guitarguy Wrote:
-------------------------------------------------------
> There is a theory in modal jazz that there are
> essentially two chord forms in any mode:
> 1: any bunch of notes that excludes the
> "character" note;
> 2: any bunch of notes that includes the
> "character" note.
>
> Type 1 is the "inside", or consonant chord - and
> obviously all kinds of voicings are possible (a
> preponderance of 4ths being preferred!).
> Type 2 is the "contrast" chord. Again, various
> voicings are possible.
>
> For dorian mode, that note would be the major
> 6th.
>
> A typical example is the two chords in the head of
> Miles Davis's "So What" (D dorian):
> "Dm11": D G C F A (= chord 1)
> "Em11": E A D G B (= chord 2)
>
> I guess what I meant to ask is, by this method of
> stacking 4ths instead of 3rds, is it essential to
> know all the chords that stacking these 7 notes in
> whatever given mode to 4 notes are? OR do ALL the
> 4th stack-chords function generally under the same
> minor or major chord function that the mode is
> approximating diatonically?
Well, not quite, as I understand it. Generally, in modal jazz, chords don't have functions, they have ambiguous identities (because quartal chords have no clear acoustic root), so naming them is optional and not very helpful.
The only thing that seems to have an impact is the presence of that "character" note - namely the one that differentiates the mode from the closest major or minor scale. This is the "contrast" note, that tends to make any chord containing it "dissonant" relative to any chord that doesn't contain it.
However, don't take my word on this. I can't remember my sources for this "two-chord" concept! (I've seen it a few times, but didn't take note of where.)
I do know that "jazz phrygian" seems to break this rule, because the jazz phrygian chord will include the b9, even though it's obviously the most dissonant note in the mode (relative to the root). Mark Levine quotes a "susb9" chord as a phrygian chord (1-4-5-b7-b9). It may be that they regard the b6 as the "contrast" note, I really don't know.
(And Levine doesn't mention that a susb9 is sometimes used as a V7 chord, so its dissonance plays a
functional role there....)
IOW, one could equally make a logical argument that a chord designed to define a mode
should contain the character note.
>
> IE Key of C, vamp for 4-8 bar or more with Dm7
> (plus whatever ext) and I choose to use Dorian
> Stacked 4th chords as a riff like sliding up
> through 3-4 diminished chords up the neck on
> guitar or similarly, riffing with triads up neck
> using in the inversions. Will this approach using
> stacked 4th chords of a mode work in this way or
> will only SOME of the chords formed work ( thus,
> studying each chord.... through practice knowing
> which stacked 4th chord(s) in based a certain mode
> will work in a vamp or in song substituting likely
> over a subdom chord.
I think you need to use your ears here. Remember that the chords are not designed to work in sequences, like chords in keys do. You can use dissonance in modal harmony, but it acts as "colour", not as something that needs "resolution".
The problem with modal harmony - at least, the problem the jazz musicians of the late 50s and 60s faced - is that it really needs to stay away from any possible hint of chord
function. So they would not use a Dm7 chord for D dorian, because of the risk of it sounding like a ii chord in C major, or a vi in F major. They wouldn't use G7 for G mixolydian, because of the risk of it sounding like V in C major.
I.e., everyone's ears in those days were trained, through sheer familiarity, to hear tertian chords in that way, as setting up certain expectations. Those expectations had to be broken. The audience (and the musicians too!) had to be forced to listen in a new way, to prevent the music sounding like "incorrect key-based music".
That's the great thing about quartals, is that they up-end the "natural" acoustic qualities of harmony. If we stack 5ths, eg C-G-D, we can hear very clearly that C is the acoustic root. G and D represent overtones of C; they naturally "fall" to C as "home". Turn that upside down, D-G-C, and they have nowhere to fall. The acoustic root is on top! So we hear the chord as "up in the air", ambiguous. Intuitively we expect the bottom note (D) to be a root, but then the G and C are dissonant in relation to it; and the D lacks it's 5th (A) to support its root claim.
The other thing the modal jazzers did, of course, was to hold that one chord-mode for a long time. Not only was the chord ambiguous - we couldn't tell where it was supposed to be going - the music didn't go anywhere anyway! So it was a two-pronged assault on convention, on expectation.
If and when the chord did change - well it would be to something totally unrelated by key. Maybe it would just shift up a half-step. Whatever the change, it would be unpredictable by definition. Either a change occurred where you didn't expect it; or it would be to a chord (or key) you weren't expecting; or both.
These days, our ears are a lot more accustomed to that "impressionist", "static harmony" sound. It's become a convention in its own right. We hear it in rock or Latin grooves as well as jazz. (And to be fair, we've always heard it in certain kinds of folk music.)
Edited 1 time(s). Last edit at 04/11/2016 02:09AM by JonR. (
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