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Week 19 of 24

Secondary Dominants & Modal Interchange

Secondary dominants and borrowed chords add chromatic richness to diatonic progressions. This week you borrow, resolve, and analyze.

Learning Goals

Build secondary dominants (V/V, V/vi, etc.) in any key
Identify borrowed chords from parallel minor (modal interchange)
Hear the pull of a secondary dominant resolving
Analyze a short progression using Roman numerals and slashes

Lesson Content

Secondary Dominants

Any diatonic chord can be preceded by its own V7 — a "dominant of the dominant." In C major, D7 → G is V/V → V. The secondary dominant tonicizes its target without fully changing key.

Modal Interchange

Borrowing a chord from the parallel minor (like bVI, bVII, or iv in a major key) introduces a darker color. The Beatles, Radiohead, and countless other songwriters use modal interchange for emotional contrast.

Roman Numeral Analysis

Slash notation (V/V, V/vi, iv borrowed) lets you label non-diatonic chords precisely. Practice analyzing songs you love: every chord gets a Roman numeral relative to the key.

Practice Activities

Activity 1: Play V/V and V/vi on the Synth

On the Synthesizer, in C major, play D7 → G → C (V/V → V → I) and E7 → Am (V/vi → vi). Feel how the secondary dominant "points at" its target.

Activity 2: Progression Identification — Advanced

Hit 20 correct with 75%+ accuracy in Chord Progression Identification on Advanced. Listen closely for non-diatonic motion.

Activity 3: Analyze a Borrowed-Chord Song

Pick a song you know (e.g., The Beatles' "Blackbird" or Radiohead's "Creep"). Label every chord with Roman numerals and circle any borrowed or secondary dominant chords.

Activity 4: Scale Identification — Advanced (Parallel Modes)

Reach 20 correct with 75%+ accuracy in Scale Identification on Advanced. Parallel mode comparison helps you hear what's being borrowed.

Activity 5: Chord Identification Refresh

Hit a best streak of 12 in Chord Identification on Advanced. Secondary dominants are just dominant 7ths in disguise — know them cold.