Triads over bass notes are tremendous for supporting upper voice melody notes and can be used create a sense of mystery and lyrical dissonance. Many can also function as dominant chords and they also work well as mobile harmony over pedal tones. They can be used to create interesting chord sequences.  They often have a strong character [...]

The Harmonic Major scale is a simple alteration of the major scale. The sixth degree is lowered and this creates an augmented second between the sixth and seventh degrees. In contrast to the Harmonic Minor scale it is a major type scale with a major third between the first and third degrees. Written out as [...]

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 [...]

Diminished scales have eight notes. They consist of a symmetrical series of alternating tones and semitones.  This scale may have originated in Persian music. Passages of music implying a scale of this type occur in classical music in the 18th century. The scale was set down in the late 19th century and later termed the octatonic [...]

Autumn Leaves is outlined as a basic chord progression in E minor, which works well on the guitar, G minor, the most widely used key in jazz and A minor which is great as a reference key. Bars 27-28 are written with the fundamental harmony, just the tonic minor chord. These two bars are [...]