Doppler Simulation and the Leslie

Julius O. Smith III Stefania Serafin Jonathan Abel Dave Berners
Music 421 Handout
Center for Computer Research in Music and Acoustics (CCRMA)
Department of Music, Stanford University
Stanford, California 94305

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 ...