How to understand 20th-century pop music as evolution of classical harmony

Question

With sufficient training, a student of harmony may build forwards from Bach through Mozart, Beethoven, Chopin, etc... understanding music of a period in terms of what has gone before.

But it's going to be harder to start with a modern song. How to bridge the gap?

Just as an example, I'm looking at Bruce Hornsby's Way It Is, which uses the chord progression ii vi V IV I V IV, which doesn't fit into any pattern I am familiar with. But I suppose someone with enough understanding would be able to find maybe half a dozen stepping stones that bridge the gap.

I'm interested in popular music circa 1950, how can I educate myself so that I can really get a feel for the construction of these songs?

My guess is that opera gave rise to operetta (e.g. Gilbert and Sullivan) and popular songs came from this angle (e.g. Gershwin).

Clearly that is a huge question, probably unsuitable for this forum.

So my question is: how to go about educating myself? What resources are available?

Answer 1

As topo morto already commented, it doesn't really make sense to consider pop as just an evolution of classical music. It has lots of influences from folk, blues, jazz that don't really make sense from a classical-harmony perspective. To a large degree, you might also just sum pop up as “relax, focus on keeping the melody simple&catchy and then harmonise it with whichever chords feel natural”.

In particular, you might as well just forget the need of resolving dominants, directly or via “stepping stones”, into their tonic. The reason this is so important in classical music is mostly that you don't consider chords as entities on their own right, more as “snapshots” of a bundle of voices. And in a dominant you have certain leading notes that “must” lead to some target.
But in pop, you can't really find consistent single voices in the chord sequences – rather, you just have a main voice (usually vocals), sitting on top of accompaniment chords which are considered as entities. But leading tones need to happen in the main melody to really have an effect. And in particular the vii-i leading does just as well fit over a proper V-I cadence, as over a V-IV.

However, the vii note in particular is rather seldom used in pop, perhaps to avoid evoking to much leading character in the first place.

In the example, the subdominant is used twice as just “I feel to cool to go to the tonic right away”. In the middle, the IV is then followed by the actual tonic (you may consider this an additional plagal cadence), but in the end it's just left standing there and the theme repeats with its relative minor.

That said, you should of course not forget that dominants and homophonic voicing with leading tones are a thing. Well-written pop and rock often uses classical composition techniques very consciously, but it doesn't feel the need to follow any classical-derived rules at all times. That's The Way for sure takes a lot of its appeal from the fact that the tonic, when it is played, feels very much “here's home”. But there's no need to establish this by finding any sort of elaborate cadence. Since pop songs don't tend to modulate much, the home key is pretty much established by the collection of all harmonies that just have been used. Cultural heritage reminds us that if there's an em and a D and a C, then G is for sure a cosy rome with a lot of paths leading to it, but we don't need to actually use them. (We have planes nowadays, don't we?)

Answer 2

One point of view is given by Peter van der Merwe in a couple of interesting books. "Origins of the Popular Style: The Antecedents of Twentieth-Century Popular Music" and "Roots of the Classical: the Popular Origins of Western Music."

Another interesting book is Alec Wilder's "American Popular Song" but it only covers the period up to about 1950.

Wikipedia has another POV entirely.

Philip Tagg has done a lot of study on the subject. http://tagg.org/index.html

Answer 3

I think you're complicating your work with a simple misconception: classical music was just the pop music of its day. It's incredibly broad, and 99% of the classical music composed is mostly forgotten - what we're playing as classical music nowadays is cherry picked, "best of the best" (which is inherently subjective, of course).

Tracing the "evolution" of music is much more complex than tracing biological evolution, because culture isn't a tree - there's plenty of cycles, and plenty of cases where multiple branches join together to form another branch. You need to match and mix - there's no single line of history you can follow. Colloquially, this is often expressed with sentences like "It's kind of a mix of Jazz with Bebop, with a little bit of African tribal music mixed in". Sometimes, people skip a few "generations" - modern rhythmic music took a lot from tribal styles, while combining them with more modern musical approaches. Mix and match.

This of course makes what you're trying to do rather complicated (and it could also be argued that it's somewhat meaningless). But whatever you do, just understanding what was before in the same culture simply isn't enough. Even European classical music, even with the popular pieces of today, the "evolution" wasn't a single line. There were plenty of musical styles that borrowed from each other to form something new. It only looks like a nice tree of music because the examples are cherry picked in the first place - and even then you have things like "he mixed the traditional Austrian school with Florentian influences" or whatever.

A lot of pop music of the past few decades follows a very simple harmonic formula that's shared all the way back to folk songs hundreds of years old - contemporaries of the "classical" music in many cases. A lot of it comes from the mixing of culture from all around the world - looking everywhere that was "forgotten" by (the cherry picked) classical music. If you want to do your tracing, you must account for this - those are the "gaps". A lot of it is Europe-specific - there's nothing inherently cheerful about a major chord or inherently sad about a minor chord, for example; that's just a cultural convention. Consequently, look to styles that break those conventions to find interesting points to further your research - sometimes, those breaks are just an invention, sometimes they are indicative of importing musical style of a different culture.

Answer 4

To address your particular example, the Bruce Hornsby song (here's a YouTube link that works) https://www.youtube.com/watch?v=GlRQjzltaMQ

He's just messing around on the white notes. Or, to put it in theory-talk, he's exploring the diatonic possibilities of C major. Watch his hands in the piano solo from 2'20" (and anywhere else his hands are shown). I can't see him hitting a single black note. ii vi V IV I V IV are all diatonic. There's no particular structure to the way he mixes them up. He's establishing where he IS, but he's not going anywhere. You could label this 'modal' rather than 'harmonic'.