I believe that MusicBrainz should add an option to add a dynamic range score to each track on a release page. Each release in a group should contain unique scores, as different releases will have different masterings e.g. a late 90s American CD might be brickwalled while a late 80s Japanese CD will probably be much more dynamic. If every track on a release is tagged with a DR score, then the release itself should also display an average DR score, which would also be displayed on the release groups page so that a user can easily browse how different releases in a group score. Each track page should also keep track of DR scores so that people looking for the best version of a specific track can easily do so, as the most dynamic release of a certain track might not appear in its original release group, but on a single or compilation.

Many listeners seek out the best possible sound quality for songs or albums they love so that they know what CD or LP to digital release to buy; adding this feature would be a blessing for them. And artists themselves like to know where to find the best version of a track for sampling purposes.

The current place to do this http://dr.loudness-war.info/, which is very cluttered and does not use HTTPS. In addition, it appears to be mostly abandoned and it does not appear to release its information under a free license. Many listings there are also added without any metadata showing where they actually came from, making it cumbersome to use.

Currently, this can be noted in annotations, but I believe it deserves a dedicated feature. Being able to easily search and catalog dynamic range would encourage more hi-fi focused people to start documenting their collections on MusicBrainz and would have the additional benefit of making it easier to document the differences between two outwardly identical CD or LP releases.

In addition, HDCD releases should have two fields: one for the undecoded CD and one for the decoded CD. Some HDCD releases shipped with a feature that used a standard brickwalled master when played normally, but when ran through an HDCD player unlocked a more dynamic mastering 20bit mastering (this can also be done with free software using ffmpeg and libhdcd). The most well known examples are probably Modest Mouse's The Lonesome Crowded West's or Green Day's Nimrod early pressings, which are very compressed by default but noticeably open up when decoded.

There is a free software way to determine dynamic range: https://github.com/simon-r/dr14_t.meter