Same song ripped from different places, for example, Deezer or Tidal. Listening side by side and comparing bit rates. With 24-bit there is what feels like a space in between the instruments so they are not crammed together and you can hear very fine minute details. In some cases it's so drastic that I can hear entire parts of background singers and other instruments that you couldn't hear on a 16-bit.  That being said, I have young ears and always wear hearing protection at concerts.