musical thoughts

More recycled material here, this is a discussion of upper structure chord voicings.

Since the voicings topics are generally well-received, here’s some more ideas for making modern jazz sounds.

An “upper structure” is sometimes called a “slash chord.” You get a symbol with one chord symbol, a slash, and a root that usually belongs to a different chord (sometimes you’ll see an inversion written as a slash chord–D/F# is an example). Upper structure chords usually have complicated spellings when notated in tertian terms, but are relatively simple to orient to when notated in slash form. Let’s look at a few examples….

F/Db = Dbmaj(#5)
Gb/C = C7(b9b5)
C/F = Fmaj9
Db/Eb = Ebsus, Eb11
In these, the note following the slash is just an alternate root. More fun is to be had by placing a major triad atop a “stripped” dominant seventh voicing (this “stripped” voicing is the tritone formed by the third and seventh of a dominant seventh chord). This makes a rootless voicing with five notes.

There are four widely encountered altered dominant chords that have spellings of this type:
A/C7 = C13(b9)
Ab/C7 = C7(#9b13) or C7alt or C7(#5#9)
Eb/C7 = C7#9
D/C7 = C13(#11)

and one less frequently encountered:
F#/C7 = C7(b9#11) very dissonant

In the list of four, note the tritone symmetry:
Ab/C7 = C7alt, but change the root and it’s F#13(#11)
A/C7 = C13(b9), but change the root and it’s F#7(#9)

These chord voicings built largely of fourths are the intended result when you see those symbols. Ab/C7 is a lot less common notation than C7alt, despite being far easier to execute.

For pianists, the right hand plays the triad (which should be pretty familiar for most of us) while the left plays the stripped seventh chord. With the bass player covering the root, this gives a rich sound that is complex, yet open thanks to the spacing between voices. A modern sound. (Modern meaning 60’s and later here.)

Let’s briefly discuss voice leading. These are dominant chords. While they can be used in a variety of ways in modern jazz, let’s look at them as dominant functioning chords first.

Ab/C7 = C7alt resolves naturally and smoothly to Fmi7(11). Just move the E up a half-step to F and hold everything else constant. You’ll also be pleasantly surprised to find that the scale associated with the alt chord is the seventh mode of the ascending melodic minor. For our C7alt -> Fmi example, you play F melodic minor over both chords! This makes it a lot easier to remember than trying to learn superlocrian or other names for this. associate the alt chord with a minor tonic, and play the (ascending melodic) minor scale from that tonic over it, and you are done.

A/C7 = C13(b9) resolves pretty nicely to Fmi or Fmaj. The voices in the A triad either hold constant or descend by half-step. Going to Fmi, the entire triad moves down in parallel, which is cool.

D/C7 = C13(#11) works best for me resolving to Fmaj.

Eb/C7 = C7#9 is a nice choice for resolving to Fmi, but also real useful in blues situations where it doesn’t really function as a dominant. It’s a rock chord. Since the G is the fifth, and the Bb is doubling the seventh, this voicing only really has one extension, the #9. So it’s not as weird sounding at first as the others in this family.

A common major formula that works out nicely as upper structures:
D/C = Cmaj13(#11), Cmaj7(#11)

And minor 7 can be expressed this way:
Eb/C = Cmi7

Sus:
F/C = Csus
Bb/C = C7sus
Bbmaj7/C = C13sus (cool!)

Some chords you’ll run into don’t have convenient tertian chord symbols, so you’ll just see them written as slash chords. The following examples are from “Naima”, by Trane:
B7b5/Eb
A7b5/Eb
Bmaj7/Bb
Gb7(13)/Bb

Blue in Green is an outstanding example of a tune that lends itself to this kind of voicings. This tune has a 10-bar form, mostly one chord to a bar. I’ll list them in sequence below by chord symbol, and give you the upper structure spelling beside each symbol. In general, the melody note can be the top note of the upper structure voicing.

Bbmaj(#11) = C/Bb
A7(#9) = C/A7
Dmi7 Db7 = F/D Db7
Cmi7 F13(b9) = Eb/C D/F7

Bbmaj(#11) = C/Bb
A7alt = F/A7
Dmi6 = F/D
E7alt = C/E7

Ami9 = C/A
Dmi7 = F/D

Doesn’t it simplify things to look at this in terms of upper structures? It sure helps me play it. That’s the value of theory.