This is what Muse does. It's been doing this for some years, so I have a
lot of customers and incompatible changes may be unacceptable. (I don't
know what proportion of the customers use ABC. Theoretically translation
between ABC version and displayed version might be possible. With luck
the final ABC version will be close enough that incompatibilities will be
very few.) Extending the grammar or using a subset is of course OK,
and adding /note to the end falls into this category.
What follows is verbatim from the Muse help file. Note that the notes given
in parenthesis to explain a chord are not ABC. They are given in ascending
order of pitch, so (A C# E) means maybe [A,^CE]. I apologise for the abuse
of the term "suspended".
----------------------
If it doesn't understand the chord it will not play it. If it understands
the beginning of what's written, it will play that - so Fm7sus4 it will play
as F minor 7th. If you pervert the chord into some other sort of writing
and write "Fine" to indicate that this is where the playing should stop, it
will play F major! Here is a selection of what it understands.
A play A major (A C# E)
Bbm play B flat minor (Bb Db F)
C#7 play C sharp seventh (C# F G# B)
Dm7 play D minor seventh (D F A C)
Dmin7 play D minor seventh (D F A C)
E#dim play F diminished (F G# B D)
Fb- play E diminished (E G Bb Db)
G0 play G diminished (G A# C# E)
Abaug play A flat augmented (Ab C E)
B#+ play C augmented (C E G#)
B! play the single note B (B)
G6 play G sixth (like Em7) (G B D E)
Cmaj7 play C major seventh (C E G B)
X play silence ( )
D+4 play D suspended fourth (D G A)
E5 Play E with no third (E B E')
/ play the same chord again - not saved in ABC format.
Note that it will not play chords written as lower case letters e.g. d7 or
fine.
for anyone who understands formal grammars:
<chord> ::= <name>[<accidental>][<modifier>] | / | X
where
<name> ::= A|B|C|D|E|F|G
<accidental> ::= #|b
<modifier> ::= [m|min|7|m7|min7|maj7|-|dim|0|+[4]|aug|!|6|5]
I've seen some confusion as to whether G6 means that the sixth (E) is played
as well as the other notes, that is G B D E G (the same set of notes as Em7)
or instead of the fifth, that is G B E G (the same set of notes as Em).
Muse interprets it as the discordant one - G B D E G. Note that G6 and Em7
will usually not sound the same. G6 is (bass to treble) G B D E but Em7 is
(bass to treble) E G B D. (Actually with some sound cards they are hard to
tell apart).
----- Original Message -----
From: Mike Whitaker <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, February 13, 2001 11:18 PM
Subject: Re: [abcusers] Chord notation
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]
CricInfo Ltd | GSM: +44 7971 977375 | Web: http://www.cricinfo.com/
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