# AI Wiki - Music - Modal Harmony ## Overview [[AI Wiki - Music - Modes]] are usually taught as scales. **Modal harmony** is the chord side: progressions and vamps that make a mode's tonic feel like home, using the mode's own chords. A rock song that loops D – C – G, a funk groove on Am7 – D9, a film cue on C – D: none of them is in plain major or minor, and none of them uses a V – I with a leading tone. Open Music Theory calls these short patterns **modal schemas** and groups the modes by the quality of their tonic chord: - **Major-tonic modes**: Ionian (major), **Mixolydian** (♭7), **Lydian** (♯4). - **Minor-tonic modes**: Aeolian ([[AI Wiki - Music - Minor Scales|natural minor]], ♭6), **Dorian** (♮6), Phrygian (♭2). Each mode differs from plain major or minor by one **colour note**, and the chords that contain that note are the ones that make the mode audible. A modal schema can appear for a few bars inside a major-key song (then it's [[AI Wiki - Music - Borrowed Chords and Modal Interchange|borrowing]]) or run through a whole song (then the song is modal). ## How modal progressions relate to the diatonic sets A mode uses exactly the same seven chords as its parent major key. What changes is which chord is home. With G major's chords (G, Am, Bm, C, D, Em, F♯°), all open on guitar except F♯°: | Home chord | Mode | The same chords, numbered from the new home | Hallmark progression | |---|---|---|---| | G | G Ionian (major) | I ii iii IV V vi vii° | I – IV – V | | Am | A Dorian | i ii ♭III IV v vi° ♭VII | i – IV (Am – D) | | Bm | B Phrygian | i ♭II ♭III iv v° ♭VI ♭vii | i – ♭II (Bm – C) | | C | C Lydian | I II iii ♯iv° V vi vii | I – II (C – D) | | D | D Mixolydian | I ii iii° IV v vi ♭VII | I – ♭VII – IV (D – C – G) | | Em | E Aeolian (minor) | i ii° ♭III iv v ♭VI ♭VII | i – ♭VI – ♭VII (Em – C – D) | So **Dorian i – IV is the parent key's ii – V**, heard with ii as home (Am – D in G major), and **Mixolydian I – ♭VII is the parent key's V – IV** (D – C in G major). The chords are diatonic to the parent key; the progressions avoid the parent's tonic or treat it as just another chord, and they stay on the modal tonic long enough, on strong beats, for it to become home. Open Music Theory makes the same point about Dorian: listeners may hear the Dorian shuttle as ii – V, but it suggests hearing the first chord as i. Roman numerals in modal music are therefore written from the modal tonic (Am = i, D = IV), not from the parent key. See [[AI Wiki - Music - Diatonic Chords and Roman Numerals]] for the diatonic sets. The mode-defining chord is always the one that contains the colour note: the major IV in Dorian (it holds the ♮6), ♭VII in Mixolydian (♭7), II in Lydian (♯4), ♭II in Phrygian (♭2), ♭VI in Aeolian (♭6). ## The modal schemas From Open Music Theory, with its song examples: **Mixolydian (major tonic, ♭7)** - **Subtonic shuttle I – ♭VII**: the Kinks' "Tired of Waiting for You" (intro and verses). - **I – ♭VII – IV** (D – C – G, A – G – D, E – D – A): classic rock. - **Double plagal ♭VII – IV – I**: two plagal (fourth-up) moves in a row; Open Music Theory notes that an "applied" IV of IV creates it. Its most famous instance is the "Hey Jude" coda. Ethan Hein adds "Fortunate Son" and calls double plagal motion a natural partner of Mixolydian. **Aeolian (minor tonic, ♭6 and ♭7)** - **Subtonic shuttle i – ♭VII**: Gotye's "Somebody That I Used to Know" (verses). - **Aeolian shuttle i – ♭VII – ♭VI – ♭VII**: the same song's choruses. - **Aeolian cadence ♭VI – ♭VII – i (or I)**: goal-directed and heroic (the Lord of the Rings Fellowship theme, the "Mario cadence"). - **i – ♭VII – ♭VI**: "All Along the Watchtower" (see [[AI Wiki - Music - Modes]]). **Dorian (minor tonic, ♮6)** - **Dorian shuttle i – IV** (Am – D, Em – A, often as i7 – IV7 or i7 – IV9): Open Music Theory ties it to funk and disco, citing CHIC's "Dance, Dance, Dance" and, more ambiguously, Daft Punk's "Get Lucky". Santana's "Oye Como Va" (Am7 – D9) is the Latin-rock classic. **Lydian (major tonic, ♯4)** - **Lydian shuttle I – II**: Fleetwood Mac's "Sara" opens with it. - **Lydian cadence II – IV – I**. Lydian is rare in [[AI Wiki - Music - Pop Music|pop]]; Open Music Theory warns that two major chords a step apart are more often IV – V of another key. **Phrygian (minor tonic, ♭2)**: i – ♭II (Em – F) in metal and flamenco-flavoured music ([[AI Wiki - Music - Metal Music]]). The core vamps on guitar, all with [[AI Wiki - Music - Guitar Open Chords|open chords]]: ```chords {title: Modal vamps with open chords} {time: 4/4} {comment: A Dorian: i – IV} | [Am] . . . | [D] . . . | [Am] . . . | [D] . . . | {comment: D Mixolydian: I – ♭VII – IV – I} | [D] . . . | [C] . . . | [G] . . . | [D] . . . | {comment: E Aeolian: i – ♭VI – ♭VII – i} | [Em] . . . | [C] . . . | [D] . . . | [Em] . . . | {comment: D Lydian: I – II} | [D] . . . | [E] . . . | [D] . . . | [E] . . . | {comment: E Phrygian: i – ♭II} | [Em] . . . | [F] . . . | [Em] . . . | [F] . . . | ``` The D Mixolydian scale, with its ♭7 (C) outlined against D major: ```fretboard D mixolydian compare: major frets: 0-5 labels: intervals ``` ## Cadences without a leading tone In major and harmonic minor, the strongest ending is V – I, driven by the leading tone a half step below the tonic ([[AI Wiki - Music - Cadences]]). Dorian, Mixolydian and Aeolian have a ♭7 a whole step below the tonic instead, so their V is minor (v) and their chord on 7 is a major ♭VII. Modal music ends phrases in other ways: | Cadence | Example | Mode | How it closes | |---|---|---|---| | ♭VII – I | C – D in D | Mixolydian | whole step up in the bass; ♭VII takes the dominant's role | | ♭VII – IV – I | C – G – D in D | Mixolydian | double plagal: two fourth-up moves | | IV – I | G – D in D | any major-tonic mode | plagal, the "Amen" | | ♭VI – ♭VII – i (or I) | C – D – Em (or E) | Aeolian | stepwise rise into the tonic | | v – i | Bm – Em in E minor | Aeolian, Dorian | soft, folk-like | | IV – i | D – Am in A Dorian | Dorian | the vamp's own motion | | ♭II – i | F – Em in E Phrygian | Phrygian | a half step from above replaces the leading tone from below | | II – I | E – D in D Lydian | Lydian | whole step down | Open Music Theory notes that ♭VII "typically has dominant function" and substitutes for V in Mixolydian. Everett is more sceptical: in modal songs, "especially when the leading tone is absent, there is often no harmonic pull to the tonic". Both observations point to the same practical truth: **without a leading tone, the tonic is established by everything else**: - **Repetition and position**: the home chord starts the loop, falls on the downbeat, and usually lasts longest. - **The bass**: a tonic pedal or a riff that keeps returning to the tonic note. - **The melody**: phrases that end on the tonic note, and the colour note sung prominently. - **Endings**: the final chord of a section or of the song. That is also why modal tonics can be ambiguous, as the next section shows. Many rock songs also mix systems: a Mixolydian verse with a proper V – I chorus, or an E7 that turns into a V7 – I at the end. Modal and functional harmony aren't exclusive. ## "Sweet Home Alabama": D Mixolydian or G major? Lynyrd Skynyrd's "Sweet Home Alabama" (1974) loops three chords, D – C(add9) – G, almost all the way through. They're the I, ♭VII and IV of D, or the V, IV and I of G. Both readings use the same notes (G major's scale = D Mixolydian), so the debate is only about **which chord is home**. **The case for D Mixolydian (I – ♭VII – IV)**: - D starts every