Weird pitch quirk I noticed with arbitraryWaveform

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Ross Fish

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In a project I'm working on, I have two pots controlling arbitraryWaveform. One of them changes the pitch and the other one is a switch case selecting a variety of wavetables.

At one point in my progress I was turning the wavetable selection pot and as the pointer in the array increased, the pitch variable in the code would slowly increase with it, by almost a whole interval upwards.

I monitored both of the ADCs for the pots and confirmed that the change that was occurring was digital in nature, and not happening on the hardware side of things.

The solution was incredibly simple: the frequency for arbitraryWaveform had to be declared before the waveform is declared, a simple order of operations issue. If anyone else is doing something similar and has issues with arbitraryWaveform maintaining pitch stability try giving this a shot and it might help.

Has anyone else experienced this?
 
Code: 
/*
             Stargazer
    Created by Ross Fish 2018
        Moffenzeef Modular
  http://moffenzeefmodular.com/

        Waveforms by Adventure Kid
    AKWF waveforms are Public Domain
  https://www.adventurekid.se/akrt/waveforms/adventure-kid-waveforms/

    Waveforms formatted for Teensy by Datanoise
  https://github.com/DatanoiseTV/AKWF_WaveForms
*/

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioSynthWaveform       waveform2;      //xy=1628,1374
AudioSynthWaveform       waveform1;      //xy=1631,1335
AudioSynthWaveform       waveform3;      //xy=1746,1425
AudioMixer4              mixer1;         //xy=1777,1355
AudioEffectWaveshaper    waveshape1;     //xy=1874,1470
AudioFilterStateVariable filter1;        //xy=1902,1362
AudioSynthWaveformDc     dc1;            //xy=2009,1298
AudioSynthWaveform       waveform5;      //xy=2013,1244
AudioAnalyzeRMS          rms2;           //xy=2020,1476
AudioSynthWaveform       waveform4;      //xy=2024,1412
AudioEffectBitcrusher    bitcrusher1;    //xy=2035,1356
AudioEffectWaveshaper    waveshape2;     //xy=2162,1188
AudioMixer4              mixer3;         //xy=2169,1262
AudioEffectWaveshaper    waveshape3;     //xy=2172,1446
AudioFilterStateVariable filter2;        //xy=2174,1361
AudioAnalyzeRMS          rms4;           //xy=2306,1191
AudioAnalyzeRMS          rms3;           //xy=2313,1447
AudioEffectMultiply      multiply1;      //xy=2332,1313
AudioMixer4              mixer2;         //xy=2467,1328
AudioOutputAnalog        dac1;           //xy=2617,1315
AudioConnection          patchCord1(waveform2, 0, mixer1, 1);
AudioConnection          patchCord2(waveform1, 0, mixer1, 0);
AudioConnection          patchCord3(waveform3, 0, filter1, 1);
AudioConnection          patchCord4(waveform3, waveshape1);
AudioConnection          patchCord5(mixer1, 0, filter1, 0);
AudioConnection          patchCord6(waveshape1, rms2);
AudioConnection          patchCord7(filter1, 0, bitcrusher1, 0);
AudioConnection          patchCord8(dc1, 0, mixer3, 1);
AudioConnection          patchCord9(waveform5, 0, mixer3, 0);
AudioConnection          patchCord10(waveform5, waveshape2);
AudioConnection          patchCord11(waveform4, 0, filter2, 1);
AudioConnection          patchCord12(waveform4, waveshape3);
AudioConnection          patchCord13(bitcrusher1, 0, filter2, 0);
AudioConnection          patchCord14(waveshape2, rms4);
AudioConnection          patchCord15(mixer3, 0, multiply1, 0);
AudioConnection          patchCord16(waveshape3, rms3);
AudioConnection          patchCord17(filter2, 0, multiply1, 1);
AudioConnection          patchCord18(multiply1, 0, mixer2, 0);
AudioConnection          patchCord19(mixer2, dac1);
// GUItool: end automatically generated code


float osc1 = 0;
float osc2 = 0;
float oscMix = 0;

float cutoff1 = 0;
float res1 = 0;
float cutoff2 = 0;
float res2 = 0;

