Analyzing the prelude in C from the WTC...

[elephant]

I´m trying to make sense of the first prelude in the first book of the WTC. Most of it I can understand, but there are a few bars I can´t figure out. I should probably add that of music theory I know next to nothing.

In bar 15 – 19, Bach takes us from C to F to D to G to C. Why the F? Of course it doesn´t sound bad, but I want to understand exactly why he uses a progression like this.

The next thing getting my curiosity going is the thing happening in bars 12, 14, 22, 28. In bar 12, Bach uses the chord g – bb – ciss – e (what is it called) instead of the C one expects, to get to a D, and then a similar kind of chord to finally get to the C – what is going on?

What is the crazy chord used in bars 26 and 30? c – d – f – g ? D and a F combined?

Finally, what more is there to learn from this prelude? Are there any resources on the web providing more info?

[mikey6]

Bar 12 is the dimished 7th of dmin (bar 13) (A7b9 without the A in modern terms)  pretty much all the other bars are th same.
bar 26 - crazy chord? G7 sus, rather common.  the dominat seventh with a suspended 4th which resolves to the dominant in the next bar.
bar 15-19 is all in C, he really doesn't 'take us' anywhere in terms of modulation.  It's a passing chord, I don't think there's really any specific purpose to use that chord - bar 16 is the subdominant on it's maj.7th (E).  Bar 15 ends on the 1st inversion chord so perhaps he's looking for a way to get back to a full close on the tonic (bar 19).

[sarahlein]

https://www-personal.umich.edu/~siglind/text.htm

https://jan.ucc.nau.edu:8765/highlight/index.html?url=http%3A//jan.ucc.nau.edu/~tas3/bachindex.html&fterm=music&la=en&charset=iso-8859-1&search=../query.html%3Fqp%3Durl%253Ajan.ucc.nau.edu%26charset%3Diso-8859-1%26qt%3Dmusic

 

[elephant]

Thanks to both of you for taking your time, the links were extremely helpful. Now I have material for a lifetime