function Sound(src){
  //sound effect class
  //builds a sound effect based on a url
  //may need both ogg and mp3.
  this.snd = document.createElement("audio");
  this.snd.src = src;
  //preload sounds if possible (won't work on IOS)
  this.snd.setAttribute("preload", "auto");
  //hide controls for now
  this.snd.setAttribute("controls", "none");
  this.snd.style.display = "none";
  //attach to document so controls will show when needed
  document.body.appendChild(this.snd);

  this.play = function(){
    this.snd.play();
  } // end play function
  
  this.showControls = function(){
    //generally not needed.
    //crude hack for IOS
    this.snd.setAttribute("controls", "controls");
    this.snd.style.display = "block";
  } // end showControls
  
} // end sound class def