What is up with this one chord in this one bach piece
March 10, 2023 11:47 AM   Subscribe

In the prelude section of Bach's prelude, fugue and allegro in E Flat Major (BWV 998), there is a chord near the end that surprises me. It's a really fascinating sound, so what's going on structurally with this chord?

The chord in question is played at 1:53/1:54 in this video. I don't know how to describe it technically, but's a very open-sounding chord -- almost a jazzy sound! How did Bach make this one jazzy chord fit into a Baroque chord progression? Technical reponses are welcome, even though they will probably go over my head.
posted by cubeb to Media & Arts (8 answers total) 9 users marked this as a favorite
It sounds jazzy because of dissonance.
posted by kevinbelt at 11:49 AM on March 10

Best answer: Very interesting question! I agree that it's a very jazzy-sounding chord. I am not a music theorist BUT:

The notes being played are an E-flat in the left hand and a C, an F and a B-flat in the right hand. The B-flat then resolves down to the A (and I think the resolution is part of what gives it that jazzy feel).

From someone named Blair Johnston on AllMusic:
just before the coda, Bach throws a fermata over a third-inversion seventh chord, complete with a rich suspension, that is so enrapturing that only a flurry of 16th notes can propel the motion forward again.
So in this F7sus4 chord (I think - there are other ways you could interpret it) you've kind of got two open-sounding "perfect" intervals (Eb-Bb and C-F) and you don't quite know where the chord is going to resolve to until that suspended 4th (the B-flat) resolves to the A. Suspension and dissonance are common in both jazz and baroque music but 7sus4 and 9sus4 chords are very very common in jazz.

(Also I think a lot modern players choose to lean into the chord in an jazzier way - I don't know what Bach's autograph version looks like but in the printings I've seen the fermata is on the resolution of the chord, but the performer in the linked YouTube video gives the onset of the chord a little extra time as well. I don't think there's anything wrong with this!)
posted by mskyle at 1:01 PM on March 10 [8 favorites]

Best answer: Also this chord is inverted and the 7th played low on the keyboard, very jazzy (see "drop chords")

It occurs to me that Hendrix used this chord voicing in Third Stone From The Sun -- he was known to dig on some Bach and use a bit of harpsichord in his music.
posted by credulous at 1:29 PM on March 10 [5 favorites]

Best answer: It may also be a tuning thing. I wouldn't be surprised if some tuning choices make the chord sound "jazzier" than others. It might be worth listening to different performances on different instruments-- for example, played here on the lute, it still stands out, but sounds a bit less outrageous.
The basics: The scale we use for European classical music developed from the older system of modes, in which each mode had its own distinct scale. So a flute in the Dorian mode could not necessarily play music written in another mode; the notes were not the same.

Then eventually people invent new instuments, and they want to play multiple pieces of music without having to retune. They also want to use multiple tonalities in the same piece of music. So equal temperament is developed: instead of modes we have keys, and we adjust the tuning so a tone, a semitone and a fifth are the same interval no matter what key you're in...

...except that's mathematically impossible. The closest you can get is where that is roughly true, but a G-sharp (for example) is still never going to be quite the same as an A-flat. A violinist or a singer can finesse this, but a harpsichordist can't. Some semitones are always going to be wider and some will be narrower. The question for the tuner/instrumentalist is, which ones?
My own ear isn't quite good enough to get as fiercely geeky about this as some early music people, but Bach's ear was razor sharp, and he loved playing games with tuning. The whole point of writing a set of preludes and fugues, one in each key, and calling it The Well-tempered Clavier is basically a dare: Can you tune your instrument evenly enough to play through all of these?

But this piece isn't part of that, and furthermore it's for lute, which has to be tuned every time you pick it up. So the lutenist, for this piece, may adjust their tuning to suit the specific intervals of E flat major.

The fermata over the chord suggests that Bach knew it would stand out. Someone better at this than me can talk about the progression it's part of; to me Bach's progressions are as inexorable and mysterious as the geometry of God. I just sing the stuff. (I always feel that Bach knows I don't understand him, and is judging me for it.)
posted by Pallas Athena at 4:15 PM on March 10 [6 favorites]

any idea what a fermata over a third inversion seventh chord would be in a cello fingering?
posted by j_curiouser at 5:47 PM on March 10

Best answer: I know cellos don’t have frets, but I don’t know what the half steps are called. Regardless, on a C-G-D-A cello, you’d play the Eb on the third “fret” of the C string, the C on the fifth fret of the G, the F on the third of the D, and the Bb on the first fret of the A. You’d need pretty lumber fingers but it’s possible.
posted by kevinbelt at 7:00 PM on March 10 [1 favorite]

Best answer: What is going on here is pretty interesting but also a bit complex to try to explain in text. But I'll try, briefly.

(Ok, on preview this is the opposite of brief. It's impossible to explain music briefly. I'll only add the usual lament, that I could have made it a lot shorter if only I'd had a lot more time to spend on it . . . )

It may be helpful to refer to the text - I'm looking at this version, and note the measures are numbered.

