The idea
The source course builds all of tonal harmony out of one relationship. Tonic is home, dominant is maximum tension, and the tritone inside the V7 does the pulling: B up to C, F down to E (Source course, Lesson 11). Every secondary dominant, every borrowed chord, every tritone substitution is an elaboration of that one gravitational pair.
Now take the tritone away. Most rock and most metal do not have it. There is no leading tone, no V7, and often no chord that is trying to become another chord. And the music still moves, still arrives, still ends.
So something else is holding it up. Nicole Biamonte's answer is that the flat-side triads (♭III, ♭VI, ♭VII) acquire functions of their own by position and repetition rather than by voice-leading obligation. Walter Everett's answer is that some of those same progressions are not modal at all. They disagree in print, about the same three chords, and both are right about something.
Watch
How to play all modes on the piano (https://www.youtube.com/watch?v=Vdmz18m277E)
- The parallel derivation at [29:12] and [33:07]. Dorian is ♭3 ♭7, Phrygian is ♭2 ♭3 ♭6 ♭7, Lydian is ♯4, Mixolydian is ♭7, Aeolian is ♭3 ♭6 ♭7, Locrian is ♭2 ♭3 ♭5 ♭6 ♭7, all from one root. Greg's rule against the other lens: "I want you to think of everything going from major." A mode heard as the second degree of C is a fingering fact. Heard as C with two notes flatted, it is a color.
- The shortcut at [33:07]: each mode borrows the fingering of the major scale it lives inside. C Lydian contains F sharp, so finger it as G major starting on C. Colors and Superimpositions on the Piano (https://www.youtube.com/watch?v=u6iHPlj7GM0)
- The brightness ladder at [17:43]. Over a fixed C root, moving the upper triad up the circle sharpens one more degree each step, and moving down flattens one more each step. At [21:53] the ladder closes, because F sharp and G flat are the same chord. Flat-side harmony is one direction on that ladder, held.
- At [18:43], the fix when a color turns harsh: voice the left hand 1-5-9 and leave the third out. How to Become a Well Rounded Jazz Pianist (https://www.youtube.com/watch?v=AnbQhgXegBA)
- At [12:57] the circle as functional motion, and at [14:10] and [15:08] the tritone as the engine with the ♭9 as a second tritone reinforcing it. Watch this so you know exactly what is missing from every progression in the rest of the lesson.
How to play all modes on the piano
- the parallel derivation of every mode from one root, which is the only way to hear a mode as a color rather than as a rotation
Colors and Superimpositions on the Piano
- the brightness ladder around the circle of fifths, and why bright and dark meet on the far side
How to Become a Well Rounded Jazz Pianist (in 42 minutes)
- the circle of fifths as the engine of functional motion, stated plainly, so you know exactly what modal harmony gives up
Listen
Four Tops, "Baby I Need Your Loving" (1964). Pass one: find the moment the harmony drops a whole step below the tonic and comes back through the fourth. Pass five: ask whether that ♭VII sounded like a chord going somewhere or a chord being somewhere. Everett dates the entry of ♭VII–IV–I into rock to this record, late summer 1964.
The Who, "I Can't Explain," and The Rolling Stones, "The Last Time" (both early 1965). Everett names these, plus Martha and the Vandellas' "Nowhere to Run" and the Beatles' "The Night Before," as the first three months in which the pattern spread. Pass five: decide whether the ♭VII feels like a descending sequence or a plagal color. Hold your answer, because that is the disagreement.
Heavenly, "Keepers of the Earth," from 0:49. Boddington Jordan and Herbst walk bars 9 to 17: an A Aeolian lead run, three rising secondary dominants, a perfect cadence in C, then a B flat diminished seventh at bar 12 acting as a secondary leading-tone chord into B major, which becomes B7 and delivers a long perfect cadence into a verse firmly in E minor. Pass one: hear how much common-practice apparatus is running. Power metal is the metal subgenre closest to functional tonality, and this is why.
Leviathan, "Fucking Your Ghost in Chains of Ice," from 0:42. One chord per two bars: E flat minor, C flat minor, G minor, B flat. The same authors read all four as one Weitzmann region, the three non-diatonically related chords descending by major thirds and the last acting as dominant back to E flat minor. Pass five: sing the common tones, not the roots.
