Youtube and LUFS (loudness units relative to full scale)

top:original, bottom: youtube version

What does youtube do with Loudness War Tracks, what happens to undersized files? I did an experiment. I play the same music three times with different levels (one minute running time). Original level: 1st version (top left in the picture) -26.5 LUFS with -10.6dBFS (True Peak) https://www.youtube.com/watch?v=tZey80ShEWw 2nd version (above middle in the picture) -16.5 LUFS with - 0.7 dBFS (True Peak) https://www.youtube.com/watch?v=Tnz3rz430bE 3rd version (top right in the picture) -9.1 LUFS with overload + 0.5dBFS (True Peak) https://www.youtube.com/watch?v=CvrkJl1pm70 What does YouTube do with it? 1st version (bottom left of the picture) -21.0 LUFS with -5.9 dB 2nd version (bottom center of the picture) -14.6 LUFS with -0.7dB 3rd version (bottom right in the picture) -14.2 LUFS with - 4dB Conclusion here: It is striking that versions 2 and 3 have almost identical loudness, although the difference was originally more than 6 dB. It is particularly striking that the quiet version was only slightly raised in level, but was not brought up to -14LUFS. Experiments with level tones or level tone series: In a Youtube video (original level with 11.1 LUFS): 1KHz -20dB 1KHZ-10dB 10KHz -20dB 10KHz-10dB That resulted in the reproduction on Youtube: with 14.3 LUFS 1KHz -23dB 1KHZ-13dB 10KHz -23dB 10KHz-13dB next attempt (original level): with -1,8LUFS 1KHz -20dB 1KHZ-10dB 10KHz -20dB 10KHz-10dB 1KHz -1dB !! This resulted in the playback on Youtube: with 14.1 LUFS 1KHz -30dB 1KHZ-20dB 10KHz -30dB 10KHz-20dB 1KHz-15dB Conclusion here: Egel what level tones, what level, in the end it becomes about -14 LUFS. So the question arises, why wasn't the quiet audio file also brought to -14LUFS? Most music download platforms such as Spotify, Apple Music etc. operate in a similar way. The desired / implemented loudness is about -14 LUFS for fully modulated titles For this reason, we are now creating two masters, one with a loudness of -16 LUFS to -14 LUFS and one with the usual CD loudness. https://mastering-online.com/ Stefan Noltem