[chuck-users] apropos jcr paradox

21 Mar 2017

      Hi,

Remembering Jean Claude Risset. Just thought I'll share my take on the 
glissandi paradox. -- Juan Reyes.

//* ******************************************************************
//*
//*  Risset's paradox aka Shepard Tone
//*                   (see Dodge's Elements of CM pp-94-96)
//*
//* This take Juan Reyes, 03/08/2017
//*
//*
//* Toggle values: baseFreq and baseDur

// sample rate
1::second / 1::samp => float srate;

// Function for normal curves to factor amplitude
fun float normfn (float x, float d)
{
     return Math.exp(-4.8283*(1-Math.cos(2*Math.PI*
     (x-((d*srate*0.5)-0.5))/(d*srate))));
}

// Toggle values
// --------------

1000.0 => float baseFreq;
3.33 => float baseDur;
baseDur*srate => float samples;
samples/7.0 => float phaseoffs;

// Frequency Factors
[0.0, 51.2, 102.4, 153.6, 204.8, 256.0, 307.2, 358.4,
409.6, 460.8] @=> float fqFactors[];

// A bank of sine oscillators
SinOsc oscBank[10];

// Gains for oscillator bank
Gain gainsArr[10];

// Signal
for(0=> int i; i < oscBank.cap(); i++)
{
     baseFreq+fqFactors[i]=> oscBank[i].freq;
     oscBank[i] => gainsArr[i] => dac;
}

// Count samples
0.0 => float sx;

while( true ) {

     for (0 => int j; j < oscBank.cap(); j++)
     {
         0.25*normfn((sx+((j+1)*phaseoffs)), baseDur)
         => gainsArr[j].gain;
     }

     if (sx > samples)
     {
         0 => sx;
     }
     else
     {
         1 +=> sx;
     }

     //     advance "1" sample.
     1.0::samp => now;
}