# Why did Bach suspend the tritone here?



## caters

Doing a contrapuntal analysis of the fugue from Toccata and Fugue in D minor and I very quickly see an extension of the subject when it comes back in the soprano. This extension is accompanied by a second countermelody that doesn't appear anywhere else in the fugue. This would usually mean that I discount the countermelody. But an odd suspension brings attention to this countermelody. I say it is odd because it is not a consonant interval becoming dissonant(which most suspensions are). It is dissonant from the start and persists.

But even then, I would expect either a long second, a long seventh, or the suspended notes becoming consonant. But the interval that is suspended is actually a tritone. Suspending the tritone itself is odd in classical music but it is especially odd for Bach. Now it isn't suspended just through the countermelody alone. Instead, for 1 beat, it is in the countermelody in a harmonic form and at the start of the next beat, it is in the extension of the subject in a melodic form. But I still count it as a tritone suspension.

So my question is, why did Bach suspend this tritone? I mean, keeping a sequence going is typical for Bach and is exactly what he does in these bars of the second countermelody where the pattern is octave, sixth, fifth. But the tritone really wants to resolve inward to F and A. In fact, this tritone could be used as an incomplete V7/III and go to the relative major. It could also be used as an incomplete vii°7 to go any number of places But no, Bach just has to suspend the tritone.

Here is what I am talking about:









So why did Bach suspend the tritone instead of resolving it? It still feels a bit unresolved when it goes to octave A's afterwards and only really feels resolved once I have reached the fifth in the final iteration of the sequence between D and A(mostly because it is the tonic of D minor).


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## Bwv 1080

Quick answer, it sounds good



> So why did Bach suspend the tritone instead of resolving it? It still feels a bit unresolved when it goes to octave A's afterwards and only really feels resolved once I have reached the fifth in the final iteration of the sequence between D and A(mostly because it is the tonic of D minor).


Yes, you answered your question here - the final iteration of the sequence is the resolution. Each time the sequence ends with a suspension. The suspension to the diminished chord is the second to last iteration which is followed by the sequence finishing on suspension that resolves to *i*. Nothing that unusual here, fortunately Bach did not read undergrad music theory textbooks.


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## EdwardBast

*The tritone is not suspended*. The E and Bb are chord tones, the root and 5th of a ii° chord. Suspensions are always non-chord tones.* The suspensions are all in the soprano, a series of 9-8 suspensions in mm. 42-45. The way to approach the passage is to begin with a harmonic analysis. Starting with bar 42 (and ignoring the arpeggiations through the 3rd of each chord on the 4th beats) the progression is:

iv - V/III - III - VI - ii° - V - i

As you can see, the root movement from m42 on is G, C, F, Bb, E, A, D. This is a garden variety circle of 5ths progression with chain suspensions in the soprano. The tritone E-Bb doesn't want to do anything but what it actually does, which is function as the next step in a sequential progression. In any case, since the progression is ii° to V, the only other thing one might expect the E to do is to remain on E during the V chord. Because the E is in the bass it can't really do that. So A is the obvious choice.

Does that help? If you have any follow up questions don't hesitate to ask.

*I'm not getting into the marginal or ambiguous case of the 6-5 here.


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