EELE 417/517: Acoustics and Audio Engineering

Modern trends in audio engineering (cont.)

TERM PAPERS DUE by NOON, submitted to the online D2L drop box by electronic upload.

Audio effects (notes)

Audio coding:  MPEG 1 Layer 3 as an example of perceptual audio coding.  Modern trends in audio engineering.

Thanksgiving Holiday (no classes)

The Thanksgiving Day holiday in the United States comes from the harvest festival tradition of 16th century agrarian Europe.

The traditional "first Thanksgiving" was held in 17th century America by the Pilgrims (1621).

George Washington instituted a national day of Thanksgiving in 1789, but the event did not gain widespread official acceptance until Abraham Lincoln issued a proclamation on October 3, 1863, setting aside the last Thursday of November as a day of thanksgiving.  Incidentally, this proclamation was issued just a few weeks before Lincoln gave his famous address at Gettysburg (November 19, 1863). 

Every president after Lincoln continued the Thanksgiving Day tradition, and Congress adopted the fourth Thursday of November as a national holiday in 1941.

The fourth Thursday can be as early as Nov. 22 (like 2007), and as late as Nov. 28. Look ahead formula: to determine the date of Thanksgiving next year: subtract one from the day of the month this year; then if next year is a leap year, subtract 1 more. If that result is less than 22, add 7.  Example:  in 2015 the date was November 26, so in 2016 (a leap year) Thanksgiving is on the 24th.  Next year, 2017, it will be on Nov. 23.

Audio signals and electrical systems .

Handout

Additional notes on electrical system grounding concepts.

Microphone examples;  begin Audio signals and electrical systems; principles of low-noise grounding and shielding

Exam #2 in class. Closed book; pencil, calculator, 1-2 sheets of hand-written notes allowed.

Transducers (cont.)

Review for midterm exam.

Quiz 5 due at class time; EELE 517 paper topics due at class time.

No MSU classes this day (Veterans Day)

Transducers:  microphones and loudspeakers .

Transducer notes

Reminder:  mid-term in class on Wed. Nov. 16

Architectural acoustics (cont.)
Sabine examples; measurement examples

Architectural acoustics (cont.)

Course term paper assigned:  Undergraduate EELE 417 assignment;  Graduate EELE 517 assignment

Quiz 5 assigned.

Notes on authoritative references and plagiarism.

Architectural acoustics -- basic Sabine equation and rationale (Chapter 12).

Absorption, reflection, diffusion.
Acoustical measurements and characterization.

Environmental acoustics and sound isolation.

STC (sound transmission class) handout and structure examples.

Computer homework Matlab solution example.

NOTE:  Mid-term exam 2  will be held in class on Wednesday Nov. 16

Computer homework problem due at the start of class (hand in hardcopy).

Environmental and architectural acoustical considerations (Chapter 13, then Chapter 12).

Quiz 4 due by class time (noon).

Environmental acoustics. Chapter 13.

Strengths and weaknesses of the human hearing system.

Note on computer homework assignment: Question about the off-axis angle of the 2 cm driver as a function of the observation angle, theta.

One way is to think of it as a two vector problem.  Vector #1 is the axis of the 2 cm driver and remains fixed, while Vector #2 is the "r2" vector from the center of the 2 cm driver down to the observation arc 2 meters from the lower driver.

Choose the origin (0,0,0) to be at the center of the 2 cm driver.  Then the axis vector Vector #1 can be represented (x, y, z) as (2,0,0), and the Vector #2 is the position on the observation arc, represented by  ( 2*cos(theta12), 2*sin(theta12), -0.2 )  .

So you have two vectors as a function of theta12, and need to find the angle between those vectors, which is the off-axis angle for the 2 cm driver. Recall that the vector cross product relates the vectors and the angle between them, gamma.   | V1  x  V2 | = |V1| |V2| sin(gamma)  .   See if you can use this viewpoint and the Cartesian cross product calculation to find the angle information you need.

Physiology of the ear.

Computer homework problem assigned.

Ear Anatomy :

Plane circular piston:  radiation impedance

Quiz #4 (D2L) is posted.

Assignment: Complete quiz (two attempts) before class time on Wednesday, Oct. 26 (noon).

Start physiology and psychology of human hearing (ch. 11). Hearing system:  frequency response of the ear

Finish plane piston model; 

Assignment: Read chapter 11.  Prepare for quiz 4 (posted to D2L soon).

Exam #1 returned.

Plane circular piston model for a loudspeaker driver:  far field off-axis, and near field on-axis.

"Simple source" model for sources with ka <<1.  Start consideration of plane circular piston model for loudspeaker driver.

Quiz #3 will be assigned.

Begin Chapter 7: radiation and reception of acoustic waves

Spherical sound sources and acoustics of a small pulsating sphere model.

Before RADAR:  Listening for enemy aircraft

Attempts to classify artillery at a great distance

Decibel and weighting functions.

Notes on the Decibel Scale for engineering

Reminder:  D2L quiz due by class time.

Assignment: practice problems 5.12.3, 5.12.12, and 5.13.2, from Kinsler and Frey.

Note:  Exam #1 is planned for Wednesday, Oct. 12, in class.  More info to follow soon.

Ch. 5 (cont.):  spherical waves

Quiz #2 (D2L) is posted.

Assignment: Complete quiz (two attempts) before class time on Wednesday, Sept. 21 (noon)

Ch. 5 (cont.): linear acoustic wave equation, plane waves, particle speed, and specific acoustic impedance.

Assignment: Practice problems (not collected) 1.13.3 (note that a “t” is missing in the cos argument), 1.15.7, 5.2.4, and 5.6.2 .

The linear acoustic wave equation:  symbols and fundamentals.

Assignment:  Read Chapter 5 of the K&F textbook.

Damped oscillators, Driven oscillators, and electrical analogies.

Reminder:  D2L quiz due by class time on Friday.

Labor Day (no class)

University Holiday.

Continue basic units and acoustical quantities.  Review of simple oscillators.

Assignment: HW#1, three problems from the K&F text:  1.3.2, 1.3.3C, 1.6.1 .

Read and understand Chapter 1 of the K&F textbook, then work on the HW#1 problems. The problem solutions will NOT be collected.  These are simply practice problems for your own preparation.

There is a D2L quiz that will go active at 10AM on 9/2/2016.  Between now and class time on Friday, September 9, 2016, you have TWO attempts at the quiz.  Your Quiz 1 score will be the higher of your two attempts.  Each attempt is allowed one hour, although it should not take that long.

Basic units and acoustical quantities.  Review of simple oscillators.

Assignment: Read Chapter 1 of Kinsler and Frey.

Also:  information about downloading MATLAB at MSU.

First class meeting at noon in Reid 201.

Reminder of the Freshmen Convocation, Thursday, Sept. 1, 7:30PM, Field House.  All ECE students are welcome and encouraged to attend!

EELE 417 course introduction and some listening experiments.  Go over the syllabus and course expectations/goals/policies.