The Mechanics of Musical Harmony
Move beyond standard chord charts to understand why harmonic progressions actually move, pull, and surprise. Discover the voice-leading mechanics, chromatic substitutions, and common voicing traps that separate amateur loops from sophisticated harmony.
Like Duolingo, but for The Mechanics of Musical Harmony. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
21 levels across 3 sections, about 42 minutes end to end, roughly 8 days at five minutes a day. It moves through Expanding the Diatonic Palette; Chromatic Color and Borrowed Chords; and Voice Leading, Pitfalls, and Complex Substitutions. It assumes you already know the basics.
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Key ideas in The Mechanics of Musical Harmony
- A major-minor seventh chord built a fifth above any diatonic chord turns it into a temporary tonic.
- In C major, the ii chord is D minor, whose dominant fifth is an A major chord with a minor seventh (A7).
- Targeting a chord with its own dominant fifth is written as V7/ii (the dominant of two).
- A secondary dominant introduces an accidental a half step below the target's root to serve as its leading tone.
- In a C7 chord resolving to F, the sharp upward pull comes from the natural third (E), while the Bb pulls downward to A.
- Secondary leading tones create urgency by shrinking the melodic distance into the target chord to a half step.
- Inserting a secondary dominant replaces passive diatonic movement with directional harmonic momentum.
- V/vi uses a raised accidental to pull forcefully into the relative minor instead of drifting there.
- V/V intensifies the arrival at the primary dominant by turning the second scale degree into a major chord.
- Choosing the right secondary dominant to tonicize a target chord
- A secondary dominant borrows energy from a temporary tonic without changing the underlying key center.
- Recognizing how an altered pitch creates a temporary leading tone pull
- Chaining non-resolving secondary dominants dissolves the listener's mental anchor to the home tonic.
- Harmonic drive requires contrasting unstable chromatic tension with moments of diatonic rest.
- A secondary two-five precedes the secondary dominant with that target chord's own minor ii chord.
- For a G major chord, its secondary ii is Am7 and its secondary V is D7, written as ii-V of V.
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives The Mechanics of Musical Harmony the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
In C major, the ii chord is D minor. Which dominant fifth chord points right toward it?
Get it right to open this lesson and 20 more in the app.
Where The Mechanics of Musical Harmony takes you
- 1
Expanding the Diatonic Palette
- Secondary Dominants: Directing Harmonic Flow
- Bass Contours and Chord Inversions
- 2
Chromatic Color and Borrowed Chords
- Modal Interchange: Borrowing Parallel Colors
- Chromatic Mediants: Engineering Cinematic Shifts
- 3
Voice Leading, Pitfalls, and Complex Substitutions
- Voice-Leading Traps and Tendency Tones
- Tritone Substitutions and Altered Tensions
- Diminished Chords as Multi-Directional Pivots
3 sections · 7 units · 21 levels. Built to play, not to enroll.
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