A simple Dart class that wraps all audio capabilities (sounds, concurrent fx and background music) for Flutter games.

GameAudio.dart

class GameAudio {
  AudioPool _pool;
  String path;
  bool isFx;
  bool concurrent;

  GameAudio(
      {@required this.path,
      this.concurrent: false,
      this.isFx: true,
      String prefix: "sfx"}) {
    initInstanceAsync(prefix).then((value) =>
        Log.v(_lP, "Sound $path loaded"));
  }

  Future<void> initInstanceAsync(String prefix) async {
    this.isFx = isFx;
    if (isFx) {
      int minPlayers = concurrent ? 8 : 1;
      int maxPlayers = concurrent ? 16 : 3;

      this._pool = AudioPool(path,
          prefix: "audio/sfx/", minPlayers: minPlayers, maxPlayers: maxPlayers);
      this._pool.init();
    } else {
      this.path = "$prefix/$path";
      Flame.audio.load(path);
    }
  }

  void _play() async {
    if (this.isFx) {
      _pool.start();
      if(concurrent) {
        Log.v(_lP,
            "Current available audioplayers: ${_pool.availablePlayers.length}");
      }
    } else {
       Flame.bgm.play(path, volume: 0.8);
    }
  }
}