Re: Harmonic reduction

[Urs Liska]

Hi Lukas,

Am Sonntag, den 21.06.2020, 19:10 +0200 schrieb Lukas-Fabian Moser:
> Hi Urs,
> 
> > The use case is the following: The example I attached shows a few
> > ways
> > to visualize the harmonic structure of (dodecaphonic) polyphonic
> > music.
> > But I would like to have this as a kind of live preview when
> > working
> > out counterpoints (with students). Therefore I don't need an
> > analysis
> > toolkit like Humdrum. Although: There actually might be tools to
> > analyze the resulting MIDI files from a LilyPond compilation, and
> > it
> > would be possible to write a script that takes the Humdrum output
> > to
> > generate some LilyPond code that is then compiled. Hm, while
> > writing
> > the previous sentence this looks like an intriguing idea, but it's
> > way
> > too short for being able to use that on Wednesday :-(
> 
> But I think it would be desirable to avoid using MIDI as an
> intermediate 
> step at all costs: For, as far as I know, MIDI only knows
> "chromatic" 
> pitches and has no way of distinguishing enharmonic equivalents.

Oh, that's a good point. Probably a major reason why the "keyscapes" I
created look only partially convincing. I'll redo these after
converting the Midi files to Humdrum (which seems reasonably possible
with two very short songs).

> 
> This might be sort-of acceptable for dodecaphonic music (I tend to 
> disagree: Dodecaphonic music has always been written by composers
> with a 
> strong background in classical diatonic theory, and it should not be 
> taken for granted that they just tossed a coin when deciding on the 
> enharmonic spelling of a given pitch), but it's obviously a no-go
> for 
> pieces governed by classical tonality.
> 
> 
> Moreover, your initial example manifestly exhibits what is known as
> the 
> "segmentation problem" in many flavours of musical analysis: Which
> notes 
> are to be grouped together in ordner to obtain a meaningful analysis
> of 
> harmony/voice leading/etc.?
> 
> For instance, it's quite hard to (algorithmically) decide which notes
> in 
> the attached Chopin are to be considered when analysing "the
> harmonic 
> progression" of the piece - except of course if you claim
> (erroneously, 
> I think) that "harmony" only lives in the lower staff here.
> 
> As another example, there's the famous bar in the first prelude of
> the 
> Well-Tempered Clavier (see attachmend) where, for the first (and 
> basically only) time in the piece, squashing all the pitches in a
> given 
> bar together does not yield a meaningful chord. (And in fact, there
> is 
> some debate on which pitch should be considered as part of the 
> underlying chord here: Many people say b, but there a strong reasons
> to 
> instead consider the c as a chord tone instead, hence regarding the 
> harmony as a 43 instead of a 642.)
> 
> Also, Schönberg gave (in his Harmonielehre) funny examples of 
> "impossible" sonorities taken from Bach's Motetten by just stopping
> the 
> music at the right (or wrong?) time, together with equally funny
> jibes 
> against the "aestheticians", or from Mozart's symphonies (also
> attached).
> 
> 
> Maybe all I'm saying here is that any such automated tool for
> "musical 
> analysis" would have to be highly configurable.

Very valid points, indeed. However, it seems I'm persistently not
making myself clear.
I'm not looking for musical interpretation/analysis, just for a
visualization of what is sounding at the same time, to get a visual
idea about the harmonies resulting from polyphonic settings.

Urs

> 
> Lukas
>