The Art of Improvisation for Classical Guitarists
by Jacques Landry (D.M.A)
Classical guitarists are trained to learn and perform music that is written down with no space for spontaneous creativity. Modern jazz players improvise on chord changes or progressions, while many new age musicians play more on "static"harmonies.
After many years of performing and teaching music, I have found the easiest way to "unlock" the creative process in a student (we all have creativity, believe it or not) is to start with the Blues progression.
The jazz players play the Blues in a somewhat different way that the more primitive "Delta Blues"players did; the basic structure is basically the same however: tonic, subdominant, dominant and tonic (I-IV-V-I) with a length of twelve bars:
Those chords sound a little bit "bland" since they do not have any extensions (9th, 13th, etc.), so we "sweeten" them to enrich the harmony:
Another step ahead is to add a few chord substitutions. This will broaden the harmonic boundaries, therefore permitting the players to use a more sophisticated vocabulary:
or:
There are many ways to harmonize the Blues structure. Take a look at the last two bars that are called the "turnaround" or cadence in classical music. This is a rest point usually using the I - vi - iim7 - V7 or C - Am - Dm7 - G7. You can substitute these four chords to make it sound different. All this sounds nice on paper, but the beauty of these chords lies in the way they are "voiced". Since we usually use four fingers (or five at the most) at the same time, we need to be careful at how the voices are "layered" on one another. Serious considerations has to be given to the voice leading, just as in traditional harmony; the voices from one chord to another have to move smoothly and common tones are to be kept from one chord to the next specially in the melody.
Instead of: I - vi - iim7 - V7 play: I - VI7 - bVI7 - V7 I - #I7 - iim7 - V7 iiim7 - #II7 - iim7 - #I7
To be able to improvise on a given chord progression, the knowledge and practical use of scales is absolutely necessary. The musician must get acquainted with the sound of these scales (or modes). From the major scale there are seven modes we can derive, one for each note, and each mode can serve a different purpose for improvisation:
On a major chord (C Major, CMaj7, CMaj9, C6/9) the Ionian and Lydian modes can be used. For minor chords( Cm7, Cm9, Cm6, Cm11) the Dorian and Aeolian modes are used, and the Phrygian can also be used although it works also well with Latin progressions.
For half-diminished chords (Cm7b5) use the Locrian mode and for the Dominant family (C7, C9, C13, etc.) use the Mixolydian and Lydian modes. Nevertheless, if you want to infuse more tension and if the harmonic context requires so (C7b5) the modes derived from the melodic and harmonic minor scales are to be used such as the Super Locrian, the Auxiliary-diminished, Mixolydian and Mixolydian 13. These modes contain the alteration (or extensions) of these complex (altered) chords and therefore create more tension.
For diminished chords, use the diminished scale. Here is a list of scales for improvising:
The best way to get your ear used to the sound of these scales is to record a chord and play many times the scale over it until it becomes natural to your ear.
Therefore I wrote an improvised line over a Blues chord
progression in G Major using some of these scales (actually part
of them, since whole scales would sound boring); the little
numbers (b9, #9, b5, #5, b7) over the notes show the extension of
the scale used. Again, record the progression on a tape recorder
and play over it, or over the internet as follows: 
The classical guitarist is familiar with solo playing and the use of the right hand fingers can be an asset in playing solo jazz on the guitar. The bass line I wrote over a Bb Blues progression is just one of many possible variations in this style of playing:
