The Tritone is an incredibly interesting – and dissonant – sound.
Not only does the Tritone drive chord functions, it also the drives the functions of the scale degrees found in our scales.
The Tritone sits between a perfect fourth and a perfect fifth. You usually find it in the form of an augmented fourth or diminished fifth.
The Tritone consists of three whole steps, also known as whole tones. As far as musical distance is concerned, the Tritone is perfectly symmetric.
What is symmetry in music?
It means that there is an equal amount distance involved before and after an inversion is applied to the interval.
The Tritone sits between a perfect fourth and a perfect fifth, otherwise known as augmented fourths or diminished fifths. You usually find it in the form of an augmented fourth or diminished fifth.
Also notice that there is an equal number of notes on either side of the A#.
The effect of this interval is very unstable and dissonant.
E to A# is a tritone.
This interval wants to become another interval, by moving in the easiest direction possible.
This generally means that it wants to move the shortest amount of distance necessary.
Each scale has a tritone, which has two half steps right next to the notes of the tritone. These notes will want to move towards the half-step. We generally refer to this as resolution. Let’s examine the areas of each scale were a half-step exists. We’ll start with the E major scale.
Notice that from A to D# we have three whole steps, or whole tones. Another way to express the number three is to use the suffix tri-, thus the Tritone. We have a half-step between G# and A. We also have a half-step between D# and E. If we were to resolve this Tritone, both notes would move in the direction of half-step. This means that the A would move to a G#, and that D# would move to an E. It is interesting to note that both the G# and E belong to our “one” chord. This important detail will be discussed further in the next chapter.
It is important to note that the tritone in any major scale lies between the 4th and 7th scale degrees.
Minor scales have tritones as well.
This is a bit more difficult to see, but there are two whole steps, as well as two half-steps between F# and C. That makes three whole steps, or whole tones: the Tritone. How should we resolve this Tritone? Both notes of the Tritone will move a half-step. That would give us the notes G and B.
I really want the student to understand that the resolution is not a rule, and by no means does it “have” to happen. It actually is quite beautiful to frustrate this resolution, by making it do something else. This resolution should be viewed as a simple relationship, not a rule. This cannot be stressed enough.
Some important relationships come up here because of this Tritone resolution.
Perhaps the most important relationship to be found in the Tritone is the fact that it ties together our major and minor scales.
How does it do this?
Let’s look at the resolution to the Tritone in the last example, which you will recall is comprised of the notes G and B. You will see that we can make two possible chords out of this. Both possibilities are diagrammed below, with the two notes from our resolution colored in yellow.
The notes from this resolution could make either a one chord or a three chord
Why would this be important?
Let’s examine the G major scale, and compare the notes in that scale to the notes in E minor.
Notice that the G major scale uses the exact same notes as the E minor scale, but arranged in a different order. This is incredibly important to remember when we reach the chapter regarding key signatures, as well as the chapter regarding modes. This relationship is going to make your musical life much easier. The Tritone is also central to what is known as the circle of fifths. This interval will be mentioned again in that chapter.