can somebody help with the harmonic analysis of bach prelude and fugue no 23 B Major?

Question

i think i have the general structure down but need help with the details. does anyone know where i can find good sources online? thanks!

Answer 1

Who are you studying with? Try asking them for help. Or contact a university theory professor and ask for help. Online sources won't help you much unless you can send and receive scanned manuscript pages for analysis. You are better off with a live person sitting next to you.

Answer 2

I'll start at the top and work down.

At ms. 5-6, there is a cadence on the dominant. A cadence usually marks a new section, so you can write "Section II" here. (For a famous example of an elision of a cadence, see the prelude to Act II of Carmen, ms. 13.)

At ms. 10-10 1/2, there is a cadence on the sub-dominant, but it isn't so spectacular, so you can make a choice.

On ms. 14-15, there is a cadence on the tonic. This renders the remaining measures as a coda. So you can write "Coda" in big letters.

The sub-dominant is prominent here. For some reason, Beethoven and Mozart seem to be fond of withholding the subdominant for the cadence, but I've never noticed that in Bach's music before. In this case, he even emphasizes it with the secondary dominant on the first beat of ms. 15.

To make the theory teacher happy, you must note all the most prominent named dissonances. In this case, that is the tonic pedal point at the beginnng and the dominant pedal point on ms. 17.

Theory teachers also like to point out the most pungent dissonances. So be sure to notice the diminished seventh in ms. 16.

Also, be sure to scrutinize the final cadence. On the first beat of the last measure, we almost have a second inversion on the tonic, or an I 6-4. But Bach stops that with a 4-3 suspension. (The B in the soprano is a fourth with the F# in the bass. This is resolved to an A#). This is followed by a dominant seventh, which is in return resolved to a tonic chord. In the last chord, there is a B in the bass and a B in the soprano, making this a perfect authentic cadence.

I just noticed something else: You've probably heard the rule that the voices making an augmented fourth (in this case, the soprano on #Aand the tenor on E) have to resolve to a sixth. This makes it illegal to resolve a full dominant seventh to a full tonic in four-part harmony. But a full dominant seventh sounds better! And a full tonic chord sounds better!

In the final cadence here, Bach fudges by adding a fifth voice in the last chord. That way, he has it both ways.

Generally, there is a lot of "motivie figuration" and many "inversions" in this prelude. My source specifically notes the inversion in the bass on the second half of ms. 12.

Notice the first four notes of the fugue.
They are the same as the first four notes of the prelude.
This probably isn't a coincidence.

I hope this is enough.
If it isn't send me your e-mail address and I will scan the two pages from my source.