Last Modified : Tue, 26 Apr 16

- Instructor: Jont Allen (NetID: jontalle); ECE 403 Websites: 2016, 2013, 2012, 2011,2010, 2009; 2008;Text:
*Electroacoustics*(Buy, TOC, Preface, Preface1, pdf), Beranek & Mellow (2012) is #1; - TA: Sarah Robinson (srrobin2@illinois.edu); Office hours: Wednesdays 2-3 PM, 2137 Beckman Institute (NO OFFICE HOURS 3/2); Allen Office hours: 2-3 Friday
- Calendars: , University; Time: 12:30, Place: 3081-ECEB, etc: Time-Place, Official;
- Topics: How to analyize a loudspeaker; acoustic wave phenomena; acoustics of rooms and auditoriums; artificial reverberation and sound localization/specialization; Transducer design (2-port networks, loudspeakers, microphones); Topics in digital audio.
- Assignments: See {$Daily Schedule$} below;Software for Labs: software
- Lab location: 5072 ECE (you should have card access to this room). Three MU boxes are kept in cabinet on the right hand side of the room when you walk in. NOTE: This lab is OCCUPIED Monday 1-2pm, Tuesday 2-4pm, Wednesday 2-4pm, Friday 2-3pm. ECE 420 students get priority for this lab space.
- Final Report: Format for final report pdf, LaTeX example: zip
- This week's schedule

L
| W
| D
| Date
| m
| TOPIC |

Part I: 1-port Network Theory (5 Lectures: L1-4,6; 1 Labs: L5) | |||||

M | 1/18 | MLK Day; no class | |||

1 | 3 | T | 1/19 | 90 | *Introduction to what you will learn this semester: You will understand how a loudspeaker works by learning the basic theory along with hands-on lab experiments. *Everyone will work in a small group (ideally 4 students per group). *Theory will be taught on Monday and Wed, while the Labs will be on Friday. *Review of ECE-210: Fourier {$\cal F$} and Laplace {$\cal L$} Transforms; Impedance {$Z(s)$} and other complex functions of complex frequency {$s$}*The Curious Case of {$\log(-1)$},{$j^j$}, {$(-1)^t$} and {$j^t$} |

2 | R | 1/21 | 90 | *Applications of the Laplace transform {$h(t) \leftrightarrow H(s)$} where {$t$} is time and {$s=\sigma+j\omega$} is complex-frequency *A detailed comparison of the step function {$u(t)$} for each transform: Why {${\cal F} {\tilde u}(t) =\pi \delta(\omega)+1/j\omega$} and {${\cal L}u(t)=1/s$} are not the same. *Impedance; Analytic functions; *Detailed example using of a 1{$^{st}$}-order lowpass filter via the Laplace Transform method *Convolution of vectors {$\leftrightarrow$} product of polynomials: {$a \star b \leftrightarrow A(z)\cdot B(z)$}, where Time-domain: {$a \equiv [a_0,a_1,a_2, \cdots]^T$}, {$b \equiv [b_0,b_1, \cdots]^T$} Freq-domain: {$A(z)\equiv(a_0+a_1z+a_2z^2 \cdots)$}, {$B(z)\equiv(b_0+b_1z+ \cdots)$} | |

3 | 4 | T | 1/26 | 90 | *Solving differential equations: The characteristic polynomial {$H(s)$}*Properties of {$H(s)=N(s)/D(s)$}: Roots of {$D(s)$} in LHP. *Simple example of a 2-port network and its formulation via the transmission matrix (ABCD) method *Definition of the Inverse Laplace transform {$ {\cal L}^{-1} $}: {$f(t)u(t) = \int_{\sigma_0-j\infty}^{\sigma_0+j\infty} F(s)e^{st}\frac{ds}{2 \pi j}$}*Homework 1: HWa (Discuss Feb 2, due Tues Feb 9, 2016) |

