Originally Published April 1995
Contributed by: Ben Ford
In my last article I talked about the dominant seventh chord and its strong tendency to move back to the root or tonic chord. This 5-1 motion (down a fifth, or up a fourth) is so important to all types of Western music, that I thought we ought to look at the big picture.
It just so happens that if you start at any note, and go down a fifth (or up a fourth) to the next note, and continue to move down a fifth or up a fourth, eventually you get right back to where you started from! For example, if
you start on a C, you would move through a sequence of notes like this:
C F Bb/A# Eb/D# Ab/G# Db/C# Gb/F# B E A D G C
Why this sequence occurs is a topic for a dissertation in Physics and Math. What matters to us is that we can use the Circle of Fifths to figure out the chords to many tunes.
Let’s say we are playing a tune in the Key of G. Notice that on the Circle, the G note is surrounded by C and D, which are the names of the 4th and 5th chords, respectively, for G major! It works exactly the same for each key: E is surrounded by A (4th or subdominant) and B (5th or dominant). Now it’s easy to see why the 4th chord is called the subdominant; it’s a fifth below the root, while the dominant is a fifth above the root.
Enough of this technical mumbo-jumbo; let’s go for a ride on the Circle of Fifths! Very often in various styles of music (especially ragtime), we can go on a little excursion outside the home key of the piece, and use the Circle to bring us back home. Example: Alabama Jubilee, in the key of C major.
The key of C major?!?! That usually means NO sharps or flats. But the first chord is A, which has the notes A-C#-E. Right out of the starting gate, we have jumped outside the key of C major. This adds variety and excitement to the piece, and even if you never before understood what was happening, chances are your ears at least told you that something unusual was going on.
How can we find our way back to C? By riding the Circle of Fifths!
The A7 chord is a dominant seventh chord, and pulls us clockwise around the Circle to D. By simply making the D chord a dominant seventh as well, we continue our momentum around the Circle to G. As expected, the G chord takes us home to C, a little breathless but none the worse for wear.
You’ll find this sort of trick used in all styles of music, but probably most often in ragtime tunes. The second part of Stone’s Rag uses the exact same chord pattern, A – D – G – C. The first part of Dill Pickle Rag is very similar;
the next time you play it, watch how it moves around the Circle of Fifths.
Music theory seems as dry as a desert to most folks, but a basic understanding of a song’s chord structure can really help you learn it more easily. It can also help you figure out how to play back up, harmonies or variations on the melody, or even to write your own music! I will talk about these topics in future articles, but for now, experiment
and have fun. Remember, as Pete Wernick says, “If it sounds good, it must be good!”