Re: Nested transposition

[Lukas-Fabian Moser]

Am 13.03.21 um 02:16 schrieb Valentin Petzel:
> As far as I know transpose should only really be used with absolute pitches,
> as it would be quite impossible to do it otherwise. Think of it like this:
> Say we are in relative mode and have c' f. Then f will be above c. If you then
> do c' \transpose f a f, then the transposed a would be above the c – so it
> would need an octave indication. But the octave the music has to be put into
> depends of the previous note. So a single transpose function cannot provide
> this.
While that is true, I think your next two remarks are overgeneralisations:
> So, always use absolute pitch with transpose!

\transpose and \relative live happily together as long as \transpose is 
_outside_, so it's fine to use

\transpose c d \relative e' { ... }.

In particular, it's no problem to \transpose a complete score, no matter 
what combination of absolute and relative note entry is used in the score.

So, I propose to rephrase your rule to:

- "Avoid using \transpose inside of \relative" ("and if you have to, 
remember to issue a new \relative block inside the \transpose").

And of course there's

- MacMillan's strengthening: "Avoid using \relative altogether" :-). (I 
don't agree but understand his rationale; I think it's a matter of 
weighing up the pros and cons.)

In my experience, there are few use cases for transposition inside 
\relative except for precisely the case situation the OP described: 
Enharmonic respelling of a complete passage, most often needed in 
situations where a whole-score \transpose creates awkward key signatures 
for some sections of the score. This happens quite often when engraving 
Kunstlieder, for example, because with them it's common to issue the 
same piece in various transposed versions. I did an edition of Norbert 
Burgmüller's "Wie der Tag mir schleichet" last year, 
https://imslp.org/wiki/5_Lieder%2C_Op.12_(Burgm%C3%BCller%2C_Norbert) 
last year, and I remember having to wrestle quite a lot with enharmonic 
respellings for that one...

> And by the way: Lilypond transposes you example correctly. Your main problem
> is that usually there should not be a C# in C tonality. Usually it is easier
> to go from C to Db, which is a minor 2nd instead of an augmented prime.

I disagree that C# is an improbable note in C tonality.

In classical ("Mozartian") harmony, a C# arises in all situations where 
a secondary dominant to ii is used, which occurs as soon as you write a 
step-wise sequence from I to ii (or the other way around). For example, 
the ubiquitous "fonte" model 
(http://openmusictheory.com/schemataContinuationPatterns) automatically 
creates a C# when used in c major.

But since of course also a Db may arise easily in a C tonality (the most 
obvious example being as a Neapolitan Sixth), I'd argue that C#/Db is 
not a good example of an unconditional enharmonic spelling preference in 
C tonality. But such examples do exist of course: There are enharmonic 
spellings that seem improbable in C tonality at least before late 19th 
century music. My candidates would be Fb, Cb, Gb and A#, E#, B# (as well 
as all pitches using double accidentals), whereas for all pitches 
occuring between those in circle-of-fifths ordering, to wit

Db, Ab, Eb, Bb, {C major scale}, F#, C#, G#, D#,

it's quite easy to construct very natural occurrences in standard c 
major/c minor tonality. And in chromatic neighbouring note situations I 
even wouldn't be terribly surprised to find Gb or A# in a C-tonal context.

Lukas