float LFO1AMP = 0;
float LFO2AMP = 0;
float LFO3AMP = 0;

float LFO1FREQ = 0;
float LFO1MATH = 0;
float LFO2FREQ = 0;
float LFO2MATH = 0;
float LFO3FREQ = 0;
float LFO3MATH = 0;

int waveSelect1CurrentState = 0;
int waveSelect1LastState = 0;

int waveSelect2CurrentState = 0;
int waveSelect2LastState = 0;

int waveSelect3CurrentState = 0;
int waveSelect3LastState = 0;

int waveSelect4CurrentState = 0;
int waveSelect4LastState = 0;

int bitRate = 0;
int sampleRedux = 0;

int expPedal = 0;

int LFO1led = 0;
int LFO2led = 0;
int LFO3led = 0;

float rectify[2] = {0.0, 1.0};

float sub = 0;

float diffWAVE = 0;
int currentWAVE = 0;
float smoothWAVE = 0;

float diffOSC = 0;
int currentADCOSC = 0;
float smoothADCOSC = 0;

float diffPEDAL = 0;
float smoothADCPEDAL = 0;
int currentADCPEDAL = 0;

int waveSelect = 0;

#define MAX_FREQ 600    // max frequency < - > arbitraryWaveform(array, maxFreq); 

#include "AKWF_R.H"
#include "AKWF_aguitar.H"
#include "AKWF_altosax.H"
#include "AKWF_birds.H"
#include "AKWF_bitreduced.H"
#include "AKWF_blended.H"
#include "AKWF_bsaw.H"
#include "AKWF_c604.H"
#include "AKWF_clavinet.H"
#include "AKWF_distorted.H"
#include "AKWF_eguitar.H"
#include "AKWF_eorgan.H"
#include "AKWF_epiano.H"
#include "AKWF_fmsynth.H"
#include "AKWF_granular.H"
#include "AKWF_hvoice.H"
#include "AKWF_overtone.H"

struct WaveTable {
  int16_t const* table;
};

#define TABLE_NUM 91 // 

WaveTable waveTables[TABLE_NUM] {
  AKWF_R_sym_saw_15,
  AKWF_R_sym_saw_25,
  AKWF_aguitar_0008,
  AKWF_altosax_0005,
  AKWF_birds_0002,
  AKWF_birds_0004,
  AKWF_birds_0005,
  AKWF_bitreduced_0002,
  AKWF_bitreduced_0006,
  AKWF_bitreduced_0007,
  AKWF_bitreduced_0011,
  AKWF_bitreduced_0013,
  AKWF_bitreduced_0016,
  AKWF_bitreduced_0019,
  AKWF_bitreduced_0022,
  AKWF_bitreduced_0026,
  AKWF_bitreduced_0028,
  AKWF_bitreduced_0031,
  AKWF_bitreduced_0032,
  AKWF_bitreduced_0038,
  AKWF_blended_0002,
  AKWF_blended_0003,
  AKWF_blended_0007,
  AKWF_blended_0012,
  AKWF_blended_0013,
  AKWF_blended_0030,
  AKWF_bsaw_0001,
  AKWF_c604_0004,
  AKWF_clavinet_0001,
  AKWF_distorted_0004,
  AKWF_distorted_0005,
  AKWF_distorted_0009,
  AKWF_distorted_0010,
  AKWF_distorted_0014,
  AKWF_distorted_0015,
  AKWF_distorted_0017,
  AKWF_distorted_0018,
  AKWF_distorted_0023,
  AKWF_distorted_0026,
  AKWF_distorted_0027,
  AKWF_distorted_0022,
  AKWF_distorted_0023,
  AKWF_eguitar_0003,
  AKWF_eorgan_0042,
  AKWF_eorgan_0043,
  AKWF_eorgan_0046,
  AKWF_eorgan_0055,
  AKWF_eorgan_0058,
  AKWF_eorgan_0059,
  AKWF_eorgan_0060,
  AKWF_eorgan_0061,
  AKWF_eorgan_0062,
  AKWF_epiano_0005,
  AKWF_epiano_0008,
  AKWF_epiano_0008,
  AKWF_fmsynth_0002,
  AKWF_fmsynth_0004,
  AKWF_fmsynth_0005,
  AKWF_fmsynth_0006,
  AKWF_fmsynth_0007,
  AKWF_fmsynth_0024,
  AKWF_fmsynth_0034,
  AKWF_fmsynth_0035,
  AKWF_fmsynth_0036,
  AKWF_fmsynth_0040,
  AKWF_fmsynth_0051,
  AKWF_fmsynth_0055,
  AKWF_fmsynth_0056,
  AKWF_fmsynth_0057,
  AKWF_fmsynth_0058,
  AKWF_fmsynth_0059,
  AKWF_fmsynth_0060,
  AKWF_granular_0009,
  AKWF_granular_0020,
  AKWF_granular_0033,
  AKWF_hvoice_0030,
  AKWF_hvoice_0033,
  AKWF_hvoice_0035,
  AKWF_hvoice_0036,
  AKWF_hvoice_0039,
  AKWF_hvoice_0048,
  AKWF_hvoice_0039,
  AKWF_hvoice_0052,
  AKWF_hvoice_0054,
  AKWF_hvoice_0056,
  AKWF_hvoice_0071,
  AKWF_overtone_0001,
  AKWF_overtone_0005,
  AKWF_overtone_0017,
  AKWF_overtone_0026,
  AKWF_overtone_0028,
};

