Secondary Dominants and Leading Tone Chords Study Notes

Quality of Secondary Triads: A secondary dominant triad ( $V$ of) must always be major.
Quality of Secondary Dominant Sevenths: A secondary dominant seventh chord ( $V^7$ of) consists of a major triad with a minor seventh.
Root Relationship: The root of a secondary dominant moves to its temporary tonic via a descending fifth (e.g., $V^7/ii$ in the key of $C$ is an $A$ chord, and $A$ to $D$ is a descending fifth).
Applicability: Every chord in a key can be preceded by its own dominant except for the leading tone chord ( $vii^{\circ}$ ). You can only tonicize major or minor chords.
Doubling Rules: Never double the third factor of a secondary dominant because it acts as a temporary leading tone ( $Ti$ ).

Function: To tonicize a chord other than the tonic.
Three Types of Secondary Leading Tone Chords: * Diminished triad: Must always be in first inversion ( $vii^{\circ 6}$ ). * Half-diminished seventh chord ( $vii^{\emptyset 7}$ ). * Fully diminished seventh chord ( $vii^{\circ 7}$ ).
Root Relationship: The root moves to the temporary tonic via an ascending minor second ( $Ti \rightarrow Do$ ).
Voice Leading and Resolution: * The root factor (temporary leading tone) resolves up by a half step. * The seventh factor resolves down by a step. * Avoid doubling the root of the secondary leading tone chord. * In a diminished triad ( $vii^{\circ 6}$ ), double the bass (which is the third factor).

Common Chord Modulation: Identified by findind the "hot chord" (the first chord with an accidental from the new key). The chord immediately preceding the hot chord is usually the pivot or common chord, indicated with a bracket.
Key Relationships: Modulations typically head toward closely related keys (e.g., moving from $B$ flat major with $2$ flats to $F$ major with $1$ flat).
Cadence Identification: An Imperfect Authentic Cadence ( $IAC$ ) occurs at a $V \rightarrow I$ progression where the resolution is not in root position with the tonic in the soprano.

Major Keys: The leading tone seventh chord is naturally half-diminished ( $vii^{\emptyset 7}$ ).
Minor Keys: To obtain a dominant or leading tone function, harmonic minor must be used to raise the leading tone. In a minor key, the supertonic seventh chord is half-diminished ( $ii^{\emptyset 7}$ ).

Everett: Asked about the quality of a secondary dominant triad. The response clarified it must be major.
Lars: Asked about the quality of a secondary dominant seventh. The response confirmed it is a major triad with a minor seventh.
Aileen: Identified the $iii$ chord in the key of $C$ as $E$ minor and discussed its dominant, $B$ major.
Jack: Discussed the three types of diminished chords used for secondary leading tones.
Danny: Asked about what factors to avoid doubling in secondary leading tone chords. The response was the root.
Sebastian: Performed a Roman numeral analysis on a chorale that modulated from $B$ flat major to $F$ major.
Lexi: Practice constructing diatonic seventh chords in minor keys using harmonic minor.