static File voiceMegaMix() {
  File file = javaxDataDir("Generated Audio/voice-mega-mix.wav");
  if (!file.exists()) {
    new AudioInputStreamsCollector c;
    for (File f : allRecordingsWithMarkers()) {
      Clip clip = spectro_clipFromFile(f);
      L<IntRange> ranges = markerIntRangesForWAV(f);
      for (IntRange r : ranges)
        addClipPartToAudioCollector(clip, r, c);
    }
    c.writeToWAV(file);
  }
  ret file;
}