Diatonic leading-tone seventh chords are built on the seventh scale degree of the major, harmonic minor, and ascending melodic minor scales. In major keys, the quality of the chord is diminished-minor (dm) being a diminished triad to which has been added a minor seventh. Diminished-minor is also known as half-diminished. In minor keys, the quality is diminished-diminished (dd), but the name is usually abbreviated to diminished or fully diminished.

The seventh on the leading note provides a good alternative pre-dominant chord to the supertonic or subdominant, the seventh falling nicely down to the root of the dominant itself. Other viable pathways of progression are to the mediant seventh or even the tonic chord itself

Leading-tone seventh chords are represented by viiØ7 and viio7 in Roman numeral analysis. Both are associated very closely with the dominant seventh chord because they have three notes in common with the V7. Also this is due to the presence of the dissonant diminished fifth, which imparts to those chords in which it is present a restless sense of instability.

Composers frequently substitute leading-tone triads and seventh chords for the dominant in the interest of variety and diversification. Since V7, viiØ7 and viio7 all represent dominant harmony, composers intermixed them freely. This is particularly true for the subtle half-step fluctuation between viiØ7 and V7.

Progressions from viiØ7 and viio7

Like the dominant seventh, with which they share three common tones, viiØ7 and viio7 usually resolve to the tonic (I or i), either directly (a–b) or through the dominant seventh (c–d).

Resolution of Tritone and Seventh Factors

The fully diminished seventh chord (viiØ7) contains two diminished fifths, which tend to resolve inward. If both are resolved, the result will be a doubled third factor on the tonic chord (a), but composers often prefer the normal doubling (b).

The two tones in the leading-tone seventh chords that are nearly always resolved are the root of the chord (the leading tone), which moves upward to the tonic note, and the seventh factor, which resolves downward by step.

You obtain a chord of the seventh when you add to the root, third, and fifth of any of the aforementioned triads a fourth note that is a seventh above the root of the chord. This seventh is usually taken from the scale or key in which the triad occurs. The consequences of the addition of a seventh to a triad lie in the fact that the seventh is a dissonant interval—in other words, it presents a certain degree of tension.

Seventh Chords in Major and Minor Keys

Although some of these chords do not appear in music literature very often, it is nonetheless important for you to understand that variances in the scales influence the quality of diatonic seventh chords. The double-letter label beneath each chord specifies (1) the quality of the triad and (2) the quality of the seventh:

Seventh Chords in Major Key

Creating a seventh chord within a specific key or scale is normally as simple as adding another third on top of the fifth of the base triad. This gives you a 1-3-5-7 structure. Major seventh chords are “pretty, delicate, sensitive, thoughtful”. In the major scale you obtain a series of seven seventh chords. Some of these chords have a major seventh, while others use a minor seventh. The major seventh has 11 semitones and is quite a sharp dissonance, whereas the minor seventh has 10 semitones and, although dissonant, is much mellower in its sound. This means that there are two kinds of seventh chords: chords of the major seventh and chords of the minor seventh. There’s more minor seventh chord in the major key. So convention rules that this are simply represented by a 7. In contrast, major seventh chords require “maj7” after the letter.

Dominant Seventh Chords

The Dominant Seventh Chord

The dominant seventh chord is a diatonic seventh chord built on the fifth scale degree of the major, harmonic minor, and ascending melodic minor scales. The major triad (root, third, fifth) and minor seventh (from root to seventh) create a distinctive sound that is universally linked to the dominant function. Dominant seventh chords are “sassy, outgoing, strong.” All seventh chords have a particular sound or quality determined by two characteristics— the type of triad (major, minor, diminished, or augmented) and the type of interval from the root to the seventh (m7, M7, or d7). Since the dominant seventh chord consists of a major triad and a minor seventh on top, its quality is described as major-minor (abbreviated as “Mm”). This gives rise to the diminished fifth interval between the third and the seventh. It is undoubtedly this interval that gives the dominant seventh chord that restless urge to find a resolution in the tonic chord. The typical pathways of progression for this chord are based on the felt need for this sharp dissonance to resolve downward by a half step. When the dominant seventh chord is used, the listener would ordinarily expect the tonic chord to follow—which means to say that the tonic chord represents the regular pathway of progression of the dominant seventh chord.

