In order to check how lossless Apple Lossless Hi-Res really is, I found an album that I already own in 24bit/96k for comparison:
View attachment 137999
I used an all digital recording from Apple Music on iPad to an iMac. While playing, the app reported Hi-Res Lossless, 24-bit/96 kHz ALAC format.
Turns out Apple track level was lower by 0.2dB which accounts for a not quite bit-perfect transmission. 50% of all samples match perfectly when the flies are reduced to 23 bits, which seems to correspond to a level reduction followed by a dither application. Not sure why 0.2dB was chosen.
All EQ settings were turned off in the Music app, volume set at maximum.
Spectrum:
View attachment 138003
Spectrum of the difference between the two recordings:
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Spectrogram Difference:
View attachment 138005