Bach Prelude in C major, bar 22

[neueliteratur]

Hi forum,

My question concerns the first prelude in Bach's Well-Tempered Clavier volume I.

Here is the music sheet: http://erato.uvt.nl/files/imglnks/usimg ... __RSB_.pdf

Please have a look at the 2nd page, from bar 22 to 24.

Bar 22 is F#dim, bar 24 is G7.

But what is bar 23?

Is that Abdim? Dhalfdim/Ab? And what is its function?

I would've had no problem if it went straight from F#dim to G7.

But this bar 23 is frustrating me.

Thanks for sharing your wisdom.

[FriendlyStranger]

I think you were right in calling it an Ab diminished chord. As to it's purpose - well it sounds nice! The Abdim is almost a G chord, the difference being the root is raised a half tone to A-flat, so the A-flat is like a suspension that resolves to the G note in the next bar (I know that suspension isn't technically the correct term here so maybe someone else knows what it's called). Hope that helps somewhat.

[jancivil]

I would not call it Ab diminished because that's an unusual thing to call something that isn't even unusual. 'bvi diminished'? No.

the function is subdominant. it's ii (taken from parallel minor) in second inversion. ii4/3, V7, I6/4, V7sus4...

[JumpingJackFlash]

the function is subdominant. it's ii (taken from parallel minor) in second inversion. ii4/3, V7, I6/4, V7sus4...

My first thought would be vii7 (diminished seventh) in third inversion borrowed from the parallel minor.

A diminished seventh on the 7th degree of the (minor) scale was much more common with Bach than on the 2nd degree, which would in any case require enharmonic change (C-flat rather than B-natural).

[fmr]

the function is subdominant. it's ii (taken from parallel minor) in second inversion. ii4/3, V7, I6/4, V7sus4...

My first thought would be vii7 (diminished seventh) in third inversion borrowed from the parallel minor.

A diminished seventh on the 7th degree of the (minor) scale was much more common with Bach than on the 2nd degree, which would in any case require enharmonic change (C-flat rather than B-natural).

I am also of the opinion that it's the diminished seventh of C, although it postponed the resolution of that chord by going from it to the dominant, and only in the next bar resolving to the tonic - something Bach does a lot, specially in more free pieces, like the preludes, fantasias, tocattas, etc.

[egbert]

Ignoring the C in the right hand (as a passing note) you have B, D, F and Ab. This is the notes of D dim 7th inverted or Ab dim 7th leading to G7 in the next bar.

[jlocri]

When you're analysing works written with classical harmony, it's not always best to try and look for chords/chord functions and all that. Things like suspensions, rhythmic displacement and augmented lines means that sometimes chords that aren't really functional exist.

For that whole bar, I think the harmony is either F minor or D diminished. Most probably F minor because the voicing is a little obscure to be a diminished chord. It depends on which notes in the upper line you're taking as non-essential. Think of those D's and B's as neighbour tones, remember that the Baroque style meant lots of ornations and additions to the lines.

Overall, I agree with the other posters that the harmony is probably some sort of predominant movement.

[fmr]

When you're analysing works written with classical harmony, it's not always best to try and look for chords/chord functions and all that. Things like suspensions, rhythmic displacement and augmented lines means that sometimes chords that aren't really functional exist.

For that whole bar, I think the harmony is either F minor or D diminished. Most probably F minor because the voicing is a little obscure to be a diminished chord. It depends on which notes in the upper line you're taking as non-essential. Think of those D's and B's as neighbour tones, remember that the Baroque style meant lots of ornations and additions to the lines.

Overall, I agree with the other posters that the harmony is probably some sort of predominant movement.

You are right about having to be careful regarding passing notes, ritards, etc., but when analysing harmony, you have to be aware of what is the main tonality, and from where the music comes and where it goes to. This prelude is in C. F minor is a chord that doesn't belong to C (it could be a chord of C minor). D diminished is even far from C (it would be a chord of E Flat minor), and would be D, F, Ab, and C. However, the C is in a weak part, and very much a passing note, IMO. OTOH B diminished is a chord of C (C minor, but Bach sometimes uses chords with chromatic alterations, and in this case the Ab is suitable to resolve that chord in G7, the dominant of C, and the G chord was somehow "called" by the F#). So, B diminished is the most obvious and coherent choice, the one that fits better in the whole, IMO. But don't just trust me. Play the chords one after the other, and tell what sounds better.

