Principle 31.10.2. Determining Chord-Scale Relationships.
When constructing the scale, avoid augmented seconds and consecutive half steps
Section 31.10 How to Determine Chord-Scale Relationships
To discover a chord-scale relationship for almost any chord, write all of the notes of the chord (including upper extensions and altered notes), then fill in the thirds with the most logical choices, avoiding augmented seconds and consecutive half steps.
In the example below, we determine the scale that best fits \(\left.\text{G}{\Delta}^{7}\left(\text{♯11}\right)\right.\) by doing the following:
- Identify the notes in the chord
- Write all chord tones as a scale within the span of an octave
- Fill in any gaps, avoiding augmented 2nds and consecutive half steps
- Analyze the resulting scale
The G Lydian scale is the most correct scale to play over \(\left.\text{G}{\Delta}^{7}\left(\text{♯11}\right)\right.\).
Subsection 31.10.1 List of Chord-Scale Relationships
Below is a list of common chord-scale relationships. When there are two scales listed for a single chord, it is because the chord has a minor third that can be filled with half step then whole step or whole step then half step. This knowledge of chord-scale relationships ultimately becomes second nature to an improvising jazz musician.
| CHORD | CORRESPONDING SCALE(S) |
| \(\left.\text{C}{\Delta}^{7}\right.\) | C major scale or C Lydian scale |
| \(\left.\text{C}{\Delta}^{7}\left(\text{♯11}\right)\right.\) | C Lydian scale |
| \(\left.\text{C}{\Delta}^{7}\left(\text{♯5}\right)\right.\) | C Lydian-Augmented scale |
| \(\left.\text{C}\text{m}^{7}\right.\) | C dorian scale or C natural minor |
| \(\left.\text{C}^ø{}^{7}\right.\) | C locrian scale or C locrian ♯2 |
| \(\left.\text{C}^ø{}^{9}\right.\) | C locrian ♯2 |
| \(\left.\text{C}^{\circ}{}^{7}\right.\) | C Octatonic Whole-Half |
| Cm\(\left.\text{}{\Delta}^{7}\right.\) | C melodic minor ascending |
| Cm\(\begin{smallmatrix}6\\9\end{smallmatrix}\) | C Dorian or C melodic minor ascending |
| \(\left.\text{C}^{7}\right.\) | C Mixolydian |
| \(\left.\text{C}^{7}\left(\text{♯11}\right)\right.\) | C Lydian-Dominant |
| \(\left.\text{C}^{7}\left(\text{♯5}\right)\right.\) | C Whole Tone scale |
| \(\left.\text{C}^{7}\left(\text{♭5}\right)\right.\) | C Whole Tone scale |
| \(\left.\text{C}^{7}\left(\text{♭9}\right)\right.\) | C Octatonic (Half-Whole) |
| \(\left.\text{C}^{7}\left(\text{♯9}\right)\right.\) | C Octatonic (Half-Whole) |
| \(\left.\text{C}^{13}\left(\begin{smallmatrix}\text{♯11}\\\text{♯9}\end{smallmatrix}\right)\right.\) | C Octatonic (Half-Whole) |
| \(\left.\text{C}^{7}\right.\)alt | C Diminished-Whole Tone |
This list is not exhaustive. Follow the process above (“How to Determine Chord-Scale Relationships”) for chords not on this list.
Additionally, it is often important to look at the relationship of a chord to the overall key of a tune to determine the appropriate scale. For example, the \(\left.\text{F}\text{min}^{7}\right.\) at the beginning of “All The Things You Are” by Jerome Kern is the \(\left.\text{vi}^{7}\right.\) chord in A♭ major, in which case it would be inappropriate to play F Dorian because the D♮ would conflict with the D♭ in the key signature. One would play F natural minor (or Aeolian) instead.
