MUS 112 Study Guide M (Chapter 13)
Dominant Seventh & Supertonic Seventh Chords
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While the seventh added to a triad has been
considered a chord tone for the past few hundred years, the interval
of the seventh is also remains a dissonance. The principles of
nonharmonic tone treatment still require the same attention to its
approach and, particularly, to its resolution.
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Characteristics of the Dominant Seventh Chord:
The V7 is freely used in any inversion, in
both major and minor keys.
The V7 can be complete or incomplete.
If incomplete, the fifth is usually omitted. A complete V7
is often followed by an incomplete tonic triad, or an incomplete V7
by a complete tonic triad.
In inversion, all chord members are usually present.
The passing second-inversion dominant seventh chord:
When used as a passing chord, the second-inversion-V7 is
found between I and I6 or the reverse, fulfilling the same
function as viio and the passing dominant triad in second
inversion. In its use between I6 and I, the seventh
descends as expected. But between I and I6, the
seventh ascends, moving in tenths with the bass line.
When the seventh chord is repeated, the seventh may
appear in another voice; the last seventh in the series resolves
conventionally (descends a step).
The seventh of the chord may display an ornamented
resolution, similar to those described for the suspension.
When the seventh chord is arpeggiated, the resolution
of the seventh may be delayed, or even implied.
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The Supertonic Seventh Chord: Like the
supertonic triad, the supertonic seventh chord is commonly used to
precede the dominant. In fact, in the "full
cadence," the progression I-ii7-V-I (most often
ii six-five) is far more common that the I-IV-V-I or the
I-ii-V-I progression. In addition, the supertonic seventh is
usually the preferred choice for a dominant preparation elsewhere in
the phrase. The supertonic seventh chord is a minor seventh
chord (mm7) in a major key (ii7), and a half-diminished
seventh chord (dm7) in a minor key (ii7). (The ii six-five
is sometimes called an "added sixth" chord in that it
sounds like a triad with an added 6th scale degree.)
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Characteristics of the Supertonic Seventh Chord:
The approach to the seventh is commonly made by way of
a suspension figure. Since the seventh is the tonic of the key,
such an approach is very easy. The chords likely to precede ii7
are vi and IV, both containing the tonic note of the key.
The first inversion of this chord is used far more
often than other positions, though all are useful. Like the ii6
and IV triads, the bass note of the ii six-five is
scale degree 4, providing an excellent preparation for the dominant
tone (5) in either V or tonic six-four.
The ii six-five is found in the most common of
the passing six-four chord progressions: IV6 - I
six-four - ii six-five.
The seventh is commonly held over to become the root
of the tonic six-four. Since the root of I six-four is a
dissonance (a fourth above the bass), the seventh of ii7,
simply by standing still, becomes another dissonance, which then
resolves down by step, taking care of both dissonances.
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Intervals in the V7 Chord: In
addition to those intervals which constitute the major triad in the
dominant seventh chord, the following intervals, in relation to the
7th, are useful: root to seventh (m7), third to seventh
(d5), fifth to seventh (m3), seventh to root (M2), seventh to third
(A4), seventh to fifth (M6).
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The V7 Chord in the Melodic Line:
Intervals from the V7 chord are often incorporated in the
melodic line.
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