Future<Sound> load(String url, [ SoundLoadOptions soundLoadOptions ])

Loads a sound from a file url.

The file extension in the url will be replaced according to the browser's capability to playback certain kinds of audio types. For example if the url ends with the 'mp3' extension and the browser does not support mp3 playback, the file extension will be replaced with 'ogg' or 'ac3'. You can customize this behavior by changing the soundLoadOptions.

var sound = await Sound.load("assets/audio/hello.mp3");
sound.play();

Source 

static Future<Sound> load(
    String url, [SoundLoadOptions soundLoadOptions]) async {

  try {
    var options = soundLoadOptions ?? Sound.defaultLoadOptions;
    var audioUrls = options.getOptimalAudioUrls(url);
    var corsEnabled = options.corsEnabled;
    var loadData = false; // options.loadData;
    var audioLoader = new AudioLoader(audioUrls, loadData, corsEnabled);
    var audioElement = await audioLoader.done;
    return new AudioElementSound._(audioElement);
  } catch (e) {
    var options = soundLoadOptions ?? Sound.defaultLoadOptions;
    if (options.ignoreErrors) {
      return MockSound.load(url, options);
    } else {
      rethrow;
    }
  }
}