Yes, the artist stuff is case sensitive (and don't get me started on Hall & Oates, Hall and Oates, and Darryl Hall and John Oates).
One of the issues is that mix-up between Artist and "Album Artist" (the latter used for compilations) from the ID3 tagging. Subsonic's organization and API prioritizes grouping by the Album Artist...but then displays the regular Artist in the individual track.
However, if you change an artist in the UI, it only changes the Artist tag, but that Album Artist that is 'wrong' is still hidden from you. There's no way in the UI to fix that.
So you first have to clean up the files individually using an external tool like iTunes. Then you have to force a reload of the folders. This is where the timestamps on the folders gets tricky, because Subsonic's scanner won't rescan the files inside a folder it *thinks* hasn't changed, based on the date it was last modified. So to fix that you need to make the folder itself seem changed. One way, you can rename it to Album X, scan, "clean database", then rename it back to Album, scan again, "clean database". A pain, yeah.
Oh, and this also means that any playlists you have will lose those files. If you want to preserve them, you'll need to export the m3u file, then after the cleanup is done, delete the playlist and import it anew, assuming that the files are the same and in the same locations.
Also, if you bring in files that aren't tagged, Subsonic will internally tag them based on the idea that it is in the album folder and the parent of that will become the Album Artist, rather than the Artist, again causing this type of issue. (I have several "King Crimson 1969" files I wish I could fix more easily because of this - I org my KC folders by the line-ups). Best to avoid that by making sure the tagging is right in another tool before adding them to Subsonic.
