I just started the test months for Apple Music and added the service to my Sonos (Play 5, Play 3, several Play 1, Connect Amp with older speakers). In my opinion the sound quality is really low, everything sounds overall quite dull, the trebles sound severely washed out.
If I play the same music directly in the music app on iPhone or iPad and use Airplay, it sounds way better.
Anyone else noticed this? Is there a way to improve the sound quality? Or is the Apple Music integration that bad in general?