Last Modified : Sun, 31 Oct 21

- Instructor: Jont Allen (jontalle@illinois.edu)
- Class Time: 12:30-15:50 Tues/Thur, Place: 3081-ECEB; ECE, UIUC, UI Calendar
- Lectures will be presented on Tuesdays and Labs on must Thursdays (see schedule for details). Lab teams will compete in small groups of 3-4 students.
- Office hours: Mondays 3-4PM, 3020 ECEB; Friday 3-4PM; ECEB-4034
- Text:
*Beranek & Mellow*(2012) UIUC-ebook; Buy; Browse; Reference text:*Electroacoustics*(pdf) **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 (HW A-E); Links to these assignments are available in the
*Daily Schedule*below.

Many of the problems are directly taken from the homework problems in*anInvitation*pdf. - Labs Labs always on Thur (but not every week: see schedule).

Session 1: Thursdays 11:30AM-2:30PM

Session 2: Thursdays 1:30AM-3:30PM. groups- Lab manual In preparation for each lab, please prepare by reading the corresponding TO DO section of the manual.

How to measure 2-ports: (video)

**Lab location: 4022 ECE (you have ICard access). Four*network-analyzers*(*MU boxes*) in cabinet on right

**Software for Labs: G7-software S19, G7-software S18 (runs on Octave and/or Matlab;Supports MS-Windows, MAC and Linux. See Lab Manual for details). - Tools: MATLAB, Octave, Latex GUI (Not sure you need to register)

- Lab manual In preparation for each lab, please prepare by reading the corresponding TO DO section of the manual.
- Exam 1, Exam2, Final Report: Format for final report pdf, LaTeX example: zip
- Loudspeaker Project (one hour Extra credit)
- This week's schedule

L
| W
| D
| Date
| TOPIC |

Part I: Basic Acoustics (Chaps. 1-2: 3 Lect) | ||||

M | 1/14 | First day of instruction, Spring 2019 | ||

1 | 3 | T | 1/15 | *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 Text: BeranekMellow, Ch 1, p. 1-17; History (pdf) |

2 | R | 1/17 | *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 Text: Ch 2, p. 21-28 (Wave Equation) and derivation pdf | |

3 | 4 | T | 1/22 | *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. 29-51 * Homework A (Discuss on Lect 5; DUE Lect 7) |

Part II: Circuit Analysis (Chaps. 3-4: 4 Lect, 1 Lab) | ||||

4
0 | R | 1/24 | *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?) *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; Integration in the complex \(s\) plane pdf | |

5 | 5 | T | 1/29 | *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 | 1/31 | *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: Carlin, Kim et al | |

7 | 6 | T | 2/5 | *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 Lect 11)*Read Ch 3, p.106-118 |

8 1 | R | 2/7 | *Lab 1 (4022 ECEB): Setup of hardware; Learn how to make impedance measurements: Lab manual*Install g7play software package *Construct circuit board to measure loudspeaker impedance, and debug it by measuring a resistor in series with a capacitor having RC time constant of 2 ms and cutoff freq=1/2\(\pi RC\). *Read: Lab manual | |

Part III: Electrodynamic Loudspeakers (Chap. 6: 4 Lects, 2 Labs, Exam I) | ||||

9 | 7 | T | 2/12 | *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 Lect 11) *Read Ch 3 ABCD Matrix analysis of circuits |

10 2 | R | 2/14 | *Lab 2 (4022 ECEB):*Measurement of 2-port RC (example from HWb) (EvalResp.m) Measure 2-ports: (video) *Read Ch 6 Electrodynamic loudspeakers | |

11 | 8 | T | 2/19 | *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 Lect 14), SpeakerModel.m*Read Ch 3, p. 94-96 Speaker motor |

12 3 | R | 2/21 | *Lab 3 (4022 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 Transducer impedance + Lab 3 of Lab manual | |

13 | 9 | T | 2/26 | *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 Lec 14) *Read Mason 1928; Text: 4.23, p.180-198 |

14 | R | 2/28 | *Lab 4 (4022 ECEB):*Face-to-face measurements of two loudspeakers * HW-C DUEAllen out of town *Read p. 106-107 | |

15 | 10 | T | 3/5 | *Optional office hrs (3081 ECEB) |

15 | 10 | T | 3/5 | EXAM I You may use your final report during the exam; Tuesday Mar 5, @ 7-9PM Room: 3020 ECEB |

Part IV: Horns with Viscous & Thermal loss; Reciprocity (Chaps. 9-4: 6 Lect, 3 Labs) | ||||

16 | R | 3/7 | *Lect: Acoustic transmission lines *Thevenin & Norton parameters of a loudspeaker: \(P_0(f), U_0(f), Z_0(s)\) * Homework D: Acoustics & Transmission Lines (Discuss on Lect 17; due Lect 20)*Read Sect. 17.19, p. 358-373 | |

