How do I synchronise sound and servo movement when using ServoEasing library

I am new to Arduino and am trying to create a sketch using a servo and a sound file on the SD card of my MKR Zero.

I want the sound to be played back while the servo moves. I am using ServoEasing but I'm having a hard time understanding how to implement the triggering of the sound file.

The servo moves at variable speeds from 0 to 180 degrees. The sound file is short, but should start when the servo starts moving and stop when the servo stops.

If anyone can help me in the right direction I would be very grateful!

sketch below >

#include <Arduino.h>

#define ENABLE_EASE_QUADRATIC // Must specify this before the include of "ServoEasing.hpp"

#include "ServoEasing.hpp"
#include "PinDefinitionsAndMore.h"

ServoEasing Servo1;

#define START_DEGREE_VALUE 90

unsigned long currentMillis = 0; 

#include <SD.h>
#include <SPI.h>
#include <AudioZero.h>

const int chipSelect = SDCARD_SS_PIN; //MKR Zero

void setup() {
    pinMode(LED_BUILTIN, OUTPUT);
    Serial.begin(115200);
      while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
#if defined(__AVR_ATmega32U4__) || defined(SERIAL_PORT_USBVIRTUAL) || defined(SERIAL_USB) /*stm32duino*/|| defined(USBCON) /*STM32_stm32*/|| defined(SERIALUSB_PID) || defined(ARDUINO_attiny3217)
    delay(4000); // To be able to connect Serial monitor after reset or power up and before first print out. Do not wait for an attached Serial Monitor!
#endif
    // Just to know which program is running on my Arduino
#if !defined(PRINT_FOR_SERIAL_PLOTTER)
    Serial.println(F("START " __FILE__ " from " __DATE__ "\r\nUsing library version " VERSION_SERVO_EASING));
#endif

#if defined(ESP32)
    analogReadResolution(10);
#endif

Servo1.attach(9);


    // Wait for servos to reach start position.
    delay(500);

    Servo1.startEaseToD(0, 1000, START_UPDATE_BY_INTERRUPT);
    delay(1000);

    Serial.println(F("Set easing type to QUADRATIC_IN_OUT for Servo1"));

    Servo1.setEasingType(EASE_QUADRATIC_IN_OUT);
    delay(1000);


  Serial.print("\nInitializing SD card...");

  // we'll use the initialization code from the utility libraries
    if (!SD.begin(chipSelect)) {
    Serial.println(" failed!");
    while(true);
  }
  Serial.println(" done.");

}


void loop() {

File myFile = SD.open("test.wav");
  // 44100kHz stereo => 88200 sample rate
AudioZero.begin(2*44100);

    uint16_t tSpeed = analogRead(SPEED_IN_PIN);

    tSpeed = map(tSpeed, 0, 1023, 5, random(100, 150 + 1)); //random value changes speed for each loop
    setSpeedForAllServos(tSpeed);

    /*
     * Move servo without interrupt handler
     */
#if !defined(PRINT_FOR_SERIAL_PLOTTER)
    Serial.print(F("Move to 0 degree with "));
    Serial.print(Servo1.getSpeed());
    Serial.println(F(" degree per second with updates by own do-while loop"));
#endif
    /*
     * Here we use the allServos functions
     */
    setDegreeForAllServos(3, 0, 0, 0);
    setEaseToForAllServos();
    synchronizeAllServosAndStartInterrupt(false); // false, since we call updateAllServos() manually below

    do {
        // here you can call your own program

        delay(REFRESH_INTERVAL_MILLIS); // optional 20ms delay
    } while (!updateAllServos());

    /*
     * Move servo with interrupt handler
     */
#if !defined(PRINT_FOR_SERIAL_PLOTTER)
    Serial.print(F("Move to 180 degree with "));
    Serial.print(Servo1.getSpeed());
    Serial.println(F(" degree per second using interrupts"));
#endif
    Servo1.setEaseTo(180);
    Servo1.startEaseTo(180);
AudioZero.play(myFile);
AudioZero.end();

delay(random(2000, 4000 + 1)); //adding a random pause between each loop

    /*
     * No need to call synchronizeAllServosAndStartInterrupt(), since I know that all durations are the same
     * Since all servos stops at the same time I have to check only one
     * Call yield for the ESP boards must be handled in areInterruptsActive()
     */
   while (ServoEasing::areInterruptsActive()) {
        ; // no delays here to avoid break between forth and back movement
    }
}


Please, post a drawing. Your text reads (to me) like the servo movement determines the start and ?frequency?volume? of the sound, but the code seems to need SPEED_IN_PIN... but what is SPEED_IN_PIN?