2-1 OVERVIEW

1. Primary Triads

a. The primary triads are triads built on the tonic, subdominant, and dominant scale degrees. They establish the tonal center (Figure 2-1).

Figure 2-1. Primary Triads

NOTE: The tonic, subdominant, and dominant scale degree notes (scale steps) are called primary or tonal notes. The supertonic chord is a secondary triad, but the supertonic scale degree can function as a primary note.

b. The primary triads are built on the same scale degrees in both Major (I, IV, V) and minor (i, iv, V) keys (Figure 2-2).

Figure 2-2. Primary Triads in Major and Minor

NOTE: In a minor key (harmonic minor), the dominant triad is Major. The third of the triad is raised with an accidental to create a leading tone.

2. Root Position

A triad is in root position when the root of the triad is in the bass voice (Figure 2-3).

Figure 2-3. Root Position Triad

3. Doubling of Root Position Triads

When a triad is in root position, the root of the chord (the bass note) is doubled. This doubled note may be in any of the upper voices (Figure 2-4).

Figure 2-4. Root Position Doubling

4. Figured Bass

a. The numerals , ,5, or 3 indicate a triad in root position.

NOTE: The 3 represents the note an interval of a third above the bass note (the third of the triad). The 5 represents the note the interval of a fifth above the bass note (the fifth of the triad). The 8 represents the note that is the doubled root of the triad (Figure 2-5).

Figure 2-5. Figured Bass

b. Usually these numerals are omitted. A bass note with no numerals is understood to represent a triad in root position (Figure 2-6).

Figure 2-6. Root Position Figured Bass

NOTE: The figured bass is a complete figured bass when all upper voices are represented in the bass figuring (including doublings). Essential figured bass is that numbering (or chromatic sign) which is needed to represent the triad. Figure 2-5 is complete figured bass. Figure 2-6 is essential figured bass.

c. Chromatic alterations are indicated by accidentals placed below the bass line.

d. The chromatic sign is the accidental (#,, or ) necessary to raise or lower the note being altered within the key. It does not have to be a # to raise or a  to lower.

e. A chromatic sign used in the figured bass refers to the note a third above the bass if no number accompanies the chromatic sign (Figure 2-7).

f. A slash through a number means to raise the note of that interval a half step (Figure 2-7).

Figure 2-7. Chromatic Alteration in Figured Bass

5. Basic Principles for Part Writing Triads

a. Keep the common tone.

b. Connect the remaining voices to the nearest available chord tones.

First, look for half step movement.

Next, look for whole step movement.

Finally, connect any remaining intervals.

c. Check your part writing for objectionable voice motion.

2-5  CADENCES

18. Authentic, Plagal, and Half Cadences

a. Authentic Cadence. The V to I or V to i chord progression at a phrase ending is called an authentic cadence. It is a perfect authentic cadence when both triads are in root position and the tonic scale degree appears in the soprano of the tonic triad. Otherwise, it is called an imperfect authentic cadence. Authentic cadences create the feeling of full stop and are commonly found at final cadences (Figure 2-37).

Figure 2-37. Authentic Cadences

b. Plagal Cadence. The IV to I or iv to i chord progression at a phrase ending is called a plagal cadence. It is a perfect plagal cadence when both triads are in root position and the tonic scale degree appears in the soprano voice of both triads. Otherwise, it is known as an imperfect plagal cadence. The plagal cadence, commonly called the Amen cadence, lacks the directional drive of the authentic cadence and provides a less final ending (Figure 2-38).

Figure 2-38. Plagal Cadences

c. Half Cadence. When any chord, regardless of inversion, moves to the V chord at a phrase ending, a half cadence occurs. A phrase that ends with a half cadence does not have a feeling of repose. It creates a feeling of suspense that is usually resolved in the next phrase with a final cadence (Figure 2-39).

Figure 2-39. Half Cadences

d. Plagal Half Cadence. When the I (i) chord moves to the IV (iv) chord at a phrase ending, a plagal half cadence occurs. As with a half cadence, the plagal half cadence creates a feeling of suspense. This is usually resolved in the next phrase with a final cadence (Figure 2-40).

Figure 2-40. Plagal Half Cadences

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