Time Varying Delay Effects

Julius Smith and Nelson Lee

RealSimple Project¹
Center for Computer Research in Music and Acoustics (CCRMA)
Department of Music, Stanford University
Stanford, California 94305

Detailed Contents (and Navigation)

• Variable Delay Lines
• Delay-Line Interpolation
  • Linear Interpolation
  • First-Order Allpass Interpolation
  
  
• Large Delay Changes
• Specific Time-Varying Delay Effects
  • Flanging
  • Phasing
  • Phasing with First-Order Allpass Filters
  • Phasing with 2nd-Order Allpass Filters
  • Vibrato Simulation
  • Doppler Effect
  • Doppler Simulation
  • Chorus Effect
  • The Leslie
  • Rotating Woofer-Port and Cabinet Simulation
  • Miscellaneous Effects
  
  
• About this document ...

It is often necessary for a delay line to vary in length. (Consider simulating a sound ray when either the source or listener is moving.) In this case, separate read and write pointers are normally used.