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Harmonics Explained

I have seen many requests and search engine hits for "Harmonics" or "Pinch Harmonics" on my site, so I have decided to create this new article which I hope will allow you to master these techniques, and also understand how and why they occur. You can read the top section of the article on technique on it’s own, but it’s good to read up on the "why" in the second secion of the article to give you a better understanding on why a harmonic is formed.

Technique

If you find that you don’t understand anything in this first section on playing harmonics, I suggest you read the Theory section below first to understand what is actually happening on your guitar. There are 4 main types of harmonic that can be played on the guitar. Each techniques involves dividing the vibrating string into several sections to produce a different frequency.

Natural Harmonics

A natural harmonic is fairly simple to play. As with all of the techniques, it’s more simple with some distortion and volume. The concept is to gently rest your finder on a point on the string.
This point corresponds to a multiple of the string length ie half the length of the string is at the 12th fret, a third of the length lies at either the 7th or 19th fret, and a quarter length lies at the 5th or the 24th fret, but not at the 12th fret. The quarter length will not form at the 12th fret as this will divide the string into half rather than quarters, even though they share the same central node.

Natural harmonics will sound for longer if you remove your finger after striking the string. Be wary though. Remove your finger too late and the harmonic will be muted slightly, too early, and the string will just play open. Ideally, remove your finger the split second the harmonic sounds.

False / Artificial / Touch / Tap Harmonics

Touch harmonics (as I shall call them) are performed by fretting a note, and then gently touching the string exactly one octave (12 frets) above that note. For example, play the 7th fret of the G or 3rd string and then lightly touch right above the 19th fret. Not actually between the frets but directly above the metal rod itself. This can be done with a bend, say the 7th fret of the G (3rd) string bent up to the 9th fret 7b9. Again distortion and volume will aid you. You can add more effects with vibrato or the whammy bar.

Pinch Harmonics

Pinch harmonics are the hardest to play in my experience. In order to understand pinch harmonics, you will want to have at least a basic understanding of natural harmonics.

The best way to start, is to find a strong natural harmonic somewhere up around the area of your pickups. I would say that the 3rd string is the easiest to do a pinch harmonic on, so start there. Just touch the third string with a left hand finger at some different points close to the area of your pickups until you find a strong natural harmonic. This really will just take some experimenting, since there are not any fret bars to guide you.

After you have found a strong natural harmonic in the area of the pickups. Pick the open 3rd string, then lightly touch the point of that harmonic with your right hand 2nd finger. Be sure to pay attention to the exact point on the string where the harmonic will
sound. This is called a touch harmonic.

Next, pick the string, then touch the edge of your right hand thumb (the part that is currently closest to the string) at the point where you found that natural harmonic. At first, try this as a 2-step process. You will pick, then touch the edge of your thumb on the string at the point of the natural harmonic. This is still a touch harmonic, you are just using the edge of you thumb to do it.

A pinch harmonic is where you pick and touch the edge of your thumb on the point of the harmonic at the same time. Be sure to have only a very small part of the pick sticking out from your thumb and finger, and pick only with the very tip of the pick.

This whole example was using an open string. But pinch harmonics can be done on any fretted note as well. Since the point where your right hand will need to pick will vary depending on what notes you are fretting, you will need to experiment. There are times when you will hear only the harmonic and other times when you will hear a combination of the fretted note and the harmonic.

If you move your right hand by small increments to the right or left, you will get different pinch harmonics for the same fretted note. This is where the science of pinch harmonics comes in.

Pinch harmonics are tricky to get at first. For the actual harmonic you have to pinch the string as you pluck it, letting your thumb touch the string at the same time as the pick.

To get different harmonics you have to search out the sweet spots by moving your right hand up or down the string till you find them. The following example is played the same way both times by the left hand but the first is pinched directly over the pickup while the second is pinched above the 24th fret. There are many more sweet spots like this, so experiment and remember where they are for future reference.

Tips on Playing

There are several tings you can do to enhance your ability to play harmonics. The main and most common aids are volume and distortion. Practice these often. It doesn’t take much time or effort to play just a couple each time you play the guitar. The more you play, the better you will be able to get those "sweet spots".

