Lydian Augmented #6

The whole tone scale with a leading tone added

Six of these seven notes are a whole step apart: C, D, E, F♯, G♯, A♯. That run is the whole tone scale, and the mode is what happens when a major seventh is dropped into it — B, sitting a half step under the octave.

One note changes everything the whole tone scale lacks. Whole tone material has no leading tone and therefore no pull towards any centre; adding B gives the scale a tonic, a direction and a cadence, while the rest of it keeps drifting.

The chord underneath

Stacking thirds from the root gives C E G♯ B, a major seventh chord with a raised fifth, written Cmaj7♯5. The remaining notes sit above it as a natural ninth and a raised eleventh.

The raised sixth is the awkward one. A♯ falls a half step below the major seventh and a half step above the augmented fifth, so it is boxed in on both sides — useful as a passing tone, difficult to hold.

Against Lydian augmented

Lydian augmented is the fifteenth-degree neighbour and the one worth comparing: C D E F♯ G♯ A B. Only the sixth separates them, A against A♯, and that degree is what turns an ordinary bright scale into a whole tone scale with an extra note.

Practically the natural sixth of Lydian augmented breaks the whole tone run and gives the ear something to hold. Raising it removes the last irregular step from the lower six notes, which is why this mode floats where its neighbour merely glows.

Not the augmented sixth chord

Searching this name runs into a piece of classical harmony that shares a word and nothing else. An augmented sixth chord — Italian, French or German — is built on the flattened sixth degree of a key and resolves outward onto the dominant; it is a chord with a job, not a scale.

The augmented sixth here is simply the sixth degree raised a half step, and the raising happens inside the scale rather than as a chromatic event. Nothing in this mode resolves the way an augmented sixth chord does.

Where it comes from

Rotating the Neapolitan major onto its second degree produces the mode. B Neapolitan major is B C D E F♯ G♯ A♯, and reading those same seven notes from C gives C D E F♯ G♯ A♯ B.

The parent family has no augmented second anywhere, and that inheritance shows here: every step in this scale is a half step or a whole step, so despite three sharps in the spelling the mode never leaps.

Frequently asked questions