In music theory, the harmonic major scale is a musical scale found in some music from the common practice era and now used occasionally, most often in jazz. It was named by Rimsky-Korsakov. In George Russell's Lydian Chromatic Concept it is the fifth mode (V) of the Lydian Diminished scale.
It can be considered a major scale with the sixth degree lowered, Ionian ♭13, or the harmonic minor scale with the third degree raised. It may also be generated by reversing and rotating the succession of intervals in the harmonic minor scale. It contains the following chords, which are also considered borrowed from the parallel minor: the minor subdominant, Dom 7 ♭9, the supertonic diminished triad, the supertonic half-diminished seventh chord, and the fully diminished seventh leading tone chord. It also contains an augmented triad.
The harmonic major scale has its own set of modes, separate from the harmonic minor, melodic minor, and major modes, depending on which note serves as the tonic.
For example, a B major scale consists of the notes: B C♯ D♯ E F♯ G♯ A♯; whereas a B harmonic major scale consists of the notes: B C♯ D♯ E F♯ G A♯. Notice the sixth note in the sequence is lowered, from G♯ to G. The B harmonic major scale can also be obtained from the B harmonic minor scale, which is B C♯ D E F♯ G A♯, by raising the D to D♯. The B♭ harmonic major scale may be derived from the E♭ melodic minor scale with a raised fourth: E♭ F G♭ A B♭ C D.
The harmonic major scale may also be considered a synthetic scale, primarily used for implying and relating to various altered chords, with major and minor qualities in each tetrachord. Thus the musical effect of the harmonic major scale is a sound intermediate between harmonic minor and diatonic major, and partaking of both. The harmonic major scale may be used in any system of meantone tuning, such as 19 equal temperament or 31 equal temperament, as well as 12 equal temperament.
The harmonic major scale is a diatonic tonality like major, melodic minor, and harmonic minor. Each pair of notes two degrees apart in the scale (e.g. its 2nd note and 4th note) form the interval of a major or minor third, as is also the case for the major, melodic minor, or harmonic minor tonalities,
One interesting property of this scale is that for any diatonic scale, there is a relative major or minor mode, and if each of these is made harmonic major or harmonic minor, the accidental required in each "harmonic" scale is actually the same note spelled enharmonically. For example, B♭/G♭ in D/B♭ harmonic major and A♯/F♯ in B/G harmonic minor; i.e., B/G harmonic minor is an "enharmonic mode" of D/B♭ harmonic major.
Like the familiar major, melodic minor, and harmonic minor scales, the harmonic major scale has the diatonic thirds property, which means that the interval between notes two steps apart (e.g. the second and fourth note, or the third and fifth note, etc..) are separated by a major or minor third, i.e. the interval of three or four semitones. There are only seven such scales in equal temperament, including whole tone, hexatonic, diatonic, acoustic, harmonic minor, harmonic major, and octatonic. This property implies that chords formed by taking every other note from some consecutive subset of the scale are triadic, raising the possibility of using triadic harmony together with melodic material from such a scale.
The harmonic major scale is also one of the five proper seven-note scales of equal temperament. Like five of those other six scales, it is a complete circle of thirds; starting from the tonic the pattern is MmmmMMm, where M is a major third and m is a minor third.
Harmonic major is not commonly taught as a tonality, so chords borrowed from this diatonic tonality are not recognized as readily as those from the tonalities of major, harmonic minor, and melodic minor. Many popular songs have borrowed chords from the tonality of harmonic major but have not been recognized as doing so. Examples are 'After You've Gone', 'Blackbird', 'Sleep Walk', 'Dream A Little Dream Of Me'.