Final Thoughts

It can be quite frustrating to get harmonics correct first time. Let me just tell you a small tip that I have just discovered. Many people often have issues with the pressure required on the strings. Lightly touching can be different for different people. I have found that if you can rest your finger across the strings and they only just move less than a millimetre, you should have the correct pressure. It’s the same pressure that you would need to slide up and down a string without it moving, but still actually touching it.

The Theory

The best place for us to start would be understanding how a string vibrates, its frequency, and some theory on nodes. On a standard guitar, the strings are fixed between two points called the nut and the bridge. When a string is plucked it vibrates at a certain frequency. The frequency is described as the number of vibrations per second, and is measured in Hertz (Hz) (One Hert 1Hz being a single vibration in one second). If you look at an image of an open string vibrating, you will notice this shape.

So why do all my strings make different sounds even though they are the same length? This occurs due to the tension on the string. Basically the tension of the string modifies how the string vibrates so that it has a different frequency. When you adjust the tension, you also change the diameter of the string. Stretching or tightening the string makes the diameter smaller.

Lets say this string is the A or 5th string. Plucking the string will cause it to vibrate at 440Hz or 440 times a second producing the A fundamental note of the string. The fundamental frequency being the lowest frequency that will produce a standing wave on a string. Harmonics, in their simplest form are multiples of this fundamental frequency. For example, the first harmonic (1 x frequency 1f) is the fundamental itself. The second harmonic 2f is twice the frequency ie 880Hz. 3f is the third harmonic, 1320Hz and so on and so on.

If we introduce a bit of simple physics here, we can see that the frequency of a note is inversely proportional to the length of the string f 1/l. In short, if you half the string length, you double the frequency of a note.

So, according to the above two statements about the frequency and the harmonics, if we want to produce a note that is exactly double the frequency of the fundamental note (ie one octave higher) we would need to shorten the string length by half, by fretting the string halfway between the nut and the bridge. Luckily for us, this happens to fall at the 12th fret. So fret the A string at the 12th fret and you will produce a note of 880Hz. This again produces a shape that is identical to the fundamental, but just half the size.

So back to harmonics. One of the main sources of confusion in the theory is why a harmonic at the 12th fret and the 12th fret note sound different to each other. This diagram will show you the image of the harmonic.

As you can see, the main difference is that when we play a harmonic, we don’t actually shorten the string entirely by half it’s size to produce a sound that is double the frequency. We create two individual vibrations or waves, one between the nut and the finger and one between the finger and the bridge. These will be very very slightly different in sound, if we were able to play them individually.

Bit more physics now. When we form these two waves they are vibrating in opposite directions to each other. In simple terms, when one wave is vibrating in an upwards direction say the nut & finger wave, the second wave is vibrating in it’s downwards direction. When these two waves are played together, they cancel each other out, almost! Remember we said that the two waves were very very slightly different? Well because of this small difference, the waves don’t cancel each other out entirely.

This produces the sweet sound of a harmonic. So we can now carry this further over the fretboard. Like we said before, a harmonic is a multiple of the fundamental frequency. We can use this to create harmonics at three 3f, four 4f, or more times the fundamental frequency.

Creating a harmonic, forms artificial nodes along the string that causes the frequency to be multiplied. The third harmonic of a string triples the fundamental frequency and divides the string into 3 waves. The third harmonic would need to form at 1/3 of the string length to cause the frequency to be trebled. This will occur at the 7th fret.

The same is true for the fourth harmonic of a string. This occurs at the 5th fret, creates four waves, and quadruples the frequency.

A few final notes. In theory it is possible to form many more harmonics all over the guitar, however this is just not humanly possible. As you divide the frequency up more and more, the point at which you have to place your finger has to be more and more precise for the harmonic to form. If the finger is not placed correctly, the string will not be divided into equal parts, and hence the harmonic will not form. This gives the muffled string sound.

A good way to find the harmonics points is to gently slide your finger up and down the strings and keep playing the string. You will hear a muffled sound that gradually forms into a harmonic and then back to muffled.