Bruce Olsen wrote:
>K:tonic mode? How do you determine if it's correct?
If I have transcribed the tune myself it's as correct as I need
it to be. The real problem, of course is with other people's
transcriptions...
>'Sources of Irish Traditional Music', 1998, gives as many as 3
>viable scoring modes for some tunes. One is last note as key, and
>2 are circular modes, but ABC lets you use 7, most of which are
>wrong.
>The problem I have with the K:specification is that it only
>determines the number of sharps or flats on the key signature,
>and it isn't required to have any relationship to the real
>scoring mode and a viable keynote. There is always a keynote for
>any of the 7 'greek' scoring modes that will give the correct
>number of sharps or flats. (Seen at a glance from the
>#/b-key-mode graph SFMODE.GIF on my website. With the first 15
>notes on the graph I can get anything from 7 sharps to 7 flats on
>the key signature with the mode as locrian.) I can score all
>Western style tunes (conventional ordering of sharps and flats)
>as locrian, which is fine with ABC, which only cares about the
>sharps or flats, but that will never give me a viable keynote.
Yes, it's perfectly true that you can misuse or abuse the abc K:
notation. You can also enter any tune in the key of C Major and
sprinkle the music with accidentals to get the tune to come out
right, and that particular abuse is available in standard notation
too!
I have an algorithm which can determine the best key/mode combination
for a given tune. It works statistically, by comparing the
distribution of note useage with an experimentally determined set
of distributeions which are characteristic for each mode. Of
course it's not perfect, since it's possible for a tune to be in
two different keys at once, and possible to write music which is in
no key at all (although perhaps such music cannot be called a "tune").
It is not fooled by tunes which don't end on the tonic, since it
weights notes by duration, paying no attention to position.
If you are interested, mail me off list for the gory details.
Phil Taylor
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