For a deceptive cadence, the submediant is undoubtedly the best option. Sharing two notes in common with the tonic triad, they are very similar. The subdominant offers another option in terms of alternative pathways than the tonic triad, although the root of the subdominant is at the same time the seventh of the dominant seventh chord. Another option involving the subdominant is to return to the dominant seventh chord immediately afterward, setting up the possibility for an alternating vamp between the two chords. A dominant seventh to mediant progression has a certain weakness about it due to the fact that the fifth of the mediant is the leading note. It might represent a viable option, though, when the dominant seventh chord is used in the third inversion. Another popular type of irregular progression of the dominant seventh chord is to another dominant seventh chord.

When omitting a note from the dominant seventh chord, you would normally omit the fifth. Should a note need to be doubled, we would avoid doubling the seventh and third of the dominant seventh because these are the tendency tones that give the chord its pull toward the tonic triad. If one of these were doubled, we would then need to introduce consecutive octaves.

Resolution of the Dominant Seventh Chord

From the dissonant seventh’s emergence in the sixteenth century until the post-romantic and impressionistic periods, composers routinely resolved downward by step in the succeeding chord and followed the V7 with the tonic triad. The dominant seventh chord can be resolved in a number of ways, but the most common resolution is by a circle progression (V7–I).

Circle Progression

1. The seventh of the V7 resolves down one scale step to the third factor of the tonic triad. The seventh factor may be in any voice (soprano, alto, tenor, or bass).
2. When the seventh is the bass note (V4/2), it must resolve to the third factor of I, and the tonic triad must automatically be in first inversion (I6).
3. If you first resolve the seventh down a step, the three remaining voices will move smoothly to notes of the I triad. In the first, second, and third inversion examples, the common tone (G) is retained in the same voice, whereas in the root position example, all three upper voices move in similar motion to the nearest chord tones.
4. In all four examples, all four factors of the V7 are present. In unusual instances, an incomplete V7 may be necessary. In such cases omit the fifth factor.
5. In this example, the seventh of the chord and the leading tone are both resolved. In such cases omit the fifth factor of the tonic triad and triple the root.

Noncircle Progressions with Resolution

Sometimes a V7 is diverted temporarily from its normal resolution to I. In these cases root movement will usually progress by second or third. A typical example of this progression type is V7 to vi (or VI in the minor). Notice the doubling of the third in the vi chord, which avoids parallel perfect fifths.

Nonresolution of Seventh Factor

In rare instances the seventh factor of the V7 chord cannot be resolved in the same voice. This typically occurs when the resolution note is not part of the succeeding chord. In most instances, however, the resolution of the seventh is only delayed and eventually occurs in the appropriate manner after a few intervening chords.
No standard voice-leading pattern has been established for nonresolution of seventh factors. Observe good voice-leading principles and avoid parallel perfect intervals.

Inversions of the Dominant Seventh Chord

Since seventh chords contain four notes, there are four positions of inversions possible:

1. Root Position
2. 1st inversion with the root on top and the 3rd on the bass (adding a small superscript 7)
3. 2nd inversion with the root and 3rd brought to the top the 5th on the bass
4. 3rd inversion with the root, 3rd and 5th brought to the top and the 7th on the bass

Of the four positions of the dominant seventh chord, the strongest is undoubtedly the root position. In a perfect cadence, we would expect the dominant seventh chord to be used in this position. In the first inversion, as the leading note rises upward, the seventh falls nicely down to the third of the tonic triad. In the second inversion, this position is approached well from the first inversion of the tonic triad. In the third inversion, the seventh tends to fall stepwise, this means that this position automatically implies resolution to a tonic chord in the first inversion. As the seventh falls, the upper parts move nicely in the opposite direction.