Last Modified : Fri, 05 Jul 19

- Instructor: Jont Allen (jontalle@illinois.edu); Office hours: By Appointment
- TA: Sarah Robinson (srrobin2@illinois.edu); Office hours: Mondays 2:30-3:30pm & By Appointment (2137 Beckman Institute)
- Class Time: 12:30 T/R (Tues/Thur), 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.
- Text:
*Beranek & Mellow*(2012) UIUC-ebook; 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.

- Homeworks: There will be 5 homework assignments (a-e); Links to these assignments are available in the
*Daily Schedule*below. - Labs (Section 1: Thursdays 12:30-1:50pm (class time); Section 2: Fridays 9:30-10:50am; Labs do not occur every week, please check the schedule. If there is no lab, there will be a regular Thursday lecture) groups
- Lab manual (check back for regular updates each time we have a new lab). In preparation for each lab, please read the corresponding section of the manual BEFORE coming to lab!
- Lab location: 5072 ECE (you have ICard access). Four
*network-analyzers*(*MU boxes*) in cabinet on right

NOTE: This lab is OCCUPIED Monday 3-5pm, Tuesday 2-5pm, Wednesday 1-5pm, Thursday 2-5pm, and Friday 12-5pm by ECE 420 students, who have priority during these times (their labs and office hours). - Software for Labs: G7-software (runs in Matlab or Octave); All 403 Files
- Tools: MATLAB, Octave, playrec: alternate audio software, Github playrec; Latex

- Exam 1, Exam2, Final Report: Format for final report pdf, LaTeX example: zip
- This week's schedule

If the LaTeX math does not render properly (e.g., Chrome), update the browser extension: google store

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 *Impedance \(Z(s)\) and complex functions of complex frequency \(s\); Example of a 1\(^{st}\)-order lowpass filter;*Read Ch 2, p. 21-29 (Wave Equation) | |

3 | 4 | T | 1/24 | *Lect: Solutions of the wave equation *Impedance (i.e., Brune) as boundary conditions \(Z(s)=N(s)/D(s)\): Residue expansions * 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)) |

Part II: Circuit Analysis (Ch 3-4) (5 Lect, 1 Lab) | ||||

4
0 | R | 1/26 | *Lect: Mechanical impedance \(Z_m(s)=\) Force/Velocity: Mass, stiffness, resistance *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)*Brune impedance and its properties: Network Postulates:Causal; stable; stable inverse; Conservation of Energy (\(\Re Z \ge 0\)) *What is a Network analyizer? (MU box Demo) * Lab 0 (3081 ECEB): Define Lab partners*Read Ch 3, p. 65-84 | |

5 | 5 | T | 1/31 | *Lect: Acoustic Impedance: \(Z_a(s)=\)Pressure/volume-velocity *2-port Transmission Matrix \({\bf T}(s)\) (ABCD) *Comparison of the step function \(u(t)\) for \(\cal F\) & \(\cal L\) transforms *Inverse Laplace Transform \({\cal L}^{-1}\) definition: Residue Thm *Discuss HW-A *Read Ch 3, p. 84-94 |

6 | R | 2/2 | *Lect: Electrical impedance: \(Z_e(s)=\)Voltage/Current *Definition of, and conversion between Transmission matrix \({\bf T}(s)\) & Impedance matrix \({\bf Z}(s)\)*Meaning of \(A(s), B(s), C(s), D(s)\) *Brune impedance: Minimum phase (MP), positive real (PR) *Review: Ch 3 Transmission \(\Leftrightarrow\) Matrix: VanValkenburg & Pipes (pdf) & Network Postulates: Kim et al, Carlin; | |

7 | 6 | T | 2/7 | *Lect: Lumped approximations of Transmission lines and the \({\bf T}(s)\) (ABCD) method *Transfer functions: all-pole (IIR), all-zero (FIR) and all-pass (pol-zero) functions *Complex Functions of a complex variable *Time vs frequency domain impedance *Thevenin and Norton equivalence representation * HW-A DUE* Homework B (EvalResp.m) (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. *Read Lec 36, pp 87-90: An Invitation ... (pdf) | |

Part III: Electrodynamic Loudspeakers (Ch 6) | ||||

9 | 7 | T | 2/14 | *Lect: Analysis of the Twin-Tee network: How to put two Transmission networks in parallel Discussion of the dB & Bode plots (log-log frequency response plots) Review of lab setup with op-amp circuit & how to verify the setup is functional *Discuss HW-B/Lab exercise (Due Feb 21, in 1 week) *Read: Lab manual |

10 2 | R | 2/16 | *Lab 2 (5072 ECEB):*Measurement of 2-port RC (example from HWb) (EvalResp.m) *Read Ch 3, p. ?? | |

11 | 8 | T | 2/21 | *Lect: Hunt's 2-port impedance model of the loudspeaker *2-port networks: Transformer, Gyrator and transmission lines Moving coil vs. Balanced armature Loudspeaker Motional impedance (Hunt Chap. 2, p. 92-97 pdf) *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)), SpeakerModel.m*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 107-112+ Lab 3 of Lab manual | |