cycle, on the downbeat, and the riff is built around it. - Hooktheory's crowd-sourced analysis labels every section D Mixolydian (I, ♭VII(add9), IV). - Guitarists hear the pull to D: Fretjam's analysis says "there's a strong D Mixolydian tonality to this progression that is difficult to ignore" and that D "functions as the I chord of its own mode, not as a V chord of G". - The ♭VII – IV – I motion back to D is the double-plagal schema Open Music Theory lists under Mixolydian. **The case for G major (V – IV – I)**: - Published [[AI Wiki - Music - Reading Standard Notation|sheet music]] and piano arrangements are commonly notated in G (one sharp), and a reader then sees 5 – 4 – 1. - G – C – D are the I, IV and V of a three-chord song; a band that thinks "G" has the simplest analysis. - The studio recording fades out instead of ending on a final cadence, so there's no last chord to settle it. **What theory says**: the question is a case of what theorists call ambiguous or "fragile" tonics in rock. Loops of three major chords a step and a fourth apart don't contain a leading tone or a V7 to define a key, so the tonic depends on metre, the riff, the melody and the listener's habits. Ethan Hein raises exactly this question about the song ("It's in D… But wait, is it really in D?"). Everett's warning that ♭VII is not automatically modal applies too: hearing the loop as V – IV – I in G is not a wrong analysis, just a different hearing. **The practical answer**: when playing or improvising, treat D as home. Fretjam's soloing advice centres on D (D major [[AI Wiki - Music - Pentatonic Scale|pentatonic]], D Mixolydian, D minor pentatonic with [[AI Wiki - Music - Blues Music|blues]] notes) and notes that G minor pentatonic "doesn't sound quite right". When reading or writing the score, G's [[AI Wiki - Music - Keys and Key Signatures|key signature]] is fine: it's the same set of notes. The analyses found for this article (Hooktheory, Fretjam, guitar forums) mostly lean towards D Mixolydian; no peer-reviewed analysis of this song was found. ```chord D xx0232 xx0132 --- Cadd9 x32033 x21034 --- G 320033 210034 ``` ## Modal vamps in genres - **Rock**: Mixolydian I – ♭VII – IV and double plagal in E, A and D ([[AI Wiki - Music - Rock Music]]); Aeolian i – ♭VI – ♭VII in minor-key rock and metal. - **Funk**: one-chord vamps, often on a dominant 9th or a minor 7th, where rhythm carries the music. Wikipedia notes that funk pieces are often built on a single-chord vamp "since rhythm and groove are the key elements of the style", and cites "Play That Funky Music" with an extended dominant as its tonic. Two-chord Dorian vamps (Am7 – D9) are the other staple ([[AI Wiki - Music - Funk Music]], [[AI Wiki - Music - Extended Chords]]). - **Reggae**: short loops of two or three chords, often minor: i – iv, i – ♭VII, and major I – IV or I – IV – V ([[AI Wiki - Music - Reggae Music]], [[AI Wiki - Music - Riddims]]). The Dorian i – IV appears too, but plain minor and major loops are more typical than in funk. - **Folk and Celtic**: Dorian and Mixolydian tunes in A, D, E and G; drones and modal accompaniment instead of V – I ([[AI Wiki - Music - Folk Music]]). - **Jazz**: modal jazz (Miles Davis's "So What") holds one Dorian chord for many bars ([[AI Wiki - Music - Jazz Music]]). ## How to practise 1. **Same chords, new home**: with G, Am, C, D and Em, play a vamp on each: G – C (Ionian), Am – D (Dorian), D – C (Mixolydian), Em – C – D (Aeolian), C – D (Lydian). Feel how the home changes while the chords don't. 2. **Sing the tonic** over each vamp, then the colour note (F♯ over Am – D, C over D – C). 