# Analysing Rondo a Capriccio: G to Ab modulation



## caters

So everything was going fine for a while as I did a harmonic analysis of Rondo a Capriccio. That is, until I got to measure 153. Then I came across this modulation from G major to Ab major and the harmony seemed a bit weird to me in some spots, so I came to ask for help deducing what is going on harmonically.

Here is the passage:









And here is what I have so far on the analysis of this modulation:









How could I mistakenly think that measures 161-162 are a diminished harmony when it is actually D major? And how does that D major fit into Ab? Just ignore that ii°, it's my mistake.

From measures 153 to 156, I'm not sure of the harmony, partly because of the alternation between C# and C natural that is going on in those measures. Measures 157-158 are where I suspect the pivot to Ab is. Why? Because Eb appears in those bars and it didn't before, and Eb is a note that is in Ab major(both the chord and the scale). Measure 159 just seems off. It looks mostly like an Eb7. But there is no Eb, instead there is an E natural, which doesn't fit into Eb7. I have 2 hypotheses as to the harmony there.

1) This could be an E°7 with an enharmonic respelling or to avoid enharmonics, C#°7 6/5, But this would mean a movement by thirds to what I suspect to be V7 of Ab, Eb7. That weakens the diminished 7th. Also, you don't usually find a diminished seventh on the #3 or #5 of the key because they are foreign to the scale

And

2) The E natural could be a non-chord tone in the bass, thus making the harmony Eb7. This makes sense comparing it to the measure right afterwards.

As for the harmony I circled in red in measure 160, the only way I know of to explain that is as an enharmonic respelling of Eb7. Everything else except the C# points to Eb7 being the harmony.

So, is the harmony in measure 159 a diminished seventh or is it Eb7 with a non-chord tone E in the bass? And is the harmony in measure 160 Eb7 with an enharmonic respelling? And what is the harmony in measures 153-158, where C# and C natural alternate, followed by what I suspect to be the pivot to Ab?


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## Bwv 1080

159 is a dim7 chord then with the E moving down to Eb 160 is an Gr augmented 6th chord - the Eb -C# is the augmented 6th which removes to the octave d in the following measure. A6 chords are the same intervals as dom chords but respelled to show the augmented 6th resolving by expanding by half step to an octave. In modern terminology they are tritone subs for secondary dominant chords


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## caters

Bwv 1080 said:


> 159 is a dim7 chord then with the E moving down to Eb 160 is an Gr augmented 6th chord - the Eb -C# is the augmented 6th which removes to the octave d in the following measure. A6 chords are the same intervals as dom chords but respelled to show the augmented 6th resolving by expanding by half step to an octave. In modern terminology they are tritone subs for secondary dominant chords


So that explains the presence of D major, it is the resolution chord of the augmented sixth. So, I would just put that D major chord in as #IV in my harmonic analysis, right? # to show that it is a chromatic chord and IV to show that it is a major chord on a chromatic alteration of the fourth scale degree of Ab.


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## Bwv 1080

#IV does not have any meaning in tonal harmony. The A6 resolves traditionally to D, the V chord of G major. The transition to Ab happens in the next measure where, instead of getting G major in the Gr6-V progression you go back to the Eb7 chord spelled this time as a dom7 instead of a Gr6 which then resolves to Ab setting up the new key


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## Bwv 1080

So beginning at 160 you could write

G: Gr6 V Gr6
——- Ab: V7 I


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## Bwv 1080

(Deleted duplicate)


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## caters

Wait a minute, so the Eb in measures 157-158 has no harmonic significance and is just a non-chord tone? I guess that means that the Bb in measure 158 is also a non-chord tone and that means that the harmony in measures 157-161 is:

V7, V7 with tonic pedal, I, vii°7/V, Ger6, V


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## Bwv 1080

Yes, I would call 157-9 as

G: V65 i viio7/V


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