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  1. #1

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    Are there some simple guidelines to determine whether a chord is functioning as a diminished 7th or a 7b9?
    There seems to be some degree of overlap.
    Would this be more obvious to a bass player?

    Thanks,
    Jonathan

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    The Jazz Guitar Chord Dictionary
     
  3. #2

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    Quote Originally Posted by darby View Post
    Are there some simple guidelines to determine whether a chord is functioning as a diminished 7th or a 7b9?
    There seems to be some degree of overlap.
    Would this be more obvious to a bass player?

    Thanks,
    Jonathan
    I think the Wikipedia article on dim7 chords is generally good, although contains a couple of inaccuracies:

    Diminished seventh chord - Wikipedia

    Leading tone dim7 chords relate to V7b9-I progression. Common tone dim7’s such as F7 F#o7 C/G or Em7 Ebo7 Dm7 are somewhat distinct.

  4. #3
    Hi Christian,

    Thanks for the response.

    So if I'm playing an Emin7b5 --> A7b9 --> D minor progression without a root in the A7b9 chord voicing (which is the way I typically play it), how would I know whether the A7b9 is functioning as an A7b9 or an A#dim7 chord? Is it strictly a function of what note you want to hear in the bass, or are they essentially interchangeable in this context?

  5. #4

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    I would see what is the next chord.

    a) Say the next chord is CMaj. If the dim7 (or any of its other 3 inversions) can be interpreted as G7b9 then it is a candidate to interpret is as dominant.
    b) Otherwhise it is probably a dim7. For example in Body and Soul Fm7, Edim7 Ebm7, (Edim7 would be C7b9, A7b9, F#7b9 or D#7b9, neither is Bb7b9 which is the V for Ebm7)

  6. #5

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    Quote Originally Posted by darby View Post
    So if I'm playing an Emin7b5 --> A7b9 --> D minor progression without a root in the A7b9 chord voicing (which is the way I typically play it), how would I know whether the A7b9 is functioning as an A7b9 or an A#dim7 chord? Is it strictly a function of what note you want to hear in the bass, or are they essentially interchangeable in this context?
    Using the hint in my previous answer, that is a dominant for D minor (your sample is II/V/I in minor)
    (what is in the bass could be great in feelings and nuances, but inversions (even substitutions) will not change the function of a chord)
    Last edited by Gabor; 09-07-2019 at 12:02 PM.

  7. #6

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    Quote Originally Posted by darby View Post
    Hi Christian,

    Thanks for the response.

    So if I'm playing an Emin7b5 --> A7b9 --> D minor progression without a root in the A7b9 chord voicing (which is the way I typically play it), how would I know whether the A7b9 is functioning as an A7b9 or an A#dim7 chord? Is it strictly a function of what note you want to hear in the bass, or are they essentially interchangeable in this context?
    Ah ok. I think you already suggested the answer when you said is it up to the bass player? Yes, unless you really want to double that A.

    I would tend to think of that chord from the third of A7 - C#o7. The it’s easy to see it resolves up a half step to D.

  8. #7

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    Also
    Em7b5 Eo7 Dm

  9. #8

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    Yea.... what Function are you worried about...

    The extensions would help define common practice functions. I mean... if your just playing the head and basic changes... generally the chord is functioning as either Dominant or chromatic. Chromatic tend to link chords as compared to typical dominant like function.

    I play bass all the time.... when you start to play chord patterns as compared to basic changes.... the differences become easy to see and hear. By that... I mean there isn't as much to guess about... there are targets... harmonic targets, and by what chord patterns you use... the Harmonic Functions are pretty obvious. It's either Dominant, or sub dominant.

    There is something to be said about camouflaging etc... and secondary dominants can easily become Sub dominant in function.... with context. Chord Patterns can and usually do have function within them selves... but being that they generally imply One harmonic Target... the dominant function aspect becomes secondary, almost sub dominant.

    Simple approach.... before one generally plays any tune.... A quick harmonic analysis is required, right. Either from playing the tune the same way a million times or from someone else. And that becomes the basic harmonic reference. How your performing the tune... and when the tune develops harmonically... you use your ears and common jazz practice to develop the new relationship and develop the relationships.

    Generally the more you expand harmonic relationships... the more options you have. You have different layers of harmonic movement and they can have different functional relationships.

