How chord changes work (usually) 8-)

[Mr_G]

What in the world???
Relax… relax…
this little chart shows how chords work together. Let me 'splain:

The I, IV, and V chords (on the left) are like the three heads of three families (Musical Mafioso families?).

1. Any chord in the I family (I,iii,vi) can meander over to any chord in any chord in the IV family or the V family.
2. Any chord in the IV family (IV, ii, vi) can meander over to any chord in any chord in the I family or the IV family.
3. The V family desperately wants to send you home to the I chord family.

Most pop, country and Bluegrass tunes follow this chart. Are there exceptions? Absolutely. But generally speaking, this is the way it goes.
There ye be… talk amongst yourselves…
Hope to see you in April at Ben’s hacienda!
mr G

[Mike_R]

Very cool!!! That would seem to be pretty handy.

The only exception that jumps to mind I see sometimes is using the vi as a substitute for the I, in which case a V can often lead to a vi.
I.E. G C D Em C D

[Mr_G]

you stole my thunder… chord substitutions are the next thing I was going to post about! Great minds thinking alike!

Mike_R is spot on.
In the diagram above, the chords to the right are substitutes for the Major chord to the left…
iii and vi can sub for the I
ii and vi can sub for the IV
vii can sub for the V

Try this:
__G _________________C ______G__________________________D
Amazing Grace - how sweet the sound. That saved a wretch like me!

__Em _______________Am ______Bm________Em_____________F#m7b5
Amazing Grace - how sweet the sound. That saved a wretch like me!

I love doing stuff like this.

Sometimes I will use sub chords for a solo break just for kicks and grins.
1x - play melody with regular chords
2x - play melody with substitute chords
3x improvise over either set of changes
4x close it down with regular changes

Thanks again, Mike_R - there are some smart folk here.
mr g

[Mike_R]

Sorry to steal your thunder! You earned your thunder, I’ll give it back

Again, this looks super handy. If anyone wants to write a song (or maybe even guess an existing progression) this is a great road map for ideas of what chord to try.

I don’t recall seeing anything like this before. Thanks for posting this!

[Mr_G]

it’s part of a book I am writing. Over 20+ years of teaching music, I have had to come up with multiple ways to get the point across… this one is pretty good.
I’ll share the thunder with you!

[Mike_R]

Days later your post triggered some noodling with a chord that I really like in some progressions that is an oddball. The III chord. So for instance, say I am in G… the “normal” 3 would be a minor (iii) or Bm. Bm has a B, D and F#, all which are in in the scale of G or Em. In Em, folks sometimes use a sharp 7, which in this case would be a D#. D# is not in the scale of G, but because of the possible use in Em it fits in a nice/different way. So if we use that D# in the 3 chord of G, that makes it a B major chord (you often see a B7 here). So now I am thinking through how that III fits in with the diagram.

I haven’t arrived at how it fits, but I am having fun noodling and thinking about it. It’s almost like you would need to have two diagrams, one for the major and one for its relative minor. The III is like a bridge between the two. It wants to resolve to the root of the minor (in my example Em) or the 4th of the major ( C ). There are probably other chords it might lead to that I haven’t stumbled into yet.

[David-Gear]

I am sure you do this but I love these types of post its Noodling with a purpose. I tend to use the iiim if playing background Rhythm like this

G/Am7/Bm7/G in place of 4 bars of G

Even the lazy version of the Bm XAF#BDE is a sweet sounding chord although purists pobably call it as an A or Bsus type and can lead onto a 2 finger C at 5 or 2 Finger D at 7

Your idea fits as it is a combination of Quality and ii or iii substitution. If my vocabulary is not quite right its close.

[Mr_G]

Doooood! That version of Bm Is gorgeous ! The song “Horse with no name” by America wrote an entire song bouncing between Am and this chord.
———O——————-
———3——————-
———4——————-
———4——————-
———0——————-
——X———————-

[Mr_G]

I will ornament a G chord with the following, or a variant:
——x——————————————-
———3————1————0———-
———0———-0————0———-
———5————3————0———-
——x————————————-——-
——x———————————-———-
Just a simple G-C-G, but when you crosspick it it sounds purty.

[Mr_G]

I’m not sure your explanation of the Maj III chord fits with this diagram, as this diagram illustrates Diatonic chord progressions i.e. diatonic = within a key.
HowEVER…in using a B major or a B7 prior to the Em chord, you are taking advantage of the properties of the Dominant chord.
Auxiliary rule about the Dominant chord…

"EVERY chord can be preceded by ITS Dominant chord, regardless of what key you are in."

If you think about it - in my diagram above it shows that the V7 chord family REALLY wants to go to the I chord family (I, iii, or vi), right?

Stretch that definition a bit, and you can say that ANY chord can momentarily be considered a “I” chord and precede it with ITS V7 chord, because the Dominant chords purpose is to push you to ITS “I” chord. Or to put it another way … the jazzers got this right… the V7 chord doesn’t really CARE about the quality (whether it’s a major, minor, diminished etc) of its “I” chord. For example… a D7 can precede a G, Gm, G7 - ANY kind of G chord. Hank Williams Sr did this all the time. For example, it was common in his songs to precede a dominant 7 chord with ITS dominant 7 chord. He might do something like this:
G…C…A7…D7…G (Some folks call the A7 the “V” of the “V” D7)

So the V7 chord is a “traffic cop” chord, and we can use that baby WHENEVER we want to to be directed towards any chord.

Did I muddy the waters much? grin

[BanjoBen]

Good stuff, y’all!

[Mr_G]

there are smart folks here!

[Mike_R]

Did I muddy the waters much?

Not at all, in fact the opposite. It connected some dots for me on the V7. As a kid/teen (last millennia) I started out with some decent basic theory background, then got away from thinking about theory as I played. Now, some of the theory is making sense of why folks do some things. You mentioned the dominant always wanting to go to its I. I use that often to change keys between songs when we don’t want a break (IE end a song in C, use a B7 to get to E). So saying that the purpose of the V7 is to push to its I makes perfect sense with how I have used it for key changes between songs. It seems that using the V of the V (or more), you could work through a few before you reveal where you want to land. In my previous example of changing keys from C to E, instead of C B7 E, I could do C C#7 F#7 B7 E. I just played with that and it works. Of course you can play some other variants C#sus2 (or dim7), but regardless, when it finally makes the change from the final V to I (B to E in this case), my ear feels like it has “arrived” at the new key (of E).

Sorry what I was discussing was off the diagram for chords within a key. It was the exceptions (what wasn’t on there) that got me thinking about why the III works in an otherwise diatonic progression.

[Mr_G]

Sorry what I was discussing was off the diagram for chords within a key. It was the exceptions (what wasn’t on there) that got me thinking about why the III works in an otherwise diatonic progression.

Don’t apologize!!! It was a very good observation. The nice thing about this theory stuff is that there are just about 10 ways to explain everything. This is a good conversation. My inner Music Theory nerd is verra happy!