How to run multiple sinOscs in class objects

Hi all, new to Processing and would appreciate some help!

I'm trying to make a class where each instance of it has a sinOsc playing at a different frequency, with a slowly decreasing (and then increasing) volume for each. I can't find much in the way of in-depth tutorials on this object, and am stuck! here's the code:

PImage img;
import processing.sound.*;
SinOsc sine;


Sphere s1;
Sphere s2;

void setup() {
  size(665, 800);
  img = loadImage("MK.png");
  s1 = new Sphere(random(0, (img.height/2)), random(0, (img.width/2)), 255, 10);
  s2 = new Sphere(random(0, (img.height/2)), random(0, (img.width/2)), 255, 17);
  sine = new SinOsc(this);
  image (img, 0, 0, img.width/2, img.height/2);

  s1.bells();
  s2.bells();
}

//variables
int time = millis();


void draw() {
  s1.run();
  s2.run();


}

`

and for the class (Sphere) itself:

class Sphere {

  //GLOBAL
  float xpos = 0;//set variables for the class, default for all of this type
  float ypos = 0;
  int col1 = 255;
  int decay = 8;
  int timer;
  Float amp = 0.5;
  Float freq = (random(80, 400));
  int trans = 255;



//CONSTRUCTOR
    Sphere(float _xpos, float _ypos, int _col1, int _decay){
      xpos = _xpos;//args for each instantiation can then alter the global vars
      ypos = _ypos;
      col1 = _col1;
      decay = _decay;
    }


void run(){
  display();

}

void display(){
fill(col1, 0, 0, trans);
  ellipse(xpos, ypos, 10, 10);//global vars now altered to reflect creation args

  if (millis() - timer >= (decay * 10)){
     trans = trans - 10;
     amp = amp - 0.1;
     timer = millis();
   }

  if (trans <= 0){
     trans = 255;
   }
}

void bells(){

  sine.play();
  sine.freq(freq);
  sine.amp(amp);

}
}

Any help would be appreciated!