Finding Natural Harmonies on a Guitar
Here is.a useful guide to finding the natural harmonies using a guitar. This blog post is in reference to the Natural Tuning vs Equal Temperament post.
1. Place your left index finger lightly halfway along a string. On a guitar, this point is the 12th fret. Take care to not put pressure on the string – you don’t want to fret the note, just lightly touch it.
2. Pluck the string with your other hand, close to the bridge (the bottom end of the string). Here’s the trick – as you pluck, release your left finger. If you time it right, a shimmering tone, one octave higher than the open string’s fundamental note, will ring out.
Take time with this until you get it; experiment with how you place the left finger, and how you release it. You’ll find that resting it over the closest side of the string makes it easier.
What you hear is the octave – 2:1, also called the second harmonic (the first is the fundamental note of the string). Play the string open again, and then play the harmonic again. Alternate between the two, and listen for the harmonic in both. You’ll notice it’s always there! What happens when you place your finger halfway along the string, is you isolate the second harmonic, so that it alone rings out.
3. Move your non-plucking finger further down the neck, to the seventh fret (count up from the tuning pegs), and repeat steps one and two. What you hear is the third harmonic – 3:1. As a musical interval, it’s a Perfect Fifth above the fundamental. (we call it a “Fifth” because when we play a major or minor scale up to this note, there are five notes in total.) Again, see how it’s always there!
Here’s where things start to get interesting. If you play the same note at the seventh fret on a guitar, it won’t quite match the harmonic. Try it – make sure your guitar is in tune as usual, and play the third harmonic on the low E string. While the note is still ringing, play the open B string – they clash! We’ll explain why soon.
4. Repeat steps 1 & 2 at the 5th fret. This is the fourth harmonic – two octaves above the fundamental. Listen for it in the open string – it’s quieter than the others, but it’s there!
5. Do the same thing at the fourth fret – but not exactly over the fourth fret. The harmonic is a small distance behind the fret. Explore until you find it. This is the fifth harmonic, 5:4 – better known as the Major Third. Play the string open, and listen for it – it’s there, but it’s really quiet! On some strings, you can hear it more clearly if you let it ring out for a few seconds, so that the fundamental and other louder harmonics start to fade.
On the E string, this harmonic is a G#. Play the fifth harmonic on the low E string, and while it’s ringing play the fourth fret on the high E string (again, make sure they’re in tune first). What a clash – ugh!
There are many more harmonics – if you slowly slide your finger all the way to the start of the string whilst plucking, you’ll find them. Some of these are really complex sounds, and we don’t need to involve them to create a working harmonious musical scale – for our purposes, the fifth harmonic, 5:4, which gives us the Pure Major Third, is as far as we need to go.