In last month’s column (
“Augmented and Diminished Forms,” March 2011 PG), we looked at how both diminished
and augmented shapes lie on the fretboard.
We will follow that idea in its
natural progression by exploring how
you can use these shapes to create automatic
voicings.
Within one cluster, raising or lowering
any single tone results in one of two
altered forms. When lowered a half-step,
the note becomes the root of a dominant
7th chord. If raised a half-step, the note
becomes the 7th tone of a minor 7b5 (or
half-diminished) chord. First, let’s consider
descending alterations into dominant
7th chords.
Much like the augmented phenomenon
we discussed last month, the
diminished parental form produces two
important structures, and through gradual
alterations they continue to expand
into variations. The diminished form
shown in
Fig. 1 produces the following
results: From the four tones (G, Db, E,
and Bb) found within it, the descending
alteration of any single tone by a half-step
produces four different dominant
7th chords.
When the same chord shapes unfold
horizontally in one key, they automatically
create four inversions on the selected
string group as shown in
Fig. 2.
Last month, we looked at how the
augmented triad shapes change quality
when moved vertically across the fretboard.
A similar pattern appears with the
diminished form. In
Fig. 3, we see how
a Gdim shape moves to D7 and then to
G7b5 when shifted vertically. Once again,
as with the augmented procedures, these
particular fingerings indicate the vertical
analysis of three automatic voicings.
Raising one of the chord tones by a
half-step alters the initial diminished
form by producing a minor 7b5 form.
This is illustrated in
Fig. 4.
To completely understand the nature
of these forms and how they relate to the
fretboard, it is essential that you transfer
these concepts to other string groups.
In upcoming lessons, the harmonic
forms we’ve covered so far will not only
continue to expand, but they’ll also
serve as the architectural groundwork
for melodic linear studies. In the coming
months, we’ll discover how to apply these
linear studies both vertically and horizontally
across the fretboard.
Ah-ha!
Minor 7b5 Chord. The basic formula
for these chords is 1–b3–b5–b7.
Another way to think of them is as
a standard minor 7th chord with a
lowered fifth. Many times you see
minor 7b5 chords functioning as a ii
chord in a minor ii–V–i progression.
Tunes such as “Stella by Starlight,
“Round Midnight,” and “Gloria’s
Step” all use minor 7b5 chords in
both diatonic and parallel functions.
Another name used for these chords
is half-diminished, a term that’s used
when the chord is functioning diatonically
as the vii in a major key.
This description distinguishes the
chord from its diminished 7th sibling
(which has a 1–b3–b5–bb7 formula).
—Jason Shadrick
The chord shapes shown in Fig. 3 can be a little tricky to play. In the above photos, you can see
how each one lines up on the fretboard. By moving each shape directly across the fretboard
you can move from Gdim to D7 and finally to G7b5. If you are feeling adventurous, explore
the different types of chords you get by moving the G7b5 shape horizontally up the fretboard.
Remember, you don’t always need the root!—Jason Shadrick
Pat Martino
Since his first recording as a leader in 1967, Pat
Martino has constantly pushed the limits of jazz
guitar with his flowing technique and powerful,
muscular tone. Showing no signs of slowing
down, Martino still travels the world performing
and giving lectures about his approach to
the guitar. Currently, Martino is working on an
autobiography and serving as adjunct faculty
at the University of the Arts in Philadelphia.
For more info, visit
patmartino.com.