(This post has not been written completely yet)
It is know that in Gypsy Jazz , it is usual to adopt lovely and well known songs to swing Gypsy jazz, usually by extending the major chords X to the X6 version of them (X+ lower relative minor of X), plus use a fast (sometimes 4 times faster than a calm beat ofthe heart) tempo , which gives its dancing swing character.
This usually increases the percentage of minor chords to the original chord progression, resulting to a higher than 50% percentage of minor chords.
The most common chord progressions in such minor jazz ar based on the simulteneous and rather fast modulations between the next minor chords with the same root e.g. D4
1) D4 natural minor,
2) D4 harmonic minor
3) D4 double harmonic minor
4) Melodic minor
And in the above example of D4 the most common chord progressions (with various permuations) is the tetrad
B7 E7 Am Dm
We should notice that no single minor scale has the above progression but , a shifting among the 1) 2) 3) scales does have this chord progression.
The most common chord progressions in such minor jazz ar based on the simulteneous and rather fast modulations between the next minor chords with the same root e.g. D4
1) D4 natural minor,
2) D4 harmonic minor
3) D4 double harmonic minor
4) Melodic minor
And in the above example of D4 the most common chord progressions (with various permuations) is the tetrad
B7 E7 Am Dm
We should notice that no single minor scale has the above progression but , a shifting among the 1) 2) 3) scales does have this chord progression.
Now is it possible to do a similar adoption of songs, that will result at about 50% of minor and major chords? The answer is yes,and it is the chromatic re-harmonization, which is most often interpolating chords X0 ,X1 X2 ...Xn between the Chords X -> and Y of the original chord progression, so that X=X0->X1->X2->X3 ....Xn=Y etc are a shortest possible path of successive chords in a diatonic scale , in other words differing by an interval of 2nds. When doing so we may start from a minor chord to end at a major chord or vice versa (from sadness to joy or vice versa) Alternatively if the initial harmony is a scale of chords which is a connected arc in the wheel by 4ths then a rule is to create a perturbation of these chords with their 1 semitone neighboring diminished or augmented chords (that are an interval of 2nd apart thus chromatic perturbation) keeping nevertheless the basic harmony as a connected arc in the wheel by 4ths . This also allows for easier solo improvisation fitting the new chromatic re-harmonization of the original chord progression. Now because in a diatonic scale the minor chords are about equal in number with the major chords, the resulting re-harmonization w ill tend to have about 50% minor and 50% major chords.
Of course the best songs to modify so are those that their scale of chords is an harmonic one in the sense that is a connected arc of chords in the wheel by 4ths.
We may compare this re-harmonization with the melodic re-harmonization of the post 154 and the harmonic re-harmonization which is to interpolate between two chords X1->X2 a third chord Y (X1->Y->X2) so that the Y is a 7nth chord in harmonic relation to X2 and resolving to X2 (e.g. if X1=C and X2=G then Y may be Dm7, in total C->Dm7->G . Other example is X1=Am X2=F and then Y=C7 , in total Am->C7->F)
Of course the best songs to modify so are those that their scale of chords is an harmonic one in the sense that is a connected arc of chords in the wheel by 4ths.
OTHER TYPES OF RE-HARMONIZATION HERE IN JAZZ HERE
7-LEVELS OF RE-HARMONIZATION
