hey, welcome to 12tone! y'know those four chords?
like, *those* four chords.
the ones that are supposedly in every hit song.
they sound like this: (bang) and it's true that this loop, often called the Axis Progression,
is the backbone of hundreds of hits in pop, rock, and other genres, but why?
what makes these four chords so special, and how did they come to so thoroughly dominate
the popular music landscape?
obviously, I'm far from the first person to ask this question, but four-chord loops are
an area that I've done a fair amount of work in, so I figured it was time I took a shot
at answering it.
let's talk about chords.
(tick, tick, tick, tick, tock)
this video is sponsored by CuriosityStream!
before we get started, there's one thing I have to get out of the way first.
I've been working on this video since December, but two weeks ago fellow YouTuber Patricia
Taxxon released her own video about four-chord loops, including a discussion of the Axis
Progression. this is actually the second time this has happened to me with video topics
in the last couple months: the other one I shelved for unrelated reasons, but this time
I decided to just go ahead and make the video anyway 'cause I think I still have something
worth saying.
that said, Patricia's video is really good, so I'll put a link in the description, and
once you're done here, if you still want more chord loop content, I highly recommend watching
it.
anyway, in order to understand the Axis Progression, I think we have to start with another, similar
chord loop, the Doo-Wop Changes.
(bang) this is an incredibly classic progression, and to be clear, I mean that literally.
like, these days we tend to associate it most strongly with the pop music of the 50s and
60s, but classical composers have been using it for centuries.
heck, Mozart used it, in his Piano Sonata number 8 among other places. and that shouldn't
be surprising: these are the four most important chords in G major.
in fact, if we ignore E minor for a second, these three are what's called the primary
triads because they literally define the shape of the key.
G major is built out of these three chords, and if that's not enough, they're even arranged
in the most traditionally satisfying way possible.
in classical theory, the guiding principle is that different chords in a key have different
functions, or jobs to do, and that good chord progressions use chords with the right functions
in the right order to create a compelling sense of motion, and that's exactly what the
Doo-Wop Changes do.
we start on the I chord, which has tonic function, meaning it provides a sense of rest.
it's our home base.
then we go to VI minor, which also has tonic function, introducing a new harmonic color
while extending that calm, restful sound.
after that comes the IV chord, which has subdominant function, which means its job is to introduce
instability, increasing the tension in the progression. and finally we get the V chord,
with dominant function, which is even more unstable but, more importantly, it's also
directional: it points you back to the I chord. this clear, linear rise in tension throughout
the progression leads to an incredibly satisfying resolution when we return to the tonic, and
the whole loop is built to maximize that sense of release.
all of the weight of these four chords lands heavily on the first one.
but when it comes to loops, that's not necessarily great.
modern chord loops aren't really trying to have one big resolution: they're more designed
to create a musical atmosphere, with relatively constant motion.
releasing all the tension at once gives you an awkward pause, a moment where everything
seems to stop, interrupting our smooth harmonic flow with a single dramatic event.
that's why, as the chord loop rose in prominence, we saw a decline in the use of the Doo-Wop
Changes.
they never went away completely: heck, Taylor Swift used them in her 2019 single Me, so
clearly they're not entirely obsolete, but these days they tend to feel a little old-fashioned,
because most of the other loops we hear are structured pretty differently.
still, like I said, these are the four most important chords in any major key, so it'd
be great if we could find a way to use them that was a bit more in line with modern loop
practice, and fortunately the fix is pretty simple: we just take this V chord and drop
it over here instead.
(bang) this does three things: first, it pushes the VI minor into the third position.
after the first chord, the third is the most strongest metric point in the loop, so which
chord we put there matters a lot.
in the Doo-Wop Changes, it was the IV chord, a subdominant sound, creating instability
that wanted to work its way back to the stable tonic, but now we've got the VI there instead,
which is itself a tonic function chord. we're effectively see-sawing back and forth between
our primary tonic, G, and our secondary tonic, E minor, with both points feeling relatively
stable.
but it's more than that: we're also now resolving to the VI chord.
again, the V chord is a directional sound that wants to go back to the tonic.
usually this means going to I, but VI minor is also a tonic function chord, so we can
resolve there too.
this is called a deceptive resolution, because it's kinda like a V-I but with a bit of a
fake-out.
it's not quite as strong as the V-I resolution, but in the Doo-Wop Changes we were approaching
this chord by 3rd, which isn't a resolution at all, so this is still a significant upgrade.
