strudel-harmony

name: strudel-harmony description: The craft of harmony and chord progressions for modern electronic and cinematic music — which progressions work and WHY, voice leading, borrowed chords, modal interchange, extended voicings (7ths, 9ths, sus), cadence and resolution, emotional function, key/mode choice. Use when someone asks "what chords", "a progression for", "make it sound sad/hopeful/epic/dark/dreamy", "what key or mode should I use", "voicing", "how to borrow a chord", "why does this feel off", or wants to move beyond basic triads.

The harmonic layer tells the listener how to feel. These are the non-obvious working rules — what producers actually reach for, and why the moves land.

Key / mode choice (the first decision)

Pick the mode before writing notes. The mode dictates which borrowed chords are available and what every melody note implies.

Dorian vs. natural minor rule of thumb: does your minor progression have a major IV (e.g. D in Am)? That's Dorian — darker modes only if you want no lift at all. The ♮6 of Dorian is the single note that separates soulful from bleak.

The progressions that always work (and why)

i–bVI–bIII–bVII (Aeolian loop)
The backbone of electronic minor: Am–F–C–G. Never resolves — circles forever. Works because the bass descends by 3rds (A→F→C→G), each root a major 3rd or 5th from the last = chromatic-mediant smoothness. The most-used loop in trance, progressive house, ambient.

i–bVII–bVI–V (Andalusian cadence)
Descending bass line A–G–F–E. The V is major even in minor (borrowed from harmonic minor), creating a gravitational pull back to i. Moody, Spanish, cinematic urgency. The descent IS the hook.

i–iv (minor to minor subdominant)
The simplest emotional trigger. Am → Dm. The iv chord is borrowed from the parallel minor when you're in major; in natural minor it's diatonic but still hits hard. "Creep" (Radiohead) pivots on this.

I–IV–V–I (diatonic major)
Statistically the most common pop loop. Avoid in isolation — too resolved. Add extensions (I^7–IV^9–V sus4) or borrow from parallel minor to inject weight.

I–V–vi–IV ("4 chords" / axis progression)
C–G–Am–F. Warm, cyclical, harmonic momentum without darkness. Ubiquitous in pop. To de-genericize: (1) add 7ths, (2) borrow the vi→IV move in minor (i–bVI) instead, (3) change the bass against the chord.

i–IV–V (Dorian) e.g. Am–D–E
The major IV (D from D Dorian/D major) is the upgrade over natural minor. Same tonic, brighter colour. Deep house signature.

I–bVII–IV (Mixolydian) e.g. C–Bb–F
The "rock" loop, but works in electronic as a grounded, not-quite-major feel. The bVII is the borrowed chord; no minor 3rd so it never goes dark — just earthy.

Borrowed chords (modal interchange)

These are the moves that make diatonic progressions feel cinematic without changing key.

• iv in major (Cm in C major / Fm in F major): instantly darkens. The IV→iv move is one of the most reliable emotional triggers in any genre.
• bVI in major (Ab in C major): warm, sweeping, "epic" lift. Used in every Zimmer cue. Puts you briefly in C minor without committing.
• bVII in major (Bb in C major): folk/rock openness, slightly unresolved. Borrowed from Mixolydian.
• bIII in major (Eb in C major): brightness from an unexpected direction. Often follows bVI.
• II in major (Lydian borrow) (D in C major): otherworldly, floating — the #4 implies Lydian even if you don't spell it out.
• bII (Neapolitan / Phrygian) (Db in C): dark, menacing, Spanish — use sparingly.

The rule: move the melody to a note inside the borrowed chord when it lands. The borrowed chord gains power when the melody occupies its chromatic note. Don't borrow harmonically while ignoring the lead melodically.

Extended voicings — what they actually do

Triads are the skeleton. Extensions add emotional texture without changing function.

Key rule: sus resolves. A sus4 chord demands its 3rd back — if it never gets it, the listener stays suspended (useful for drones). A sus2 is gentler: can sit indefinitely. Use chord("Csus2").voicing() or chord("Fsus4").voicing() in Strudel.

