Music Theory for Songwriters — Learn While You Write
Every chord labeled by function. Every suggestion explained. Song Cage surfaces borrowed chords, secondary dominants, voice leading, and modulation routes — right where you’re writing. You absorb theory naturally without leaving your song. No AI. No guesswork. Just music theory, built in.
Theory That Teaches As You Use It
Every chord in Song Cage is labeled with its Roman numeral function — so you always know whether you're on the I, the IV, or the vi. Hover over any chord and a tooltip explains why it works in that position, what function it serves, and where it typically resolves. You absorb music theory naturally, without leaving your song.
- Roman numeral labels on every chord — always know the function
- Contextual tooltips explain why each chord works in position
- Learn borrowed chords, secondary dominants, and cadences naturally
- No separate theory lesson — understanding builds as you write
Borrowed Chords and Modal Interchange
Song Cage shows you chords borrowed from parallel modes — the bVII from Mixolydian, the iv from Aeolian, the bII from Phrygian. Each borrowed chord is labeled with its source mode so you understand exactly where it comes from and why it adds color to your progression. No guesswork, no memorization required.
- Borrowed chords from parallel minor, Dorian, Mixolydian, and more
- Every chord labeled with its source mode
- Modal interchange panel shows all available options at once
- Context-aware — borrowed chords ranked by how well they fit your progression
- Explanations of why each borrowed chord works in context
No AI — Powered by Music Theory
Song Cage doesn't use AI to generate chord progressions or suggest what comes next. Every suggestion is powered by music theory algorithms — harmonic function, voice leading rules, common cadence patterns, and modal interchange logic. The same principles a trained musician uses, built into the software.
- No machine learning models — every suggestion is theory-based
- Harmonic context scoring, not statistical pattern matching
- Voice leading optimization based on interval math, not training data
- You learn by doing — not by having a model do it for you
- Transparent — you can always see why a chord was suggested
Chords That Know Your Melody
Write a melody first, and the chord palette re-ranks automatically. Chords where your melody notes are chord tones rise to the top — root notes weighted highest, then thirds, then fifths. The tooltip breaks down every factor: which notes match, how smooth the voice leading is from the previous chord, and how well the chord connects forward. You see exactly why each chord fits, not just that it does.
- Chords ranked by how many melody notes are chord tones
- Weighted scoring — root, third, fifth valued differently
- Voice leading distance from previous chord shown alongside
- Tooltip breaks down every factor in the score
- Works with melody you’ve written — no separate input needed
Modulate Between Keys With Confidence
Select a chord and open the Modulation Explorer to see related keys arranged by harmonic closeness. Pick a destination and Song Cage generates cadential routes — from a simple V→I pivot to a full ii⁹→V¹³→Imaj7 with voice-leading-optimized extensions. The 9th carries into the dominant’s 13th. The tritone sub gets a Lydian #11. Preview any route, then place it on the timeline in one click.
- Visual key map shows related keys by harmonic closeness
- Cadential routes generated from simple to extended
- Voice-leading extensions chosen automatically — 9th, 13th, #11
- Preview routes before placing them on the timeline
- Every extension choice explained — never arbitrary
Common Questions
Do I need to know music theory to use Song Cage?
No. Song Cage teaches you music theory naturally through labeled chords and contextual tooltips. Every chord is shown with its Roman numeral function, and hovering or tapping reveals an explanation of why it works in that position. You absorb theory as you write, without needing to study it separately.
What are borrowed chords and how does Song Cage use them?
Borrowed chords are chords taken from parallel modes — for example, using chords from C minor while writing in C major. Song Cage includes a modal interchange panel that shows every available borrowed chord, each labeled by its source mode (Dorian, Mixolydian, Aeolian, etc.). This lets you add color to your progressions while understanding exactly where each chord comes from.
Does Song Cage use AI to suggest chords?
No. Song Cage’s chord suggestions come from music theory algorithms, not machine learning models. Every suggestion is based on harmonic context, voice leading, and common cadence patterns — the same principles a trained musician would use. This is a deliberate design principle: you learn by doing, not by having a model do it for you.
How do I modulate between keys in a song?
Song Cage’s Modulation Explorer shows related keys arranged by harmonic closeness. Pick a target key and it generates cadential routes — from a simple V→I pivot to extended sequences with voice-leading-optimized extensions like ii⁹→V¹³→Imaj7. Preview any route, then place it on your timeline in one click. No theory textbook required.
What are secondary dominant chords and how do they work?
Secondary dominants are major chords or dominant 7ths that temporarily act as the V of a diatonic chord. For example, A major (V/ii) resolves to Dm in the key of C. Song Cage detects these automatically, labels them with their resolution target (→ ii), and ranks them by how well they fit your current progression.
Everything Works Together
Chord Progression Builder
Context-aware chord suggestions, 37 chords per key, voice leading optimization, and modulation routes.
Lyric Writing
Rhymes, slant rhymes, and synonyms — click any word and the tools appear instantly.
Guitar Songwriting
Fretboard diagrams, multiple voicings, and capo transposition for every chord.
Start Learning Music Theory While You Write
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