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

Chapter 2

P. Dutilleux and U. Zölzer

This chapter introduces digital filters for shaping of the audio spectrum and focuses on the main building blocks for this application. We start with basic filters such as lowpass filter topologies and show parametric filters where a coefficient inside the filter directly controls the cut-off frequency and the bandwidth. Filters with finite impulse response (FIR) are introduced and the efficient implementation by the fast convolution technique is discussed. Then typical equalizers such as shelving and peak filters and time-varying filters such as wah-wah filters, phaser and time-varying equalizers are presented.

Contents

• Introduction
• Basic Filters
  • Lowpass Filter Topologies
  • Parametric AP, LP, HP, BP and BR Filters
  • FIR Filters
  • Convolution
• Equalizers
  • Shelving Filters
  • Peak Filters
• Time-varying Filters
  • Wah-wah Filter
  • Phaser
  • Time-varying Equalizers
• Conclusion
• Sound and Music
• Bibliography

Keywords: Digital Filters, Equalizers, IIR Filters, FIR Filters, Fast Convolution, Resonators, Shelving Filters, Peak Filters, Time-varying Systems, Phaser, Wah-wah

Contents