First off, the piece is in Eb major, and we are at the part of the prelude where we expect it to cadence in Eb major, and circle around a bit, cadencing ever more conclusively in Eb major to signal the end.

(In simplified form, "cadence in Eb major" means go V-I in Eb major a few times. V-I in Eb major consists of the chords Bb or Bb7 (which is the V or V7) followed by Eb major, the I chord.)

So in measure 36, it starts this process quite nicely, landing on Eb major just as expected.

****Your chord is the fulcrum of a "musical pun"

What happens next is a bit of a surprise, though. The Eb major chord instantly adds a Db - making it an Eb7. That is the V7 chord of ab minor, and that Eb7 chord takes us straight on in to ab minor on the first beat of measure 37. We then repeat Eb7 - ab minor in m. 37. So when we arrive again on ab minor on the first beat of m. 38 - extending that ab minor chord through the entire measure - we have pretty convincingly modulated from Eb major to ab minor.

Now, whenever you move from one key to another, you have to ask if you are just briefly touching the new key, or maybe staying there for a couple of beats or a measure or two before returning - or are you really modulating to the new key and staying there.

So far we had cadenced twice in ab minor, the second time more convincingly, and what happens next makes us think that - oh, yeah, we are really going to do a solid cadence in ab minor here. And so maybe there will be a whole new section of the piece picking up in ab minor? Maybe we'll spend 30 seconds or a minute or two here? Or what?

(FYI ab minor is a "colorful" choice of key to move to from Eb major, not really where you would expect to go to for a lengthy period of time in a "traditional" tonal scheme. But, who knows . . . )

What gives us the impression that we are going to really truly stay in ab minor - rather than just quickly landing there and then retreating right back to Eb major - is all of m. 38 stays on the tonic of ab minor, and then in m. 39 we move to what looks to be an Fb major chord. The way it is presented is slightly ambiguous, but it really looks to be some kind of Augmented 6th chord in ab minor, which would be a very colorful type of chord, but also a way to bring us to a REALLY strong cadence in ab minor, totally solidifying our arrival in that key.

An Augmented 6th type cadence would look like: Aug 6th chord - V7 - i. In ab minor, that would be Fb major (typically, though not always, with an added note like D) - Eb7 - ab minor.

So we have the Fb minor chord extended all the way through m. 39 and that is the EXACT setup we are looking for to then go Eb7-ab minor - a huge cadence and very solid landing in our new key of ab minor.

Then we arrive on the first beat of measure 40 (your chord) and what do you know: Bach is following through on this plan, exactly as predicted, with just one twist: We have our Eb7 chord (Eb in the bass, Bb in the soprano, just as we expected) BUT he has thrown in a clever double passing tone between the Cb and Fb of the Fb major chord and the Db and G of the Eb7 chord.

So on beat 1 of m. 40 we land on C-F in the inner voices - which sounds EXACTLY like the type of dissonance that Bach loves to use, and which is going to resolve nicely to Db-G, giving us our Eb7 chord, which will then resolve to ab minor, firmly establishing us in that new key.

But THEN Bach, the old rascal, totally tricks us. Instead of resolving the C-F upwards to Db-G, he resolves the Bb downwards to A natural.

WFT?!??!!! (he is hoping we will say to ourselves . . . .)

What has gone wrong?!

Because when that Bb slides down to A natural, we suddenly realize we are not in ab minor at all but we have slipped right back into Eb major!

Because with the A natural, that chord is now an F7 chord (in 3rd inversion, as others above have pointed out - meaning that the 7th of the chord, the Eb, is in the bass). F7 is the dominant (V chord) of Bb, and Bb is the dominant of Eb.

When you go from the dominant of the dominant (F7) to the dominant (Bb7) to the tonic (Eb), now THAT is about the strongest type of cadence there is.

So Bach has led us by our noses down the garden path to ab minor, but then at the last moment rearranged things to end up not in ab minor at all, but rather at a very convincing cadence back in Eb major.

Just to be sure, he repeats the V-I (end of m. 41 to m. 42), then spends four full measures on an Eb pedal point (mm 42-46 - note the repeated bass Eb in the left hand), then concludes with a deceptive cadence (m. 46-47) followed by a strong authentic cadence. (m. 47-48).

If you didn't understand a word of the last paragraph, here is what it means: It's literally a textbook example of how to end a piece strongly in Eb major.

So one thing that is going on here is that Bach has led us down a merry path to ab minor, made it seem like we were going to really modulate and stay there, but at the last moment, diverted back to a solid Eb major ending. Your chord (m. 40 beat 1) is the fulcrum on which that whole thing turns, and the way Bach sets up our expectations to hear it as one chord, then turns them around completely in one single note (the Bb resolving to A natural, m. 40 beat 1-2) is a big part of what makes that chord sound really amazing.