4 | R | 1/28 | 30 | *Definition of an impedance as an Analytic function {$Z(s)$} Causal; stable; stable inverse; Conservation of Energy ({$\Re Z \ge 0$}) *Residue expansions and Inverse Laplace Transforms *Inverse Laplace Transform {${\cal L}^{-1}$} definition: Residue Thm | |

5 | R | 1/28 | 60 | Lab 1: 3081 ECEB: Define Student groups *Learn about hardware; Demo of SysID | |

6 | 5 | T | 2/2 | 90 | *Impedance functions: Minimum phase (MP), positive real (PR), and transfer functions as: all-pole (Strictly-IIR), all-zero (Strictly-FIR) and allpass (AP) functions *Functions of a complex variable *Calculus of Analytic functions: {$dH(s)/ds$}, {$\int_C H(s) ds$}. |

2-port Linear System Theory (5 lectures: L7,9-12; 2 Labs: L8,L11; Exam I) | |||||

7 | R | 2/4 | 90 | *Lab 2: 5072 ECEB: Setup of hardware; Learn how to make impedance measurements: Circuit Schematic *Calibration of hardware | |

8 | 6 | R | 2/9 | 60 | *2-Port networks; Definition of T [Pipes (53)] matrix and conversion method between Z and T matrix [Van Valkenburg (65)] (pdf)*Carlin: 5+1 network postulates (pdf) *Hunt's 2-port impedance model of the loudspeaker |

9 | T | 2/9 | 30 | *Discuss HWb Lab exercise (due: Feb 16) | |

10 | R | 2/11 | 90 | *Lab 3: 5072 ECEB *Measurement of 2-port RC example of HWb *Implement Op-Amp circuit and remeasure 2-port of HWb | |

11 | 7 | T | 2/16 | 90 | *Lecture 3081 ECEB: *2-port networks: Transformer, Gyrator and transmission lines *Moving coil vs. Balanced armature Loudspeaker *Hunt 2-port {$Z$} impedance matrix equations: {$E=Z_e\, I|_{V=0}, F = B_0 l\, I|_{V=0}, E = -B_0l\, V|_{I=0}, F=Z_m\, V|_{I=0}$} *Motional impedance (Hunt Chap. 2) *The Maxwell Faraday Law of Induction in differential and integral form;Ampere's Law & Ampere's Force Law*Homework 3: HWc due 3/3;Try HW in LaTeX* Read: Kim and Allen (2013) pdf |

12 | R | 2/18 | 90 | Lab 4 *First measurement of a loudspeaker input impedance | |

13 | 8 | R | 2/23 | 60 | *Reciprocal and reversible 2-port networks (T and Z forms) *The Reciprocal calibrationmethod (i.e., cascaded loudspeakers) *Thevenin & Norton parameters of a loudspeaker: {$P_0(f), U_0(f), Z_0(s)$} *Forward, backward and reflected traveling waves *Uniform Transmission lines & reflections at junctions |

14 | T | 2/23 | 30 | Review for Exam I, Lectures 1-12, HW-a,b,c | |

15 | R | 2/25 | No class: Exam I, 7-9PM Room: 3081 ECEB, Thr Feb 25, 2016 | ||

Part II: Acoustic Waves and Horns (5 lectures+Exam II) | |||||

16 | 9 | T | 3/1 | 90 | *Acoustic transmission lines *Disc HWc-v1; Due: 3/3 |

17 | R | 3/3 | 90 | *Lab 5: 5072 ECEB *HWc Due Today; *Allen & Robinson out of town today *HWd: Acoustics & Transmission Lines (due Mar 17) | |

18 | 10 | T | 3/8 | 90 | *Review of Acoustic Basic Acoustics (Pressure and Volume velocity, dB-SPL, etc.) * Acoustic Intensity, Energy, Power conservation, Parseval's Thm., Bode plots;*Discuss HWd, due Mar 17 |

19 | R | 3/10 | 90 | *Lab 6 | |

F S | 3/11 | 90 | Engineering Open House | ||

20 | 11 | T | 3/15 | 90 | *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); |

21 | R | 3/17 | 90 | *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 * HWd due; handout solution | |

