Modeling disortion

L0st · January 25, 2025, 1:49am

I haven’t delved deeply enough nor completely understand the process but figured I’d ask anyway…

How does one code a different distortion. For example - a rat distortion (lm308) vs. a big muff fuzz pedal (jrc4558)? Is there a variable set that can be modified within daisydsp or - and I hope this isn’t the case - would I have to figure out how to model the circuit?

tele_player · January 25, 2025, 4:26am

Nothing is provided at that level, you’d need to figure it out.

xconverge · January 26, 2025, 12:50am

This post actually got me curious to start to play around a bit

github.com

bkshepherd/DaisySeedProjects/blob/main/Software/GuitarPedal/Effect-Modules/distortion_module.cpp

#include "distortion_module.h"
#include <q/fx/lowpass.hpp>

using namespace bkshepherd;

static const char *s_clippingOptions[5] = {"Hard Clip", "Soft Clip", "Fuzz", "Tube", "Multi Stage"};

static const int s_paramCount = 6;
static const ParameterMetaData s_metaData[s_paramCount] = {
    {
        name : "Level",
        valueType : ParameterValueType::Float,
        valueBinCount : 0,
        defaultValue : {.float_value = 0.5f},
        knobMapping : 0,
        midiCCMapping : -1
    },
    {
        name : "Gain",
        valueType : ParameterValueType::Float,

This file has been truncated. show original

There is a LOT to learn and work with, especially if you want something to sound exactly like a clone of something else…

keyth72 · February 3, 2025, 10:48pm

Maybe not exactly what you’re looking for, but you could use neural nets. It’s kind of a one size fits all approach and you don’t have to know anything about the circuit, but you have to record the device or have access to recordings of it to create new models. The downside is it’s more computationally expensive than analytical methods. This is how NeuralDSP, ToneX, NAM neural amp modeler, and my own GuitarML creates models (or profiles, if you like) of real amps and distortion pedals.

Here are a few open source examples of neural nets for amp/pedal modeling on the Daisy seed: