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

Chapter 13Modulators: LFOs and Envelope Detectors

The basic definition of “modulate” is to change something. In our plugins, we will use modulators to alter plugin parameters in real time on a constant update basis. This means that our plugin parameters will undergo a constant updating of their values and we will generally make updates on every sample interval. Modulators will take static plugins like filters and delays and turn them into dynamic time-varying processors such as envelope followers and chorus/flanger/vibrato devices. There are two fundamental kinds of modulators we will use in our FX plugins: LFOs and envelope detectors (or simply detectors). LFOs generate time-varying waveforms such as sine, sawtooth, and triangle with relatively ...