short waveShapesLFO1[6] = {
  WAVEFORM_SINE,
  WAVEFORM_TRIANGLE,
  WAVEFORM_SAWTOOTH,
  WAVEFORM_SAWTOOTH_REVERSE,
  WAVEFORM_SQUARE,
  WAVEFORM_SAMPLE_HOLD,
};

short waveShapesLFO2[6] = {
  WAVEFORM_SINE,
  WAVEFORM_TRIANGLE,
  WAVEFORM_SAWTOOTH,
  WAVEFORM_SAWTOOTH_REVERSE,
  WAVEFORM_SQUARE,
  WAVEFORM_SAMPLE_HOLD,
};

short waveShapesLFO3[6] = {
  WAVEFORM_SINE,
  WAVEFORM_TRIANGLE,
  WAVEFORM_SAWTOOTH,
  WAVEFORM_SAWTOOTH_REVERSE,
  WAVEFORM_SQUARE,
  WAVEFORM_SAMPLE_HOLD,
};

float mapfloat(float x, float in_min, float in_max, float out_min, float out_max)
{
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

void setup() {
  waveform1.begin(WAVEFORM_ARBITRARY);
  waveform2.begin(WAVEFORM_ARBITRARY);
  AudioMemory(20);  // put your setup code here, to run once:
  dac1.analogReference(EXTERNAL);
  analogReference(EXTERNAL);
  pinMode(2, INPUT); // Sub OCT switch
  pinMode(13, OUTPUT); // Teensy LED
  pinMode(3, OUTPUT); // Main LED
  digitalWrite(13, HIGH);
  digitalWrite(3, HIGH);
  // Serial.begin(9600);
}

void loop() {

  // MAIN OSCILLATOR FREQUENCY & AMPLITUDE

  waveform1.amplitude(0.8);

  currentADCOSC = analogRead(A1);
  diffOSC = currentADCOSC - smoothADCOSC;
  smoothADCOSC = smoothADCOSC + (diffOSC * 0.01f); // Decimal value is digital lowpass, lower value = more slew
  osc1 = mapfloat(smoothADCOSC, 0.0, 1023.0, 1.0, 500.0);
  waveform1.frequency(osc1);

  // MAIN OSCILLATOR WAVETABLE SELECTION
  currentWAVE = analogRead(A3);
  diffWAVE = currentWAVE - smoothWAVE;
  smoothWAVE = smoothWAVE + (diffWAVE * 0.008f); // Decimal value is digital lowpass, lower value = more slew

  waveSelect = map(smoothWAVE, 0, 1023, 1, 91);

  struct WaveTable* waveTable  = &waveTables[waveSelect];
  int16_t* wave = const_cast<short int*>(waveTable->table);

  waveform1.arbitraryWaveform(wave, MAX_FREQ);
  waveform2.arbitraryWaveform(wave, MAX_FREQ);
 
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