No it doesn’t. It shows their mastering/tuning techniques are different or they have access to different sources. Compression, wrt codecs, has nothing to do with the difference in sound you’re hearing.
It’s definitely about compression. Implementations can differ significantly for the same formats, as anyone who remembers the initial MP3 frenzy can tell. The fact you cannot discern two random codecs at their max quality doesn’t mean Apple and Spotify cannot have a meaningful difference with their streaming codecs (both custom afaik).
Pack your bags. Just Google it, or you can start here [1]. A relevant quote “This is because Spotify applies Loudness Normalization to your tracks as they're played to listeners”
A brief search shows that both Apple and Spotify offer 256kbps AAC. ABX testing these two would be pointless. They’re both above transparent. It’s NOT the codec.
Send me to heaven if X would allow for parametric EQ settings based on headphone/sound system. This would appeal to *actual audiophiles [2]. This would confuse the hell out of normals, so bullet point marketing is what we get.
[1] https://artists.spotify.com/faq/mastering-and-loudness [2] https://github.com/jaakkopasanen/AutoEq
What is it then? At any rate, if this new offering can match Apple Music quality then it’s a win - and not “pure marketing”.
While Spotify IS applying file compression (ala mp3) to every one of their records (and this affects the sound quality) I have not heard any reports of them applying any additional post-EQ or volume compression in the way that, say, a radio station might. I believe you may be mistaken as to what the Loudness Normalization feature is doing.
It is simply turning down the volume of tracks that have been mixed/mastered to excessive loudness levels so that they match the average loudness of more sensibly-mixed/mastered songs. Turning the volume of the louder track down has no effect whatsoever on it's audio quality. The meta-effect, then, is that the normalization disincentivizes the practice of mixing/mastering songs too hot; something which DOES have a negative effect on the audio quality of a song.