1. Leading Tone Triad.
a. The diminished leading tone triad (viio ) is found in both Major and minor keys (Figure 7-1).
Figure 7-1. Diminished Leading Tone Triad
b. The leading tone triad is often called an incomplete dominant seventh with omitted root. The leading tone triad is identical to the top three notes of the dominant seventh chord. The leading tone triad can substitute for the dominant seventh chord (Figure 7-2).
Figure 7-2. Common Tones, viio - V7
c. Unequal Fifths. The root and fifth of the leading tone triad in first inversion often ascend to the root and fifth of the tonic chord. These fifths are NOT parallel perfect fifths. In the viio6 triad, the interval between the root (B) and the fifth (F) is a diminished fifth, not a perfect fifth. Unequal fifths are acceptable (Figure 7-3).
Figure 7-3. Acceptable Unequal Fifths
2. Triad Positions.
a. The leading tone triad is most frequently used in first inversion (Figure 7-4).
Figure 7-4. First Inversion Leading Tone Triad
b. The leading tone triad is rarely used in root position. When it does occur, it is usually when the root movement of the chords in the progression is the cycle of fifths and all the chords are in root position. This pattern is called a harmonic sequence (Figure 7-5).
Figure 7-5. Root Position Leading Tone Triad
c. Secondary triads are uncommon in second inversion, but can be used as passing chords. A secondary triad passing six-four chord can be explained as melodic non-harmonic tones in relation to the surrounding harmony.
a. The third of the chord is normally doubled in the first inversion diminished leading tone triad. This avoids doubling tone of the notes of the dissonant interval of the tritone, TT (the leading tone and the subdominant of the key) (Figure 7-6).
Figure 7-6. Normal Doubling, viio6
b. When the fifth is in the soprano voice, the fifth is usually doubled (Figure 7-7).
Figure 7-7. Doubled Fifth, viio6
c. The root of the chord can be doubled in a harmonic sequence to preserve the similar voice motion in the upper voices (Figure 7-8).
Figure 7-8. Doubled Root, viio6
4. Use of the Leading Tone Triad
a. The leading tone triad (viio6) serves largely as a passing or neighboring chord centered around the tonic triad.
(1) The leading tone triad is used as a passing chord between the tonic triad and its first inversion. The bass voice moves in stepwise motion (Figure 7-10).
Figure 7-10. viio6 as a Passing Chord Between I and I6
(2) The leading tone triad can also be used between the first inversion and root position tonic triad (Figure 7-11).
Figure 7-11. viio6 as a Passing Chord Between I6 and I
(3) The leading tone triad is used as a neighboring chord between two like (root or first inversion) tonic chords (Figure 7-12).
Figure 7-12. viio6 as a Neighboring Chord
b. The leading tone triad frequently occurs after the subdominant triad (IV) in place of the dominant chord when the soprano voice ascends (Figure 7-13).
Figure 7-13. Leading Tone Triad After Subdominant
|David L. Heiserman, Editor||
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Revised: June 06, 2015