The major key universe

Minor keys are complicated, because there are so many different minor scales. Major keys seem simpler, because there is only the one major scale. At least, that is how things worked in Western Europe between 1700 and 1900. In present-day Anglo-American pop, though, we need to expand our idea of what a major key is.

It’s very common for major-key songs to use notes and chords from outside the major scale. The most common of these is the flatted seventh scale degree and the corresponding bVII chord. These are omnipresent features of any music descended from the blues. The usual explanation is to say that rock, R&B and related styles will sometimes use Mixolydian mode rather than the major scale, which gives you that flat seventh. This is a good explanation for “Don’t Stop Til You Get Enough” and “Wanna Be Startin’ Somethin'” by Michael Jackson, which use flat rather than natural sevenths all the way through. But pure Mixolydian is not the usual sound of rock and pop. It’s very common for songs to combine major with Mixolydian. Consider “Waterfalls” by TLC.

The song is in Eb, and the chord progression is a loop of Eb, Bb, Db, Ab. The Eb and Bb chords are I and V in Eb major. The Db chord is the bVII from to Eb Mixolydian. The Ab is the IV chord in both Eb major and Eb Mixo. (The tune is full of bluesy inflections too, but let’s ignore those for now.) Should we really think of this as constant flipping between major and Mixolydian? I don’t feel a “mode shift” halfway through the loop, it all feels like one continual bluesy mood. I would rather we approach the tune as Eb major with some flat sevenths (and other blues-derived inflections) in it.

The same idea applies to “7” by Prince.

The tune is in A, and the chorus begins on an A chord. On the line “with an intellect”, the chord changes to G. On “savoir faire”, it changes back to A. On “I am yours”, the chord changes to E. On “one day”, it switches briefly back to G before landing on A on the word “die.” It’s only three chords, but if you analyze it in the standard terms, then there is no single key that they all belong to. The G chord is the bVII from A Mixolydian, while the E chord is the V chord in A major. It seems weird to think of the song as being in two different modes; I would rather approach the whole thing as A major with a variable seventh.

Finally, consider the descending riff in the Beatles’ “Let It Be.” 

All of this is from C major except for that brief Bb chord in the second bar. It’s the bVII chord in C Mixolydian. Are we really going to call this modal interchange, or are we going to say that Paul McCartney flatted the seventh of C major for one beat?

The idea of “expanded major” with a flexible seventh degree might seem unconventional, but this way of thinking would bring our concept of major keys more in line with the classical concept of minor keys. In Western European classical tradition, it is not really true that there are multiple minor scales. There’s just the minor scale, and this scale has flexible sixth and seventh degrees. Over time, European theorists gave names to the different scale variants. If the seventh was raised, they called that “harmonic minor”. If the sixth and seventh were both raised, they called it “melodic minor”. Eventually, those two scales took on lives of their own, but in European canonical works, the various minor scales are not distinct entities. JS Bach never heard the terms “harmonic” or “melodic” minor; there was just minor, with its flexible sixth and seventh scale degrees.

So here is how I would prefer that we think of major. The base scale is still the plain-vanilla major scale:

If you flatten the seventh, you get C Mixolydian mode.

But in tunes like “Waterfalls” and “7”, I would prefer we think of the parts with the flatted seventh degree as just… major with a flat seventh.

Does major have other flexible scale degrees? You could treat the fourth as flexible. If you raise the fourth degree of the C major scale from F to F-sharp, you get C Lydian mode.

Prolonged stretches of Lydian mode are rare in rock and pop, but raising the fourth temporarily is not unusual at all. Many songs use the major II chord, which includes the raised fourth. In C major, that would be a D chord. In European tradition, you would follow the II chord with the V chord, treating it as a secondary dominant. However, in rock and pop, you often move from II to IV, which my NYU theory colleagues call a “Lydian cadence”. You can hear it in the Beatles’ “Eight Days a Week”.

The song is in D, and the verses are a loop of D, E, G, D. The E chord contains G-sharp, the sharp fourth. I would rather consider this tune to be D major with a flexible fourth than to say that it includes a bar of D Lydian mode.

Melodic minor is the minor scale with both raised sixth and seventh degrees. The major-key equivalent of this idea would be a major scale with flatted sixth and seventh degrees. This is unusual, but not unheard of. 

Jazz musicians call this scale Mixolydian b6, the rare theory concept with a self-explanatory name. Wikipedia calls it the “Aeolian dominant scale“, a name I had never heard until ten seconds ago. Jazz musicians think of C Mixolydian b6 as being the fifth mode of F melodic minor. 

The highest-profile use of major with a flat sixth and seventh from my lifetime is “Single Ladies (Put A Ring On It)” by Beyoncé. It’s in E Mixolydian b6.

I would definitely rather consider this tune to be in E major with a flat sixth and seventh than to imagine that modes of melodic minor were on anyone’s mind. The same is true of the Beatles’ “Dear Prudence“, which implicitly uses D Mixo b6 for its many Gm(maj7) chords.

By the way, the internet cites other examples of Mixo b6 like “My Iron Lung” by Radiohead and “She Came In Through The Bathroom Window” by the Beatles. However, those tunes make more sense to me as mode mixture, alternating a major tonic with a minor subdominant chord. Those minor iv chords don’t feel like part of the overall major tonality, they feel like they are imported from outside. “Single Ladies” and “Dear Prudence” juxtapose major thirds with flat sixths directly, so I’m inclined to think of them as belonging to single unified “keys”.

Could you understand the blues to be the major scale with a flatted third, fifth and/or seventh? This is a common explanation, but I don’t think we should be approaching the music that way. Historically, the blues probably comes from West African melodic and tuning traditions, not from alterations of the Western European diatonic scale. The blues did hybridize with European tonality over time, but I don’t like the idea that it’s a deviation from the “baseline” of major tonality. However, there is a good reason to invoke the blues in this conversation. The blues is not a system of discrete pitches, but rather, a set of variable pitch zones. If we get used to thinking of blues-derived pop styles as having variable scale degrees, that can help open the door to understanding the off-the-grid flexibility of the blues itself.