This week in aural skills, we’re working on various harmonic tropes based on IV-I root movements. This chord progression is technically called the plagal cadence, but is more memorably nicknamed the “Amen” cadence because it’s a traditional European hymn ending. (It has nothing to do with the Amen break, though they do sound good together.) The plagal cadence is the mirror image of the classical V-I authentic cadence.
Where does the word “plagal” come from? The Online Etymology Dictionary says that it’s probably from Greek plagios, meaning “oblique” or “side”, and that word in turn comes from the Proto-Indo-European root *plak-, “to be flat”. This root also gives us flag (a flat stone for paving), flake, and plank. Plagal probably shares an etymology with “flatness” because the important voice-leading element is scale degree four resolving down to three. While we’re talking about word origins, amen comes from a Hebrew word meaning “truth,” in this context meaning “an adverbial expression of agreement.”
Plagal cadences
Let’s start with plain, simple IV to I, the harmonic backbone of Anglo-American popular music. In C, it’s F to C. The blues version is F7 to C7.
“Everyday People” by Sly and the Family Stone (1969) is in G, and it’s a loop of G and C.
John Lee Hooker’s version of “Ezekiel Saw The Wheel” (1951) is in Db, and it alternates Db and Gb throughout.
Ray Charles’ arrangement of “You Are My Sunshine” (1962) is in F, and it spends most of the tune alternating F7 and Bb7.
The added flat sevenths make the voice leading possibilities of I7 – IV7 full of rich and intriguing dissonances. In C7, there is a tritone between E and B-flat. In F7, there’s a tritone between E-flat and A. The tritone moves a half step between the two chords. Also, E-flat, the flat seventh of F7, is the flat third of C7, and the rub between E-flat and E-natural is essential to the sound of the blues. You can see and hear the voice leading of C7 and F7 here – the thirds are green and the flat sevenths are blue.
Double plagal cadences
What if you treat the IV chord in a IV – I progression as the temporary tonic, and precede it with its own IV chord? That gives you a double plagal cadence, IV/IV to IV to I, or bVII to IV to I. In C, that’s Bb to F to C. In the blues, you’d play it Bb to F7 to C7 or Bb7 to F7 to C7. The term “double plagal cadence” might be alien to rock listeners, but the sound is one of the most familiar things out there.
The Beatles love a good double plagal cadence. Pop theory references always point to the end of “Hey Jude” (1968). It’s in F, and the chords are F, Eb and Bb.
You can also find double plagal cadences in “She Said She Said”, “Lovely Rita”, “Dear Prudence”, “Get Back”, “You Never Give Me Your Money”, “Polythene Pam” and probably many other tunes of theirs.
Beyond the Beatles, you can hear double plagal in “The Fortunate Son” by Creedence Clearwater Revival (1969). It’s in G, and the verses are a loop of G, F and C. (The choruses are a little different.)
At this point, I am obligated by convention to bring up “Sweet Home Alabama” by Lynyrd Skynyrd (1974). It’s in D, and the chords are D, C and G. But wait, is it really in D?
The Grateful Dead also love double plagal cadences, because they pair so well with Mixolydian mode. (My son’s piano teacher calls Mixolydian “the hippie scale”.) You can hear double plagal in “St Stephen“, “I Know You Rider“, “Morning Dew“, “Scarlet Begonias”, “Sugar Magnolia”, “Playing in the Band”… it would probably be shorter to list Dead tunes that don’t use double plagal.
Triple plagal cadences
The bIII to bVII to IV to I progression has a nice bluesy sound. In C, it’s Eb to Bb to F to C. I guess you could do the whole sequence as dominant seventh chords, but I don’t know of any examples.
The choruses of “Jumpin’ Jack Flash” by the Rolling Stones (1968) are triple plagal cadences. The tune is in B, and the chorus (“But it’s allllll right now”) goes D to A to E to B.
“People in the Front Row” by Melanie Safka (1972) is in G. It’s a rotation of the triple plagal cadence, a loop of G, Bb, F, and C.
Quadruple plagal cadences
The longest plagal chain in common usage is the epic sequence of bVI to bIII to bVI to IV to I. In C, that’s Ab to Eb to Bb to F to C. I haven’t heard anyone do this all with dominant sevenths, but I guess you could.
