Real World Circle of 5ths
Online there must be a hundred explanations of what the Circle of 5ths (Cof5) is, most of which come off as technical dissertations for music majors. And I suppose there is some justification for that since it has many technical uses. But I have run into music majors who just toss off Cof5 as a tool for making key changes when writing music, without appreciating that it can help people understand how to make music - how music works in the first place.
I didn't appreciate it either until I gave myself a project a few years ago. I wanted a way to easily remember the flow of guitar chords from one to the next in the patterns that seemed to show up in most songs. And I also wanted to put to use the large numbers of 'fancy' chords that I had learned but never seemed to be able to just pull out and play at the best time. Over the years I had found beautiful, cool sounding chords like 13b9's and -7b5's but never seemed to use them. They didn't flow automatically from my fingers. What to do?
First I thought it would help to remember where any chord seemed to 'want' to go next. By 'want' I just mean that, to my ears, some chords demand to be followed by some other, very specific chords. When I hear a G7, for example, it seems to 'want' to go to a C next. A G7b9 really 'wants' to get to the C. And a G7#5 really, really, really 'wants' that C. It wants to 'resolve' to the C. What's this all about?
It helps to understand what chords are in any major scale. Pick the easiest scale to deal with, C, and look at the 4-note chords built on each note of the scale. We get:
C Major 7
D Minor 7
E Minor 7
F Major 7
G Dominant 7 (or just plain G7)
A Minor 7
B Diminished 7
This pattern of Major 7, Minor 7, Minor 7, Major 7, Dominant 7, Minor 7, Diminished 7 is always the same, for ANY key, not just C. And look, there is just one Dominant 7 chord in any major scale. And wouldn't you know, it's always on the FIFTH note of the scale. In the C major scale the chord on the fifth note is G7. In the Bb major scale the chord on the fifth note is F7. The Eb scale has as it's fifth chord Bb7. On and on.
And also, wouldn't you know, that G7#5 I was talking about above that just had to get to a C, is the fifth chord in the C major scale. All the G7's are. That is, G7b5, G7#5, G7b9, G7#9, G7sus4, plus other chords that are built on the G7 like G9, G11, G13. Even the altereds of these last, like G9#5, are included. All of them are based on the fifth chord of the C scale, G7.
Now here's a leap for you. Since there is only one Dominant 7th chord in any major scale, that chord identifies the scale it is in. In essence any 7th chord (note: not Major 7th, just plain 7th or any of its 'altereds' mentioned above) says loud and clear "I am the chord built on the fifth note of a major scale." Not only that, it also seems to continue "...and I really, really 'want' to move to the chord on the first note of that scale."
Think about that for a minute. You are playing along on some tune and you come to a 7th chord. Regardless of the key you have been playing in, this 7th chord is telling you that right now, even for just a moment, you are playing the chord that is built on the fifth note of a major key. If you are playing in C and you come to a G7, well that just reaffirms that yes, you are still in the key of C. If you are playing in C and you come to a C7, however, the C7 is telling you that no, Dorothy, you are not in Kansas anymore. At least for the moment, that C7 is telling you that it is the chord built on the fifth note of a major scale. Well, what major scale has C as it's fifth note? Key of F. And the C7 really 'wants' to 'resolve' to an F.
Why didn't you take the blue pill? Here's the big full-circle leap. If you change that F to an F7, it 'wants' Bb. Change the Bb to Bb7 and it 'wants' the five-down chord Eb. Change Eb to Eb7 and it says in essence; "I'm five notes up from my new key, Ab."
Ab7 goes to Db,
Db7 to Gb.
Gb7 to B.
B7 to E.
E7 to A.
A7 to D.
D7 to G.
G7 back to C. We've gone around in a circle, hitting every note there is. (Well, yeah, Gb is the same as F# and so forth. You get the idea.)
And that's the Circle of Fifths. Most of it, anyway.
That is, there is a tendency for Dominant 7th chords to move to chords that would be their root-tonics in a major scale. This tendency drives music. Your ear hears the need for movement, for resolution. The Dominant 7th-type chords create tension, the movement to a chord five notes down the scale provides the release.
Some songs are completely filled with nothing but Cof5 sequences. (Listen to “Giant Steps”). Others, like the simplest blues, have only one (the final two chords that 'turn' a blues into the beginning of the next chorus. e.g. B7 to E.) But it is a very rare tune to have none.
The Cof5 is the basis for my publication "Building Blocks of Music for Guitar: Using the Circle of Fifths for Useful Chords and Progressions" that is available on this website for $10. Also, please have a look at my other publication "Building Blocks of Music for Guitar: Using the ii-V-I Sequence for Useful Chords and Progressions", plus other files and some handy freebies also available on this site.
