BookatlasPiano Rabbit Hole: Improvisation Theory & Practice

Module 15 — Chromatic Harmony, Borrowed Chords, and Modal Interchange

This module is where harmony starts sounding more emotionally surprising without necessarily sounding “outside.”

The big idea is:

You can temporarily borrow chords from the parallel major or minor key without actually changing the home key.

This is called modal interchange or borrowed harmony.

15.1Parallel major and minorRemember:63 words15.2The diatonic chords in C majorC major gives:55 words15.3The most famous borrowed chord: iv in majorIn C major:70 words15.4Why F → Fm → C works so beautifullyF:71 words15.5Borrowed chord versus modulationIf you play:50 words15.6The borrowed iv is extremely practicalTry these:69 words15.7The voice-leading formulaIn any major key:70 words15.8Borrowed ♭VIFrom C minor, another useful chord is:60 words15.9Borrowed ♭VIIFrom C minor:51 words15.10Borrowed ♭IIIFrom C minor:49 words15.11The useful borrowed-chord palette in majorIn a major key, common borrowed chords from parallel minor include:48 words15.12Borrowed vIn C major:61 words15.13Borrowed chords often weaken classical function but enrich colorThis is important.57 words15.14Modal interchange means borrowing from a parallel modeThe idea is broader than just major/minor.37 words15.15A simple progression made richerBasic:85 words15.16Borrowed iv after IVThis is worth practicing constantly:51 words15.17Why Fm6 works so well before CFm6:39 words15.18Minor plagal cadenceiv → I49 words15.19Borrowed ♭VI → VA dramatic classical/cinematic move:52 words15.20Borrowed ♭VII → IVTry:34 words15.21Borrowed ♭III → IV → ITry:40 words15.22Chromatic mediantsNow a related but broader concept.78 words15.23Hear C → EPlay:38 words15.24C → A♭Play:30 words15.25Chromatic mediants are not the same as secondary dominantsImportant distinction.45 words15.26Borrowed chords versus secondary dominantsCompare:49 words15.27Another powerful chromatic line: 5 → ♯5 → 6Try:81 words15.28Combine both linesTry:62 words15.29Make the chromatic line explicitKeep a top or inner note:65 words15.30Borrowed chords can support melody notes outside the keySuppose you're in C major but melody has A♭.54 words15.31Example: melody A♭Possible harmonies in C-major context:52 words15.32Modal mixture in minor keysBorrowing works in the other direction too.51 words15.33Picardy thirdA piece in minor ends on a major tonic.49 words15.34Borrowing IV into minorIn C minor:50 words15.35Modal sound from ♭VIIIn C major:57 words15.36Modal harmony often avoids strong V–I gravityFunctional harmony:49 words15.37Reharmonization by modal interchangeSuppose melody is originally harmonized:66 words15.38Borrowed chord testFor every candidate borrowed chord ask:46 words15.39Voice leading is the glueChromatic harmony sounds convincing when individual notes move smoothly.48 words15.40Another smooth chromatic chord: E♭C:27 words15.41Don't judge chords only by root movementTwo roots may look unrelated, but upper voices may connect beautifully.37 words15.42Build a minor-plagal endingTry:70 words15.43Another endingTry:33 words15.44Another pop/modal endingTry:40 words15.45Chromatic mediant color exercisePlay:35 words15.46Melody-first chromatic reharmonizationSuppose melody note is E.49 words15.47Borrowed chords can create a bass lineExample:68 words15.48Play that bass alone firstC B B♭ A A♭ G41 words15.49Chromatic bass can be more important than chord labelsWhen you hear a sophisticated arrangement, sometimes the magic is not “a fancy chord.”34 words15.50Improvising over borrowed chordsIf progression is:59 words15.51Over ♭VIIIf:42 words15.52Modal interchange is not “use random black keys”The borrowed notes have structural meaning.33 words15.53Your practical borrowed-chord toolkitFor now, memorize these in a major key:81 words15.54Combine secondary dominants and borrowed chordsTry:43 words15.55Analyze the emotional architectureThe progression above does:57 words15.56Use borrowed harmony sparingly at firstA single Fm in a C-major song can be striking.37 words15.57Reharmonization assignmentTake a simple melody in C you've already harmonized.48 words15.58A useful diagnostic questionWhenever you see a chord outside the key, ask:48 wordsHomework for Module 15Play:305 wordsModule 15 mini-test1. What is a borrowed chord?273 words
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