Harmonic Planing and Constant Structure Chords

Harmonic Planing and Constant Structure Chords

Harmonic Planing, also known as Harmonic Parallelism, can be a very valuable tool in the 21st-century composer’s toolbox!   The picture above is tongue in cheek, with its airplane and parallel lines, but it can also get us in the mood for a different way of looking at harmonic progressions.

Intervallic Motion

All of you composers out there probably remember the above chart very well!  We composers all learned the rules of voice leading and of good motion for contrapuntal writing.  We learned that contrary motion was one of the foundations for good four-part writing in functional harmony and we learned to avoid pitfalls like parallel octaves, fourths and fifths.  Hopefully we learned that these rules or guidelines apply to a certain period and a certain style and are not the defining principle for writing all music these days!   We can still write tonal music using these guidelines, but we can also branch out if we wish.

The advanced composition students of the Harmonia studio decided to explore several aspects of non-functional harmony:  harmonic planing or harmonic parallelism, “constant structure chords” and other related topics.


Harmonic planing or harmonic parallelism immediately takes us out of the realm of contrary motion!

HarmonicPlaning - Russian Dance from Petroushka

“Russian Dance” from Stravinsky’s 1910-11 ballet  Petrouchka

The above example is a delightful use of “harmonic planing”.  Notice how the chords in the right hand are all first inversion chords following the melodic line.  This particular example is diatonic and tonal, but goes beyond the rules of functional harmony and voice leading.   In this example, parallel 4ths abound and help make the dance even more exciting!

Notice that the quality of the chords still stays within the bounds of C major diatonic chords.  If we only read the right hand chords, without the harmonic addition of the left hand, the chord qualities of the first two measures would be diminished, major, minor, minor, minor, major, diminished, minor, minor, diminished.  These qualities of course correspond to the scale degree of each chord within the key of C major:  7, 1, 2, 3, 2, 1, 7, 6, 6, 7.   When we add the left hand harmony, we have a V-I-V progression, with some very interesting harmonies above the extended V.

Here is a wonderful two-piano performance of Russian Dance:

Here are some other examples of harmonic planing:

HarmonicPlaning - Ravel La Tombea Minuet

The above example is from Ravel’s Le tombeau de Couperin: Menuet.  Note that all the chords are diatonic, in the key of G dorian.   In this example we have parallel 4ths, 5ths and octaves!  Early 20th-century composers who chafed at the old rules found a wonderful new way of moving from chord to chord without compromising either tonality or beauty.

HarmonicPlaning - Sunken Cathedral

Debussy’s La cathédrale engloutie (Sunken Cathedral or Engulfed Cathedral) uses a host of compositional tools that would have been taboo in previous periods.  Imagine the melody of this piece being harmonized using functional, traditional harmony!  The sense of ancient mystery is very much dependent on these tools that were quite new at the turn of the 20th century.  The above example is the climax of the piece.

Here is a wonderful analysis/performance of the entire Sunken Cathedral:

Since the Harmonia students were using our own version of Musical Words to create chromatic themes, motifs and melodies, we needed a harmonic tool that would also move away from diatonic planing.


In the above example, again from Le tombeau de Couperin: Menuet, Ravel moves beyond diatonic planing.  The melody line is chromatic, so the chords are no longer diatonic.  For all the melody notes except the last, each note is the root of either a major or minor chord, and is harmonized in root position chords.  This gives an even richer harmonization to the melodic ideas Ravel harmonized earlier with diatonic chords.

Here’s a performance of the entire Menuet:


The Harmonia students explored several different avenues of harmonic planing, moving beyond diatonic planing to something called “Constant Structure” chords.   Constant structure chords harmonize a melody using one primary chord quality.

In the example below, Bela Bartok uses all major chords in first inversion in the right hand, creating a sense of cohesion while also allowing a freely shifting tonal center.   He also creates a wonderful contrary motion with the descending left hand, as the section moves to a climax at the fortissimo measure.  This example is from Six Dances in Bulgarian Rhythm #6, from his Mikrokosmos.ConstantStructureChords - Bartok Bulgarian Rhythm 6

Here is the entire Dance #6.   Bartok employs harmonic planing, constant structure chords and various reworkings of these tools to create a constantly moving, intense and exciting piano solo.

In jazz, Bill Evans and Herbie Hancock explored constant structure chords in the early 1960’s.   Here is a chord chart for Cole Porter’s “Night and Day”, in which Bill Evans uses constant structure chords to harmonize the melody:

ConstantStructureChords - Night and Day

Notice that the first 7 chords are all major 7th chords, followed by 6 chords which are all minor 7th chords.   These constant structure chords allow the piece to have a freely shifting tonal center, until three chords from the end, where the F min 7th – Bb dominant 7th – Eb maj 7th progression finally gives us a standard ii-V-I cadence in Eb major.

Harmonia students enjoyed exploring many possibilities of harmonic planing, constant structure chords, and their own variations of these tools.  After they created melodies or themes using the translation table in Musical Words, each then developed his/her own interpretation of the harmonies we’ve just discussed.  Some of them used all 7th chords of various qualities, some used all major chords in different inversions, and some used combinations of qualities, inversions and voicing.

In summation, let’s return to the melody Ab-A-Eb-E-Bb-Gb-Bb-A, which is the musical spelling of “Harmonia”, using the translation table described in Musical Words.   We might choose to harmonize these notes in several different ways, using the various tools we’ve been exploring.  Notice that the composer has many choices within these melodic and harmonic guidelines.   The composer can choose the range of each note, thereby creating different shapes for his/her melody.   S/he can also select the inversion, chord quality, voicing, and rhythm.


When the composer is satisfied with the melodic/harmonic outline in piano format, the real work begins.  At that point the composer chooses the instruments and the specific notes, orchestrating the piece to showcase particular instruments or to establish an atmosphere.

In the next few weeks, we’ll be looking at some specific examples of new compositions which use the tools we’ve just discussed.  Stay tuned to this article for links to examples from Harmonia student composers.  These composers are gifted middle-school and high-school students.  No matter what your age or level, we think you’ll be inspired by their work!

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