teensy neopixel fade during audio

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

#define NUM_PIXELS 60 // number of pixels on one strip
#define PIX_PIN 2 // neopixels
#define sigPin 21 // input from touch traces

#define THRESHOLD 600 // analogRead threshold
int WHITE_LEVEL = 50; // 0-255 white brightness
#define RING_1 10 // number of LEDs in this ring
#define RING_2 20 // number of LEDs in this ring
#define RING_3 30 // number of LEDs in this ring
#define RING_4 40 // number of LEDs in this ring
int FADETIME = 500; // ms to take to fade the pixels
int DEBOUNCE_TIME = 200; //debounce time

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUM_PIXELS, PIX_PIN, NEO_GRBW + NEO_KHZ800);
elapsedMillis sinceSig;

// GUItool: begin automatically generated code
AudioPlaySdWav           playWav1;       //xy=317,272
AudioOutputI2S           audioOutput;    //xy=624,286
AudioConnection          patchCord1(playWav1, 0, audioOutput, 0);
AudioControlSGTL5000     sgtl5000_1;     //xy=560,221
// GUItool: end automatically generated code


// Use these with the audio adaptor board
#define SDCARD_CS_PIN    10
#define SDCARD_MOSI_PIN  7
#define SDCARD_SCK_PIN   14

int state = 0; // this tracks state transisions 0-6
/*
 * 0: nothing happening
 * 1: 1st ring lit, wait for touch
 * 2: 1st + 2nd ring lit, wait for touch
 * 3: 1st + 2nd + 3rd ring lit, wait for touch
 * 4: 1st + 2nd + 3rd + 4th ring lit, wait for touch
 * 5: 1st + 2nd + 3rd + 4th ring lit PLUS playsound and immediately move to state 6
 * 6: fade out all rings while sound decays, then move ot state 0
 */

void setup() {
  Serial.begin(9600);
  pinMode(PIX_PIN, OUTPUT);
  pinMode(sigPin, INPUT_PULLDOWN);
  pixels.begin();
  
  // Audio connections require memory to work.  For more
  // detailed information, see the MemoryAndCpuUsage example
  AudioMemory(8);

  // Comment these out if not using the audio adaptor board.
  // This may wait forever if the SDA & SCL pins lack
  // pullup resistors
  sgtl5000_1.enable();
  sgtl5000_1.volume(0.5); // lowered this a lot to attempt to fix distortion, has little effect

  SPI.setMOSI(SDCARD_MOSI_PIN);
  SPI.setSCK(SDCARD_SCK_PIN);
  if (!(SD.begin(SDCARD_CS_PIN))) {
    // stop here, but print a message repetitively
    while (1) {
      Serial.println("Unable to access the SD card");
      delay(500);
    }
  }
  delay(500);
  Serial.println("ring 1");
  lightRing(1);
  delay(1000);
  Serial.println("ring 2");
  lightRing(2);
  delay(1000);
  Serial.println("ring 3");
  lightRing(3);
  delay(1000);
  Serial.println("ring 4");
  lightRing(4);
  delay(1000);
  dingBell();
  delay(2000);
}




void loop() {
  
  int senseRead = analogRead(sigPin);
  if( (senseRead > THRESHOLD) && (sinceSig > DEBOUNCE_TIME)){ // will have to determine THRESHOLD val in final install
    sinceSig = 0;
    increment_state();
  }
  
  switch(state){
    case 0:
      // normal waiting state
//      Serial.println("case 0");
      break;
    case 1:
      // light first ring, wait for timeout
//      Serial.println("case 1");
      lightRing(1);
      break;
    case 2:
      // light next ring, wait for timeout
//      Serial.println("case 2");
      lightRing(2);
      break;
    case 3:
      // light next ring, wait for timeout
//      Serial.println("case 3");
      lightRing(3);
      break;
    case 4:
      // light next ring, wait for timeout
//      Serial.println("case 4");
      lightRing(4);
      break;
    case 5:
      //ding bell and fade all 4 rings
//      Serial.println("case 5");
      dingBell();
      break;
  }

}

void increment_state(){
  state = ((state+1) % 6);
  Serial.print("incremented state, it is now ");
  Serial.println(state);
  sinceSig = 0;
}


void playFile(const char *filename) {
  Serial.print("Playing file: ");
  Serial.println(filename);
  // Start playing the file.  This sketch continues to
  // run while the file plays.
  AudioNoInterrupts();
  playWav1.play(filename);
  // A brief delay for the library read WAV info
  delay(5);
  AudioInterrupts();

}

void dingBell() {
//  delay(100); 
  if (random(10) >= 5) {
//    playFile("SDBELL1.WAV");
    playFile("SDTEST1.WAV");
  } else {
//    playFile("SDBELL2.WAV");
      playFile("SDTEST2.WAV");
  }
  delay(2500); // only after adding this did the playback become less distorted (still not perfect)
  fadeRings(4);
}

void lightRing(int num) {
  // light #num rings warm white
  // don't forget strip.display() at the end
  switch (num) {
    case 1:
      for (int i = 0; i < RING_1; i++) {
        pixels.setPixelColor(i, 0, 0, 0, WHITE_LEVEL);
      }
      break;
    case 2:
      for (int i = 0; i < RING_2; i++) {
        pixels.setPixelColor(i, 0, 0, 0, WHITE_LEVEL);
      }
      break;
    case 3:
      for (int i = 0; i < RING_3; i++) {
        pixels.setPixelColor(i, 0, 0, 0, WHITE_LEVEL);
      }
      break;
    case 4:
      for (int i = 0; i < RING_4; i++) {
        pixels.setPixelColor(i, 0, 0, 0, WHITE_LEVEL);
      }
      break;
  }
  pixels.show();
  //  state = 0;
}

void fadeRings(int num) {
  // fade all rings for a set time, the same time it takes the sound to decay
  float tempLevel;
  for (int j = FADETIME; j > 0; j--) {
    tempLevel = ((float)j / (float)FADETIME);
    tempLevel = tempLevel * WHITE_LEVEL;
    switch (num) {
      case 1:
        for (int i = 0; i < RING_1; i++) {
          pixels.setPixelColor(i, 0, 0, 0, int(tempLevel));
        }
        break;
      case 2:
        for (int i = 0; i < RING_2; i++) {
          pixels.setPixelColor(i, 0, 0, 0, int(tempLevel));
        }
        break;
      case 3:
        for (int i = 0; i < RING_3; i++) {
          pixels.setPixelColor(i, 0, 0, 0, int(tempLevel));
        }
        break;
      case 4:
        for (int i = 0; i < RING_4; i++) {
          pixels.setPixelColor(i, 0, 0, 0, int(tempLevel));
        }
        break;
    }
    pixels.show();
    delay(1); // this is to make each loop a lil more than 1ms
  }
  state = 0;
}