[fmr]

Ignoring the C in the right hand (as a passing note) you have B, D, F and Ab. This is the notes of D dim 7th inverted or Ab dim 7th leading to G7 in the next bar.

B, D, F and Ab is the chord of B diminished, not D diminished. D diminished would be D, F, Ab and Cb. In baroque, classic and romantic, you have to classify the chords according to what is written. If Bach wantd a D dim chord he would have writen Cb, but that would lead to a completeley new universe (the one of E Flat minor), and he is in C.

[JumpingJackFlash]

Skeletonised, the passage looks something like this:

[VicDiesel]

I would've had no problem if it went straight from F#dim to G7.

Additionally, the whole piece is a string of 4-measure phrases and this is the only 3-measure phrase, which led Czerny to insert a chord between that F# and Ab, a Cmin in 6/4 inversion iirc.

You also find that extra measure in the Bach/Gounod Ave Maria.

Victor.

[jancivil]

When you're analysing works written with classical harmony, it's not always best to try and look for chords/chord functions and all that. Things like suspensions, rhythmic displacement and augmented lines means that sometimes chords that aren't really functional exist.

For that whole bar, I think the harmony is either F minor or D diminished. Most probably F minor because the voicing is a little obscure to be a diminished chord. It depends on which notes in the upper line you're taking as non-essential. Think of those D's and B's as neighbour tones, remember that the Baroque style meant lots of ornations and additions to the lines.

Overall, I agree with the other posters that the harmony is probably some sort of predominant movement.

I would call it F minor just as easily. This is a GOOD point, it's not the best idea to look for roman numbers but function. Looking to follow names of chords for JS Bach, a contrapuntal composer, is asking that cart to pull the horse of his musical thinking, which is getting the most forward drive in part writing.

This harmony is subdominant function. He is anticipating the tonic in the melody (B C D) while he sets up a cadence. If you're going to analyze it harmonically use Occam's razor: ii, V, I. Seriously. A diminished chord on the flat 6th degree never happened here.

[jancivil]

Skeletonised, the passage looks something like this:

That (23) is a vii chord? it certainly does not sound like one as it does not work like it; it has a subdominant function in the context of the formal plan.

The B you have there is one of three passing notes in the tune and you have it as the root of a harmony. I do not buy this argument in any way. Posing JS Bach as block chords in this way is antithetical anyway.

[fmr]

Skeletonised, the passage looks something like this:

That (23) is a vii chord? it certainly does not sound like one as it does not work like it; it has a subdominant function in the context of the formal plan.

The B you have there is one of three passing notes in the tune and you have it as the root of a harmony. I do not buy this argument in any way. Posing JS Bach as block chords in this way is antithetical anyway.

I think the problem is trying to "think" Bach music in strict vertical terms. Bach had a strong polyphonic thinking, and his harmony, although strong, is always put at service of the "voices". That's why, in the chorales, you have so many strange harmonic passages, resembling some kind of chromaticism.
IMO, the chord is, indeed, a diminished seventh over B, which would resolve naturally in C min. However, as is many times the case in Bach, he "twisted" the resolution of some notes (voices), while resolving others, and transformed the diminished seventh, which is a chord that belongs to minor tonalities, into a dominant seventh. In this case, he resolved the Ab (the seventh of the chord) while maintaining all the other notes - very much "by the book".
Later, in the romantic period, the diminished seventh, together with the augmented sixth, became the two preferred chords for changing tonality. The diminished seventh, with it's four notes, all minor thirds, is particularly suitable, since by changing the notes enharmonically, you change the tonal universe completely.
Besides all this, you may very well consider the C as a pedal note, since it is already there for several bars, sometimes consonant, sometimes, dissonant, but resolving only when we reach the dominant seventh. If you withdraw the C from all the three chords (21, 22 and 23), you will notice that all of them make sense.

[JumpingJackFlash]

That (23) is a vii chord? it certainly does not sound like one as it does not work like it; it has a subdominant function in the context of the formal plan.

The B you have there is one of three passing notes in the tune and you have it as the root of a harmony. I do not buy this argument in any way. Posing JS Bach as block chords in this way is antithetical anyway.

The progression vii7 to V7 is fairly common and, as fmr said, the resolution of it here is textbook.
The B in that chord cannot be a passing note, by definition it does not "pass" anywhere (unlike the C). It is an integral part of the chord.