Lydian Augmented

Lydian with a raised fifth

Lydian is 1 2 3 ♯4 5 6 7, the major scale with a raised fourth. Raise the fifth as well and the tonic triad stops being major: C, E and G♯ are two major thirds stacked, an augmented triad, which divides the octave into three equal parts and sounds the same in every inversion.

The scale therefore has no settled home chord, only a chord that keeps moving — maj7♯5, and with the raised fourth added, maj7♯5♯11. That chord shows up in jazz ballads and in film scoring, almost always in passing between two more stable chords.

The two raised degrees also sit a semitone apart, F♯ and G♯ from C. Running the scale straight through, that pair is where the ear catches: the augmented fifth resolves upward to the sixth as readily as it stays put, which is the ambiguity the whole sound is built on.

Not the same as Ionian ♯5

Two scales in this catalogue cover a maj7♯5 chord, and the difference between them is one note. Ionian ♯5 is the third mode of harmonic minor and keeps a perfect fourth. Lydian augmented is the third mode of melodic minor and raises it.

Deciding between them is a matter of what the surrounding harmony leans on. If the maj7♯5 sits inside a minor key whose dominant carries a leading tone — the harmonic minor situation — Ionian ♯5 is the mode that belongs there. If it appears as a passing colour in a major or modal context, Lydian augmented is the usual choice, and the raised fourth keeps the perfect fourth from clashing with the major third.

The practical version of that: a perfect fourth over a major third is the one interval that makes a major seventh chord sound wrong, and Lydian augmented is the mode that removes the problem. That is why jazz reaches for it over the harmonic minor alternative far more often.

How much it is actually searched for

Measured demand for this mode is small and concentrated on its neighbours: Lydian itself is looked up regularly, Lydian dominant more than either, and Lydian augmented turns up mostly in lists of melodic minor modes. That places it third in its own family, well behind the altered scale and Lydian dominant.

Saying so is more useful than inflating it. Anyone reading this page has almost certainly arrived from a mode list rather than from a piece of music, so the two things worth carrying away are the one-note difference from Lydian and the one-note difference from Ionian ♯5.

There is a real use behind the theory, though, and it is narrow: a major seventh chord that needs to sound unresolved while staying consonant. Composers reach for it at the end of a phrase that should not close. Applied as a general-purpose major scale it simply sounds out of tune, because the augmented fifth never settles.

Frequently asked questions