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: Sarah Robinson: 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 |

Part 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 17; due on Tues 3/28 (Lect 19))*Read ?? | |

F S | 3/10-3/11 | [Engineering Open House] | ||

17 | 11 | T | 3/14 | *Lect: Reciprocity calibration of a loudspeaker *Discuss HW-D *Read Lab 3-4, p. 14-19 |

18 4 | R | 3/16 | *Lab 4 (5072 ECEB): Reciprocity calibration; verification with a probe microphone (Etymotic Research-7C)*Read: | |

12 | M F | 3/18 | Spring Break | |

19 | 13 | T | 3/28 | *Lect: Speaker Acoustic Thevenin calibration using 2 or more acoustics loads *Read: Thevenin model of source |

20 5 | R | 3/30 | *Lab 5 (5072 ECEB): Speaker Acoustic Thevenin calibration using 2 acoustics loads (Duct tape)* HW-D DUE* Homework E (Discuss on Lect 23; due on Tues 4/13 (Lect 24)); Starter files for middle ear simulation (txline.m, gamma.m)*Read: ABCD for Thevenin source | |

21 | 14 | T | 4/4 | *Spherical wave around a sphere; Radiation (wave) impedance of a sphere *Spectral Analysis and random variables: Resistor thermal noise (4kT) Noise Theory, About Nyquist *Wave equations and Newton's Principia (July, 1687); d'Alembert solutions in 1 and 3 dimensions of the wave equation *Read Solution to spherical wave equation |

22 | R | 4/6 | *Lab 6 (5072 ECEB): Measure the speaker radiation impedance \(Z_{rad}(s)\) and compare to the spherical radiator*Read: Radiation impedance of sphere | |

23
6 | 15 | T | 4/11 | *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 |

24 | R | 4/13 | Lect: Topics in Audio *Vacuum Tube guitar amplifiers pdf *Transmission Lines discussion; Monster speaker cable *Loudspeakers: lumped parameter models, waves on diaphragm *Throat and Radiation impedance of horn * HW-E DUE* Review for Exam II (HW-D,E) | |

25 | 16 | T | 4/18 | NO Class: Exam II Tuesday April 18, @ 7-9PM Room: 3081 ECEB |

Part V: Topics in Audio Engineering | ||||

26 | R | 4/20 | *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) | |

27 7 | 17 | T | 4/25 | *Lect: Baffling loudspeaker topics *Read Ch7, p. 289-320 |

28 | R | 4/27 | *Guest Lecture: Mead Killion CEO Etymotic Research, Elk Grove Village IL | |

29 | 18 | T | 5/2 | *Lab; Last class; Open discussion of Lab report content; what you learned this semester |

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) |

- 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 are available pdf.

- 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

- 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 3/28 (Lect 19): Horns, reciprocity, Thevenin model of Johnson resistor noise
- HW-E, Assigned 2/28 (Lect 19), DUE Tues 4/13 (Lect 24): Middle ear model

- Lab manual
- 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: (video) a) RC lowpass (EvalResp.m), b) Twin-Tee notch filter
- Lab 3, Thurs 2/23, 5072 ECEB (Lect 12): Speaker electrical impedance: a) Loaded, b) Unloaded, c) Compute speaker motional impedance

(syms algebra: MassCal.m, calculation: calcHuntParams.m)

- Lab 4, Thurs 3/16, 5072 ECEB (Lect 18): Reciprocity calibration with probe mic verification

(syms algebra: RecipCal.m)

- Lab 5, Thurs 3/30, 5072 ECEB (Lect 20): Thevenin Equivalent circuit via 2 acoustic loads (Duct Tape cavities)
- Lab 6, Thurs 4/6, 5072 ECEB (Lect 22): Measure speaker acoustic radiation impedance \(Z_{rad}\)
- Lab 7, Thurs 4/20, 5072 ECEB (Lect 26): Optional lab (team's choice): a) earbud in ear simulator, b) Wave horn baffle, c) AR-3 Acoustic Supension baffle

- Exam I Lect 1-12: Tuesday March 7, 7-9PM, 3081 ECEB
- Exam II Lect 13-22: Tuesday April 18, 7-9PM, 3081 ECEB

- Final written report DUE May 5; final group presentations Monday May 8, 1:30-4:30pm (UIUC policy)
- The final report is broken down into 25 topics each worth 1 points, for a total of 25 points.
- Individuals will be given points for their role in the presentation (up to 5 points each).
- Up to 5 points of extra credit will be given to the team, if the report is properly formatted (e.g., using LaTeX with high quality figures and equations, etc.).

- Each person should submit a copy of the final report, with a 1 page personal statement your role in the project, along with the role the other team members (i.e., include self- and team-evaluations).

- 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.

- Carlin Network postulates pdf
- Conversion tables for 2-ports (page 1) and ABCD tables from Pipes (pages 2-3): pdf
- Short table of various Fourier Transforms 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 (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**

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