How can I learn the theory behind chord progressions?

Question

How can I learn about the relationships between chords to build chords progressions?

Every book I read explains how to build chords, but they don't teach how to put the chords in progression. They just teach you some common chords progressions like I-V-IV, but they don't teach the "why" of this progression.

Let's say I have a Bb7/G# chord. How can I know the next chord that would fit in the progression and why this chord?

In particular the chord progression is:

Bb7/G# Gm6 Ebmmaj7/F# Bb

These chords are from the song "Aguas de Marzo" by Tom Jobim. They are very weirds chords to me. If I play the chord Bb7/G# alone it sounds very dissonant. But play the fours chords following the rythming of the song and it sounds beatiful.

What is the area of music theory who study the "why" of this, and not only the "how", which is what I have read in every book of "chord theory" for guitar. Any book you would recommend?

Thanks.

Answer 1

Look for a book on harmony? Schoenberg builds things up from chord positions to progressions (and rants about The War And Other Things!) in "Theory of Harmony" while Piston uses examples taken from common practice music in "Harmony," to name just two books. Some knowledge of counterpoint may also be helpful, e.g. to better understand voice leading.

Answer 2

This progression works because of its strong chromatic movement. Note that there are two chromatic lines moving downwards. One of them (in the bass) was already noted in Dom's answer. The first is the bass line: Ab-G-Gb-(F) (the Gb can move down to the F, which is the fifth of the Bb chord). The other chromatic movement is F-E-Eb-D. Apart from the chromatic movements, the other notes (Bb and D) are common to all four chords. What you basically have here is a line cliché.

The movement of Ebm-maj7 to Bb can also be viewed as a iv-I resolution, which is very common in many genres. The iv chord is borrowed from the parallel minor key.

As for recommendations on how to learn about chord progressions: since you seem to be interested in Bossa Nova, have a look at jazz harmony. An excellent book is The Chord Scale Theory & Jazz Harmony by Nettles and Graf. And don't forget to use your ears in addition to trying to "understand" a progression. The progression in your question is a great example of a progression that can be understood quickly by hearing the two chromatic lines, instead of thinking about some functional connection between the chords.

Answer 3

Just studying the basics of music theory and voice leading should give you the tools to notice what's going on. No matter what the chords in the progression, it's pretty easy to figure out what is going on by looking at the notes in the progression, how the move, and what they emphasize.

I quickly sketched out one possible voicing for this progression in Finale to show you how the notes most likely would move:

There are a few things to notice which are:

• The Bb and D is common in every chord.
• The first chord is in 3rd inversion which is rather unstable.
• The bass line is chromatically descending in the first three chords then moves to the note common in all three chords.
• The voices other then bass move very little.
• The very dissonant interval of Eb to D (M7/m2) resolves to a very consonant F to D (M6/m3).
• The ending motion can be viewed as a plagal cadence in first inversion.

As you can see there is a lot to look at in these four chords, but the reason why someone may like it is simple. While the line may start dissonant, the constant descending chromatic motion in the bass and the combination of common tones and small motion in the other voices keeps the chords related and "spins" until there is an obvious resolution reached on the last chord.

Answer 4

There are several summaries of common chord syntax based on a given style. Like this one in Kostka & Payne which is meant to model common-practice tonal music syntax. Note that this is based on the circle of fifths which is understandable but can be critiqued in that one can easily argue that not all idiomatic progressions are derived from the circle of fifths progression.

Or the one on page 37 of this article by Tymocko.

Note that Schoenberg's famous chart of the regions (mentioned above) is more of a map of key relations, but doesn't prescribe a suggested or typical syntax. In fact Schoenberg's HarmonieLehre has surprisingly little advice or commentary about chord syntax.

Answer 5

It seems to be about how "close" (smaller interval) notes change within a chord progression. EG. a change from A to D involves a strong common note (the A), the E moving to a F#, and the C# moving to a D.

I say "Moving" because that's how the ear percievs it: Even though all but the A note have changed when going from A to D, we hear that there's a change in the E and C# because they've only changed by a tone and semitone respectively.

This theme accounts for a lot of chord progressions- for example Whiter Shade of Pale uses (something like) C G Am G F Em Dm C .. etc

They might seem a bit random but there's a descending note through the chords whcih follows a major scale in C (notes C B A G). Your ear picks this up (assuming you're attoned to western music chord structures) and you find you 'know' what comes next even before you hear it. That's not because it's a cliche- it's your brain doing some anticipation, and the song author knows this and probably did it quite deliberately. It's a suimilar but different story at the beginning of Stairway to Heaven.

It's not a hard and fast rule - but then nothing is in music. For example the smalles change would be to have a chord drop or raise a semitone in its entirety. That's not so common and doesn't sound great.

Part of working out a chord structure is to work out what you want to achieve in terms of mood, and which chord you want to end up on ready for the next section, and deliver something whcih plays withthe human ear. It;s entirely up to you whether you go by the manifestation I've mentioned above, but that is one reason why chord sequences are arranged as they are.

Answer 6

One of the things that helped me in understanding how to put chords into progressions came from pure experimentation. I was practicing various types of harmonized chords around the major scale. I would practice playing all the harmonized sus4 chords of a scale then the sus2, 6 chords, 7 chords, etc. I harmonized chords around different types of minor, major, and exotic scales.

I would go up and down the harmonized scale alternating between two different types of chords such as 6 chords and 7 chords. {The first two chords of your example are actually very close to this} I would try things like alternating two harmonized 6 chords followed by two harmonized 7 chords.

I would take a single chord and listen to how it sounded paired with other chords by moving any single note up or down a variety of half and whole steps. I would move pairs of notes by half steps and whole steps. I would move entire chords up and down half and whole steps.

In experimenting and practicing the variety of harmonized chord types, I began to hear which chords complimented each other and which chords could go to other chords.

Answer 7

Written and played properly, it's also used as a blues turnaround. Often with the notes played as triplets, the first 3 being Ab-F-Ab, etc. Ending with F and D played together.