On Tue, Feb 13, 2001 at 01:41:25PM -0800, [EMAIL PROTECTED] wrote:
> We don't have to standardise existing musical notation (thank goodness).
> We just need a way of unambiguously expressing things in abc notation
> so that processing programs have enough information to make their own
> decisions about how to present things to the user.
Which is what I was trying to say, only much more lucidly put.
To quote the draft spec:
> The chord has the format <note><accidental><type>/<bass>, where <note>
> can be A-G, the optional <accidental> can be b, #, the optional <type>
> is one or more of
> m or min minor
> maj major
> dim diminished
> aug or + augmented
> sus sustained
> 7, 9 ... 7th, 9th, etc.
> and /<bass> is an optional bass note.
This, to my mind, needs a little bit of tightening up to remove potential
ambiguities. Thinking aloud here, and I'll cope with being shot down in
flames.
/<bass> needs to explicitly say "*with* any needed accidental"
<type> should be replaced by <type><modifiers>
where <type> can be one of
<nothing> major (1 3 5)
m minor (1 b3 5)
dim or o diminished (1 b3 b5)
aug or + augmented (1 3 #5)
I *think* we only need these four.
<modifier> can be one OR more of:
noX remove degree X from the chord (e.g, C7(no3)
5 same as 'no3'
6 add 6th
[maj]7 add b7th (7th if 'maj')
[maj]9 add b7th (7th if 'maj') + 9th
[maj]11 add b7th (7th if 'maj') + 9th + 11th
[maj]13 add b7th (7th if 'maj') + 9th + 11th + 13th
[add]X add the Xth note of the scale
sus2 drop the 3rd to the second
sus4 raise the 3rd to the fourth
<accidental>X apply the accidental to the X degree (must be present in
the 'chord so far')
<modifier> can be bracketed to remove ambiguity, or we could make
ambiguous accidentals always bind to the left
X<accidental>X can be shortened to <accidental>X
Examples:
C C major
Cm/G C minor with G bass
Bb(b5)/D D Bb E (my favourite chord!)
A9sus4/E E A D G B E (*grin*)
E(#9) or the 'Hendrix' chord: most guitarists would call it
E7add#9 E7#9, and I'm sure there's a formal way of making
that unambiguous
The only gotcha I can see here is the full diminished chord (1 b3 b5 bb7),
which we CAN notate as dim6, but feels wrong. We need to be able to
distinguish it from what I've seen called the 'half-diminished 7th'
(1 b3 b5 b7) and from the straight diminished triad (1 b3 b5)
Anyway: some thoughts: use or ignore to taste.
--
Mike Whitaker | Work: +44 1733 766619 | Work: [EMAIL PROTECTED]
System Architext | Fax: +44 1733 348287 | Home: [EMAIL PROTECTED]
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