C major · Tritone substitution
Tritone substitutions in C major
Every dominant in C major, and its substitute
- G7V7CsubV7C
D♭7 substitutes for G7, the dominant of C major. They share the same tritone, so the bass can fall a semitone instead of a fifth. Shared notes: B and F in G7, C♭ and F in D♭7.
- A7V7/iiDmsubV7/iiDm
E♭7 substitutes for A7, the dominant of D minor. They share the same tritone, so the bass can fall a semitone instead of a fifth. Shared notes: C♯ and G in A7, D♭ and G in E♭7.
- B7V7/iiiEmF7subV7/iiiEm
F7 substitutes for B7, the dominant of E minor. They share the same tritone, so the bass can fall a semitone instead of a fifth. Shared notes: D♯ and A in B7, E♭ and A in F7.
- C7V7/IVFsubV7/IVF
F♯7 substitutes for C7, the dominant of F major. They share the same tritone, so the bass can fall a semitone instead of a fifth. Shared notes: E and B♭ in C7, E and A♯ in F♯7.
- D7V7/VGsubV7/VG
A♭7 substitutes for D7, the dominant of G major. They share the same tritone, so the bass can fall a semitone instead of a fifth. Shared notes: F♯ and C in D7, G♭ and C in A♭7.
- E7V7/viAmsubV7/viAm
B♭7 substitutes for E7, the dominant of A minor. They share the same tritone, so the bass can fall a semitone instead of a fifth. Shared notes: G♯ and D in E7, A♭ and D in B♭7.
Why the substitute works
What makes a dominant seventh want to resolve is the tritone between its third and its seventh. Move the root a tritone and that interval is still there, with its two notes swapped: the third becomes the seventh and the seventh becomes the third. So the substitute pulls to the same place, and the bass slides down a semitone to get there.
Play the two buttons in each row one after the other. Same arrival, different road.