Acoustic Modeling with Digital Delay

Delay effects, such as phasing, flanging, chorus, and artificial reverberation, as well as digital waveguide models (Chapter 6), are built using delay lines, simple digital filter sections, and sometimes nonlinear elements and modulation. We will focus on these elements in the simpler context of delay effects before using them for sound synthesis.

• Delay Lines
  • A Software Delay Line
  
  
• Acoustic Wave Propagation Simulation
  • Traveling Waves
  • Damped Traveling Waves
  • Dispersive Traveling Waves
  • Converting Propagation Distance to Delay Length
  • Spherical Waves from a Point Source
  • Reflection of Spherical or Plane Waves
  • An Acoustic Echo Simulator
  • Program for Acoustic Echo Simulation
  
  
• Lossy Acoustic Propagation
  • Exponentially Decaying Traveling Waves
  • Frequency-Dependent Air-Absorption Filtering
  • Dispersive Traveling Waves
  • Summary
  
  
• Digital Waveguides
  • Physical Outputs
  • Physical Inputs
  • Interacting Physical Input
  
  
• Tapped Delay Line (TDL)
  • Example Tapped Delay Line
  • Transposed Tapped Delay Line
  • TDL for Parallel Processing
  • General Causal FIR Filters
  
  
• Comb Filters
  • Feedforward Comb Filters
  • Feedback Comb Filters
  • Feedforward Comb Filter Amplitude Response
  • Feedback Comb Filter Amplitude Response
  • Filtered-Feedback Comb Filters
  • Equivalence of Parallel Combs to TDLs
  • Equivalence of Series Combs to TDLs
  • Time Varying Comb Filters
  
  
• Feedback Delay Networks (FDN)
  • FDN and State Space Descriptions
  • Single-Input, Single-Output (SISO) FDN
  • FDN Stability
  
  
• Allpass Filters
  • Allpass from Two Combs
  • Nested Allpass Filters
  • More General Allpass Filters
  • Example Allpass Filters
  • Gerzon Nested MIMO Allpass
  
  
• Allpass Digital Waveguide Networks
  • Signal Scattering
  • Digital Waveguide Networks