When playing music from Apple Music in the Sonos app (not AirPlay), most tracks seem to correctly apply album-based loudness normalization. That’s great! However, if the song is only in Cloud Music Library (i.e. uploaded from my Mac and unavailable to be matched in Apple Music), no normalization is applied, and the song can be wildly louder or quieter, which makes the Apple Music–Sonos integration completely unusable for me, especially if I want to shuffle a playlist of mixed sources, which may have me frantically running for the volume slider between each track.

These Cloud Music Library tracks have normalization data (iTunNORM tags) in them, whether scanned by Apple Music when adding to the library, or by a third party app. Apple Music has used iTunNORM tags since it was called iTunes, and it has always worked fairly reliably in Apple Music’s iOS apps (except when Apple randomly introduces AirPlay bugs, which they occasionally deign to fix). As of iOS 18.5, that mostly works as expected, with its own flaws and quirks that are outside the scope of this issue. 

Please apply album-based loudness normalization to all tracks, regardless of their source.