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Thursday, June 4, 2020

325. MELODIC IMPROVISATION WITH TETRACHORDS DEFINED EACH ONE BY ONE CHORD

A tetra-chord (ana ncient greek word meaning 4-strings) is simple a 4-notes scale.

A tetrachord defined by a major or minor chord is simply 4 notes that include the 3 notes of a minor or major chord and also a 4th one (thus an 4 notes extension of the chord with 2nd or 4th).

The next are the 9 4-chords defined by major or minor chords


Diatonic gendre (part also ofthe stanrd pentatonic scale)
major: (2-2)-3  (major with 2nd)
minor: 3-(2-2) , (minor with 4th)
Enharmonic gendre
major 4-(1-2) , (major with 4th)
major 4-(2-1) , (major with 4th)
minor (2-1)-4 ,(minor with 2nd)
minor (1-2)-4 ,(minor with 2nd)
Chromatic gendre
major/minor  (3-1)-3 , (major with 2nd or minor with 4th)
major (1-3)-3 , (major with 2nd)
minor 3-(3-1) , (minor with 4th)


When we improvise we just  put consecutivlly a repetitive combination of  the previous 10 patterns
 in which ever combination and permutation our feelings indicate.
If we are are set to be inside a single diatonic scale, then we just take care to spend more time in the even or odd order of notes and less in the intermediate and imediatly the melody has a nice underlying structure of chords. We may switch this long/short order from even to odd order of notes and vice versa as the feelings require.
Each 4-chord  can be played with our 4 fingers of the left hand.

Such an improvisation defines  also the chord progression that accompanies it. And as the chords have the 3 basic relations of Chromatic, Melodic , Harmonic, so also these tetrachords cab be  in the chromatic , melodic, harmonic relation 
If we utilize two or three consecutive in time such tetrachords we may define melodic themes that are accompanied with 2 or 3 chords as in post 313 E.g. for 2-hords such melodic  themes the net notes will be at most 8.