So far all warmups were based on the premise that the chord notated in the exercises (and what is heard on the play-along MP3s) is also the four note chord played for the arpeggio. In this post we’ll break from that pattern and us chord substitution rules to achieve the sound Dominant 9th and Major 9th and Minor 9th chords.
Basic chord substitution was what allowed us to explain the mysteries of Bebop scales. (Anybody who wants to know more aboud chord substitution should check out Randy Felts: “Reharmonization Techniques”, Berklee Press, 2002.)
The following three basic substitution rules allow us to create the sound of various 9th chords by applying arpeggios we have already practiced:
- Major 9th chords: A IΔ7 chord can be substituted by a iii-7 chord. E.g. in a C-Major tune, CΔ7 is the major chord on the first scale degree. We can substitute this with a Minor 7th chord on the third scale degree, i.e. E-7. Playing the E-7 arpeggio over the CΔ7 chord effectively creates the sound of CΔ9.
- Minor 9th chords: A ii-7 chord, as well as vi-7 chord may each be substituted with a Major 7th chord a minor third up. The ii-7 chord can be substituted with a IVΔ7, the vi-7 with the IΔ7. E.g. in the key of C-Major, a D-7 can be substituted with FΔ7 and an A-7 with a CΔ7. Both substitutions create a Minor 9th sound.
- Dominant 9th chords: A V7 chord may be substituted with a viiØ chord. E.g. in the key of C Major, a G7 chord can be replaced by a BØ. Playing a BØ arpeggio over G7 effectively produces a G9 sound.
In order to experience these 9th sounds hands on, we can reuse existing play-alongs from previous arpeggio warmup exercises. For example Exercise 1A from the major 7th warmup post
and its play-along: Major Chords Descending in Fifths.
By substituting the Major 7th arpeggios with Minor 7th arpeggios starting on the third scale degree of the Major scale, we get the following:
Applying this trick to all the Major, Minor, and Dominant exercises yields hundreds of new arpeggio based warmups all producing the interesting sound of the 9th!