Death, "Spirit Crusher," at the chorus, from m. 51. Schuldiner declines the A major dominant the chorus sets up and uses G and C power chords instead. Pass five: ask what made it an arrival, given that nothing resolved. Source weight. This reading comes from an undergraduate honours project at the University of Akron, not from peer review, and the author's name was not confirmed for this course. The observation is checkable by ear, which is why it is here. Do not cite it as scholarship.
The comparison
The exact parallel. Biamonte does to rock exactly what the source course does to Bach and Coltrane. She keeps the classical questions (what is the tonic, what is the phrase function, what is consonant here) and changes the answers. Her three objects are the double-plagal progression ♭VII–IV–I, the Aeolian progression ♭VI–♭VII–I, and triad-doubled scale systems, where each degree of a pentatonic or hexatonic collection carries a triad. All three foreground ♭III, ♭VI and ♭VII against a major or a minor tonic, and she proposes them as an expanded diatonic system for post-1960s rock. Her corpus is several hundred songs of the radio classic-rock canon, late 1960s to 1990s.
That is the source course's claim, transplanted. A chord is still a moment in a process, and the process is still bigger than the chord. Greg's version of the same thought, from the lesson: a modal shift inside a key "is technically a key change from a vocabulary perspective, but it doesn't sound like a key change. It sounds like a color change."
Where it breaks, first break. The flat-side triads have no leading tone and no cadential drive. In the source course, function is an obligation created by voice leading: F must fall to E, B must rise to C. In Biamonte, function is contextual and statistical, recovered from where a chord tends to appear. The word survives the transplant and the mechanism does not. Do not tell yourself a ♭VII "wants" to go to I. It goes there because that is what the pattern does.
Where it breaks, second break. Everett denies the premise. He reads ♭VII–IV–I as chromatic, not modal: a descending-fourths sequence parallel to a chain of applied dominants, establishing "neither scale nor tonal center." His evidence is historical, and it is precise: the pattern arrives in rock in 1964 and 1965, in a run of records he names, rather than emerging from any modal practice. Biamonte hears a double plagal cadence. Everett hears a sequence. They are describing the same three chords.
Teach this as a live fight, not as a settled fact. Brett Clement, who has his own stake in it, classifies Biamonte's approach as a parallel-scale theory and builds a relative-scale theory against it. Three peer-reviewed theorists, one chord succession, no agreement. That is the honest state of rock harmony as a field, and it is a better lesson than any of the three answers.
Where it breaks, third break. The metal you actually want to write may have no harmonic common practice at all. Boddington Jordan and Herbst coded a hundred tracks released since 2000, twenty each from power metal, black metal, metalcore, melodic death metal and progressive metal. Power metal is close to common-practice tonality, with secondary dominants and applied diminished sevenths, the relative major at 11.4 percent of all chords, and an Aeolian chromatic mediant modulation used almost exclusively by that subgenre. Black metal is the opposite pole: all twenty-four possible triads appear, ♯iii in a quarter of tracks, and the analysis needs Weitzmann regions rather than function. Progressive metal had no defining harmonic feature and was the least consistent subgenre in the study. When a progressive band is tied to a secondary subgenre, its harmony follows that subgenre's norms instead.
The conclusion for you is direct. Progressive metal's rhythmic and formal technique is systematic and teachable. Its harmony is per-band. You are not learning a common practice here, you are choosing one.
At the piano
Build the three patterns in one key and then all twelve. In A: double-plagal is G, D, A. Aeolian is F, G, A minor. Play each as complete triads, then as bare fifths, then as stacked fourths. Biamonte correlates those three voicing syntaxes with timbre and genre: complete triads for acoustic textures, power chords for distorted electric, quartal voicings where jazz has touched the style. The same three chords are three different pieces depending on which you choose.
Find the cross-relations. Take the A minor pentatonic (A, C, D, E, G) and put a major triad on every degree. That is Everett's Type 5 system, which he says is new with rock: each minor-pentatonic degree roots a major triad, the collection doubled in major thirds and fifths as well as octaves, and the five chords are not functionally related. Formula: I–♭III–IV–V–♭VII. Play it slowly and listen for the C natural in the A minor scale colliding with the C sharp in the A major triad. Biamonte calls those collisions cross-relations and connects them to Chris McDonald's "modal subversions" in grunge, which McDonald attributes to the power chord being adopted as the default sonority precisely because it is modally ambiguous.
