How to explain: "Abdim7 -> Adim7 -> Eb"

[neueliteratur]

Hello,

I'm trying to analyze Chick Corea's Armando's Rumba, which has a passage that goes like this:

C7, F-, D7/F#, G-
Abdim7, Adim7, Eb/Bb, %

How would you explain Abdim7 and Adim7?

All I can say is that it allows chromatic bass movement (F F# G Ab A Bb), but is that the only function?

Thanks for any help.

PS) if there was no Adim7, I'd interpret Abdim7 as Ddim7 which makes VIIdim7 --> I, but since there is Adim7, I'm stuck...

[Musicologo]

Your PS is the way. Adim7 is Ebdim7.
So it's VII0 -> i0 -> I

That i0, Adim7 (Ebdim7) is simply a kind of retardo of Eb.

Adim7= A,C,Eb,Gb that's going to fall on Bb,Eb,G. Note that you have a bunch of sensibles on Adim7. The A going to Bb, the Gb going to G. The Eb is already there.

[PurpleCatfishBettie]

That's one thing i never got; when notating 7th chords. It's been sussed out in the thread here, that aº7 is made up of A,C,Eb,Eb; but how do you know that? It's a 'doubly diminished 7th chord,' but how do you know it's not a dim chord with a minor 7th?

Is it that; in jazz the 'min7flat5' replaces the 'diminished (/w) minor 7th' found in classical? The two are functionally equivalent as far as i can tell.

See, if you had 'Bmin7flat5; it would be the same as 'bº7m7' ...

BDFA

In this particular case, the 'aº7' could be more clearly notated as 'aº7º'

It just seems to me that, specifying the type of 7th (maj,min,dim) would bring beginners up to speed; same with 9ths (maj,flat). But, i'm not from a jazz background, so maybe it would all make more sense if that had been the case.

[Nystul]

That's one thing i never got; when notating 7th chords. It's been sussed out in the thread here, that aº7 is made up of A,C,Eb,Eb; but how do you know that? It's a 'doubly diminished 7th chord,' but how do you know it's not a dim chord with a minor 7th?

Is it that; in jazz the 'min7flat5' replaces the 'diminished (/w) minor 7th' found in classical? The two are functionally equivalent as far as i can tell.

See, if you had 'Bmin7flat5; it would be the same as 'bº7m7' ...

BDFA

In this particular case, the 'aº7' could be more clearly notated as 'aº7º'

It just seems to me that, specifying the type of 7th (maj,min,dim) would bring beginners up to speed; same with 9ths (maj,flat). But, i'm not from a jazz background, so maybe it would all make more sense if that had been the case.

That little circle before the 7 indicates specifically the diminished seventh chord (minor third, diminished fifth, diminished seventh). If the seventh is to be minor, it is called a half-diminished chord, and the little circle has a slash put through it. The half-diminished can also be notated as a m7b5 like you suggested.

Ninths are major unless otherwise indicated.

It's clear as mud for beginners. But then, knowing the right notes is just the start of the battle. Trying to figure out style appropriate voicings, rhythms, etc. when all you have is a little chord symbol is even worse.

[PurpleCatfishBettie]

Nystul, thanks.

[psenior]

You could try looking at Abdim7 as either G7b9, Bb7b9, Db7b9 or E7b9 and Adim7 as either D7b9, F7b9, Ab7b9 or B7b9 but, honestly, I feel that a lot of the time Chick plays sonorities that sound interesting but logically don't make any sense. This might be one of those times.

Anyway, here's a link to some videos and a partial transcription of the tune:
http://pianologist.com/music-production ... ologist%29

[someone called simon]

what does the "-" indicate after the F and the G?

F-, G-

I've never seen that before.