Everyone knows it, a progression so common that entire genres of music are based on it: the I-IV-V. What makes it so powerful? The answer is surprisingly simple, and that simplicity is what makes it both easy to learn and no matter how many times you hear it, you never get tired of it.
Tension and Release
All good music has its foundation in this basic concept. Some more recent forms of music don’t use harmony so much to achieve it, but they employ other techniques. Still, the concept remains: build up tension in the listener’s ear, make them expect something, and then satisfy that expectation. Here’s how it’s applied with the I-IV-V.
In a given key, C for example, there are certain notes that pull towards certain other notes. Try singing or playing the C Major scale and stopping at B (or Ti if you’re into the solfege). You can do it through force of will, but in the space of those seven notes your ear has already come to expect that B will be followed by C (or Ti to Do). You will want to hear it.
Similarly, try singing or playing the C Major scale and stopping at F (or Fa). It has a pull to G (Sol). It isn’t as strong a pull as B to C, but you should be able sense it a little bit in your ear.
Harmonic Applications
These pulls that certain notes exert is the foundation of Western harmony. Johann Sebastian Bach figured it out in the 1700’s, and now we have the Blues and other Blues-based genres of music (pretty much all the pop music that’s happened for the last 50 years). So, when we start building chords on these tones, the progression really asserts itself. Refer to the illustration for the following explanations.
The IV chord (in this case, an F Major chord) has the root note of the key in it (C, indicated by the dotted line), as well as the 4th of the key (F) and the 6th (A). Keep in mind the 4th has a pull towards the 5th, though not an incredibly strong one. The 6th is more neutral in terms of pull. It could go up to the 7th or down to the 5th just as easily. The root is home, so since the IV chord shares that tone with the I chord, it can go back to the I chord fairly easily. At the same time, the IV chord can just as easily go to the V chord because of the pull of the 4th tone of the key.
The V chord has the 7th tone of the key in it (B), which as you’ve already discovered wants to go to the home tone more than anything in the world. Furthermore, the 5th tone of the key (the root note of the V chord) also goes back to the home tone very comfortably (this is for acoustic reasons that Pythagoras discovered centuries ago, but I won’t get into it right now).
So, in the V chord, there are two notes that both pull toward, and comfortably go back to, the home tone of the key (C). This explains why so many progressions end up going V-I. A whole lot of other things can happen before that, but more often than not it’s going to end in a V-I.
And I haven’t even mentioned 7ths. That’s another article altogether. But hopefully, this helped a little bit in explaining the most commonly used chord progression in the history of Western music.
more articles by Brien Henderson
- Anatomy of the Blues Scale
- A Great Site for Old Music
- Every Musician Should Read This
- Saxes: Work Your Pinkies!, part 1
- Spice Things Up With The Tritone Sub
- Writing Your Own Music: How To Get Started
- Intro to chords in Jazz
