function(id) {
      var self = this;
      var duration = self._duration;

      // If we pass an ID, get the sound and return the sprite length.
      var sound = self._soundById(id);
      if (sound) {
        duration = self._sprite[sound._sprite][1] / 1000;
      }

      return duration;
    }
function(id) {
      var self = this;
      var duration = self._duration;

      // If we pass an ID, get the sound and return the sprite length.
      var sound = self._soundById(id);
      if (sound) {
        duration = self._sprite[sound._sprite][1] / 1000;
      }

      return duration;
    }
function ( id ) { var self = this ; var duration = self . _duration ; // If we pass an ID, get the sound and return the sprite length. var sound = self . _soundById ( id ) ; if ( sound ) { duration = self . _sprite [ sound . _sprite ] [ 1 ] / 1000 ; } return duration ; }
Get the duration of this sound. Passing a sound id will return the sprite duration.
@param  {Number} id The sound id to check. If none is passed, return full source duration.
@return {Number} Audio duration in seconds.
Get the duration of this sound . Passing a sound id will return the sprite duration .
Returns the duration of the sound