concatAudios() {
    let audios = [].concat(this.audios);
    const scenes = this.children;

    forEach(scenes, (scene, index) => {
      forEach(scene.audios, audio => {
        if (index > 0) {
          const duration = this.getPrevScenesDuration(index - 1);
          audio.start = duration + audio.start;
        }

        if(!audio.hasSSTO()) {
          audio.setSs("0:00.000")
          audio.setTo(scene.duration)
        }

      });
      audios = audios.concat(scene.audios);
    });
    return audios;
  }
Combine all sounds audio into an array
@private