss on Lect 18; due on Tues 4/4 (Lect 21))
*Read ??
F
S 		3/10-3/11 Engineering Open House
17 11 T 3/14 *Lect: The Webster Horn Equation; Reciprocity
*Read ??
18
4 		R 3/16 *Lab 4 (5072 ECEB): Reciprocity calibration; verification with a probe microphone (Etymotic Research-7C)
*Discuss HW-D (due 4/4)
*Read ??
12 M
F 		3/18 Spring Break
19 13 T 3/28 *Lect: Acoustic wave equation.
*Acoustic horns: Tube acoustics where the per-unit-length impedance {${\cal Z}(x,s)\equiv s \rho_0/A(x)$} and admittance {${\cal Y}(x,s)\equiv s A(x)/\eta_0 P_0$} depend on space {$x$} (Horns)
*Read ??
20
5 		R 3/30 *Lab 5 (5072 ECEB): Acoustic Thevenin calibration using 2 acoustics loads (Duct tape)
*Read ??
21 14 T 4/4 *Spherical wave off of a sphere; Radiation (wave) impedance of a sphere
*Spectral Analysis and random variables: Resistor thermal noise (4kT).
*Wave equations and Newton's Principia (July, 1687); d'Alembert solutions in 1 and 3 dimensions of the wave equation
*HW-D DUE
*Homework E (Discuss on Lect 24; due on Tues 5/2 (Lect 29)); Starter files for middle ear simulation (txline.m, gamma.m)
*Read ??
22 R 4/6 *Radiation impedance of a Horn pdf
*Vacuum Tube guitar amplifiers pdf
*Transmission Lines discussion; Monster speaker cable
*Loudspeakers: lumped parameter models, waves on diaphragm
*Throat and Radiation impedance of horn
*Read ??
23

6

15 T 4/11 *Lab 6 (5072 ECEB): Measure the speaker radiation impedance {$Z_{rad}(s)$} and compare to the spherical radiator
*Read ??
24 R 4/13 *Lect: How does the middle ear work? Ans: The Middle ear is a transmission line.
*Read: Rosowski, Carney, Peak (1988) The radiation impedance of the external ear of cat (pdf)
*Discuss HW-E
*Review for Exam II, which covers Lectures 13-22, HW-C,D
*Read ??

25 16 T 4/18 NO Class: Exam II Tuesday April 18, @ 7-9PM Room: 3081 ECEB
V: Electrodynamic Loudspeakers (Ch 6)
26 R 4/20 *Lect: Baffling loudspeaker topics
*Read Ch7, p. 289-320
27
7 		17 T 4/25 *Lab 7 (5072 ECEB): Choice of 1) Earbud in ear simulator, 2) Horn baffle, 3) AR-3 Acoustic suspension baffle
*Work on lab report (Example LaTeX)
28 R 4/27 *Lect: Guest Lecture (??) by Mary Mazurek, Audio Engineer WFMT Chicago
*Read Ch 11, p. ??
29 18 T 5/2 *Lab; Last class; Open discussion of Lab report content; what you learned this semester
*HW-E due
W 5/3 Instruction ends
R 5/4 Reading Day
F 5/5 Group lab reports due by midnight: Please give me both a paper and pdf copy. NO DOC files
*Final Exams begin (Our final is the lab project presentation on loudspeakers)
M 5/8 Group presentations 1:30-4:30pm (during officially scheduled Final Exam)

Textbook

  • The primary text is Acoustics: Sound fields and transducers Beranek and Mellow; Academic Press 2012;
  • The reference textbook is Electroacoustics: The Analysis of Transduction, and Its Historical Background by Frederick V. Hunt. ISBN 0-88318-401-X.
    • Chapters 2+ of the reference textbook is available pdf.

Z

Reading Assignments:

  • Part I: Beranek 1-17, 21-29, 37-48
  • Part II: Beranek 65-84, 84-94, 106-118, Kim et al,Carlin, VanValkenburg-Pipes)
  • Part III: Beranek 119-128, 94-96, ??
  • Part IV: ??
  • Part V: 289-320, Ch 11

Homeworks:

  • HW-A, Assigned 1/24 (Lect 3), DUE Tues 2/7 (Lect 7): Acoustics and LT/FT
  • HW-B, Assigned 2/7 (Lect 7), DUE Tues 2/21 (Lect 11): T, Z matrix + Transmission line theory
  • HW-C, Assigned 2/21 (Lect 11), DUE Thurs 3/2 (Lect 14): Electrodynamic ABCD model with Gyrator, Motional impedance & {$Z_A(s)$} TL load
  • HW-D, Assigned 3/9 (Lect 16), DUE Tues 4/4 (Lect 21): Horns, reciprocity, Thevenin model of Johnson resistor noise
  • HW-E, Assigned 4/4 (Lect 21), DUE Tues 5/2 (Lect 29): Middle ear model (Lect 21, Due Lect 29)

Labs:

  • Lab Manual (pdf)
  • Lab 0, Thurs 2/2, 3081 ECEB (Lect 6): a) Define teams; b) Define goals of Labs
  • Lab 1, Thurs 2/9, 5072 ECEB (Lect 8): a) Op-amp circuit construction; b) MU calibraton with a 1 kohm resistor
  • Lab 2, Thurs 2/16, 5072 ECEB (Lect 10): Measure 2-ports: a) RC lowpass, b) Twin-Tee notch filter Model EvalResp.m
  • Lab 3, Thurs 2/23, 5072 ECEB (Lect 12): Speaker electrical impedance: a) Loaded, b) Unloaded, c) Compute speaker motional impedance
  • Lab 4, Thurs 3/16, 5072 ECEB (Lect 18): Reciprocity calibration with probe mic verification
  • Lab 5, Thurs 3/30, 5072 ECEB (Lect 20): Thevenin Equivalent circuit via 2 acoustic loads (Duct Tape cavities)
  • Lab 6, Thurs 4/11, 5072 ECEB (Lect 23): Measure speaker acoustic radiation impedance {$Z_{rad}$}
  • Lab 7, Thurs 4/25, 5072 ECEB (Lect 27): Optional lab (team's choice): a) earbud in ear simulator, b) Wave horn baffle, c) AR-3 Acoustic Supension baffle

Note: Final written report DUE May 5; final group presentations May 8, 1:30-4:30pm.

Exams:

  • Exam I Tuesday March 7, 7-9PM, 3081 ECEB
  • Exam II Tuesday April 18, 7-9PM, 3081 ECEB

The final report:

  • Each team's final report will be due on the first day of exams (Friday May 5, 2017). The final report is broken down into 25 topics each worth 1 points, for a total of 25 points. Up to 5 points is given as extra credit if the report is formatted correctly (e.g., using LaTeX, quality figures, etc.). Your personal final report grade may also include self- and team-evaluations, and your performance in the oral presentation.

Final grade distribution:

  • The final grades are computed as follows: Each homework counted for 5 points (25). The two exams were each worth 25 points, for a total of 50 points. The lab project is worth 25 points. This adds to 100 points.

Notes and References

  • Carlin Network postulates pdf
  • Conversion tables for 2-ports (page 1 of Vanvalkenburg, 1965) and ABCD tables (pages 2-3 of Pipes, 1953): pdf

General interest

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