[izacus]

Usually it's not just the bitrate, but also the compression in mastering process that's different (see https://en.wikipedia.org/wiki/Dynamic_range_compression for context). The "HiFi" versions are less compressed and on my highend audio system the difference between Tidal HiFi masters and Spotify is pretty stark and obviously noticable.

(The difference obviously has nothing to do with compression format.)

I hope Spotify will match the quality because Spotify Connect is way more reliable than the Cast broken mess.

[CarelessExpert]

Where is the evidence that Tidal is actually using masters that exclude DRC for their HiFi mixes?

I can't find anything that suggests this is actually true.

The only thing I can find indicates that their HiFi versions are based on MQA-supplied 24-bit masters, but that doesn't tell you whether or not DRC was applied to the source mix that MQA used.

And given that an uncompressed mix would require remastering by the artist/studio (DRC is not just a byproduct of conversion to a 16-bit format), you'll forgive me if I'm incredibly skeptical of this claim.

[nr2x]

Exactly, it's literally a different sound file - not just format/delivery/etc.