The usual reference here is “Hey Joe“, best known from Jimi Hendrix’s recording (1967). It’s in E, and after the intro, it’s a continual loop of C, G, D, A and E7.
You can also hear a quadruple plagal cadence in “Take Me To The River” by Al Green (1974). Listen to the prechorus going into the chorus at 0:45. The tune is in E, and the prechorus goes C, G, D, A, landing on E7#9 in the chorus. The verses are full of double plagal cadences too, D to A to E. (Yes, Talking Heads fans, I love that version too, but it leaves out some chords.)
“The Time Warp” from The Rocky Horror Picture Show (1975) is in A, and the chords in the chorus (“Let’s do the time warp again”) are F, C, G, D and A.
See the voice leading of single, double, triple and quadruple plagal cadences. And here’s a song I made to help you hear them, which I put over the Amen break.
Could you do quintuple plagal cadences? Or more? Maybe someone has, but I’ve never heard such a thing. I tried writing a series of plagal cadences that goes all the way around the circle of fifths, and it gets boring fast. All of these progressions work because they are temporary departures from the tonic, and they only become meaningful when you return home again.
The plagal sigh
The plagal cadence has a variant: rather than IV – I, you go IV – iv – I. In C, that’s F to Fm to C. NYU’s theory syllabus calls this the “plagal sigh” because of the 6^ – b6^ – 5^ voice leading (A to A-flat to G in the key of C). I have also seen this progression called the combination major/minor plagal cadence, or less formally, the Beatles cadence. You can hear it during the verses of “In My Life” (1965). The song is in A, and on the line “all my li-i-i-ife”, the chords go D to Dm to A.
John Lennon also deploys it in “If I Fell” (1964), going into the bridge. The song is in D. On the line “but I couldn’t stand the pain”, the word “pain” lands on the G chord. In the next line, “and I would be sad”, the word “I” is on Gm. Finally, in the line “if our new love was in vain”, the word “love” is on D.
You could consider the main groove in “Dear Prudence” (1968) to be a plagal sigh: D to D7 to G to Gm. John may have gotten the idea from the “blues lament bass” that you hear in every Robert Johnson song.
The usual reference for the plagal sigh in rock is “Creep” by Radiohead (1993). It’s in G, and it’s an endless loop of G to B7 to C to Cm. I do not love this song.
When I asked my Twitter friends to recommend me some good hymns, ÜberManqué recommended “Doxology” as performed by The Roberta Martin Singers (1968). It’s in Eb, and it seems like it’s going to end with a classic plagal Amen, Ab to Eb, but they sing an exquisite Abm6 before resolving. This song, I love.
The plagal sigh is a doorway into the vast universe of mode mixture. You could think of the minor iv chord as a borrowing from the parallel minor key. But that is beyond the scope of this unit; we’ll get to it later in the semester.
Excellent stuff! I’d add that Jumping Jack Flash is actually in the minor key, and uses borrowed chords (tonic and IV) from the parallel major. The same phenomenon happens in Hey Joe (E and A from parallel major, and C, D, G are from parallel minor), Summer Breeze (Seals and Crofts), Crazy (Seal), Old Man (Neil Young), Pictures Of Matchstick Men (Status Quo), Geno (Dexy’s Midnight Runners), Don’t Bring Me Down (ELO), Fly Away (Lenny Kravits), and the middle section of A Day In The Life (Beatles)
The question of whether a Rolling Stones song is “really” in major or minor seems a bit beside the point, since the Stones are coming out of the blues world where the distinction is a meaningless one anyway. It only makes a practical difference if you need to choose a key signature, and who is even notating Stones songs to begin with? I prefer to think of major and minor in a song like this as being like blue and yellow; you can have a bluer green or a yellower green, but either way, the “real” color is green.
I guess it would be better in this analogy if the “real” color was blue but then blue is a primary color so it doesn’t work.
I would call them hybrid/parallel keys, or just modal mixture, as having a consistent tonic note can allow a lot of freedom with non-diatonic chord choices without modulating. Since all the root notes of the chords in those songs belong from the minor scale, and only a few chords have their minor/major qualities swapped or borrowed from the parallel major, the more elegant way to think of it is parallel mixing. This is very common in rock and pop and as well even without plagal cadences (any minor song with a borrowed major tonic uses additional borrowed chords for “flavor”)