Designing Audio Effect Plugins in C++, 2nd Edition

Chapter 10Basic DSP Theory

You want to get a grip on the underlying DSP theory of filters for several reasons: it helps to understand the anatomy of the filter because you want to be able to implement new filter designs as they appear, rather than wait for someone else to code it; a deeper understanding of the theory can only help your coding strategy; and the same DSP analysis and mathematical models can be applied to all sorts of non-EQ effects like delay, chorusing, reverb, and compression. In order to intuitively understand the foundation of DSP theory, you need to review some math and engineering concepts.

10.1 The Complex Sinusoid

The analysis and design of digital filters uses the sinusoid as its basic stimulus function. Since Fourier ...