Re: MusicXML representation of "additional" staff

I agree that it is confusing. I just grabbed a MIDI of the debussy piece, this is how the measure is represented in an import (MuseScore)




> On 22 Apr 2016, at 22:21, Glenn Linderman <v+smufl@g.nevcal.com> wrote:
> 
> On 4/22/2016 12:06 PM, Dennis Bathory-Kitsz wrote:
>> On Fri, April 22, 2016 2:55 pm, Christina Noel wrote:
>>> From what I can tell of the original pasted image that sparked this
>>> discussion... does it have a semantic meaning at all?
>> 
>> [...]
>> 
>>> What meaning does this particular clef symbol actually add to the
>>> music?
>>> 
>> 
>> This is not unique to Debussy. Attached is an image of a score I'm currently
>> setting for a composer. You can see multiple clefs on one staff, similar to
>> the Debussy.
>> 
>> Dennis
>> 
> 
> OK. It is not unique to Debussy. But what does it mean? Perhaps another sample was intended to be enlightening, but it didn't actually answer the question asked.
> 
> If I were to try to actually play that, what notes would I play, and would I actually obtain help from seeing those extra clef symbols, and what help would they give me?
> 
> As a very first step in the explanation (and without seeing the clefs at the left edges of the staffs in your sample, which, since you omitted them I can only assume to be treble clef for the top staff and bass clef for the bottom staff), I wonder, seeing the 15ma kind of grabbing the notes mostly surrounded by the dashed lines with funny angles at the bottom, whether the first note to the right of the treble clef intruding on the bass staff, should be interpreted as a middle C&D raised two octaves, or a treble A&B raised two octaves?  The latter interpretation would sort of bump into my interpretation of the notes on the treble staff being treble FG&B raised two octaves, so I would conclude that the interpretation intended is probably middle C&D, and then I'd further conclude that the treble clef is more confusing than helpful, in the sense that its presence only confuses the interpretation of the pitch of the notes on the bass staff, although one can argue that it assists in realizing that the 15ma applies to these notes (but that seems to be what the dotted line is also doing, so the treble clef becomes redundant, confusing, or, as Christina seems to be arguing, without semantic meaning [because it doesn't affect the interpretation of the pitch of the following notes]).
> 
> There's certainly not a lot of time to figure out the interpretation of all that stuff while playing the quarter note before it... definitely not a piece for the faint-hearted to sight-read at first exposure.
> 
> And it is not at all clear why, if those notes are intended to be interpreted as middle C&D raised two octaves, why they are attached to the bass staff, rather than being placed just below treble staff in its middle C&D positions?  The shown placement seems to overaccentuate the tonal distance between the notes.  And if they were placed relative to the treble staff, there would be no need for all those extra clefs to be redundant, confusing, or semantically meaningless.
> 
> In the Debussy sample, it also seems to be confusing: the clef does not appear in the proper position to help avoid counting leger lines. It should be two staff spaces higher to help with that.
> 
> Glenn