[EVdotIO]

Spotify doesn't "master", you upload an uncompressed version of the track, and they will encode to OGG with a target LUFS. Classical music isn't impacted by this; it's loud rock, pop and EDM with aggressive limiting where the volume gets turned down. When people complain about the sound quality, it's largely junk masters handed over to Spotify, not the encoding process. Granted, if you _really_ try to listen to artifacts, they are usually in transients.

[nvarsj]

Yeah I know how Spotify works. What I mean is the end user has no idea where the source comes from, how it was mastered or ripped, or what Spotify's criteria is for quality. It is opaque, and there have been examples of bad digital masters/rips used by Spotify. It seems all you can do is report bad tracks when you encounter them: https://community.spotify.com/t5/Social/Jitter-due-to-bad-CD.... The OP even gave examples of classical tracks which have audible problems.

None of this is an issue if you rip your own CDs or buy lossless from reputable sources in my experience. Spotify you're at the mercy of whatever crap Spotify has been given.