11.11Melody as 9, 11, 13, altered tension

For any chromatic chord, ask:

What is the melody note relative to the chord?

Example:

Melody D over Cmaj7:

Melody A♭ over G7:

♭9.

Melody E♭ over D7:

♭9.

Melody B♭ over E7:

♯11/♭5-ish depending spelling/context.

This is where ballad harmony becomes very expressive.