You can still see the difference in a high detail spectrogram like RX9 produces. There are some artifacts beyond just cutting off above 20khz. There are also f

You can still see the difference in a high detail spectrogram like RX9 produces. There are some artifacts beyond just cutting off above 20khz. There are also full range mp3s, since iTunes by default doesn't apply a hard 20khz lowpass like LAME does.