[from JPSL No. 9]
with playable MIDI files
The chord here is C7(b9,13). The C# is really Db (the flat 9) and the A is the 6th or 13th of the chord. However, the top three notes, the upper structure, form an A major triad. The ear hears the triad as a unit, while at the same time the individual notes retain their harmonic function within C7. Sometimes this sound is referred to as "polytonal", or being in two keys at once, but this isn't correct; much more than this is necessary for creating a truly polytonal effect, something rare in jazz. In an upper structure all the tones must be explainable as normal harmonic tones of the underlying chord. The upper structure may be a major or a minor triad, although most teachers speak only of major. Other types of triad, though, tend to lose their identity as triads and the resulting chord is simply a complex voicing.
Upper structures are usually considered over dominant 7th chords. But they can occur over other types of chords also. Usually only normal (diatonic or altered) tones of the underlying chord are available; but in certain particular voicings an outside tone may be used effectively.
There's no set way to refer to upper structures. I suggest using numbers, from 2 to 7, to specify the root of the triad in terms of the underlying chord scale.
U.S. tend to be conceived downward from the melody note. Let's consider dominant 7th U.S. from this point of view. Since any triad has 3 positions (root, third or fifth on top), there are potentially 6 upper structures for each melody note (3 for major, 3 for minor). Omitting any voicing containing the "avoid" notes ( 4 and 7 ) which clash with the 7th chord tones, we can have, under a root melody note:
The triads 4 maj. and mi. contain F natural; and 1 maj. is omitted because it contains only chord tones of C. Actually, the 6 mi. (A mi.) U.S. hardly qualifies, since the 6th degree virtually sounds like a chord tone.
Four structures can be built under b9:
Skipping to #4:
If you continue to explore the upper structures this way, you'll find there are a total of 32, not counting the 3 major triads of the root. There are five major U.S. that are very common:
These should certainly be learned in all keys. Note that U.S.#2, #4 and 6 use notes of the diminished scale; #4 and b6 use notes of the altered scale. U.S. 2, on the other hand, derives from the lydian dominant mode and tends to be used in non-V dominant situations (see the discussion of Lydian Dominant in Issue 6, p. 62). These two minor U.S. are also very typical:
These are all natural, first-choice voicings for their appropriate melody notes; but be sure to explore all the other upper structures. A common device is to play arpeggios using upper structures. Most pianists can play triad arpeggios readily, which makes it easy to do something like
Upper structures can be played in sequence:
The following is something of a cliche:
Here the upper structures belonging to diminished harmony are trailed with a tritone underneath.
If we use a lydian scale for major harmony, there are 4 upper structures available:
(U.S. 3 mi. is limited to chord tones.) The major scale, in its nature, is not hospitable to alterations; but there is a possible exception, the raised 9th, which can give an upper structure on 7 maj.:
The ear is the final judge, and this chord, though "dissonant", still sounds like a major 7th chord.
Similarly, if the major 7th is present, a minor 7th can also be used in a suitable voicing.
Such voicings would be used at the end of a tune or in carefully selected harmonic contexts!
In the dorian mode, several familiar upper structures enhance the "modal"quality of the scale.
I've observed that the use of 2mi is in favor among players today, as long as the chord is not part of a II-V progression. It has a suspended flavor:
The already juicy minor-major 7th chord, or tonic minor, has several rich upper structures:
A very common altered voicing for the tonic minor uses a raised 11th in a 7-maj. US.:
Notice the doubled leading tone (A) as well as the doubled #11 (E) in this particular voicing. Yow!
I could go on describing upper structures used with other chords such as half-diminished (U.S. 7), diminished, and so on; but these can be found through exploration. By far the majority of them are used with dominant seventh chords. An exercise by jazz teacher Dan Delaney (see No. 8, p. 86) uses a string of arbitrary notes, randomly drawn from all 12 tones; the student plays suitable upper structures under those notes over a given chord, e.g.
As shown, "avoid" notes can be skipped over. You can write down a page of melody notes to create your own version of this exercise. It should be executed at sight, without memorizing. By practicing a variety of keys you will quickly master the most common upper structures.