Modelagem computacional de efeitos de distorções não lineares para guitarra elétrica

Abstract

This work objective is to review and to simulate some of the guitar distortion algo-rithms, either simulating tube amplifiers or distortion pedals that have characterized the timbralcharacteristics of these instruments over the last 50 years. In recent times, the dissemination ofdigital signal processing has enabled the simulation of such devices either by embedded systems orby studio recording software plugins. There are basically two approaches for the simulation of thesedevices, a black box and a white box. In the black box approach, static waveshapers simplify thesystem by approximating its response by a nonlinear function that resembles the devices operation.Some of the equations presented in the literature are simulated in this work, and the resulting outputsignals in the time and frequency domains are given. In the white box approach, circuit parametersare used in modeling the physical system. These models can either be simulated by Wave DigitalFilters or by a system of ordinary differential equations in the state space representation, which issolved by numerical methods. White box approaches yield more precise results, but demand morecomputer resources, therefore a compromise between efficiency and precision must be found for realtime simulation.