Re: [PATCH] autochange.scm: Use averaged chord pitches to determinestaff.

[David Kastrup]

<address@hidden> writes:

> On Wed, Jul 22, 2009, Trevor Daniels <address@hidden> said:
>
>>> Anyway, I think that it would make a lot more sense if the staff
>>> were determined by the "average" pitch of the chord. And, I think
>>> I've solved this in the attached patch.
>
> What would make the most sense is to consider the range of the
> intended instrument.  music for a mid-range instrument (eg classical
> guitar) is conventionally presented on the same suboctave G clef a
> tenor vocalist uses.
>
> Some music for low brass and winds uses c-3, c-4, and f-4 clefs.
> Hopefully these automatic clef changes are an optional feature, many
> players find any clef change annoying.

I'll agree that any optionally usable clefs should be specified in
advance.  A "clef" in this respect may also consist of "8va" notations.
There are instrument-dependent "thresholds of pain" involved: singers'
clefs will just not change in midpiece.  I don't think that the right
hand of a (non-bass) accordion would ever change clefs (even though I
have a button accordion going down to deep A, needing 5 ledger lines,
which is not all that untypical).

The best strategy probably would be to specify badnesses for clef
changes (separate for in-bar and between-bar), ledger lines (with
progressive badness for the vertical arrangement and/or badness for
ledger lines which actually change the system spacing), a large badness
for the first clef change, another one for a repeat ending with a
different clef than it begins...

> Look to the earliest publications of Ottaviano Petrucci (Canti C,
> Canti B, Odhecaton), available in facsimile at the best music
> libraries (and direct from Broude Brothers if you care to purchase)
> for examples of how rare clef changes were even when movable C clefs
> were the norm.

What do you mean "even when"?  We are talking about singers (with a
limited range) and the movable clef was placed such that you did not
need clef changes or ledger lines in midpiece.

> Initial clef should be chosen based on overall range,

But today's available clef choice is much smaller.  And quite a few
instruments have a fixed clef (which you, if at all, extend using 8va
notation).

-- 
David Kastrup