Extended voicings muddy mixes when stacked dense. The fix: spread voicings (open voicing across 2+ octaves), drop the 5th, don't double root + extension simultaneously in the bass. Strudel's .voicing() does this automatically — trust it.

Voice leading — the invisible glue

Voice leading is why one progression flows and another feels choppy. Rules:

1. Keep common tones stationary. C major → Am: C and E are shared — don't move them.
2. Stepwise motion in inner voices. When you must move, move by step (semitone or tone), not leaps.
3. Bass can leap; upper voices should crawl. The root-position bass provides the harmonic anchor; the inner voices create the smoothness.
4. Avoid parallel 5ths / octaves between any two voices moving together — creates a hollow, medieval sound (unless that's intentional).
5. Inversions are your shortcut. Am/E → F/C means the bass descends stepwise (E→C) instead of leaping. The chord change stays audible; the seam disappears.

In Strudel, chord("<Am F C G>").voicing() applies automatic voice leading — it minimizes jumps by default (anchor defaults to c5). Force register: .voicing().mode("above:c3") for low-register pads.

Cadence and resolution

Authentic cadence (V→I): strongest closure. Use it at a section END, not mid-loop.
Plagal cadence (IV→I): softer, "amen". Church warmth or ambiguous close.
Half cadence (→V, stop): leaves the listener hanging — perfect for build endings.
Deceptive cadence (V→vi): V resolves to vi instead of I; surprise, continuation. Great for avoiding predictable drops.
Modal cadence (bVII→I): no leading tone, open feeling. The Mixolydian/Dorian signature; never fully closes.

Mistake to avoid: ending a loop on I every four bars. The loop becomes a series of cadences and sounds like it restarts rather than flows. Favour progressions that end on a non-tonic chord or on a chord that implies the loop re-entering (bVII→back to i, etc.).

Emotional function quick-reference

Common mistakes

• Using only root-position triads: the voicing IS part of the emotion. First inversion alone changes the weight of a chord.
• Borrowing a chord but ignoring melody: the melodic line must acknowledge the borrowed note or it sounds accidental.
• Modal ambiguity without intent: Dorian and natural minor share the same tonic triad — if your progression never reaches the IV or bVI, the listener can't tell which you're in. Commit.
• Over-extension: stacking 7–9–11–13 on every chord blurs harmonic identity. One or two extensions per chord reads cleaner.
• The key-change trap: transposing a loop up a minor 3rd for a "big moment" only works if the original section established a strong tonic. Move without gravity = confusion.

In Strudel

// Chord symbols + auto voicing (voice-leads by default, min-jumps to anchor c5)
chord("<Am F C G>").voicing()

// Set register
chord("<Am F C G>").voicing().mode("above:c3")

// Extended chords
chord("<Am7 Fmaj7 C9 Gsus4>").voicing()

// Scale-degree melody (never hits a wrong note)
n("0 2 4 3 1").scale("A:dorian")

// Arpeggiate a borrowed chord
chord("<Am Dm F E>").arp("up")

See [[strudel-pro-tips]] for chord().arp(), .off() harmonics, and scale-index details. See [[strudel-modifiers]] for the full .voicing() parameter list. See [[strudel-melody]] for melodic construction over these progressions.

Related: [[strudel-arrangement]] [[strudel-melody]] [[strudel-groove]] [[strudel-mixing]] [[strudel-sound-design]] [[strudel-genres]] · mechanics: [[strudel-compose]] [[strudel-pro-tips]] [[strudel-modifiers]]

Sources: Strudel Tonal Docs · Strudel Voicings · LANDR: Cinematic Chord Progressions · ComposerDeck: Modal Interchange · Native Instruments: Voice Leading · Signals Music Studio: Sus Chords Advanced · Scaled Guitar: Dorian vs Natural Minor · Abducted Android: Ambient Chord Progressions · WeMakeDanceMusic: EDM Progressions · ProductionMusicLive: Voice Leading