Main Title
The Polarity of Tonic, Dominant and Subdominant
The Central Polarity
Harmonic Dualism or Harmonic Polarity is, at its core, a dualism of above and below, which corresponds to outward and inward. Its posits a realm of the "overtonal" and a realm of the "reciprocal" that has geniune musical meaning in the context of harmonic experience. It is the stuff of Bach and Beethoven and it is also the stuff of the Blues. This page explains the fundamental concept.
Here is our central polarity, with C in the center (tonic) and G the fifth (dominant) above and F, the subdominant, below:
F — C — G
In tonal music, there is a fundamental movement between these three tones, and the chords that we will soon build on top of them. C has a tendency to move downwards to the F, toward the subdominant, but the subdominant, as the outer pole, has a tendency to swing upwards to the G, to the dominant, which then pulls backwards to the tonic. We can think of this as the primary motion of tonal music:
If this is unclear at this moment, it will be more clear when we listen to the musical examples in section 5D.
This fundamental motion can also go around the other way, although this is less common in classical music and more common in popular music, especially music influenced by Blues and Gospel harmonies. We can think of this as the reciprocal motion of tonal music.
The creation of the three primary triads in major
At this moment, we move from a linear, scalar, melodic concept of music to a new concept based on vertical harmony. You all instinctively have a sense of harmony due to your involvment in music, and many of you play guitar or piano and already play chords. It's time now to look at the creation of chords systematically and philosophically.
To begin, the central polarity of the tonic, subdominant and dominant notes expand to form three triads, built in diatonic thirds above the fundamental note.
- The bottom note in each case (F, C, G) is known as the root of the chord.
- The top note in each case (C, G, D) is known as the fifth of the chord.
- The middle note in each case (A, E, B) is known as the third of the chord.
You will notice right away how the three chords seem to flow in opposite directions from the central tonic. The dominant chord flows upward out of the fifth (G) of the tonic, while the subdominant chord flows downward from the root (C) of the tonic. As we will see, this upward and downward realm corresponds to the outward and inwardly creative realms that are ruled the dominant and subdominant principle.
Here are some important observations regarding these three chords:
- The G that is the fifth of the tonic triad becomes the root of the dominant triad.
- The C that is the root of the tonic triad becomes the fifth of the subdominant triad.
We can see that these chords, taken collectively, employ all the notes of the scale. Based on the individual scale degrees, we can see that the triads are built upon these steps of the scale, in ascending order:
| Subdominant | Tonic | Dominant |
|---|---|---|
1 (C) |
5 (G) 3 (E) 1 (C) |
2 (D) 7 (B) 5 (G) |
Active tone, Supporting tone and Bass tone
A very useful concept is to think of the root, third and fifth of any triad as being the Bass, Active and Supporting tones of the triad:
- The bottom note of each of these chords form the bass of the chord.
- The middle note forms the active tone
- The top note forms the supporting tone.
In all cases, the active tone is a major third above the root, while the supportive tone is a perfect fifth above the root. This importance of this will be clearer when we build these same harmonies above the minor mode. In minor, the bass and supporting tones remain unchanged while the active tone shifts down a half-step, forming the sound of the minor triad.
Tonic, Dominant and Subdominant in minor
We can see that a similar central spine can be created around the tone that exists as the relative minor of C major, in this case, A minor.
While such a relative minor mode could have been created from the Dorian or Phrygian modes, the Aeolian mode became the scale that most directly reflected the polarity of major and minor, due to the fact that each of the chords of tonic, dominant and subdominant form a minor triad, in perfect symmetry with the major triads of the major mode.
(By contrast, in the Dorian mode, based on D, the subdominant chord would have been major—GBD. In the Phrygian mode, based on E, the Dominant chord would have been diminished—BEF. As we will see, the minor mode does in fact partake of some Dorian and Phrygian energy, but as a fundamental scale, the aeolian mode, the "natural minor" mode, forms the most perfect symmetry with the major, as regards chordal function).
The chords of the minor mode are based on the exact same scale tone relationships (compare this chart with the one above)
| Minor Subdominant | Minor Tonic | Minor Dominant |
|---|---|---|
1 (A) |
5 (E) 3 (C) 1 (A) |
2 (B) 7 (G) 5 (E) |
except now we see that the active tone, the middle tone in each chord, is a minor third above the bass, rather than a major third (D to F, A to C and E to B are all minor thirds). The supporting tone, the top note, remains a perfect fifth in all cases.
Thus we can see now a central system beginning to form:
- A spine of three notes is created a perfect fifth above and below a central tone.
- A triad of three tones is created above each of the notes of the spine.
- If the central note is derived from a major scale, the resultant triads are major.
- If the central note is derived from a the relative minor scale, a third below, the resultant triads are minor.
For the next part of this section, we will look at harmonic polarity and the tonic, subdominant and dominant poles by having a first introduction to that great American jazz form, the 12-bar Blues.
PREVIOUS: 5B Introduction to Polarity
NEXT: 5D The Blues and Harmonic Polarity