On Jul 22, 2009, at 11:12 PM, David Fedoruk wrote:
In my discussion with my jazz professional, we looked at complex
chords, in fact we deliberately looked for complex ones to find out
how they were expressed. We found, quite amazingly that the more
complex the chord got the more ambiguous its name became.
The other thing we noted is that frequently, the note which was noted
in a complex chord name was part of the melody. Thus, naming it
became irrelevant in the context of performing.
This is common in the Real Books and some other books have adopted the
same thing. The chord is really a Dmin7 but the transcriber turned it
into a Dmin9 because the melody note was an E. It;s not necessary to
do this, but that's up to the person using LilyPond and not LilyPond
itself.
Further from this note about seriously complex chords, an indication
of c13th not only means that you add a thirteenth but alerts the
player that some of the expected 7th and 9ths will likely be left
out. As much as it is an indication of what note to play, it can also
imply what not to play.
This is the musician's intuition. As a guitarist, many of the
voicings I play leave many notes out of the chord. Routinely the 5th
is omitted (even if flatted or augmented, since that's usually in the
melody), sometimes the root (which the bassist has covered anyway),
and often some of the intermediate voices. It's not uncommon to just
play the guide tones (3rd and 7th) plus a leading tone (9th, 11th, 13th).
You are right, the bass lead sheet is the origin of the indications
for the keyboard player. In looking through much music, they are rare
events (ususaly) occuring at cadence points where it was important
that the keyboard and bass players knew more precisely what the other
was playing. From my observations what they most frequently do is
indicate the inversion of the named chord to be used. The only tune I
found with used them for extended portions of a tune was Bill Evans
"Waltz for Debbie" where it is a part of a specific modulation. But
again it is simply pointing out the correct inversion of the chord
from the bass part.
You're talking about slash chords here? | Dmin7 Dmin7/C | Bb7
A7 | etc. The purpose of those chords is usually to define the
characteristic descending or ascending bass line.
One other custom I was told about was that unlike the usual custom of
placing the key signature at the beginning of each line, the correct
way for jazz musicians to write a score is to note the key signature
and time signatures only at the beginning of a piece or where they
change. The Sher books follow this custom. However this is not really
a problem for lilypond because it can be more or less easily done
with methods already in Lilypond.
I haven't figured out how to do that, yet (it's probably really
simple). It's typically done in jazz charts to avoid confusion when
the song modulates to a new key. If the song starts in G (1 #) and
then modulates to F after four bars, the F# noted as part of the key
signature on the next line can confuse the musician. In many jazz
songs (e.g., "Joy Spring") the tonal center moves so many times that
the idea of the song being in "a" key is just notional and only
indicates the first bar or four.
The Sher publications I'm using are based themselves on sources that
Lilypond has already noted, So it seems there is at least some
general agreement that these sources are authentic and close to what
is actually used.
In terms of accuracy, the Sher books are about the best jazz fake
books available. In terms of conventions in jazz notation, the old
Real Books have become the de facto standard notation.
I will note one thing i observed when actaully taking a score to the
piano is that the notation of em7 b5 told me more quickly which notes
to change in the chord. When I came to a half dimished symbol i had
to think through more steps to get to the right notes. I don't know
if others have this experience, but it could answer the question of
why its use began.
It's use began, I think, with jazz musicians who played 300 nights a
year and for whom the meaning of these things was automatic as a
result of repetition. The idea was to speed up the mental process of
reading unfamiliar tunes by using ideograms. I can use them, but I
too prefer "Em7b5" to EØ" as a notation.