Diminished chords and 7b9

Hi there

I'm playing 'Have you met miss jones at the moment'

My first three chords are

Fmaj7
D7b9
Gmin7

My question is, how does the D7b9 fit in as a harmonic function?

I have found that I can use a diminished chord as chord two, with an ambiguous root, giving the chord tones F#, Ab, C and Eb. Putting a D root onto this gives D7b9.

What I specifically can't get, is why I can seemingly interchange between Dmin7 as the second chord (the vi min7), and this D7b9 and both sound fine. Why is it ok to use the major third in the D7b9 when D should be Dmin7 to fit with diatonic harmony (of F Major)? Is it because essentially it's a passing but inconsequential diminished chord but calling the root D making it D7b9 is just adding a convenient 6-2-5- root movement?

Is this like passing harmonic colour from the diminished or is there an actual key change going on with the D7b9?

Any simplification would be much appreciated!

[ugly_bassplayer]

The D7b9 is simply the V7 of the Gm7 chord.

[Richard Lindsey]

Originally Posted by ugly_bassplayer

The D7b9 is simply the V7 of the Gm7 chord.

Exactly. IOW, a secondary dominant.

[Billnc]

In your Dmi7, the F natural can also be viewed as D7+9, so your observations are correct. Your chord spelled out is a common guitar inversion for D7-9 with the root omitted (and yes it's also the regular diminished chord think of the possibilities that opens up!).

In the end the function is simply V chord though.

[boylebass]

In my real book the 2nd chord is F#o7, not D7b9, but if you add a D in the bass the the F#o7 you get the D7b9.

I would not play the chord you suggest you describe as diminshed- F# Ab C Eb. This is not a diminshed chord, it's Ab7. Dominant 7th chords include a diminished triad, but once you add a 4th note to the chord, you must spell it triadically or else we'd be calling chords all kind of strange things. It's also helpful to stick with flats or sharps when you spell a chord, even when you've got to use bb or ##.

I feel that the F# in the second bar is an important part of the composition. If the composer want a tidy ii-V7-I to the C chord then the chord in the 3rd bar wouldn't be Gmin7, it would be G7. The chord in the 4th bar would be C, not C7.

Furthermore, don't play any Ab's in the A section. Save them for the bridge.

Lastly, and I'll get back on topic, the chord<s> in question (D7b9 or F#o7) is/are a common dominant for minor chords.

Bill, I kinda' dig your idea of the D7+9, 'specially because this tune has both of those notes in the progression (the F and the F3), but I tend to play this tune pretty straight. 2 on the outside, walk the bridge...

PS there's no such thing as an 'ambiguous root'.

[VroomVroom]

Originally Posted by boylebass

PS there's no such thing as an 'ambiguous root'.

Oh, I don't know....isn't that what tritone subs are all about? I will suggest, however, that there's no such thing as an 'inconsequential diminished chord'.

[mailboxmoney]

Yes the D7b9 is V7 of ii, in other words it's a vi chord made into a "secondary" dominant (V7) to enhance voice leading to the ii, Gm7. The chord spelling F# Ab C Eb over D root would be Ab7/D, or D7b9b5, a common alteration for a dominant. The sense of ambiguity for the root is enhanced by the presence of the tritone sub (Ab7) over the D. You could play D or Ab under the voicing F# Ab C Eb and they'd both work. The use of the #9 over the D7 is a nice alteration as well.

BTW D7b9 is D F# A C Eb, or F#dim7/D (also Adim7/D, Cdim7/D, and Ebdim7/D).

[boylebass]

If I was playing a song by Monk, I would play Ab7/D, but this song is by Richard Rogers. Please don't Monk-ify the man who wrote our beloved state song.

Hey these replies are great - thank you all so much

This has made it very much easier to make sense of.

I will have another look at this tomorrow with a bit more clarity!

[slybass3000]

The choice between D7b9 (could be played with a F# bass) and F#o7 resides in the scales tones,not the arpeggios because they are pretty much the same. The scale used on the D7 going to Gmin would be the fifth mode of the G min harmonic scale which would give you only two notes outside of the key center F Major:F# and Eb.

If you play the F# diminished scale you'll have more tones outside from F Maj: F#,G#,B,Eb. It would be easier to make nice melodic lines for a beginner using the G min harmonic then the diminished scale IMO.