3. **End phrases modally**: write four-bar phrases ending ♭VII – I, then ♭VI – ♭VII – i, then IV – I; compare with V – I. 4. **Improvise over a vamp** with [[AI Wiki - Music - Playing with Backing Tracks|a backing track]], starting from the pentatonic box you know and adding the colour note ([[AI Wiki - Music - Guitar Improvisation]]). 5. **Analyse a rock song**: find the chord on the downbeat of each loop, the bass note at section ends and the melody's last note; decide the home before naming the mode. ## Common mistakes - **Naming the mode from the scale, not the home.** G major's notes over a D – C – G loop are D Mixolydian if D is home; the same notes over G – C – D are G major. - **Hearing a modal i – IV as ii – V.** In Dorian, Am is home; the D doesn't "want" to go to G. - **Calling any ♭VII "Mixolydian".** One ♭VII in a major song is borrowing; a whole song that orbits the tonic with ♭VII is Mixolydian. - **Adding V7 – I to a modal vamp.** A dominant seventh with its leading tone pulls the music back into major or minor and erases the mode's colour. - **Expecting strong endings.** Modal loops often don't resolve; that open, circular feel is the point. ## Key Points - Modal harmony uses a mode's chords with the modal tonic as home; the chords are the parent key's diatonic set, numbered from the new tonic. - Dorian i – IV = the parent key's ii – V heard from ii; Mixolydian I – ♭VII = the parent's V – IV heard from V. - The colour-note chord defines the mode: IV in Dorian, ♭VII in Mixolydian, II in Lydian, ♭II in Phrygian, ♭VI in Aeolian. - Modal cadences replace V – I with ♭VII – I, ♭VII – IV – I, ♭VI – ♭VII – i, IV – I, v – i or ♭II – i; repetition, metre, bass and melody establish the tonic. - "Sweet Home Alabama" is D – C – G: D Mixolydian if D is home (the more common reading), G major V – IV – I if G is; the notes are identical and the debate is about the tonic. - Funk favours one-chord and Dorian vamps, reggae short major or minor loops, rock Mixolydian and Aeolian progressions. ## Open Questions - Which of the songs Sébastien is learning are modal, and in which mode? - How do Phrygian dominant and the modes of harmonic minor work as harmony (not only as scales)? See [[AI Wiki - Music - Modes of Melodic and Harmonic Minor]]. ## References - Gotham et al., *Open Music Theory* 2e, "Modal Schemas": https://human.libretexts.org/Bookshelves/Music/Music_Theory/Open_Music_Theory_2e_(Gotham_et_al.)/07%3A_Popular_Music/7.12%3A_Modal_Schemas - Gotham et al., *Open Music Theory* 2e, "Blues-Based Schemas": https://human.libretexts.org/Bookshelves/Music/Music_Theory/Open_Music_Theory_2e_(Gotham_et_al.)/07%3A_Popular_Music/7.08%3A_Blues-Based_Schemas - Walter Everett, "Making Sense of Rock's Tonal Systems", *Music Theory Online* 10.4 (2004): https://mtosmt.org/issues/mto.04.10.4/mto.04.10.4.w_everett.html - Hooktheory TheoryTab, "Sweet Home Alabama" by Lynyrd Skynyrd: https://hooktheory.com/theorytab/view/lynyrd-skynyrd/sweet-home-alabama - Fretjam, "Scales for soloing over Sweet Home Alabama": https://fretjam.com/scales-for-soloing-over-sweet-home-alabama.html - Ethan Hein, "Identifying plagal cadences": https://www.ethanhein.com/wp/2024/identifying-plagal-cadences/ - Wikipedia, "Extended chord" (funk one-chord vamps): https://en.wikipedia.org/wiki/Extended_chord ## Related - [[AI Wiki - Music - Modes]] - [[AI Wiki - Music - Diatonic Chords and Roman Numerals]] - [[AI Wiki - Music - Borrowed Chords and Modal Interchange]] - [[AI Wiki - Music - Cadences]] - [[AI Wiki - Music - Common Chord Progressions]] - [[AI Wiki - Music - Secondary Dominants]] - [[AI Wiki - Music - Extended Chords]] - [[AI Wiki - Music - Rock Music]] - [[AI Wiki - Music - Funk Music]] - [[AI Wiki - Music - Reggae Music]] - [[AI Wiki - Music - Folk Music]] - [[AI Wiki - Music - Jazz Music]] - [[AI Wiki - Music - Finding the Key of a Song]] - [[AI Wiki - Music - Guitar Improvisation]]