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

17 | 11 | T | 3/12 | *Lect: Reciprocity calibration of a loudspeaker: How To. *Discuss HW-D *Read Lab 3-4, p. 14-19 |

18 4 | R | 3/14 | *Lab 5 (4022 ECEB): Reciprocity calibration; verification with a probe microphone (Etymotic Research-7C) | |

12 | M F | 3/16 | Spring Break | |

19 | 13 | T | 3/26 | *Lect: Speaker Acoustic Thevenin calibration using 2 or more acoustics loads *Read: Thevenin model of a resistor: pdf |

20 5 | R | 3/28 | *Lab 6 (4022 ECEB): Speaker Acoustic Thevenin calibration using 2 acoustics loads (Duct tape)* HW-D DUE* Homework E (Discuss on Lect 23; DUE Lect 24); Starter files for middle ear simulation (txline.m, gamma.m)*Read: ABCD for Thevenin source | |

21 | 14 | T | 4/2 | *Lect: 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 | 4/4 | *Lab 7 (4022 ECEB): Measure the speaker radiation impedance \(Z_{rad}(s)\) and compare to the spherical radiator*Read: Radiation impedance of sphere | |

23
6 | 15 | T | 4/9 | *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 | 4/11 | 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 | 4/16 | NO Class: Exam II You may use your final report during the exam @ 7-9:30PM Room: 3081 ECEBGrade report pdf |

Part V: Topics in Audio Engineering (Chaps. 10-11: 3 Lects., 2 Labs) | ||||

26 | R | 4/18 | *Lab 8 (4022 ECEB): Choice of 1) Earbud in ear simulator, 2) Horn baffle, 3) Acoustic suspension baffle (AR-3)*Work on lab report (Example LaTeX) | |

27 7 | 17 | T | 4/23 | *Lect: Baffling loudspeaker topics *Read Ch7, p. 289-320 |

28 | R | 4/25 | *Guest Lecture (confirmed): Mead Killion CEO Etymotic Research, Elk Grove Village IL | |

29 | 18 | T | 4/30 | *Final Lect; Open discussion of course and lab report content; Class discussion: What did you learned? |

W | 5/1 | Instruction ends | ||

R | 5/2 | Reading Day | ||

F | 5/3 | Group lab report deadline extended: Please give me both a paper and pdf copy. NO DOC files *Final Exams begin (Our final is the lab project oral presentation on loudspeakers) | ||

F | 5/10 | Group presentations 8-11 AM3081 (official schedule 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 1/22 (Lect 3), DUE Lect 7 : Acoustics and LT/FT
- HW-B, Assigned 2/5 (Lect 7), DUE Lect 11: T, Z matrix + Transmission line theory
- HW-C, Assigned Lect 11, DUE Lect 14: Electrodynamic ABCD model with Gyrator, Motional impedance & \(Z_A(s)\) TL load
- HW-D, Assigned Lect 16, DUE Lect 20: Horns, reciprocity, Thevenin model of Johnson resistor noise
- HW-E, Assigned Lect 20, DUE Lect 24: Middle ear model

- Lab Lab Manual
- Lab 0, Lect 4, Thurs 1/24, 3081 ECEB : a) Define teams; b) Define goals of Labs
- Lab 1, Lect 8, Thurs 2/7, 4022 ECEB : a) Op-amp circuit construction; b) MU calibraton with a 1 kohm resistor
- Lab 2, Lect 10, Thurs 2/14, 4022 ECEB : Measure 2-ports: (video)

a) RC lowpass (EvalResp.m),

b) Twin-Tee notch filter - Lab 3, Lect 12, Thurs 2/21, 4022 ECEB : Speaker electrical impedance:

a) Loaded,

b) Unloaded,

c) Compute speaker motional impedance

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

- Lab 4, Lect 18, Thurs 3/14, 4022 ECEB : Reciprocity calibration with probe mic verification

(syms algebra: RecipCal.m)

- Lab 5, Lect 20, Thurs 3/28, 4022 ECEB : Thevenin Equivalent circuit via 2 acoustic loads (Duct Tape cavities)
- Lab 6, Lect 22, Thurs 4/4, 4022 ECEB : Measure speaker acoustic radiation impedance \(Z_{rad}\)
- Lab 7, Lect 26, Thurs 4/18, 4022 ECEB : 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 5, 7-9PM, 3081 ECEB
- Exam II Lect 13-22: Thursday April 16, 7-9PM, 3081 ECEB

- Final written report DUE May 3; final group presentations: 8:00-11:00 a.m., Fri, May 10 (UIUC Exam schedule)
- 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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