modes & chords | JIM FUNNELL 🎹 Pianist, Composer, Educator

The mixo b2 b6 bebop dominant scale (here used as an E7(b9b13) chordmode):

scale degrees	1 b2 3 4 5 b6 b7 7 8
chordmode	E F G# A B C D D# E

The mixo #2 #4 bebop dominant scale (here used as an F7(#9#11) chordmode):

scale degrees	1 #2 3 #4 5 6 b7 7 8
chordmode	F G# A B C D Eb E F

Although the mixo b2 b6 and mixo #2 #4 bebop dominant scales laid out in the tables above have different starting pitches, they are made up of the exact same notes (in other words, they can be viewed as modes of each other).

In both cases, the added chromatic passing tone corresponds to the major seventh (7) scale degree (as is the case in several of the more “traditional” bebop scales such as the bebop dominant scale, the bebop harmonic minor scale, and the seventh flat 5 diminished scale listed on this Wikipedia page).

Further, the notes they are made up of are the chord tones belonging to two separate dominant chords, whose roots sit a semitone apart (E7 (E G# B D) and F7 (F A C Eb) in our examples). Labeling either of these scales bebop double dominant hence seems quite fitting.

It can be noted that besides the mixolydian b2 b6 (1 b2 3 4 5 b6 b7 8 / E F G# A B C D E) and mixolydian #2 #4 (1 #2 3 #4 5 6 b7 8 / F G# A B C D Eb F) modes, several other 7-note scales are contained within the 8-note bebop double dominant scale presented above:

the double harmonic major scale (1 b2 3 4 5 b6 7 8 / E F G# A B C D# E);
the fourth mode of the double harmonic major scale presented in the previous bullet point, also known as the double harmonic minor scale (1 2 b3 #4 5 b6 7 8 / A B C D# E F G# A);
the harmonic minor scale (1 2 b3 4 5 b6 7 8 / A B C D E F G# A).

What are a few things that can be done when an altered dominant chord presents itself in a tune? The first notion to be aware of is that the altered chord derives from the altered mode, otherwise known as mode VII of melodic minor. Below are a few tricks to break out of the diatonic sound of the scale (i.e. by introducing intervallic leaps in addition to the stepwise motion inherent to seven-note scales), and gain a little freedom with it. We will use Eb7alt as an example throughout this post.

First, let’s have a look at 5 different triads that can be played in the context of upper structure triad voicings (USTs) for an altered chord. We’ll use these triads as “numerators” of the UST voicings, the “denominator” always being the basic chord sound (i.e. chord tones 1, 3, and b7 sounded together):

I°
bIImi
bIIImi
bV
bVI

Both minor triads on the one hand, or both major triads on the other hand, can be combined to form two distinct hexatonic scales, which can in turn be used as interesting melodic devices to play lines over the altered chord:

Hexatonic 1 = bIImi + bIIImi
Hexatonic 2 = bV + bVI

Granted, these two hexatonics are only slightly different. Let’s put them under the microscope:

Hex. 1	Emi + F#mi	E F# G A B C#
Hex. 2	A + B	A B C# D# E F#

The only difference between the two scales is that hexatonic 1 has a G (and no D#), while, conversely, hexatonic 2 has a D# (and no G). From an additive point of view (when both hexatonics are combined), we fall back onto the full, seven-note altered mode (D# E F# G A B C# D#) derived from melodic minor (E F# G A B C# D# E). But looking at the two hexatonics from a subtractive viewpoint (taking the G and the D# out of the scales), then the fact that we are left with the same five notes (E F# A B C#) becomes apparent. These notes make up a pentatonic scale (bIII minor pentatonic/bV major pentatonic relative to the degrees of the altered mode), which can also be used as an even more angular melodic device, in the sense that it is more salient than the hexatonics from an intervallic perspective: