The intriguingly named Neapolitan Minor and Major scales are unusual seven note scales. They can be seen as the harmonic and melodic minor scales with a lowered second (supertonic).
NEAPOLITAN MINOR
The Neapolitan Minor works really well for improvisation and has a Middle Eastern sound with an augmented second between the sixth and seventh degrees. This scale can be viewed as an altered harmonic minor scale with the second degree lowered by a semitone or a Phrygian mode with the seventh degree raised by a semitone to form a leading tone and it is sometimes written as a Phrygian #7 scale. It can also be seen as a Double Harmonic scale with the third degree lowered by a semitone. Viewed as two four-note tetrachords and compared to modes in the major/minor system, the lower tetrachord is Phrygian/Locrian and the upper tetrachord is harmonic minor. Written out as an alteration of a major scale ( 1 2 3 4 5 6 7) the steps are 1, b2, b3, 4, 5, b6, 7.
Starting from the note C , the notes are:
C Db Eb F G Ab B C
As with all scales and modes, I often play this scale from E and use the bottom string of the guitar as a pedal tone. Playing the scale from E, the notes are:
E F G A B C D#
As a scale starting from E, it is interesting to play it as an alteration of E Phrygian and treat is as a tonal extension of the C major system with subsidiary modes.
Triads (leading tone chord has a major second interval instead of a third between the root and the third note in the scale series due to the presence of two adjacent semitones)
E min F Maj G aug A min B Maj b5 C Maj D# 2(9) b5 (third contracted to major second)
Seventh chords * the last chord is in effect a diminished seventh with the third lowered to form a second or ninth.
E min/maj7 F Maj7 GMaj7#5 A min7 B7b5 C Maj7 D#6/9 b5
It is also interesting to play starting from A as an alteration of the A harmonic minor scale and look at how this changes the structure of harmonic minor chords.
A Bb C D E F G#
Triads (leading tone chord has a major second instead of a third between the root and the next note)
A min Bb Maj C aug D min E Maj b5 F Maj G# 2(9) b5 (third contracted to major second)
Seventh chords * the last chord is in effect a diminished seventh with the third lowered to form a second or ninth.
A min/maj7 Bb Maj7 C Maj7#5 D min7 E7b5 F Maj7 G#6/9 b5
NEAPOLITAN MAJOR
The Neapolitan Major also works well for improvisation with its unusual series of tones and semitones. This scale is the Neapolitan Minor with a raised sixth, and is actually a minor scale, due to the presence of a minor third step between the first and third degrees. The scale has a series of five consecutive whole tones (major seconds) imparting a whole tone character and the scale has the same series of intervals in its retrograde version. This scale can be viewed as an altered melodic minor scale with the second degree lowered by a semitone. Viewed as two four-note tetrachords and compared to modes in the major/minor system, the lower tetrachord is Phrygian/Locrian and the upper tetrachord is major and melodic minor. Written out as an alteration of a major scale ( 1 2 3 4 5 6 7) the steps are 1, b2, b3, 4, 5, 6, 7.
Starting from the note C , the notes are:
C Db Eb F G A B C
I play this scale from E and use the bottom string of the guitar as a pedal tone. Playing the scale from E, the notes are:
E F G A B C# D#
Triads (leading tone chord has a major second instead of a third between the root and the next note)
E min F aug G aug A Maj B Maj b5 C# dim D# 2 b5 (third contracted to major second)
It is also interesting to play starting from A as an alteration of the A melodic minor scale and look at how this changes the structure of melodic minor chords.
A Bb C D E F# G#
Triads (leading tone chord has a major second instead of a third between the root and the next note)
A min Bb aug C aug D Maj E Maj b5 F# dim G# 2 b5 (third contracted to major second)