If you have any memory of the 90s, you may remember a song called Machinehead by the British band “Bush” (or if you were in Canada like me: “Bush X”). That song was the first thing that came to mind when I recently received a question from a Waay user about when to use fifth chords, also known as power chords.

I hadn’t thought of this song in years, so I found it interesting that it just appeared in my head. And I think I know why. There are countless examples of songs with fifth chords, but there’s something particular to many of them: you can hum along to the chords. They can sound like melodies, and melodies are very memorable. Even if you’ve never heard Machinehead before, you’ll be able to hum the guitar part in no time (which starts with octaves and then the fifths join in).

That’s not common for most chord progressions. Try it with a progression of more complex chords, whether triads, sevenths, or extended chords. Seriously, try it: here’s a rich Jeff Buckley progression:

There’s too much going on in those chords to hum along with just one voice. You’d need a choir! (Side note: please listen to this song in full, it is amazing.)

So, why is that? Why is the fifth chord so “hummable”? Well a fifth chord has two notes: the root and the fifth. It’s missing what almost every other chord has—a third—and that leaves it feeling kind of hollow. The third gives a chord its major or minor quality, and without it the chord doesn’t quite sound the same. It can sound less like a chord and more like a note with an “effect” applied. (Same goes for octaves, like in the beginning of Machinehead.)

“Wow! I don’t usually write reviews, but [Waay] blew me away. Well made, clear courses, and great exercises.” ⭐️⭐️⭐️⭐️⭐️

–Art Zz , Feb. 11, 2022

Let’s return to the Waay user’s question: when would we want to use a fifth chord? Given everything above, here are a few ideas that come to mind:

• You want a chord progression that has its own melody.
• You want to change the chords very quickly without the progression sounding busy/messy.
• You want to add lots of distortion without the sound turning to mud. (The simplicity of the fifth chord pairs well with distortion.)
• You want to leave lots of space harmonically, maybe to let other parts shine through, or because that’s how you envision the song.

I’d love to hear other answers to this question. When do you like using fifth chords? When do you think they work really well (and not)? Comment below.