It sounds like an attempt to spam the search results but please read on…
One of the features that causes the music of modern ‘masters’ to sound so fresh and different is the use of scales and chords that get away from the beaten track. Not only do they make use of unorthodox scales and their harmonies but they sometimes convert one into the other. At the risk of repeating myself, there are many hundreds of scales possessing 3, 4, 5 and six notes on each ‘root’. There are also 36 seven-unit scales including the familiar major and minor scales and their modal derivatives.
[In my opinion there is no such thing as a ‘diatonic’ scale. Music written where melodies and chords chiefly use the notes of the scale in use (whatever scale it is – major, minor, modal, pentatonic, etc. etc….) is referred to as being ‘diatonic’, not the scale itself.]
Here’s how it all works:
Notes of harmonic progressions can be converted into melody and notes of melody (continuity) can be converted into harmony (simultaneity). The idea is that the raw materials haven’t changed, merely their presentation. Personally, I buy into this quite happily.
Of course, as soon as melody becomes harmony the ‘rules’ change. Chords, which may involve any combination of notes sounded together, are subject to acoustic considerations in order to maintain clarity, with wider intervals lower down and closer, more dissonant effects reserved for the higher register. This is how the natural harmonic series works and, although our systems of harmony evolved quite separately, the sonorous quality of orchestration nevertheless follows these principles. (Colouristic or percussive effects are likely to break this pattern.)
Arpeggio forms are the most obvious example of the melodic exploitation of chords but the technique can be refined, using unessential notes that respect the prevailing tonality or tonal ‘cell’. Just to be clear on this, a whole passage of harmony, all of its ‘voices’, can be used as notes of melody but, in the real world, care will be needed to achieve a musical result. We have to write a good tune.
More adventurous forms can take the two elements out of synch so that, for example, a melody from harmony x can be used over harmony n (and vice versa) but don’t expect to find yourself at Number One the following week. A case that succeeds in more orthodox surroundings is the anticipated ‘lead-in’ to the next passage in a composition, where the approaching tonality, say, at an abrupt modulation, is foreshadowed, even if there is a temporary ‘clash’ before the resolution.
The ‘rules’ also change when harmony becomes melody. A melody has the characteristics of trajectorial motion so that inertial and other qualities become apparent. It has a two-dimensional presence with the rising and falling in pitch representing the vertical dimension and the passage of time the horizontal. Human expectations are based upon our physical conditioning in everyday life and reactions to music follow suit.
A chord, on the other hand, can just ‘be’.