#239 AudioDSP/SuperCrunch

AudioDSP crunchy symmetrical Schetzen distortion effect based on the pedalSHIELD.

waveform

Notes

SuperCrunch.ino is a crunchy distortion effect from the pedalSHIELD examples. The pushbuttons control the volume of the output signal.

Core algorithm:

distortion is derived on a symmetrical clipping system based on Schetzen formula

Schetzen Formula for symmetrical soft clipping is as follows:

         { 2*x                for  0  <= |x| <= 1/3  }
f(x) =   { (3-(2-3*x)^3)/3    for 1/3 <= |x| <= 2/3 }
         { 1                  for 2/3 <= |x| <= 1   }

Performance

A vast improvement on the asymmetrical Crunch, and a much warmer fuzz than the simple clipping of Distortion.

Delivers quite a warm crunch with pretty good frequency response, although the upper registers of the guitar are a bit beyond the capability of the Arduino.

AudioDspDriver Library

This example uses a private AudioDspDriver library that contains my refactoring of the core algorithms for driving the board. I may split this out as a stand-alone library at some point.

Construction

Breadboard

The Schematic

Build

Credits and References