and lastly, we've weakened the resolution to the I chord: instead of ending on a V-I
resolution, nicknamed an authentic cadence because of how strong it sounds, we end on
a plagal cadence, or IV-I resolution.
this is a much more characteristic sound in rock and pop: going from IV to I still feels
like an arrival, but it doesn't have the same sense of finality to it, so it doesn't interrupt
the harmonic flow.
taken together, these three changes result in a secondary tonic that's much closer in
prominence to the primary tonic, taking some of the weight off the shoulders of the I chord
and allowing for more consistent motion throughout the loop.
now instead of spending all our time setting up a big resolution to I, we're alternating
between two smaller resolutions, each of which feels comfortable but neither of which feels
complete.
and that has profound implications for how the loop is used.
like, the Doo-Wop Changes almost always starts at the beginning: we have a tendency to hear
the first chord in a section as the I chord, and since the loop is so clearly telling us
which chord that is, it feels strange to find it anywhere else.
if I start playing it on VI minor: (bang) and let that loop for a little while, it pretty
quickly shifts to sounding like it starts on the G chord anyway.
the E minor just isn't stable enough, so without any other metric cues your ear just makes
the adjustment to the thing it assumes is supposed to be happening.
ok, I'm gonna stop it now.
but if I do the same thing with the Axis Progression, starting on VI minor (bang) and letting it
run, something different happens.
your ears just sort of accept E minor as the real I chord and start reading everything
else in that key.
instead of being VI, IV, I, V, it's I, bVI, bIII, bVII. both modes are stable.
this means the we're actually sort of dealing with two different progressions at the same
time, which I'll call the major axis and the minor axis, and the power of this loop comes
in no small part from its ability to play with the boundaries between these different
tonalities.
the reason this works so well, though, is because of the interaction of a couple different
biases we tend to have when listening to chord loops.
the first one is something we've already mentioned: first chord bias.
that is, we tend to assume that the first chord we hear is the I chord. it's the most
metrically significant position, so naturally it's where the most harmonically important
chord belongs.
next up is major scale bias: Western popular music has historically been mostly written
in major, so when we hear a new song, we tend to hear it as major until we find a good reason
not to.
this is amplified by primary chord bias, where we assume the chords we're hearing are important
ones in the key: as we said, three of the four chords in the Axis Progression are the
three primary triads the major scale is built out of, whereas in minor they're mostly just
some chords. this makes it a much stronger tonal progression in major, even if the order
of the chords makes it not quite as strong as the Doo-Wop Changes.
but functional tonality isn't the only way to think about harmony.
regular viewers of the channel may remember that last year I published some of my own
scholarship on the harmony of four-chord loops, using a pretty different approach.
I'll put a link to the video in the description, but the short version is this: instead of
considering how each chord fits within a larger key, we just look at how each chord fits with
the ones on either side.
to keep things simple, I decided to break these relationships up into two categories:
set-ups, where the motion from one chord to the next is strong, and not set-ups, where
the motion is weak.
I defined strong harmonic motion as moving either by perfect 5th, like the authentic
(bang) or plagal cadence, (bang) or by step, like the deceptive cadence, (bang) and weak
motion is anything else.
looking at where the set-ups are in a loop helps you determine how the harmonic weight
is distributed, which gives you a better sense of how it wants to behave.
in that video, I laid out four possible chord functions, but for our purposes I only care
about two: the signpost, which doesn't get set up but does set up the next chord, and
the destination, which is the opposite, getting set up and then not setting anything else
up after.
effectively, the signpost starts a chain of resolutions that ends up at a destination.
most loops have one of each: in the Doo-Wop Changes, the signpost is the IV chord, which
passes through the V before resolving to I, our final destination.
because the signpost and destination are opposite each other, the Doo-Wop Changes are what I
call a piston loop, with a steady rise and fall to its harmonic motion.
the Axis Progression, on the other hand, is a Cascade Loop, which means the signpost is
right after the destination, making the chain of resolutions as long as possible.
the whole loop feels like it's falling down toward a single point, and despite what you
might assume if you're used to the major axis, that final destination is actually the minor
tonic. it's the only chord that doesn't set up the next one, instead approaching it by
major 3rd, and since its our only destination, we're inclined to hear it as the I chord.
now, on something like the Doo-Wop Changes, all these biases align: major scale bias and
destination bias both point us to the same place, and first chord bias just tags along,
giving us only one real form for the loop. but on the Axis Progression, major scale bias
and destination bias disagree, leaving first chord bias to serve as a tiebreaker.
we can put either one in the strongest metric position, and whichever one we do is probably
going to sound like the I chord.
in fact, because of that flexibility, we can actually play around even more: around the
mid-2000s, we started to see the rise of a third form of the axis progression, beginning
on the IV. (bang) that said, I'd argue that, harmonically speaking, this form is unstable.
if I loop it for a while: (bang) it pretty quickly collapses to one of our main axes,
at least to my ears.
