chord Substitution Rules Frederick Burton
- the “I” chord when played for 4 beats can be substituted by the “vim7” or the “iiim7” chord of the same key. This is because those three chords share 2 or more common tones.
- the “iim7” chord may be substituted for the “V” chord. What is interesting about this rule is that the iim7 is the “ii” chord and can be inserted for (2) beats before “its” V chord creating a ii-V chord progression. Or simply substituted for the whole 4 beats creates a nice chromatic pattern for a smoother sound and feel.
- the “tritone” (an interval of three wholesteps) can replace its parent dominant chord. For those who are classically in-tuned this is called a “secondary” dominant or in this case a “V” of “V” chord or V/V. After you find the V/V chord then you will have to lower (flat) the secondary dominant. A tritone is found in every dominant seventh chord and is marked by instability. The tritone defines the two dominant chords. Using the G7 as an example. Its “b5” is a Db7 chord
- : A minor 6 chord leading to a dominant chord one whole root tone above is a misspelled chord. The minor 6 chord should be changed to a (5) min7b5 chord of the dominant chord. Example: (Gm6 going to A7b9) should be (Em7b5 to A7b9).
- This rule simply states that, when leading into a minor type chord (m7, m9, m11, m7b5, m6), always alter the dominant 7th chord before it. (G9 to Cm), (G7b9 to Cm, G7#9 to Cm) etc. It’s alway good to try out different voicings, extensions, and alterations and let the ear be your guide. Also the thing to remember about this rule is the any chord that posesses a “b7” in it is a “leading” chord and any chord with a major 7 stops the harmony
- dominant 7th chords a minor third apart can substitute for each other. The same holds true for min7 chords. EXAMPLE: Gm7, Bbm7, Dbm7, Em7 all can lead to F. Also, major 7th chords can move in minor 3rd’s. EXAMPLE: Gm7 leads to Fmaj7, Abmaj7, Bmaj7, Dmajor7.
- the (4) major 7 or (4) dominant can be used for the one chord. EXAMPLE: Fmaj7 or F9 can be used in place of Cmaj7. Also in reference to this rule, the “bVII9” chord may be substituted for the “iv” chord.
- diminished chord becomes a “7b9” chord by using them over a root a half tone lower than any note in the diminsihed chord. Each diminished provides (4) 7b9 chords A C diminished= C, Eb, Gb, Bbb(A, therefore creating for different diminished chords- Cdim7, Ebdim7, Gbdim7, Adim7. Therefore- Cdim7=B7b9, Ebdim7=D7b9, Gbdim7=F7b9, Adim7=Ab7b9.