Book on DAFX - Digital Audio Effects Edited by Udo Zölzer ISBN: 0-471-49078-4 John Wiley & Sons, 2002

Chapter 10

X. Amatriain, J. Bonada, A. Loscos and X. Serra

This chapter deals with spectral processing where the audio signal is represented by spectral models such as sinusoids plus a residual signal. We introduce two spectral models: Sinusoidal and Sinusoidal plus Residual. With these models we can identify and extract higher-level information of a sound, such as: harmonics, pitch, spectral shape, vibrato, or note boundaries. This analysis step brings the representation closer to our perceptual understanding of a sound. Techniques for analysis, higher-level feature analysis and synthesis are introduced and a variety of new audio effects based on these spectral models are discussed. Effect applications go from nearly lossless time stretching, pitch transposition, vibrato, spectral shape shift, gender change to harmonizer and morphing effects.

Contents

• Introduction
• Spectral Models
  • Sinusoidal Model
  • Sinusoidal plus Residual Model
• Techniques
  • Analysis
  • Feature analysis
  • Synthesis
  • Main Analysis-Synthesis Application
• FX and Transformations
  • Filtering with Arbitrary Resolution
  • Partial Dependent Frequency Scaling
  • Pitch Transposition with Timbre Preservation
  • Vibrato and Tremolo
  • Spectral Shape Shift
  • Gender Change
  • Harmonizer
  • Hoarseness
  • Morphing
• Content Dependent Processing
  • Real-Time Singing Voice Conversion
  • Time Scaling
• Conclusion
• Bibliography

Keywords: Modeling, Spectral Models, Signal Representations, Transforms, Fourier Transforms, Feature Extraction

Contents