DAFX: Digital Audio Effects, Second Edition

10.1 Introduction

In the context of this book, we are looking for representations of sound signals and signal-processing systems that can give us ways to design sound transformations for a variety of musical applications and contexts. It should have been clear throughout the book that several points of view have to be considered, including a mathematical, and thus objective, perspective, and a perceptual, and thus mainly subjective, standpoint. Both points of view are necessary to fully understand the concept of sound effects and to be able to use the described techniques in practical situations.

The mathematical and signal-processing points of view are straightforward to present, which does not mean easy, since the language of the equations and of flow diagrams is suitable for them. However, the top-down implications are much harder to express due to the huge number of variables involved and to the inherent perceptual subjectivity of the music-making process. This is clearly one of the main challenges of the book and the main reason for its existence.

The use of a spectral representation of a sound yields a perspective that is sometimes closer to the one used in a sound-engineering approach. By understanding the basic concepts of frequency-domain analysis, we are able to acquire the tools to use a large number of effects processors and to understand many types of sound-transformation systems. Moreover, as frequency-domain analysis is a somewhat similar process to the one performed ...