A quick first noisemaker patch with Teensy Audio library and a single pot.

TeensyAudioFirstSynth.ino

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

// GUItool: begin automatically generated code
AudioSynthWaveformSine   sine1;          //xy=69.01041030883789,238.01041412353516
AudioSynthKarplusStrong  string1;        //xy=114.01040649414062,78.01041412353516
AudioSynthSimpleDrum     drum2;          //xy=163.01040649414062,358.9999921321869
AudioSynthSimpleDrum     drum3;          //xy=188.01040649414062,424.9999921321869
AudioSynthSimpleDrum     drum1;          //xy=195.01040649414062,311.9999921321869
AudioSynthNoisePink      pink1;          //xy=197.01040649414062,160.01041412353516
AudioSynthWaveformSineModulated sine_fm1;       //xy=206.01040649414062,229.0103998184204
AudioSynthSimpleDrum     drum4;          //xy=228.01040649414062,488.9999921321869
AudioMixer4              mixer2;         //xy=379.0104064941406,211.01041412353516
AudioMixer4              mixer1;         //xy=501.0104064941406,379.9999921321869
AudioMixer4              mixer3;         //xy=527.010383605957,251.01041412353516
AudioFilterBiquad        biquad1;        //xy=650.0103912353516,310.9999942779541
AudioOutputI2S           i2s1;           //xy=871.010368347168,251.0000410079956
AudioConnection          patchCord1(sine1, sine_fm1);
AudioConnection          patchCord2(string1, 0, mixer2, 1);
AudioConnection          patchCord3(drum2, 0, mixer1, 1);
AudioConnection          patchCord4(drum3, 0, mixer1, 2);
AudioConnection          patchCord5(drum1, 0, mixer1, 0);
AudioConnection          patchCord6(pink1, 0, mixer2, 0);
AudioConnection          patchCord7(sine_fm1, 0, mixer2, 2);
AudioConnection          patchCord8(drum4, 0, mixer1, 3);
AudioConnection          patchCord9(mixer2, 0, mixer3, 0);
AudioConnection          patchCord10(mixer1, 0, mixer3, 1);
AudioConnection          patchCord11(mixer3, biquad1);
AudioConnection          patchCord12(biquad1, 0, i2s1, 0);
AudioConnection          patchCord13(biquad1, 0, i2s1, 1);
AudioControlSGTL5000     sgtl5000_1;     //xy=916.0103530883789,661.0000877380371
// GUItool: end automatically generated code


static uint32_t next;

void setup() {
  // put your setup code here, to run once:

  Serial.begin(115200);

  // audio library init
  AudioMemory(15);

  next = millis() + 1000;

  AudioNoInterrupts();

  drum1.frequency(60);
  drum1.length(1500);
  drum1.secondMix(0.0);
  drum1.pitchMod(0.55);
  
  drum2.frequency(60);
  drum2.length(300);
  drum2.secondMix(0.0);
  drum2.pitchMod(1.0);
  
  drum3.frequency(550);
  drum3.length(400);
  drum3.secondMix(1.0);
  drum3.pitchMod(0.5);

  drum4.frequency(700);
  drum4.length(150);
  drum4.secondMix(0.0);
  drum4.pitchMod(0.0);
  
  pink1.amplitude(0.5);
  
  sine1.frequency(8);
  sine1.amplitude(1);
  
  sine_fm1.amplitude(0.5);
  sine_fm1.frequency(440);
  
  // Butterworth filter, 12 db/octave
  biquad1.setLowpass(0, 800, 0.707);

  sgtl5000_1.enable();
  sgtl5000_1.volume(0.5);

  AudioInterrupts();

}

void loop() {
  // put your main code here, to run repeatedly:
  int ar = analogRead(0);
  int filtFreq = map(ar, 0, 1023, 40, 1000);
  biquad1.setLowpass(0, filtFreq, 0.707);
  sine1.frequency(map(ar, 0, 1023, 1, 100));
  sine_fm1.amplitude(0.01* map(ar, 0, 1023, 50, 5));
  
  static uint32_t num = 0;

  if(millis() == next)
  {
    next = millis() + 500; // (2*ar) + 100;

    switch(num % 4)
    {
      case 0:
        drum1.noteOn();
        string1.noteOn(random(40, 800), 0.4);
        break;
      case 1:
        drum2.noteOn();
        break;
      case 2:
        drum3.noteOn();
        break;
      case 3:
        drum4.noteOn();
        string1.noteOff(0.2);
        break;
    }
    num++;

    Serial.print("Diagnostics: ");
    Serial.print(AudioProcessorUsageMax());
    Serial.print(" ");
    Serial.println(AudioMemoryUsageMax());
    AudioProcessorUsageMaxReset();
  }
}