tritonesubstitutsioonid

Tritone substitution is a harmonic device used in jazz improvisation and composition. It involves replacing a dominant seventh chord with another dominant seventh chord whose root is a tritone away. For example, in the key of C major, a G7 chord, which is the dominant chord, can be substituted by a Db7 chord. A tritone is an interval of three whole steps, or six semitones. The G7 chord consists of the notes G, B, D, and F. The Db7 chord consists of the notes Db, F, Ab, and Cb (which is enharmonically equivalent to B).

The reason this substitution works is due to the shared important notes between the two chords. The tritone interval within the G7 chord is formed by B and F. In the Db7 chord, the tritone is formed by F and Cb (B). These two notes, the leading tone and the seventh of the original dominant chord, are crucial for creating the tension that resolves to the tonic. By swapping the dominant chord with one whose root is a tritone away, the essential tritone interval is preserved, albeit inverted or with enharmonically equivalent notes. This creates a similar harmonic tension and resolves to the tonic chord in a pleasing way.

Tritone substitutions are often used to create smoother voice leading or to add harmonic color. They can lead to interesting melodic possibilities for improvisers, as the altered dominant chord offers a different set of melodic notes to explore. The substitution can also be seen as a chromatic approach to the tonic chord, adding a jazzy flavor.