Sound check/volume normalisation (new feature on Android) not fully implemented.

Hi there. I have been waiting years for Apple to introduce Sound Check on Android.

Historically, across iTunes usage since 20 years ago, and Apple Music on iPhones/iPads, Sound Check correctly adjusts the volume of each song to maintain a constant playback volume between songs from different albums that are mastered at different levels. This is also standard on most other streaming services and players of local digital files.

So a few months ago, Sound Check was rolled out/added to the menus on Android [Galaxy S10+ which is for reasons of it being able to hold 2TB of flac files from my own CD collection] - for which I am thankful. But as I've come back to use it... it demonstrably does not work properly on Android Apple Music. In various playlists, every so often a song that should be at a similar level is *extremely* quiet.

Furthermore, when playing back a full album, some songs (which are the same type of song, mastered to same level) are made much quieter by sound check, while others are not. This would not be the case if the implementation were correct.

The example I have this morning is on the album Manifesto for Futurism by Dali's Dilemma.

Track 2 plays back hugely quieter than 1 and 3 with Sound Check enabled. With Sound Check disabled, all tracks are at a good relative volume. Crucially it is also fine with Sound Check on an iPhone. Ergo, it seems to be an issue with Sound Check implementation specifically on Android, rather than missing metadata on some of those files.

This is enough of an issue that as a user who is used to in general usage the same volume from every track (as this has been a standard feature of digital music and streaming for the entire time of the existence of those media), still has a better time volume-wise when Sound Check is turned off with a sigh, and so Apple Music on Android remains a service that effectively does not offer volume normalisation.

edit: users here seem to have the same experience

https://www.reddit.com/r/AppleMusic/comments/1hzs2uj/sound_check_is_finally_here_on_android/

Please investigate, and thanks again.