Tritone is the interval of three whole tones between two notes. In other words, when we play simultaneously two notes that have three tones of distance between them, we are playing a tritone. One example of tritone is in the notes F and B.
As said in the article “Harmonic Function”, the dominant chord has tension sonority. The responsible for this feeling is exactly the instability of the tritone.
The tritone effect provides one of the most complex dissonances in western music. Its sonority gives the idea of movement, instability and when it is not followed by a resting chord, the listener becomes distressed, afflicted, because the tritone should be “solved”. This is why many thriller melodies in horror famous movies have just two notes and are successful. It just to put tritones playing intermittently and the viewer will be scared stiff.
All the dominant chords has a tritone, because the tritone is the responsible for the “tension feeling” in the dominant function. Let’s see some V7 chords (fifth degree with dominant seventh) for you to check. See the notes that compose the G7 chord: G, B, D and F.
Between B and F we have 3 tones of distance.
Other example: See the notes that compose the E7 chord: E, G#, B and D.
Between G# and D we have 3 tones of distance.
Very well, it is enough to realize that in major chords with seventh there is a tritone between the 3rd and 7th degrees.
One thing that is important to highlight is the chromatic effect produced by this tritone. In the case of G7, that solves in C major, the notes B and F are a semitone below and above, respectively, of the tonic and the third of C. In other words, there is a chromatic effect that makes the chord “walk” to C, as it has the necessity of solving on it.
Another kind of chord with dominant function is the minor with seventh and flatted fifth (do you remember it? This chord appears in the seventh degree of major harmonic field, known as half diminished chord).
Check the notes of Am7(b5): A, C, D#, G
Between A and D# we have 3 tones of distance.
Observation: not always the half diminished chord will act like dominant. Depending on the context, it can act like another function (we will see this in other studies).
Tritone – The sound of devil
Well, maybe you are asking yourself: “Why the hell of the title of this section is ‘the sound of devil’?”.
For a long time, tritone was forbidden in the Western church due to fact of transmitting this tension effect. This dissonance was seen as malignant by the church, because they used to believe that the perfection of God would be translated into harmonic sounds, not in non-harmonics as the tritone.
This concept made that in the Middle Age, the tritone received the name of “diabolus in musica” (devil in music), and it was forbidden to be played (threatening composers to go to bonfire).
Later, they realized that this definition didn’t have biblical bases, and the tritone was then allowed. It is common to see some mistakes pseudo-religious trying to distort Bible even today. But let’s return to the dominants…
Tritone in dominant chords
The dominant chord can appear in two ways: as altered dominant or non-altered dominant. It is called altered dominant when the 5th, 9th, 11th or the 13rd are altered, in other words, out from the scale that forms the mixolydian mode.
We know that the mixolydian mode is formed by the following degrees:
1st major, 2nd major, 3rd major, perfect 4th, perfect 5th and 7th minor.
Therefore, a non-altered dominant chord is the V7 chord that has the notes of the chord (1, 3, 5, 7) and/or any one of the extensions above (major 2nd, perfect 4th or major 6th). If the chord is V7 shows any one of these altered extensions (minor 2nd, diminished 4th, augmented 4th or minor 6th) or even the augmented 5th or diminished 5th note from the chord, it will be an altered dominant chord.
For example, the G7(#5) is an altered dominant chord, because it has an augmented 5th. The G7(b9) chord is also altered because it has a flatted 9th (or the minor 2nd, for those who prefer). And the chord G7(6) is not altered, because it has a major 6th, which is part of natural mixolydian scale.
This nomenclature is useful because the dominant chord gives us many resources in improvisation. Altered dominants have an approach quite different from non-altered dominants due to their different sonority structure. In the articles of scales application you will see these differences.
A term that is also well used to altered chords it is what we call “dissonance”. The meaning of dissonant is what needs to be solved, or something that is also strange to the original tonality. The term “consonant” means exactly the opposite: stability related to the tonic.
Songs with tritones
Talking about ambience, songs with heavy tension have many tritones, like the 5th symphony, 1st movement from Beethoven, for example. The Heavy Metal is also a good example of a music style that incorporated the dominant function in its basic harmonies.
But the dominants are not restricted to heavy and intense songs; they appear in several places, even in peaceful songs, followed by the tonic solving.
Using dominants to do modulation (changing of tonalities) is another extremely common application, what makes this kind of chord one of the most explored in music nowadays, and maybe the most studied. If you want to be a good musician, the dominant (and the tritone) must be part of your vocabulary and repertoire. You are actually taking a big step reading this article. The team of Simplifying Theory is here to show you the way! Go on studying and learning here in our website and you will be a complete musician.
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