Practice the ladder from the video. Over a held C voiced 1-5-9, run the right-hand triad down the circle: F, B flat, E flat, A flat, D flat, G flat. Improvise four bars over each. This is the fastest way to learn what "flat side" means as a sound rather than as a label.
Exercises
1. The parallel-mode grid
Do. On C, play all seven diatonic modes derived by flatting from Ionian, not by rotating a parent scale. Write the alteration list for each from memory. Then do it on F sharp.
Done when: you can play any named mode on any of the twelve roots within two seconds of being asked, and you never think of a parent key while doing it.
2. The three patterns, twelve keys
Do. Play ♭VII–IV–I and ♭VI–♭VII–I in all twelve keys, in three voicing syntaxes each (complete triads, power chords, quartal), hands together, at 60 bpm.
Done when: you can start any of the six combinations in any key without hesitation and say which syntax suits a given track.
3. The Everett test
Do. Take the three 1964 to 1965 recordings from the listening list. For each, write one paragraph arguing it is a double plagal cadence and one arguing it is a descending-fourths sequence, citing what you hear.
Done when: both paragraphs are defensible, and you can say which you believe and what would change your mind.
4. The triad-doubled pentatonic
Do. Build the major-triad-on-every-degree system on A minor pentatonic. Write an eight-bar riff that uses four of the five chords and includes at least two audible cross-relations.
Done when: you can play it at tempo and point to each cross-relation by pitch name.
5. Weitzmann by ear
Do. Transcribe the four-chord cycle at 0:42 in the Leviathan track into Sibelius. Then find the common tones between each adjacent pair and mark them.
Done when: the transcription matches E flat minor, C flat minor, G minor, B flat, and you can play the cycle holding the common tones in one hand.
6. Remove the dominant
Do. Write a sixteen-bar progression that arrives convincingly on a tonic and contains no leading tone anywhere. Then write a second version that uses the leading tone once, at the end.
Done when: a listener identifies the arrival point correctly in both versions, and you can describe the difference in one sentence.
Compose
Write a two-minute instrumental piece in a minor tonic with no leading tone in any voice at any point.
Constraints. The vocabulary is the tonic triad, ♭III, ♭VI, ♭VII and IV. Harmonic rhythm changes at least twice, and one of those changes signals a new section. No modulation. Somewhere in the middle, one chord is voiced three ways in succession (complete triad, power chord, quartal) with nothing else changing, so the listener hears voicing syntax alone doing structural work.
Write it at the piano first, then arrange for two guitars, bass and drums. Keep the piano version to compare what survives.
Checkpoint
- Play all seven modes on three different roots, derived by flatting, without reference to a parent key.
- Play both flat-side progressions in all twelve keys in all three voicing syntaxes.
- State Biamonte's reading of ♭VII–IV–I and Everett's, name the historical evidence Everett uses, and say which you find stronger.
- Play the triad-doubled A minor pentatonic system and name two cross-relations in it.
- Hand over your Leviathan transcription with common tones marked.
- Say, in one sentence, what the Boddington Jordan and Herbst corpus study means for a composer intending to write progressive metal.
Read
- Source course, Lesson 11 (/library/garnett-course.pdf). Read the tonic and dominant sections first, then read this lesson again. Its claim is that tonic and dominant polarity is the atomic unit of tonal harmony, and this lesson is what happens when a repertoire declines that unit and keeps composing anyway.
- Biamonte, "Triadic Modal and Pentatonic Patterns in Rock Music" (free PDF linked above), 95 to 110. Read for the three named patterns and the voicing-syntax argument, and skim the hexatonic rankings. Her own candour is worth noting: she says pitch-focused analysis over-weights pitch, and defends it on the grounds that the chord pattern is the most stable element across versions of a song.
- Everett, "Making Sense of Rock's Tonal Systems" (https://www.mtosmt.org/issues/mto.04.10.4/mto.04.10.4.w_everett.html). Read the Type 5 discussion and the ♭VII–IV–I passage. Note that his Table 1 is an image and his prose never names a Type 2, so any summary you find that describes Type 2 is inventing it.
- Boddington Jordan and Herbst (author PDF linked above). Read the power metal, black metal and progressive metal sections. Twenty tracks per subgenre is a small sample, and they say so.
- Clement, "Modal Tonicization in Rock" (https://doi.org/10.7290/gamutm0rf). You need only the opening framing, where he sorts modal theories into relative-scale and parallel-scale camps. The rest is L18.