Hope this helps,

Sly

Ok I think i'm getting something now

I just went up the natural minor scale from Gm and to make it fit with the chord tones of D7b9 I had to make an alteration when I got to the seventh to put in the F#. That makes it the harmonic minor scale.

I guess that maybe explains why it's called the harmonic minor...

I have to say though, I'm still a bit unsure as to what has happened to the key centre in bar 2. Is it a key change (with the inclusion of the new F sharp), or is it just like a temporary change of parent scale, or what?

I guess I could say, in bar two, is the key centre still F major or has it moved?

I was told by a jazz guy recently to group chords into clusters according to the key centre rather than thinking modally about each individual chord. This is why I'm trying to figure out what's going on on bar 2.

Woah I just did a google and found this

http://www.theguitarcolumn.com/2009/...-analysis.html

he has it down as an F#dim on bar two as well. It just says 'passing chord' on the analysis.

[ugly_bassplayer]

You can use both chords, D7b9 or F#dim.
The original chord on the chart is F#dim , but you can sub that chord with a D7b9 (depends on how you want to voice the chord), wich as I already stated is also V7 of Gm.

[Richard Lindsey]

Originally Posted by afromoose

Ok I think i'm getting something now

I just went up the natural minor scale from Gm and to make it fit with the chord tones of D7b9 I had to make an alteration when I got to the seventh to put in the F#. That makes it the harmonic minor scale.

I guess that maybe explains why it's called the harmonic minor...

I have to say though, I'm still a bit unsure as to what has happened to the key centre in bar 2. Is it a key change (with the inclusion of the new F sharp), or is it just like a temporary change of parent scale, or what?

I guess I could say, in bar two, is the key centre still F major or has it moved?

I was told by a jazz guy recently to group chords into clusters according to the key centre rather than thinking modally about each individual chord. This is why I'm trying to figure out what's going on on bar 2.

Yes, you're still in F. You haven't changed key. The Gm7 has a perfectly natural, even diatonic function in F. The "jazz guy" you mention was right in this case.

Originally Posted by ugly_bassplayer

You can use both chords, D7b9 or F#dim.
The original chord on the chart is F#dim , but you can sub that chord with a D7b9 (depends on how you want to voice the chord), wich as I already stated is also V7 of Gm.

When you say 'V7 of Gm', does this mean V7 assuming that Gm is the harmonic minor?

Is it that in a minor key you always use the harmonic minor parent for chord formation or something? Is V7 in minor keys always V7b9 or something?

Originally Posted by Richard Lindsey

Yes, you're still in F. You haven't changed key. The Gm7 has a perfectly natural, even diatonic function in F. The "jazz guy" you mention was right in this case.

Hey! It's not the Gm7 I'm talking about, it's the D7b9, which has an F sharp, which isn't in F major.

I'm wondering what's happened to the key centre on bar 2 where the D7b9 is. Thanks!

[ugly_bassplayer]

Originally Posted by afromoose

When you say 'V7 of Gm', does this mean V7 assuming that Gm is the harmonic minor?

Is it that in a minor key you always use the harmonic minor parent for chord formation or something? Is V7 in minor keys always V7b9 or something?

It depends on the minor mode or the voicing of the chord.
I was just stating that it was a dom7 chord fonction.
If you have Gm with a Eb on melody or voicing then the V7 can be dom7b9, if it has a E , you can go dom7 or dom9.
You have to look up your chord subs & natural extionsions of chord families.

[ugly_bassplayer]

Originally Posted by afromoose

Hey! It's not the Gm7 I'm talking about, it's the D7b9, which has an F sharp, which isn't in F major.

I'm wondering what's happened to the key centre on bar 2 where the D7b9 is. Thanks!

There is an F# because it borrows the V7 chord in Gm.
D7b9 is V7 in Gm.

Originally Posted by ugly_bassplayer

There is an F# because it borrows the V7 chord in Gm.
D7b9 is V7 in Gm.

Okay, that makes sense. So is this borrowing temporary then, and purely to make the harmonic movement stronger? Is G minor still chord ii?

[ugly_bassplayer]

Originally Posted by afromoose

Okay, that makes sense. So is this borrowing temporary then, and purely to make the harmonic movement stronger? Is G minor still chord ii?

I think you got it. It's called secondary dominants.
Yes Gm is still ii.