Harmonics… a lot of people know how to do them, but not everyone knows exactly what they are, and if you really understand them, you can use them in way more creative and interesting ways. This article is going to take a slightly different approach to explaining them than the videos above do, but all the same stuff will be covered (with the exception of a few techniques for playing harmonics, which are just outright difficult to explain with words alone).
First off, what is a harmonic? When you pluck your guitar string, it goes up and down a certain number of times per second. This is the note’s “frequency”, which is measured in Hertz (Hz). I’m sure you’ve seen A=440Hz on your tuner or something like that before. That is our modern tuning standard, and it means that the A above Middle C (which you can play on the 5th fret of the high E string of your guitar) has a fundamental frequency of 440 Hertz.
What does “fundamental” mean? Well, no sound in nature has just one frequency. That’s called a sine wave, and you can only create those by use of synthesizers. Sounds consist of multiple frequencies interacting with each other, most of which are multiples of the fundamental (which is usually the lowest frequency). The fundamental and all the multiples of it are “harmonics”. The fundamental is the 1st harmonic, the next harmonic will have a frequency that is 2x the fundamental, the 3rd harmonic will be 3x the fundamental, etc etc. So the 2nd harmonic of A=440 would have a frequency of 880Hz, the 3rd harmonic would have a frequency of 1320Hz, and so forth.
So what notes are all those harmonics? That’s where a little something called the “Harmonic Series” comes in handy. The Wikipedia page I’ve linked there contains lots of great information, but the main thing to pull from it is the table under the “Harmonics and tuning” section. It tells you which intervals each harmonic equates to. The first 16 harmonics in the harmonic series are Do – Do – Sol – Do – Mi – Sol – Te – Do – Re – Mi – Fi – Sol – Le – Te – Ti – Do (or 1 – 1 – 5 – 1 – 3 – 5 – ♭7 – 1 – 2 – 3 – ♯4 – 5 – ♭6 – ♭7 – 7 – 1) all ascending. So the first harmonic (open string) is your fundamental, the 2nd harmonic is an octave above that, the 3rd harmonic is a perfect 5th above that, the 4th harmonic is a perfect 4th above that, etc. (if you do not understand what I mean by “perfect 5th” and “perfect 4th”, please refer to my lesson on intervals)
You may have noticed a pattern in the intervals there. Every time you double the number of a harmonic, that harmonic is an octave higher. For example, the 2nd, 4th, 8th, and 16th harmonics are all octaves of the fundamental (1st) harmonic. The 3rd, 6th, and 12th harmonics are all perfect 5ths, each one an octave higher than the last. This also means that each prime number harmonic gets you a new interval! (a prime number is a number that is only divisible by itself and 1. Here is a list of the first 1,000 prime numbers)
Okay, now we know what harmonics are, but how do we play them? The first type of harmonics we are going to play are called “natural harmonics”. To play these, you simply rest your finger on the string in certain spots. You don’t press the string down against the fret, you just lightly touch the string. The easiest spots to get these harmonics is right above the 12th, 7th, and 5th frets. The reason these are the easiest spots is because they are the lower harmonics (the 2nd, 3rd, and 4th ones specifically) and are a little bit more powerful. Higher harmonics are not as strong, and are therefore more difficult to hit, heavy distortion or compression makes it easier.
What you’re basically doing here is preventing the fundamental from ringing out while emphasizing a particular harmonic. Theoretically, the string is not moving at that spot where you are resting your finger. You are dividing the overall vibration of the string into several smaller waves. This diagram illustrates the idea well.
The vibrations in the string are being divided into whole number fractions of the fundamental, and those fractions are how you figure out where to put your finger to get each harmonic. If you want to hit the 2nd harmonic, you put your finger halfway between the nut and the bridge. If you want to hit the 3rd harmonic, you put your finger 1/3 of the way between the nut and the bridge. Get it?
Now we can move on to artificial harmonics. The only difference between artificial harmonics and natural harmonics is that where natural harmonics were played on an open string, artificial harmonics are played on a string where you are fretting a note. The same rules apply though, you merely have to touch the string 1/2, 1/3/, 1/4… between the fret and the bridge. The video shows several ways to play artificial harmonics, including “pinch harmonics” which are not a special type of harmonic, just another way of playing them.
So now you’ve got all the necessary information to know which notes all those harmonics are. You also know how to figure out exactly where that “sweet spot” is to hit them, which is where most harmonics tutorials really fall short. I know a lot of really talented players that make excellent use of harmonics, and many people want to learn how to do it from them, but the truth is: they don’t have a damned clue! They just fiddled around until they got it. Then they just kept doing it over and over until their hands just knew where to go. Personally, I’d rather not waste time blindly searching for that “musical G-spot” when I could use science to help me find it right away… it leaves me with more time to play music!