Doppler Simulation and the Leslie

Julius O. Smith III Stefania Serafin Jonathan AbelDave Berners
Music 421 Handout
Center for Computer Research in Music and Acoustics (CCRMA)

Abstract:

An efficient algorithm for simulating the Doppler effect using interpolating and de-interpolating delay lines is described. The Doppler simulator is used to simulate a rotating horn to achieve the Leslie effect. Measurements of a horn from a real Leslie are used to calibrate angle-dependent digital filters which simulate the changing, angle-dependent, frequency response of the rotating horn.

• DAFx-02 paper (PS) (PDF)
• DAFx-02 presentation (HTML) (PPT) (PDF)

Detailed Contents (and Navigation)

• Introduction
• The Doppler Effect
  • Vector Formulation
  
  
• Doppler Simulation
  • Doppler Simulation via Delay Lines
  • Time-Varying Delay-Line Reads
  • Variable Delay Line in Software
  • Multiple Read Pointers
  • Multiple Write Pointers
  • Stereo Processing
  • System Block Diagram
  
  
• Leslie Simulation
  • Rotating Horn Simulation
  • Leslie Free-Field Horn Measurements
  • Separating Horn Output from Base Leakage
    • Algorithm
    • Results
  
  
• Rotating Woofer-Port and Cabinet Simulation
• Conclusions
• Acknowledgements
• Bibliography
• About this document ...