"I got rythm" Analysis?

[leppard81]

Somebody posted this link in another thread a few days ago:

http://people.uncw.edu/russellr/rhythm.html


It tells the chord changes for the tune "I got rythm" and then delivers some even more jazzed chord variations. Anyway Í´m trying to analyze the first 8 bars, and so far not everyhing is clear on WHY this works:

Here´s the basic progression and my reasons why I think that it works:

Bb Gm | Cm F7 |Bb Gm | Cm F7 |
Bb Bb7 | Eb Ebm | Bb F7 | Bb |

Everything is diatonic in here ecxept the Bb7 which functions as a secondary dominant ( is this the right expression?? its when you make the chord leading to another one a dom 7 chord, therefore it tricks the listener into thinking that there´s a new tonal center. In this case Bb7 leads to Eb...)


Here´s the jazzed up progression:

Bb Bb7/D | Eb Edim | Bb/F Dbdim | Cm F7 |
Bb Bb7/D \ | Eb Ebm | Bb/F F7 | Bb ||


Compared to the basic version this features a B7/D, which is again a secondary dominant leading to Eb (Eb is a substituion for Cm here). Since I´m no jazzer I dont really know what to make of the the Eb- Edim measure. Playing a major chord and its diminished version on half step higher occurs a few time in this prog, also its only one single note that changes between these 2, yet I dont know WHY it is like that (EDIT: Now that I think about it; it seems that THAT IS indeed the reason why it works as there´s just a single note alteration between these two chords). Also I cant explain whats going on in measure 3 and 6 in the jazzed up version. Any suggestions?

thanks for your help!

ALEx:-)

[Poparad]

Both diminished chords in the second version are used to lead into the chords that follow them. In each case, the bass note of the next chord is a half step away. The Edim7 moves to a chord with F in the bass (up a half step) and the Dbdim7 moves down to Cm7 (down a half step). Half step resolutions are very strong, especially with dim7 chords.


This example of the A section is very uncommon today. In fact, I've never played a tune that used it. The website showed this is an example of the evolution of the A section, and all the examples that follow this are very common today.

[leppard81]

Thanks for your reply, Poparad!

One more question though about your first paragraph: Are there any more short rules on how to apply half step resolutions with dim7-chords. Or is this about it? No need to dive too deep into theory, allthough it would be interesting, but so far adding a fitting diminished chord to a progression seems to be a great songwriting tool. e.g. I-IV-bVdim-IV sounds pretty cool.......

[Poparad]

Usually it's placed a half step below the next chord, in which it's really acting as a V-I. If you take the root out of the V7b9 chord, you get a dim7 chord. For example, A7b9 to Dm7 becomes C#dim7 to Dm7.

The other common use is to simply put it a half step above the next chord, like in the last A section of All the Things You Are (Dbmaj7, Dbm7, Cm7, Bdim7, Bbm7).

[leppard81]

Cool! So what I (theoretically) could do to get a progression would be using a secondary dominant progression and substitute a V with VII and get something like this for example:

A7-D-Ebdim-E

Though I still dont get how the use of a "Eb Edim" bar in the key of Bb can be justified. Maybe because E-dim is on a bV-degree, therefore connected to the blue note in. or can it just be taken as a passing chord? Or am I stretching this one too far now?


ALEX :-)

[leppard81]

As I read through a few other posts on here, i think your answer in this thread
http://www.ibreathemusic.com/forums/...ad.php?t=11044

kinda makes it clear a bit more...

thanx
ALEX :-)

[Poparad]

It's not in the key. It's simply connecting the chords together chromatically.

[leppard81]

Ok, I see. So its actually easier than I made it up my previous post. thanx again, seems to be a neat approach, not only for jazz........

ALEX :-)

[leppard81]

One more thing please, as i thought a bit more about my thread:

Beside the view that you link the chords chromatically via diminished chords, I could also assume that a Bb-Bdim-Cm-C#dim-Dm progression is actually a diatonic progression using secondary dominants, but subtsituting the V7 with a vii-dim . I know I actually did this in a post abovem but I just wanna make sure I´m really right about this. Am I?


thanks again
ALEX :-)

[Poparad]

Right. That progression can also be seen as Bb-G7b9-Cm-A7b9-Dm

[leppard81]

Great! Thanks again for your help....!