    Think of how one uses subs.... the obvious II V chord pattern. The II- chord can be the target... or the V7 chord... or even the implied I of the II V. I know... too much BS, but playing jazz isn't just memorize and play.... Harmonic Targets can change... which lead to Functional changes etc...

  10. #9

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    Not very clear post... sorry.

    Simple version.... Dim. chords have either Dom. or Chromatic Function.

    If the Dim. Chord can become a Secondary chord of the target.... using either of the two tritones, it can have Dominant function. Most Ascending Dim. Chords can have Dom. Function. Descending and auxiliary usually have Chromatic Function.

    Ex. II-7 #IIdim7 / III-7.... #IIdim7 can become V7b9 of target III-7 ( D-7 D#dim7 / E-7.... D#dim7 becomes B7b9)

    *if the IIdim7 chords moves to I6/3rd.... usually would have Chromatic function. Think of Chromatic function as Sub Dominant... delaying what ever type of movement your creating.... not resolving.

  11. #10

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    Take the time to notate out all the common Dim. patterns and then the possible Dom7thb9 possible chords from those Dim. chords.

    ex ... #Idim7, key of C... C#dim7. Chord tones...C# E G and Bb.... the possible Dom b9 chords are with roots 1/2 step below each chord tone.

    So.... C7b9, Eb7b9, Gb7b9, and A7b9 those chords can be either V7 of or bII7 of.

    C7b9 is V7 of F or bII7 of B. Obviously V7 chords have stronger Dom function than bII7 or Sub of V7...

    Anyway.... the common Dim chords are,

    #Idim7, #IIdim7, #IV7dim7, #V7dim7... all ascending

    bIIIdim7, bVIdim7.... descending and

    Idim7, Vdim7....auxiliary....

    So chart out all possibilities... see the common examples and you'll have organized examples of Jazz Common practice of use of re-harms or use of V7b9 chords for Dim chords

    And then you start using with reference to Chord Patterns.... ex. C7b9 can have it's related II- chord, G-7b5 C7b9 etc... that II V is one of many common practice jazz chord patterns.

    Chord Patterns are how jazz players.... comp or solo. Where they draw from for creating harmonic and melodic relationships when they play tunes. You have a beginning reference, (the basic tune chords and melody), you create relationships with that Reference,
    (you play chord patterns from basic changes or melody), and then you Develop those relationships... with interaction with band etc...

    yea it takes some time... but when your done.... your done.

  12. #11

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    Quote Originally Posted by Reg View Post
    Take the time to notate out all the common Dim. patterns and then the possible Dom7thb9 possible chords from those Dim. chords.

    ex ... #Idim7, key of C... C#dim7. Chord tones...C# E G and Bb.... the possible Dom b9 chords are with roots 1/2 step below each chord tone.

    So.... C7b9, Eb7b9, Gb7b9, and A7b9 those chords can be either V7 of or bII7 of.

    C7b9 is V7 of F or bII7 of B. Obviously V7 chords have stronger Dom function than bII7 or Sub of V7...

    Anyway.... the common Dim chords are,

    #Idim7, #IIdim7, #IV7dim7, #V7dim7... all ascending

    bIIIdim7, bVIdim7.... descending and

    Idim7, Vdim7....auxiliary....

    So chart out all possibilities... see the common examples and you'll have organized examples of Jazz Common practice of use of re-harms or use of V7b9 chords for Dim chords

    And then you start using with reference to Chord Patterns.... ex. C7b9 can have it's related II- chord, G-7b5 C7b9 etc... that II V is one of many common practice jazz chord patterns.

    Chord Patterns are how jazz players.... comp or solo. Where they draw from for creating harmonic and melodic relationships when they play tunes. You have a beginning reference, (the basic tune chords and melody), you create relationships with that Reference,
    (you play chord patterns from basic changes or melody), and then you Develop those relationships... with interaction with band etc...

    yea it takes some time... but when your done.... your done.
    I appreciate the detail. I don't understand how you're using the terms "ascending", "descending" and "auxiliary".

    Am7 - D7b9 is descending? Fmaj7 - F#dim is ascending? Is that it?

  13. #12

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    yea... close..
    Ascending .... Cmaj7 C#dim7/ D- etc... going up, ascending root motion
    descending.....D-7 Dbdim7 / Cmaj7 etc....going down, descending root motion
    auxiliary.... Idim7 to I maj7.... same root.

    the reharms or sub of V7b9 chords for Dim. chords is next step... the terms descending etc... are with relationship to the original chord sequence that makes use of Dim chords.