Café brothers and sisters, my pal Bob sent me an email trying to sort out how to deal with minor key progressions in jazz improv. I thought I'd share with anyone interested:
You are confused because it is confusing!I'm trying to get a handle on the minor scale. I understand the
diatonic major scale, but the minor scale makes me cross eyed. I look
at my theory books but I can't make sense of it. I'd like to
understand the diatonic scale in the minor mode, if that makes sense.
So I looked through my theory books, and I get this for the harmonic
Cm(maj7) what the hell is that? - Cm6 - D half dim. 7 - Ebmaj7#5
(what is that!) - Fm7 - G7b9 - Abmaj7 - B dim 7
Can you help me make sense of this minor diatonic scale - perhaps I'm
not using the right language, but you must know what I'm getting at -
I want to know the chords in the whole scale range - just like in the
major diatonic scale.
There's no single "the" minor scale. Whichever minor scale or mode is being used is contextual, so you'd have to look at the melody notes (if any) or progression to figure out what to do (ah, chord tones as always as starters!)
So, the choices (in the mainstream of most often used sounds) are
• Natural minor (the aeolian mode)- 12b345b6b7-(b3 b6 b7 being the characteristic notes)
• Melodic minor- 12b34567 (b3 with natural 6 and 7)
• Harmonic minor (12b345b6 7) (b6/natural7 and the telltale minor 3rd between them).
As you suspect, the payoff for the minor ii V (iim7b5 to V7b9) is indeed the harmonic minor scale.
Now, the way it works is:
Dm7b5 G7b9 ('the' minor 2-5) comes from C harmonic minor, you can build the chords and tensions from the scale and all notes sound fine against the chords.
When you resolve to an actual Cm7 as the I chord (or Cm6 in Djangoland), you want to lose the b6 of harmonic minor, and depending of the mood, choose your mode of choice (or don't worry about WHAT mode, find the melody notes you like)- because on that I chord you may like a natural 6, which could be C melodic minor OR C dorian, or a b6 which could be C natural minor, OR indeed you may like the angular sound of the C harmonic minor.
Lots of choices but take heart, if you play 'inside' the choices are finite, and all the action happens making choices between b6/6/b7/7.
That ii v is the bread and butter of the 'minor sound' for trad jazz (late swing-bebop).
As for the other harm chords like bIIImaj7#5- yes, you go 'yikes' because it doesn't appear in jazz literature until the 60's with Wayne Shorter and Herbie Hancock (whoa, something a half century old is new fangled in this tradition!)...in C the notes are Eb G B D.
Played by itself it sounds cool and crazy.
• Put an F in the bass and you have b7 9 #11 13 of an F7(9 #11 13) chord- the lydian b7 chord.
• Put a C in the bass and it's an awesome James Bond sounding Cm(maj7 9). That's the 'what the hell is that' one chord, it is dissonant and not used a lot in older styles (but it can be the 2nd chord in the Ellington classic "In a Sentimental Mood"), but all over the place in later jazz.
• Put a B in the bass and it's 3 #5 1 #9 of B7(#9 #5).
In extended harmony, no chord is an island- many extended chords are a combination of two seemingly simple chords- even Cmaj7 is a C triad on the bottom and an Em triad on top. If you get that, you can spy these 'combo platters' all over jazz harmony, and it simplifies things greatly and leads to more clarity when you solo- it's all good!
As always, knowing the chords of the scale will lead you to good things improvisationally when you want to leave the outline concept behind, and outline OTHER chords against the actual chord of the moment- like in the above, where you'd arpeggiate that Ebmaj7#5 over F7 or Cm.