Basic Music (TC 12-41/ NAVEDTRA 10244) describes the spelling and quality of the mediant triad. In major keys, it may appear in root position with doubled root (modal note) or occasional doubled third (tonal note). In first inversion the third is normally doubled.
FIGURE 9.20: Mediant Triad
In minor keys, the major quality mediant triad may appear in root position or first inversion with doubled root. The fifth of the chord (subtonic scale degree) must descend to the submediant scale degree.
FIGURE 9.21: Mediant Chord in Minor
The Augmented quality mediant triad may appear in root position with doubled root, or in first inversion with doubled third.
FIGURE 9.22: Augmented Mediant Triad
Basic Music (TC 12-41/ NAVEDTRA 10244) describes the spelling and quality of the subtonic triad. This chord is not considered in the chord chart because it only occurs in minor and has an unusual character. It occurs in root position or first inversion with doubled root progressing to the major quality mediant chord. The subtonic chord maybe preceded by either i or iv.
FIGURE 9.23: Subtonic Triad
SUBTONIC SCALE DEGREE
The subtonic scale degree may be harmonized with the subtonic or the minor quality dominant chords. The following chord will be the subdominant or submediant. The effect of such movement is that of passing chords without progression.
FIGURE 9.24: Subtonic Scale Degree