12 | M F | 3/19 | 90 | Spring Break | |

22 | 13 | T | 3/29 | 90 | *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 *HWe due 4/26; Starter files for middle ear simulation (txline.m,gamma.m); Similar to HW3 of ECE537 |

23 | R | 3/31 | 90 | Lab 7; {$Z_{mot}$}" Measure Mass-loaded speaker impedance {$Z_e(f)$} & Speaker Faced-Up vs. Faced-Down | |

24 | 14 | T | 4/5 | 90 | *Lecture: How does the middle ear work?*Review for Exam II: HW-c,d,e |

25 | R | 4/7 | 90 | NO Class; Exam II, Thur @ 7 PM in 3081 ECEB | |

26 | 15 | T | 4/12 | 90 | Review of the Fourier Transform [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., {$u(t) \equiv \int_{-\infty}^t\delta(t)dt$} it a function? (pdf)* Read: Kim and Allen (2013) pdf |

Part III: Signal Processing (3 lectures L27,29-30; 2 Labs: L28,31;) | |||||

27 | R | 4/14 | 90 | Lab 8 Reciprocity calibration (2 speakers F2F) & pressure measurement in cavity *Work on lab report (Example LaTeX) | |

28 | 16 | T | 4/19 | 90 | * Lecture: Middle ear as a delay line This lecture is out of place, and needs editing for 2017 * Read Rosowski, Carney, Peak (1988) The radiation impedance of the external ear of cat: Measurements and applications (pdf) |

29 | R | 4/21 | 90 | *Lab | |

30 | T | 4/26 | 90 | *Lab | |

31 | R | 4/28 | 90 | *Lecture by Mary Mazurek, Audio Engineer WFMT Chicago HWe due | |

32 | Finish Lab Reports | ||||

33 | 18 | T | 5/3 | 90 | Group presentations |

34 | W | 5/4 | 90 | Group presentations | |

R | 5/5 | Reading Day; Final project due by midnight: Please give me both a paper and pdf copy. NO DOC files | |||

- | F | 5/6 | Final Exams begin (Our final is the Lab project paper on loudspeakers) |

- The textbook is
**Electroacoustics: The Analysis of Transduction, and Its Historical Background**by Frederick V. Hunt. ISBN 0-88318-401-X. - Chapters 2 and 3 of the textbook are available pdf.

- The final grads were computed as follows: Each homework counted for 5 points. The two exams were each worth 25 points, for a total of 50 points. The final was broken down into 33 topics each worth 30/33 points, for a total of 30 points. This all adds to 100 points. Example: Score = 0.2*mean(HW)+.5*mean(Exams)+Final (within 1 point due to rounding and normalization).

- Carlin Network postulates pdf

*Conversion tables for 2-ports (page 1) and ABCD tables from Pipes (pages 2-3): pdf

- Passive Radiator speaker
- UIUC Physics 406
*Acoustical Physics of Music*Lecture Notes; This popular course provides a*very*different approach to many of the same topics we discuss in ECE403 and in ECE537. - HP scattering-matrix application notes pdf Δ, link
- A Vinyl record grove magnified 1000 times jpg Δ image
- Stiff piano strings by Richard Feynman djvu Δ
- Old guitar strings by Jont B Allen (1976) "On the aging of steel guitar strings"; Catgut Acoustical Society Newsletter, Nov., Vol 26, pp 27-29 (pdf)
- Audio projects that failed (it seems the website failed. Toobad it was great!)
- Q sound 3D audio
- Neural Audio DTS
- Holosonics Nonlinear-Ultrasonic Loudspeaker
- You can use SYSRES (windows zip, linux-bin) to take frequency response measurements at home.
- Nonlinear acoustics: Bernoulli's Equation and conservation laws Navier-Stokes
- 3D Middle ear and cochlea view
- AAC+ encoding Slate article
- All-pass filters: a helpful explanation
- Prof. Haken's Continuum Fingerboard
- Coursera
**Introduction to Digital Sound Design**

Not fully proofed beyond here |

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