Substitute Dominants

Substitute Dominants

Substitute dominants replace existing dominant seventh chords, creating a resolution of down a half-step instead of forward through the cycle of fifths. This process is sometimes refered to as tritone substitution, because the roots of the original dominant and the substitute dominant will be a tritone apart, and because both chords use the same tritone for guide tones.

**Substitute Dominants**
Substitute Dominants
\|\| I subV⁷/_VIII^--> \| ^V/_3rd subV⁷/_VI^--> \| VIm⁷ subV⁷/_V^--> \| V⁷ subV⁷/_IV^--> \| IV^maj7 subV⁷/_III^--> \| IIIm⁷ subV⁷/_II^--> \| IIm⁷ subV^7--> \| I \|\| \|\| C C⁷ \| G/_B Bb⁷ \| Am⁷ Ab⁷ \| G Gb⁷ \| F F⁷ \| Em⁷ Eb⁷ \| Dm⁷ Db⁷ \| C \|\|

Substitute dominants share the same guide tones as the replaced dominant chord. For G7, the primary dominant of C, the guide tones are B (the third of G7, ti of the key) and F (the seventh of G7, fa of the key). These notes are the guide tones of Db7, with F now being the third, and B now being Cb, the seventh of Db7. Notice the roots G and Db are a tritone apart.

**Substitute Dominants**
Substitute Dominant	Original Dominant	Example in C		Diatonic Target	Example in C
Substitute Dominant	Original Dominant	subV⁷	original dominant	Diatonic Target	Example in C
^subV7/_VII	V⁷/_VII	C⁷	F#⁷	^V/_3rd	^G/_B
^subV7/_VI	V⁷/_VI	Bb⁷	E⁷	VIm⁷	Am⁷
^subV7/_V	V⁷/_V	Ab⁷	D⁷	V⁷	G⁷
^subV7/_IV	V⁷/_IV	Gb⁷	C⁷	IV^maj7	F^maj7
^subV7/_III	V⁷/_III	F⁷	B⁷	IIIm⁷ or ^I/_3rd	Em⁷ or ^C/_E
^subV7/_II	V⁷/_II	Eb⁷	A⁷	IIm⁷	Dm⁷
^subV7 (/_I)	V⁷ (/_I)	Db⁷	G⁷	I^maj7	C^maj7