Phase100.dsp

declare name "Phase100";
declare author "JPC";
declare version "1.0";
declare license "CC0-1.0";

// Modélisation de la Fame Sweet TonePhaser PH-10 (un clone de la MXR Phase 100)

// Référence :
//     Kiiski, R., Esqueda, F., & Välimäki, V. (2016).
//     Time-variant gray-box modeling of a phaser pedal.
//     In 19th International Conference on Digital Audio Effects (DAFx-16).

import("stdfaust.lib");

allpass1(f) = fi.iir((a,1.),(a)) with {
  a = -1.+2.*ma.PI*f/ma.SR;
};

allpassCutoffFromPubliCoef(a) = (a+1.)*sr/(2.*ma.PI) with { sr = 44.1e3; };

process(x) = dry + wet with {
  dry = x*d;
  wet = (x <: (+:a1:a2:a3:a4:a5:a6:a7:a8:a9:a10)~*(fb))*w;

  lfotype = checkbox("[1] Color");
  ls = hslider("[2] LFO speed", 0.5, 0., 1., 0.01);
  w = hslider("[3] Wet gain [unit:dB]", -6., -60.0, 20., 1.) : ba.db2linear : si.smoo;
  d = hslider("[4] Dry gain [unit:dB]", -6., -60.0, 20., 1.) : ba.db2linear : si.smoo;
  fb = hslider("[5] Feedback", 0., 0., 0.9, 0.01);

  lf = 0.069 * exp(4. * ls);

  fixedFreq = allpassCutoffFromPubliCoef(-0.89);

  modLfoRangeMin = allpassCutoffFromPubliCoef(-0.84);
  modLfoRangeMax = allpassCutoffFromPubliCoef(-0.39);
  modLfoFreq = os.lf_trianglepos(lf) * (modLfoRangeMax-modLfoRangeMin) + modLfoRangeMin;

  modNoLfoRangeMin = allpassCutoffFromPubliCoef(-0.49);
  modNoLfoRangeMax = allpassCutoffFromPubliCoef(0.77);
  modNoLfoFreq = abs(os.oscsin(lf)) * (modNoLfoRangeMax-modNoLfoRangeMin) + modNoLfoRangeMin;

  modFreq = ba.if(lfotype, modLfoFreq, modNoLfoFreq);

  a1 = allpass1(fixedFreq);
  a2 = allpass1(fixedFreq);
  a3 = allpass1(modFreq);
  a4 = allpass1(modFreq);
  a5 = allpass1(modFreq);
  a6 = allpass1(modFreq);
  a7 = allpass1(modFreq);
  a8 = allpass1(modFreq);
  a9 = allpass1(fixedFreq);
  a10 = allpass1(fixedFreq);
};