As some user-defined fields that I used for classical music tagging have become standard fields in the meantime, I thought to properly identify them.
They are:
Composer
Conductor
Soloists
Orchestra
Instrument
Period
maybe also:
Lyrics
Lyricist
By now, in my case only 5 user-defined fields remain:
Work
Note: An album may contain 12 tracks but only 3 works with each work having 4 movements, Classical music is rather work driven than album driven.
Opus
Note: This is the classical naming of a work ID.
Movement
Note: A single work usually consists of 3-5 movements
Instruments
Note: The standard field instrument(s) should be a list field, as a lot of classical works are performed by a combination of 2 to 6 instruments
Choir
Note: An orchestra may perform with different choirs, sometimes it's just a choir, so it should be distinguished.
Other standard fields:
Album
Note: That would simply be the title of the CD
Artist
Note: As it is not really defined who the artist is in this case, it could be used to summarize or even be empty. In my case I also put the composer here
Name
Note: Usually set by YaDB, in my case a combination of work title and opus number
It would be nice, if they could be added to Media Center as standard fields. Then it would be possible to create a number of standard views specific to classical music. My standard classical view is: Period>Subgenre>Composer>Work>Opus>Conductor>Orchestra>Movement, but I also have views starting with composer or conductor or orchestra.
Genre=Classical
Subgenre=Ballet, Band, Chamber, Choral, Classical Mix, Concerto, Dance, Gregorian Chants, Keyboard, Mass+Requiem, Modern, Opera, Overture, Serenade, Symphony, Vocal, Waltz
Any other suggestions? Did I forget anything?