Teensy - can't hear audio output

Hi
I am trying to use the teensy 3.6 to control some on board audio. but i am having problems getting the audio output to work. I have even tried the example code from this video - which is just making a simple ramp TEENSY-Synth PART 1: BUILD IT - YouTube and there is no audio coming out either

my code is below. I am using the teensy audio shield, i was just trying to use the DAC and the corresponding pins -but now with no sound i thought i would try the audio shield.

below is my code. Any help would be greatly appreciated

I am using a custom made sensor that I am wanting to control the sound, i'm scaling and smoothing the input and i can see that working in the serial monitor - just no sound is coming out

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

// GUItool: begin automatically generated code
AudioSynthWaveform       waveform1;      //xy=242,258
AudioOutputI2S           i2s1;           //xy=546,380
AudioConnection          patchCord1(waveform1, 0, i2s1, 1);
AudioConnection          patchCord2(waveform1, 0, i2s1, 0);
AudioControlSGTL5000     sgtl5000_1;     //xy=820,60
// GUItool: end automatically generated code



// set up pot
const int STRETCH = 14;


// Define the number of samples to keep track of. The higher the number, the
// more the readings will be smoothed, but the slower the output will respond to
// the input. Using a constant rather than a normal variable lets us use this
// value to determine the size of the readings array.
const int numReadings = 100;

int readings[numReadings];      // the readings from the analog input
int readIndex = 0;              // the index of the current reading
int total = 0;                  // the running total
int average = 0;                // the average

int inputPin = A0;//currently stretch

void setup() {
  Serial.begin(9600);
  AudioMemory(20); // Dynamic memory is allocated to be used exclusively by the Audio library
  sgtl5000_1.enable();
  sgtl5000_1.volume(0.6);
  waveform1.begin(WAVEFORM_SINE);
  waveform1.amplitude(0.75);
  waveform1.frequency(50);
  waveform1.pulseWidth(0.15);
 // initialize serial communication with computer:

  // initialize all the readings to 0:
  for (int thisReading = 0; thisReading < numReadings; thisReading++) {
    readings[thisReading] = 0;
  }
  
}

void loop() {
   // subtract the last reading:
  total = total - readings[readIndex];
  // read from the sensor:
  readings[readIndex] = analogRead(inputPin);
  // add the reading to the total:
  total = total + readings[readIndex];
  // advance to the next position in the array:
  readIndex = readIndex + 1;

  // if we're at the end of the array...
  if (readIndex >= numReadings) {
    // ...wrap around to the beginning:
    readIndex = 0;
  }

  // calculate the average:
  average = total / numReadings;
  // send it to the computer as ASCII digits
  
  delay(1);        // delay in between reads for stability
   int potValue = average;
   float scaledPot = (float)potValue / 5  ;


  Serial.println(scaledPot);
  waveform1.frequency(scaledPot);
 // bitcrusher1.bits(scaledPotTwo);

}

Put the "custom sensor" in a drawer, lock the drawer, and send the key to a friend, for a while. With a hardcoded frequency, do you hear anything? If not, the problem has nothing to do with the sensor, and everything to do with what looks like incomplete code.