Ever since the first time I played the riff to Ironman by Black Sabbath as a beginner, I learned that if you play a note on the any of the top 3 strings* (E, A, or D) and you add a second note (one string down, and two frets up) it sounds great together. The now famous ‘power chord’ became essentially the basis of the entire hard rock/metal genre. What I didn’t know at that time was that I had stumbled across the strongest harmony in the wester music harmony: The root and the 5th – also known as a “perfect fifth”.

I assume pretty much all of you know this interval well, as pretty much every song ever contains a chord with it present. But let me ask you this: did you ever think that what works with a single note, could also work with a chord? Or a scale? Or even a key? Let me save you a lot of time here – it does.

5ths gone wild
Let’s start with a chord. I will use the key of C for these examples. The 5th above C is the note G. What happens if we play a C chord and add notes of the G chord at the same time? We essentially add the 9th and the major 7 notes to the chord. Try it – stack up every versions of a C and G chord and listen to some of the beautiful sounds.

This isn’t just me right?
I was watching an Eric Johnson Hot Licks video the other day. In it, he mentioned that when he is soloing using the Cmin pentatonic scale he often likes to add and jump back and forth into the Gmin pentatonic scale. Hmmm, here it is again C & G – a.k.a. the 5th. Like Eric, I have done this myself for years and it works fantastic. So if you normally use the pentatonic scale for soloing and feel ‘stuck in the box’ – try switching it up to the 5th for a while! Mix and match. Your old lines may sound less tired.

Same with harmonizing lines or working with a key. If you write a melody using notes of C Major, have the second guitar/key/bass harmonize it using the key of G Major.

.. the possibilities are endless.

The Rabbit Hole
This blog post is designed to get you thinking about the concept: ‘If it works for a note will it work for a chord or key’. So, …. If the 5th works… what about 3rds? Or 4ths? 7ths?? etc. I will let you do the legwork on this one, but let me assure you – this journey is time well spent. It can open up your ears, your chord playing, soloing and songwriting to places it may have never gone.

* This interval exists on all strings but the shape alters slightly as you cross the B string due to tuning.