Secondary Leading Tone Chords

Contemporary Theory III Secondary Leading Tone Chords

Identifying Secondary vii Diminished Triads (vii^o)

Many of the concepts discussed in the previous chapter apply here, since the leading tone diminished chord also serves a dominant function in tonal music. The leading tone diminished triad (vii^o) contains the same upper three pitches as a dominant 7^th (V7) chord in the same key. While the 3^rd of the secondary dominant is raised, the same note raised by an accidental is the root of the vii^o triad. Rather than moving down a P5 to the tonicized pitch, the note a half-step up from the altered root of the vii^o is tonicized.

The vii^o triad contains the 7^th, 2^nd, and 4^th scale degrees in a key, but it is often found in first inversion. This facilitates contrary motion in resolution. The 2^nd scale degree of the key of the tonicized chord is found in the bass in first inversion, and is typically doubled in four voices.

Secondary vii Diminished Seventh Chords (vii^o7)

The secondary vii^o triad is built on a raised scale degree, which has an accidental. The vii^o7 chord is built on the same altered scale degree. It may be either half-diminished or fully diminished with a chromatically lowered 7^th above the root in major keys. The most frequently used secondary vii^o7 chords are of the fully diminished variety. This chord is actually borrowed from the parallel minor key into the major key. Borrowed chords will be discussed in the next lesson.

Spelling Secondary vii Diminished Seventh Chords (vii^o7)

This chord may be spelled four different ways, depending on the key or tonicized pitch to which it belongs. In general, the raised note is always the root and the lowered note is the seventh. This is a clue to the harmonic goal of the vii^o7 chord. For example, in the key of C major the vii^o7/vi is spelled G#-B-D-F. The F-natural (7^th of the chord) is lowered from F# in the key of A, which is vi in C. Note that the vii^o7 chord must be spelled as a stack of minor thirds, which makes it completely symmetrical, and it can only be transposed three times. This chord, as well as the secondary V7, is frequently used as a pivot chord to a new key in a chromatic modulation. In this case, it may be spelled correctly in the new key, and “incorrectly” in the original key. This enharmonic spelling will be discussed further in the lesson on Modulation.

Voice-Leading Secondary vii Diminished Triads (vii^o)

Resolve each note according to its chromatic inflection, or tendency. Raised pitches continue upwards, as a general rule, and lowered pitches move down. The raised root of the secondary vii^o7 chord resolves up by half-step to the tonicized pitch. The diminished 7^th of the vii^o7 chord typically resolves down by half-step. In first inversion, these two voices move in contrary motion smoothly to the doubled root of the tonicized chord. The other two voices may move downward stepwise, or into an inverted chord of resolution with the 3^rd or 5^th doubled.