Upper Partials and Chord Extensions…

* Diminished chords can not be expanded to the thirteenth as the fifth is a fundamental characteristic of Diminished chords and can not be displaced.

Using Cmaj7 as an Example

From any voicing of a Cmaj7 chord. You can then use the upper partial as a passing tone or just add it to the Cmaj7, creating a new C major type chord.

Here are four voicings of Cmaj7 from the book, A Guide to Advance Chords for Ukulele by Curt Sheller

The top note (string 1) of each chord is heard as the melody note of the chord.

D, F, F# and A can be added to make Cmaj7 a Cmaj9, Cmaj11 (rare), Cmaj7#11 or a Cmaj13 (rare). A 9th can also be added a C6 chord for a 6/9 chord.

Adding the 9th — D

• 0 0 0 2
• 0 0 0 4 Cmaj9

Adding the 11th —F

• 5 7 7 7
• 5 7 7 8 Cmaj11 very rare and typically for major chord types the 11 is an augmented 11 (#11): 5 7 7 9)

Adding the 13th — A

• 9 11 8 10
• 9 11 8 12 (Cmaj13, Another rare chord. Typically C6 is called for).
  • 0 0 0 0
  • 2 4 3 3
  • 5 7 5 7
  • 9 9 8 10

Basically add the note not in the original chord to create a new chord voicing.

Harmonizing Melodies

This is the same principle used to harmonize any melody note. An example is to harmonize a D melody when a Cmaj7 chord is called for. A D melody note and a Cmaj7 chord creates a Cmaj9 chord. Find the Cmaj7 with a C as the highest note on the voicing and move the C note to D. For a modern sound play the voicing with E as the top note and lower the E to D for more contemporary sounding chord.

This principle can be applied to any melody note, not just notes from the scale that the chord came from. Just find the closest chord voicing to the melody note and raise or lower the chord tone on that string to get the correct melody note.

Summary

A little theory or a lot of theory depending on where one is in their development goes a long way.

One of the most influential musicians in my development always said "Tools not rules". Learn the principles behind music and it's a liberating moment in your development.

For complete study of 4-part chords and how to create them, ( Blatant self promo coming ), see my Advanced Chord Series of books for Guitar and Ukulele.