[CM] CMN key signature, bar lines, and accidentals

Larry Troxler lt@westnet.com
Wed, 18 Dec 2002 21:27:06 -0500

I'm a bit confused at the moment as to how CMN handles accidentals and
note-names in the context of key-signature and barlines.

The version I am using is dated 12-november.

For example, in cmn.html there is this:

(cmn staff treble (meter 2 4) 
  (chord (notes f5 af4 df5) (rq 5/4)) 
  (chord (notes f5 ef5 df5 a4) (rq 3/2)) 
  (chord (notes f4 gf4 af4 d5) (rq 5/4) stem-down))

Now, from the graphic output that is directly below this, I see that the
"a4" in the second chord is actually interpreted as an a-flat, because
the second chord lies in the first measure and the second instance of
the note does not have a natural sign in front of it (the flat from the
first a-flat is not canceled).

I've also run across similar problems in my efforts to use CMN: sharps
and flats seem to be redundantly indicated within the same meaure,
accidentals are notated even if they are the "default" for the current
key signature, and accidentals are not canceled properly if a natural is
placed later in the measure.

I have a hunch then, that I have a basic misunderstanding of what note
names mean in CMN.
Am I correct in thinking that, as opposed to Common Music, an "A4" in
CMN does not mean a 440 hz note, but rather an A on the staff with no
sharp, flat, or natural sign in front of it?
Do accidentals/naturals on note names in CMN correspond to what is
notated, and not the frequency of the note?

If that is so, for me it is not very intuitive. For example, the leading
tone of the G-major scale to me is not called an "f", it is an
"f-sharp". For me, it seems strange to have to say "F4" instead of "FS4"
when adding an f-sharp to a G-major staff.

Also, it means that to change bar-line placement or key signature and
notate the same music would require one to go through all the notes and
adjust their accidentals by hand.

So, is there a way to change this behavior so that the note name
reflects the actual frequency, and then CMN would decide how to notate
it based on the current key and measure history? I ask this because I
see that there are several global parameters related to accidentals, but
they don't seem to be explained in cmn.html.

Looking forward to any explanations or counter opinions. Hopefully
there's just a couple of those global setting that need to be changed.

Larry Troxler