I don't really hear that C as the I chord. if we sprinkle in some extra metric and melodic
cues, though, it can totally work: the classic example is Umbrella, by Rihanna: (bang) but
listening to that makes it clear to me that this isn't really an entirely new axis: Gb
may be the first chord, but it doesn't really feel like the I chord.
the melody and the harmony both seem to settle on Bb as the root, and that makes sense: it's
our destination, one of the two possible tonics, and while it's not the first chord, it's still
in a stronger metric position than Db, the other tonic option, so it wins.
somewhat surprisingly, though, we almost never see the other variant form, starting on the
V chord.
(bang) in his paper on the Axis Progression, Dr. Mark Richards only identified a handful
of examples of this, most notably Wannabe by the Spice Girls: (bang) which is actually
really interesting, 'cause the melody seems to emphasize neither tonic, instead settling
on D#, a note that's equally relevant in both chords. in theory, this should behave just
like the other variant, with the final chord, in this case B, becoming the primary tonic
due to its stronger metric position, and if we look at the other sections of the song
that does appear to be what's happening, but that weird, floating melody may actually help
explain why this version is so rare: if I had to guess, I'd say that destination bias
is probably a bit stronger than major scale bias, so burying the destination in the weakest
metric position makes it hard to stabilize anywhere.
without a strong first chord to lean on, the progression winds up floating in the space
between the two tonics 'cause it can't quite justify either one.
but while it's strongest in this form, that ambiguity is present in pretty much every
instance of the Axis Progression.
the major axis always has a shade of minor and vice versa, which is part of what makes
this loop so much more complex than the Doo-Wop Changes.
you can use external cues like the melody and other song sections to try to figure out
which axis you're using, but more often than not, you're kinda using both at once, which
isn't something we see much of in traditional harmony, but it's a really common thing in
chord loops.
overall, I think the Axis Progression is a great introduction to loop theory: it's familiar
enough that most musicians can start to explain it, but with enough open questions that they
can't explain it completely without learning some new tools along the way.
really understanding the Axis Progression requires understanding not just functional
harmony, but also harmonic weight, metric positioning, tonal flexibility, and a whole
lot more.
it's a perfect encapsulation of so many modern ideas about chords, all wrapped up in a really
simple-looking package, and while some folks might say it's overused, I think it's worth
recognizing just how many different ways there are to use it.
it's actually kinda funny that I got to reference the Spice Girls in this, 'cause my friend
Alex recently learned about them for the first time.
he even documented the experience in a video over on Nebula.
y'see, Alex is 19, and whenever he hangs out with the rest of the Nebula crowd we wind
up grilling him on pop culture stuff we all grew up with and he's never heard of, so eventually
we decided to turn that into a series.
it's called Alex Goes Bananas, and every episode a different creator challenges him to learn
about and explain a band, movie, or other piece of pop culture from the 90s.
I made him listen to Rob Zombie, and he's also covered Limp Bizkit, Moulin Rouge, and,
at the request of Vanessa from Braincraft, he even learned about the Spice Girls.
it's a really fun series, whether you know these bands yourself or you're just learning
along with him. and that's just the tip of the iceberg: Nebula is a streaming service
built by some of YouTube's top educators, including Adam Neely, Lindsay Ellis, Legal
Eagle, and for some reason me, and there's all sorts of great original videos exclusively
available on Nebula. and it gets even better: we've worked out a deal where, if you sign
up for CuriosityStream with the link in the description, not only will you get over 40%
off their annual plan, you'll also get a Nebula account for as long as you remain a CuriosityStream
member.
I honestly can't believe they agreed to this: for less than 12 bucks a year, you'll get
access not just to Nebula, but also CuriosityStream's entire library, including personal favorites
like Can A Computer Write A Hit Musical?, which…
I mean, I think the title does a good job telling you what that's about, but still,
it's really fun.
again, link in the description, 12 bucks for the entire year.
and hey, thanks for watching, thanks to our Patreon patrons for making these videos possible,
and extra special thanks to this video's Featured Patrons, Susan Jones and Jill Sundgaard.
if you want to help out, and help us pick the next song we analyze too, there's a link
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