Jazz Improvisation with Modal Scales

                Last week we discussed the history, composition and used of modal scales.  One musical use for modal scales mentioned last week was in jazz improvisation.  Musicians can relate each chord in the changes of a song to the modal scale that most closely resembles the chord tones.  Today we will dig deeper into this concept.

                In our previous lessons on chord progressions, we discussed the diatonic chords in both major and minor keys (triads and seventh chords).  The slides for that portion of the lesson are included below.  An examination these slides reveals that the most common chords in music are the major seventh (or major triad), minor seventh (or minor triad), dominant seventh and the minor seven flat five (also known as half diminished).  These are also the chords that are used in music's most common chord progression, the 2-5-1 chord progression.  I mention both triads and seventh chords here, but seventh chords are usually more common in jazz music.  Although fully diminished seventh chords (and diminished triads) do exist in music, they are used less often.  For the purpose of this lesson, we will examine the most common chords listed above, and the modal scales that they relate to best.

                Major triads and major seventh chords contain four of the seven pitches found in the Ionian scale of the corresponding tonic.  The other pitches of the scale are musically pleasant passing tones that can be used when traveling from one chord tone to another.  The 2nd and 6th scale degrees can also be thought of as chord tones since they are sometimes used as color tones or upper extensions.  The 4th scale degree is labeled by some jazz musicians as an avoid tone.  This does not mean that it cannot be used.  Just that it is not a good pitch option for structurally or rhythmically significant portions of a melodic improvisation.  The 4th scale degree can still be used as a passing tone between chord tones.  This means that a musician can used the Ionian scale as a pool of acceptable pitches when creating jazz improvisation over a major triad or major seventh chord. 

                In the same way, the pitches of minor triads and seventh chords most closely resemble the pitches of the Dorian scale.  The pitches of dominant seventh chord most closely resemble the pitches of the Mixolydian scale.  Finally, the pitches of minor seven flat five chords most closely resemble the pitches of the Locrian scale.  This means that a musician can use these scales as a pool of acceptable pitches when creating jazz improvisation over these chords.  In addition, the Lydian scale can be used when improvising over an major seventh chord with a raised 11.  The sharp 4 of the Lydian scale helps to accentuate the raised 11 of this chord.   

               When engaging in modal jazz improvisation, a musician should be able to instantly recall the associated modal scale for each chord change that occurs in the music.  While the music remains on a given chord, the associated modal scale acts as a temporary key signature.  The musician can create tasteful melodies using the notes of this temporary key signature.  One practice that aids in the tasteful construction of melodies is using the chord tones as the main melodic pitches and the other tones of the scale as passing tones or anticipations.  Another good practice is to use contrast.  Melodic jumps can be contrasted with stepwise motion and upward motion can be contrasted with downward motion.  Finally, the use of repeating patterns and melodic motifs can cause an improvisation to be more relatable and memorable to the audience. 

In modal improvisation, another tasteful practice is to accentuate the differences in pitch between adjacent modal scales.  Some chord progressions (like 2-5-1) will share the same pool of pitches (Dorian - Mixolydian - and Ionian that are all from the same key center).  However, when the music moves to a chord who's scale is based in a different key center, accentuating the new pitch (or pitches) helps to embed the sound of the chord changes within the improvisation.  A teacher once told me that he should be able to hear the chord changes in my improvisation even when there is no accompaniment present. 

Jazz improvisation is a beautiful form of musical expression.  I think of it as instant melodic composition guided by a framework of predetermined chords.  Although there are many methods a musician can employ when improvising, the use of modal scales (as discussed in this lesson) can be a great starting point.   

  In this Learning Music With Ray video I discuss the use of modal scales in jazz improvisation.  I list the most common chords used in jazz and the modal scales that best outline the notes of each chord.  Finally, I demonstrate a modal improvisation over the chord changes of one of my original songs, and explain the improvisational choices I made.