Tritones definitely add colour to your playing or performances, however there is always a lot of confusion as to what they really are.
A tritone is actually an interval. An interval is simply distance between two defined points. On a piano, distance is measured in intervals. A tritone would be the distance between the root and the flatted 4th. So, C to F# would be called a tritone.
A long time a go, triton’s were banned in many churches due to it’s harsh and resonant sounds. It was also known as the “devil’s interval”.
Ironically, the tritone happens to be the key ingredient in a Dom 7th chord. The notes of a G7 chord are G-B-D-F. The interval between B and F is a tritone.It is ironic because Dominant chords tend to provide a lot of movement in compositions. Chords like a minor or Major don not give a feeling like a another chord is coming next. You could end a phrase on a major or minor chords and the ear would be perfectly happy is a pop music. However, a dominant chord wants to resolve to another chord and has that incomplete feeling.
What Is Resolution?
Let’s think about the real use of resolution. When there is a conflict, a resolution needs to be made. That resolution can cause either a “typical” response or a “deceptive” response.
If you are caught vandalizing, the “typical” response might be a fine. The “deceptive” or “atypical” response might mean that you have to clean up not only that building but all the surrounding buildings. We are accustomed to typical responses in our everyday life.
Applying this to music. We also have typical and atypical responses or “resolutions”, we also have these kinds of resolutions in music.Certain chords will naturally move to other chords. The dominant 7th chord is a very good example of this.
Dominant Motion (Resolution)
The typical resolution for a dominant 7th chord is to resolve down a 5th (up a 4th) to a Major or minor chord.
G7 resolves to C Major or minor
D7 resolves to G Major or minor
F7 resolves to Bb Major or minor, and so on…
You might be thinking “What about Blues chords? They don’t resolve the same way. In Blues, many dominant 7ths are strung together which is what gives it that unique sound, it is what you call deceptive resolution.