You can think of that chord on m. 40 beat 1 as sort of a musical pun: You start out thinking it means one thing, but when you add the complete musical context, it shifts and means something completely different than what you were expecting.

****Actually, your chord is the fulcrum of a very extended musical pun, making us reconsider - and hear in a completely new light, retrospectively - practically a whole musical phrase

But . . . there is even more! Because as soon as we hear m. 40 beat 1 as F7, which is leading us back to Eb major, we have to ask ourselves: How did we get here?

And the answer is, we get here via the chord in m.39 - that Fb major chord.

We had thought it was some kind of an Augmented 6th chord leading us to a big cadence in ab minor.

But guess what: In hindsight, it was not an Augmented 6th chord at all. Instead, it was a Neapolitan 6th chord - in the key of Eb major.

I won't try to explain exactly what Neapolitan 6th chord is (read the wikipedia article above), but I will say these things about it:

* It is one of the most colorful chords in the harmonic language
* When you add it before the strong cadence chords I mentioned above (dominant of dominant to dominant to tonic, or F7->Bb7->Eb) you end up with an EVEN STRONGER cadential pattern leading us back to Eb major.

So basically we retroactively extend the F7-Bb7-Eb cadence to include the Fb major chord - and then even the ab minor, which we now realize was not really a modulation at all, but rather a quick excursion to the minor IV, which is a close relation of the Neapolitan 6th (minor IV has two notes in common with Neapolitan 6th - the Ab and the Cb).

And so now in hindsight that whole feint to ab minor was in fact just a set up for a truly massive cadential formula leading back to the final cadence in Eb major: flat IV - N6 - V/V - V - I (ab minor - Fb minor - F7 - Bb7 - Eb).

So altogether, it is a musical pun - but instead of being a simple pun on one single chord (m. 40 beat 1) it is a truly amazing extended musical/harmonic pun on practically a whole phrase - one that leads you by the nose down one garden path almost all the way to the end, but when you get to the end it diverts you onto a different path that makes you completely reinterpret everything you have heard for the past several measures in a new and unexpected way.

(And what's doubly amazing here is that this "new and unexpected way" is actually exactly what you do expect to happen exactly at this stage of the piece. But part of Bach's genius is that even though you know exactly what is going to happen, he manages to make it happen in a way that completely surprises you nonetheless.)

If you want another analogy, it's something like an O Henry story, where the revelation in the last line makes you totally reconsider everything that happened in the story - every relationship, and everything you thought you knew on first reading, you have to put in a new light now.

That's why "musical pun" gives an idea of what m. 37-40 are about - chords that appear to mean one thing, but upon further revelation actually mean something else.

But what's going on is much deeper than what we usually mean by a "pun" which is sort of shallow trick of language. Musically, this isn't shallow at all but among the very deepest kinds of meanings that music can have.

Partly it is because it is bringing all of your musical expectations to bear, and leading you to hear the chords one way, and then in the greater context (and in hindsight) in a different way. But musically the different meanings don't just replace each other, like a trick or sleight of hand, but rather they layer on top each other in an additive sort of way. You end up with a different and deeper idea of how ab minor and Eb major relate to each other, and how they are connected.

"I don't even understand what all those words mean," you are going to say. Two responses to that:

#1. Bach understood all this, and much, much more. This isn't haphazard - he knew exactly what he was doing. Everything I've explained above is literally freshman-level music major stuff. Bach knew and understood all this and much more.

#2. Explaining music in words is not very easy. It takes a wagonload of words to explain things that are actually pretty simple.

But (TL;DR?) listen to the chord at m. 36 beat 1 and compare it to the chord at m. 38 beat 1. Those are the two chords (or tonalities as musicians might prefer to call them). Bach is playing with our expectations and exploring how those two tonalities are related - and which one is really the "home base" tonality here, the most important one, and which is secondary and must relate back to the other one.

The crux of the connection between these two tonalities is the chord on m. 40 beat 1, which is like a pivot chord - an extremely clever and unusual one - that is set up in such a way that could lead us back to the ab minor tonality, making it the more important of the two and the "home base," or it could return us to the Eb major tonality, making it the most important of the two and the home base tonality.
posted by flug at 2:55 AM on March 11 [37 favorites]

Best answer: A tiny grace note to that wonderful explanation: one reason you may perceive that chord as "jazzy" is that the top three notes are stacked perfect 4ths. The bebop pioneers were experimenting with all kinds of shit including chords built out of fourths rather than thirds ("quartal harmony") and so this kind of sound would not be out of place in mid-late 20th century jazz. The fact that the performer sits on it before letting the Bb resolve to A is evocative to us now, with 21st century ears, of harmonies where that Bb NEVER resolves because the chord is a thing in its own right and not a consequence of counterpoint. I imagine Bach's contemporaries heard it differently (and were probably even more WTF when they did).
posted by i_am_joe's_spleen at 1:41 PM on March 12 [5 favorites]

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