Reading Chord Symbols(Minor 7b5, Dominant b9)

* Why Eb Major? Locrian is the 7th mode of the Major scale, and the chord built off the seventh scale degree is mi7b5. The RELATIVE MINOR from Eb Major is C Minor (sixth degree of Eb Major). If Cmi is six and Dmi7b5 is seven, then ifwe are in a minor key where Cmi is ONE, Dmi7b5 will be TWO. All we need now is the FIVE...

In a iimi7 V7 IMaj7 progression, the Dorian modeis used with the iimi7 chord. This Dmi7 could serveas the iimi7 chord for a iimi7 V7 IMaj7 in C Major.

Remember, when reading a chord symbol everything is notated from left to right. We know from before that Dmi7 is a D minor triad with a flat 7. If we continuereading left to right, a Dmi7b5 is a D minor triad with a flat 7, and the fifth is loweredby one half step.

Dmi7 Uses Dorian Mode (Key of C Major)

In a iimi7b5 V7b9 imi7 progression, the Locrian modeis used with the iimi7 chord. This Dmi7b5 could serveas the iimi7b5 chord for a iimi7b5 V7b9 imi in C Minor.

Dmi7b5 Uses Locrian Mode (Key of Eb Major*)

* There are actually many choices for scales to be played over dominant chords that have been "altered". A dominant chord always needs its root, 3rd, and 7th, but any other chord tone can be altered to create more or less tension. See Jamey Aebersold's Scale Syllabus for other scale options over various chords, including dominant 7b9 chords.

In a iimi7 V7 IMaj7 progression, the Mixolydian modeis used with the V7 chord. This G7 could serveas the V7 chord for a iimi7 V7 IMaj7 in C Major.

G7Sticking with the key of C, the V7 chord is G7Uses Mixolydian Mode (Key of C Major)

In a iimi7b5 V7b9 imi progression, the Half-WholeDiminished scale is used with the V7b9 chord. This G7b9 could serve as the V7b9 chord for a iimi7b5 V7b9 imi in C Minor.

G7b9 Uses Half-Whole Diminished Scale*

In the above G7b9 scale there are only three altered tones, but let's take a look at that b9 first...

(iimi7b5 V7b9 imi in the key of Cmi)

The b5 from the first chord and the b9 from the second chord are actually the same note. The alterationsfor both chords (b5, b9) are referring to the Ab.

Dmi7b5 G7b9 Cmi

A dominant scale with a flat 9 usually (but not always) has a sharp 9 as well. It's sort of like the natural 9from the Mixolydian Scale (in this case A) has been split in two, with part of it going one half step lowerand the other part going one half step higher (Ab, A#). Because of this, it is also very common for iimi7b5 V7b9 imito be notated as iimi7b5 V7#9 imi.

Mixolydian Mode (Key of C Major)

G7 Natural 9Half-Whole Diminished Scale

G7b9 Natural 9 splitinto b9/#9

(This #4 iscommon in this scale becauseit makes the scalesymmetrical.)

Two options for a 2-5-1 progression in a minor key:

Dmi7b5

Uses Half-Whole Diminished Scale

G7b9 Cmi

Dmi7b5

Uses Diminished Whole Tone Scale*

G7#9 Cmi

*The 7#9 chord is often associated with the Diminished Whole Tone Scale, which contains 4 altered notesto create tension.

Remember to refer to the scale syllabus for a variety of options for these and other chords.

Diminished Whole Tone Scale

G7#9 b9 #9 #4 #5

2