Tonic, Dominant and Subdominant (Pre-Dominant)

This chapter is a short review of the basic concepts concerning the relationship between tonic, dominant and subdominant harmonies.

Tonic

Tonic is the chord of rest, resolution. In tonal music, it is the magnet drawing all harmonies towards itself. It is the center of gravity around which the various other harmonies revolve. Even distant harmonies, like comets, are ultimately influenced by its gravitational pull.

In the major key, the brightness of the major tonic brings a sense of confidence, stability, triumph. When tonic becomes minor through modal shift, there is change of mood to something more inward and perhaps mysterious. Minor music need not be sad—one thinks of the opening of Mendelssohn's A Midsummer Nights' Dream, where the minor music is full of dance-like wonder, but even here it is the mysterious wonder of the fairie world of Shakespeare's play, not the bright happy world of the courtly dance.

In a minor key, the shift to major is often quite dramatic. In Baroque music it was virtually forbidden to end a work in the minor key, with all minor-key music by necessity ending with a Picardie third. The only exception to this rule was in dramatic music, some oratorio or opera, where by dramatic necessity the tragedy of a scene or a text necessitated a minor cadence.

The submediant chord in major and the mediant chord in minor form relative tonics to the main tonic of a key.

In Major, vi serves as the relative tonic, often providing a softening effect to the sustained brightness of the major tonic.

In minor, the mediant III triad often serves as the relative tonic, pulling the minor mode into a brighter tonality through the termporary establishment of III as a center of gravity, with the lowered VII triad (Bb in C minor) serving as the dominant of the relative tonic. Modulating to the relative tonic in minor is as easy as falling off the proverbial log. If the log is a large log, modulating to the relative tonic is probably even easier.

Dominant

Dominant is the chord of dynamic stress. In common practice harmony, it is the chord that requires resolution. Due to strong placement of the leading tone of the key as the third of the chord, it urges itself upwards to the tonic triad.

Dominant harmonies come in a few flavors:

(**it should be noted that viiº can sometimes go to the iii chord when encountered in the context of a circle of fifths progression, i.e.—I, IV, viiº, iii, vi, ii, V, I. Here, the diminished fifth relationship between IV and viiº is lessened by the strength of the overall progression. We say this in the C minor fugue from the Bach Toccata, you may recall).

Historical note:

In later 19th century harmony and ultimately in Musical Impressionism, the stress of the dominant seventh type chord is placed in a broader harmonic context where the chord takes on a different emphasis, one of dynamic coloration. Increasingly, in part because the ear had had centuries to get accustomed to the sound of the major triad with the lowered seventh, the chord became less and less demanding of resolution and more of an accepting coloration with evocative poetic overtones. In Ravel and Debussy, for example, dominant seventh chords simply float along, often moving in parallel motion without any need or resolution. This is in part what gives impressionistic music its soft, brushed-over quality.

Subdominant

Subdominant has two characteristics:

1) The reciprocal realm.

In terms of harmonic dualism, always recall that we can create all the notes of the justly-tuned major scale by going up by fifths from, say C. Thus we find G, D, A, E and B, but not the F. The F can only be found by finding the reciprocal fifth of the tonic, the generating tone of the generating tone.

This gives the entire realm ruled over by the subdominant a more inward and mysterious quality. The C triad, when the subdominant of the subdominant (the Bb) is added, pulls tonal music into the subdominant, which is perhaps more like moonlight to the bright sunlight of the Dominant realm.

Recall that all other secondary domninant: V/ii, V/v, V/vi and V/iii are born from the overtonal realm above the dominant. Only the V7/IV points towards the subdominant.

2) The realm of the pre-dominant.

The subdominnat realm is as far from tonic as tonal music can venture. Once the subdominant is established, there is an inevitable swing back to the dominant realm. In this way of thinking, subdominant harmony can be thought of as pre-dominant harmony, in that these chords are eventually (if not immediately) followed by some form of dominant chord.

There is a family of triads that are all seen to precede the dominant:

IV and ii are well known to you. The next two chapters will cover the Neapolitan 6th and the Augmented 6th chords, respectively.

NEXT: 6B: Neapolitan 6th chord (The Phrygian II)

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