static File voiceMegaMix() {
  File file = javaxDataDir("Generated Audio/voice-mega-mix.wav");
  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;
}