Melodic Minor Modes and Chords

[drumdead10000]

hi, i understand the idea of taking a major scale and writing out all the modes and taking every other note from each mode and putting them together to make a chord... i assume that you do the same things with the melodic minor scale right??? but i was reading the mark levine jazz theory book and according to it the chords formed are:
I. C minor major
II. Dsus b9
III. Eb Major 7 #5
IV. F7#11
V. C minor major/G
VI. A half-diminished
VII. B7alt

how can the II chords be Dsus b9 when every other note of the 2nd mode of the melodic minor scale are: D F A C

[JonR]

hi, i understand the idea of taking a major scale and writing out all the modes and taking every other note from each mode and putting them together to make a chord... i assume that you do the same things with the melodic minor scale right??? but i was reading the mark levine jazz theory book and according to it the chords formed are:
I. C minor major
II. Dsus b9
III. Eb Major 7 #5
IV. F7#11
V. C minor major/G
VI. A half-diminished
VII. B7alt

how can the II chords be Dsus b9 when every other note of the 2nd mode of the melodic minor scale are: D F A C

In jazz, melodic minor harmony is not used in the way it is in major or minor keys - to provide chords for use in sequences in the tonic key.
With the exception of the tonic chord itself - which does come from melodic minor - minor keys use chords taken from natural and harmonic minor.

The melodic minor modes are instead used mainly to provide substitute chords to replace normal diatonic chords in other major and minor keys.

Eg, B7alt - harmonised from the VII of C melodic minor - is used as a V7 chord in the key of E minor, or sometimes E major. That's because the Eb in the scale works as a D#, while the D becomes a #9.

A lydian dominant chord (from mode IV) is used as a tritone sub for any V7 chord, esp an altered V7. So F7#11 will resolve in exactly the same way as B7alt: to Em or Emaj. (The only real difference between the two chords, esp if you add extensions, is the root note.)

Dsusb9 (from the II step) might be used as a phrygian mode chord. IOW, in D phrygian mode - in modal jazz, NOT on the iii step of Bb major! - you could use normal D phrygian (D Eb F G A Bb C D), or D "phrygian natural 6" (D Eb F G A B C), which is of course 2nd of C melodic minor.
(Dsusb9 - D-G-A-C-Eb - can be harmonised from either scale, but the melodic minor mode suggests the major 6th, B, which makes a better chord extension on the key chord than a b6.)
In modal jazz, btw, they tend to use sus chords of various kinds, not normal tertian chords (built in 3rds). Quartal chords (built in 4ths like sus chords) give a more suitable sound.

Am7b5, when harmonised from C melodic minor, gives you a major 9th (B) which - again - makes a consonant upper extension on the chord, which the usual locrian Bb doesn't. (This mode is known as "locrian natural 2")
This might be used as a ii chord in G minor or G major.

The 5th mode chord (Cm(maj7)/G), as Levine explaines, functions as a tonic chord in C minor - not as a V. (You can harmonise a V7 chord from this mode, G7 or G9, but it will have a b13 and P11, both "avoid notes".)

Make sure you read Levine's text and examples, which explains the usages of these chords pretty well.

Mostly they are used because (with the exception of the V chord) of the lack of avoid notes. (unlike the chords they typically substitute for.)
Eg on the IV and VII mode chords (F7#11 and B7alt) you can use any scale note as an extension. Indeed you can build any kind of harmonisation as a superimposed chord and it will sound good on that basic root or 7th chord.
So, in any situation where you use a B7alt chord (generally to resolve to Em), you can put any C melodic minor chord on top of it - it will simply give you a selection of cool alterations on the basic B7.