MP3s ripped from CDs or bought digitally (usually) come pre-tagged,
including "genre". "Genre" has an eclectic set of options including folk,
rock, soundtrack, children's, Christmas, gospel, international, electronic,
and electronica/dance, to name just a few. Some CDs of Jewish music
came tagged as Christian (!) or gospel, and I changed those to Jewish
(a new category) at the time. An MP3 can have at most one genre
(hence options like folk-rock, I guess).
Some of these genres are orthogonal to each other.
Jeff Wayne's "War of the Worlds", "Pirates of Penzance", and "West Side
Story" are all soundtracks, but they are not similar musically.
Children's isn't a genre; it's an audience or application.
"Nowell Sing We" and "Rudolf the Red-Nosed Reindeer" are both Christmas
songs, but they're not the same at all (I would sort the former with
"early", another category I had to invent because "classical" just doesn't
fit the middle ages and renaissance). (Ok, I wouldn't have the
latter in my collection, but work with me here...) I have no idea what the
difference between "electronic" and "electronica/dance" might be, and how
the latter differs from "dance".
I think the makers of the tagging system conflated style and
purpose. We're running into this a lot with international dance
music (often dances are set to folk songs), or with everything from folk
to blues to rock ending up together because they're "Jewish", or SCA
dance music being scattered across "SCA" (this must have been a custom
category for someone), "dance", "classical", "folk" (?), and probably
others. And I'd like to be able to tag the subset of folk music
that is children's music (for selective exclusion), without losing its
folk-ness.
I'm coming to the conclusion that the correct way to do this is to use
"genre" for what it is musically and some other tag for usage (if it has
a primary usage). Looking at the tags available to me in iTunes, it
looks like I should use "grouping" for this. (I've never seen this field
filled in, so I don't know what conventions surround it.) So early music
is early music and some of it might be grouped as "dance", folk is folk
and rock is rock and some of each might be grouped as "Jewish" (or perhaps
"Jewish liturgical", since that's what I'm really after), and the Hebrew
folk songs that are used for Israeli dances would "folk" (genre) and grouped
as "dance", and so on. (Maybe we want to distinguish SCA dance and
international folk dance; that's an implementation detail.) But before
I try to do anything along these lines I'd like input: how do you capture
multiple dimensions of your music? (Another option, just to
throw it out there, is to use playlists as buckets. We're doing some
of that but it doesn't feel sustainable to me.) I want to be able to
find music by genre or by purpose, which says to me I want two searchable
fields.
We are currently using the comments field to support tags iTunes doesn't give
us. For example, there's no off-the-shelf way to tag the language of a song!
So for the languages we care about we have entries in the comments field
like LANG_HEBREW. We're also doing something similar to tag the Child
ballads (TAG_CHILD_#_) so we can easily find the dozen variations on "Maddy
Groves" scattered through the library. (Child ballads are a special interest
of Dani's.) We're also using this field for meta-data about our
own recordings (e.g. TAG_WEAK); "comments" probably isn't a good place
for that but those were the first tags we added so we grabbed the obvious
field and now we're kind of stuck unless we want to do a lot of work.
A problem with using "comments" is that you can't systematically
add to a comment field, only replace it. So if we wanted
to use it for other tags (like usage) and wanted to apply those in
bulk, we couldn't without stomping some of our existing tags. Well, we
could write a perl script, I guess, but I looking for something a little
closer to the GUI.
So how do the rest of you track extra information? Or are we the
most finicky among our circle of friends? :-)