let oscs = [];

// Note ratios

let notes = [1, 1.125, 1.25, 1.334, 1.5, 1.667, 1.875, 2];

// Base frequency

let BASE = 300;

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

  // Loop through all the oscillators

  for (let o = 0; o < oscs.length; o++) {

    let osc = oscs[o];

    // Get the oscillator's volume level

    let volume = osc.amp().value;

    // If it's reached 1, fade it out over 5 seconds

    if (volume >= 1) osc.amp(0, 5);

    // If it's fully faded out...

    else if (volume <= 0) {

      // Stop the oscillator

      osc.stop();

      // Remove it from the array

      oscs.splice(o, 1);

    }

  }

}

​

// Create a new oscillator on each keypress

function keyPressed() {

  let osc = new p5.Oscillator();

  osc.setType('sine');

  osc.freq(BASE * random(notes));

  osc.start();

  osc.amp(0);

  // Fade it in over 5 seconds

  osc.amp(1, 5);

  // Add it to the array of oscillators

  oscs.push(osc);

}