How to Write Harmonies for Guitar, Piano, and Vocals

Ever wonder how Boston, The Allman Brothers, Iron Maiden, and The Eagles wrote harmonized guitar parts? Or why Simon and Garfunkel sing the notes they do in songs like "Sounds of Silence?"

This video is an extensive demonstration of that process and all of the considerations one might take when trying to write harmony lines such as those. Below is a summary of the concepts covered.

Harmonized Thirds

A simple way to harmonize above a melody is with diatonic thirds, which you can think of as skipping over the next note of the scale.

For example, in the key of G, we can harmonize the first note (G) with the third note (B). Similarly, we can harmonize note 2 (A) with note 4 (C). Apply this pattern to each note of your melody, and you'll have a harmony line in thirds.

Sixths

If intervals are unfamiliar, I recommend reading Chapter 2 of the Chord Progression Codex first.

Take that harmony line written in thirds and move it down an entire octave. If you calculate the distances between the notes, you'll see that they're actually sixths — not thirds. This is because thirds and sixths are complements of each other. When you invert a third, you end up with a sixth, and vice versa.

It's important to remember that your melody may not always want whatever is up a third! For example, if your original melody is voicing the 5th of a chord, then adding a 3rd above it will introduce some type of 7th quality to the overall sound that may not be desired.

However, if your melody is voicing the 3rd of a chord, then harmonizing up a 6th will summon the root note of the underlying chord. This is why you should experiment with diatonic sixths just as eagerly as you would thirds.

Fourths and Fifths

These two intervals are again complements of one another. If a third or sixth doesn't sound good above or beneath your original melody, try one of these instead.

There is a famous "rule" that you should not harmonize with parallel fifths. That restriction does not apply whatsoever to modern rock genres and can be safely ignored until you decide to learn counterpoint and similar classical theory.

Use Them All!

When writing a harmony line, I like to include combinations of everything we've discussed here. I also pay close attention to the motion of my harmony: are the two voices moving in parallel with one another? Or are they in contrary motion? Or oblique motion?

Those concepts are covered in my lesson on voice leading.

Learn More

For a deeper understanding of intervals and how they work, check out Chapter 2: Music Theory Fundamentals in the Chord Progression Codex. For more on voice motion, see the Voice Leading lesson.