EE 313 Linear Systems and Signals - Lecture 11

Audio Effects

• Audio Effect Tutorials
  • Stella, Reverb and Delay Explained, start at 1:11 mark. Delay controls when the echoes arrive, whereas reverb consists of delays that are not controlled.
  • Johnny DeMarco, "EFFECTS 101: Delay", effects of feedforward and feedback delay
  • Johnny DeMarco, "EFFECTS 101: Chorus", use of feedforward delays to make one voice sound like many
  • Johnny DeMarco, "EFFECTS 101: Reverb", reverb (resonant sound from a large room)
  • Danilo Vicari, "Top 10 DELAY Guitar Riffs...iffs...iffs", using controlled guitar delay to create other voices
• Songs
  • Chris Isaak, "Wicked Games", an example of vibrato effort using a guitar whammy bar. Vibrato is a slowly varying modulation effect.
  • The Smiths, "How Soon is Now?", opening guitar riff has a tremolo effect by guitarist Johnny Marr, with a second voice playing slide guitar. Tremolo is rapid change in volume to give a sensation of motion, and is rapidly varying modulation effect. "Songs that Changed Music: The Smiths - How Soon Is Now".
  • Post Malone, "Circles", demonstrating use of delay, chorusing, and reverb in the vocals, and delay and reverb in the instruments. "Vocal Effects of Post Malone - Circles".
• Performance RNN: Generating Music with Expressive Timing and Dynamics

Lecture

• Lecture slides on Infinite Impulse Response (IIR) Filters in PowerPoint format.
  • Fall 2024, Part 1
    • Mini Project 2 Ideal Lowpass Filters
    • Audio effects: long delay (echo) and short delays (chorusing)
    • Origin in discrete-time and continuous-time domains
  • Fall 2024, Part 2
    • Analyzing LTI system responses in three domains
    • First-Order IIR filter transfer function and region of convergence
    • Demo: Three-Domain Connections

• Fall 2018 lecture notes taken by Mr. Houshang Salimian (TA): Part 1 and Part 2

Supplemental Information

• Fall 2023:
  • Part 1:
    • Doccam: Review of Lecture 10 Part 2 LTI Cascades
    • Doccam: First-Order Averaging Filter
    • Doccam: Zero for First-Order Numerator Polynomial
    • Doccam: First-Order Averaging Filter
  • Part 2:
    • Doccam: Review of first-order IIR filters from z to frequency domain
    • Demo: Three-Domain Connections
  • Fall 2021: FIR and IIR filter uses and difference equations, and FIR matched filters

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  Last updated 11/12/24. Send comments to Prof. Evans at bevans@ece.utexas.edu