What is voice leading?

Sit down at the piano and play the chords C and F in root position, back and forth, like so: (C E G) to (F A C). Pretty clunky! Now invert the C chord; that is, move the bottom note up an octave. Alternate that version of the C chord with the F chord, like so: (E G C) to (F A C). It sounds smoother! You just experienced the magic of voice leading.

To understand how voice leading works, imagine that each note in a chord is being sung by a different person. For three-note chords, you will need three people. Let’s call them David Crosby, Steven Stills and Graham Nash. (In the photo, they’re sitting Nash, Stills, Crosby.)

Imagine that Crosby always sings the lowest note in each chord, Stills always sings the middle note, and Nash always sings the top note. (I have no idea if this is how they sang in real life; it’s just a thought experiment.) You want to arrange your chords so that the guys don’t have to do big interval leaps. If you play both chords in root position, then Crosby has to jump from C up to F, Stills has to jump from E up to A, and Nash has to jump from G up to C. They can do it, but it’s awkward. This is considered to be bad voice leading.

To improve your voice leading, the key fact you need to know is that it doesn’t matter what order the notes go in a chord. The notes C, E and G will always produce a C chord, regardless of which one is on top and which one is on the bottom, or how widely spaced they are. All you have to do is move notes up and down by octaves until you get the desired voice leading. When you invert the C chord, Crosby, Stills and Nash get much happier: Crosby goes from E to F, Stills goes from G to A, and Nash goes from C to C. Nash can even just sustain the C while Crosby and Stills move their notes, which will sound beautiful.

Now let’s give the guys a slightly more complicated chord progression to sing, the Axis progression: C, G, Am, F. Let’s start by naively putting each chord in root position: (C E G), (G B D), (A C E), (F A C). Once again, this is awkward. Crosby jumps from C to G, then steps from G to A, then jumps from A to F. Stills jumps from E to B, then steps from B to C, then jumps from C to A. Nash jumps from G to D, then steps from D to E, then jumps from E to C. Once again, we are going to invert some chords to make each guy’s melody line easier to sing. Here’s one solution: (E G C), (D G B), (E A C), (F A C). Notice that in those last two chords, two of the notes don’t even move. Crosby sings E to D to E to F, Stills sings G to G to A to A, and Nash sings C to B to C to C. This is easy as pie to sing, and it sounds nice and smooth.

How about something more complicated? We could do a jazz progression with seventh chords: Cmaj7, Am7, Dm7, G7. Since these chords have four notes, we’re going to need a fourth guy. Let’s call him Neil Young.

As you would expect by now, if we play these chords in root position, it will sound awkward: (C E G B), (A C E G), (D F A C), (G B D F). Here’s one way you could invert the chords to smooth this out: (E G B C), (E G A C), (F A C D), (F G B D). See how little movement there is from one chord to the next? Crosby, Stills, Nash and Young give you high fives and fist bumps.

Here’s an interactive Noteflight explainer of all of the above.

In Western Europe, the voice leading conventions solidified before anyone considered chords to exist as abstract entities. All harmony was the product of simultaneous melody lines. Even when composers started using chords in the modern sense, they continued to treat the notes in those chords as if they were being sung contrapuntally by a choir. The European canonical composers followed strict rules for their counterpoint writing, which reliably produced good-sounding harmonies. In my ultra-traditional grad school music theory sequence, I learned those voice leading rules, and they were mind-numbingly arcane. When I followed the rules, my counterpoint exercises sounded nice, but I definitely found them lacking in musical interest. I guess I like my harmony to have sharper corners.

Jazz takes a more relaxed attitude toward voice leading. You do want to keep the notes in chords close together most of the time, and there are various complex strategies for doing so, but you’re allowed (in fact, encouraged) to use more dissonance and parallelism than you can in European canonical music. The chords have more notes in them, too, which gives you more choices. The musicians who make R&B tend to have a jazz background, so the voice leading in that music is usually smooth in a loose and jazzy way.

And what about rock? My classically trained colleagues consider its voice leading to generally be appalling. Some of this is due to the guitar’s affordances: moving chords around in parallel is easy, and smooth voice leading is hard. Also, rock’s chord progressions often move by step, and for those progressions, you have to take heroic measures to avoid parallel voice leading. Rock musicians tend to voice lead a little better on their vocal harmonies, just because that’s the most natural way to sing, but not always. If, like me, you grow up listening to a lot of rock, you get used to the sound of bad voice leading, and it becomes just another color in the palette.

There’s one last thing I haven’t talked about, which is letting voice leading dictate your chord progressions. This can be a fun way to write, especially if you want to break out of the cliches. Start with some chord. Then duplicate it and move one note by a half step. Duplicate that chord and move a different note by a half step. Keep going, letting things evolve in this incremental way. Don’t worry about the identities of the chords, just proceed by intuition. You will find some rich and weird stuff this way.