Harmonics

In this lesson we will be look at various techniques for generating harmonics and try and understand how they are created. Harmonics can produce really nice bell like tones as well as those high pitched squeals you may hear from rock and metal guitarists.

When a guitar string is plucked, the string vibrates at several different frequencies. The vibration along the entire length of the string is known as the fundamental and vibrations occurring between points along the string (known as nodes) are referred to as overtones. Harmonics are played every time you pluck a note on the guitar but you don't usually hear them directly. The fundamental and overtones, when sounded together, are perceived as a single tone. The fundamental tone is the dominant frequency in any note, but along with it various other frequencies are produced. These are the pretty sounding harmonics we are trying to get at. With a little practice we can suppress the fundamental tone and bring out some of these other tones using two main methods.

When you use your finger to produce a harmonic, you modify how the string vibrates and split the length of the string forcing it to vibrate in thirds, fourths etcetera. The tone of the harmonics decrease exponentially meaning the higher up the fret board you go the lower the harmonic will sound.

The diagram above shows the string being divided along its length creating harmonics

Natural Harmonics

The easiest way to hear what a harmonic sounds like is to use open string or natural harmonics. These are harmonics played on open strings by placing your finger over a special node point to bring out the sound of the harmonic. Natural harmonics are played on open strings and harmonics not produced by open strings are seen as being artificial harmonics.

Try touching the string directly over the 12th fret and then pluck the note to hear a natural harmonic. Pull your hand away from the string once it has been plucked. If done correctly you should hear a pretty high pitched bell like sound one octave above the note of the open string. Make sure you are not pressing down on the string. You are just resting your finger on the string directly over the 12th fret and not pushing down at all. It may take a bit of practice but this is the easiest method for generating harmonics.

You can use the same technique to create harmonics on the 4th, 5th, 7th and 12th frets. Experiment and listen to the interesting sounds they produce.

Pinched Harmonics

Another important method for creating harmonics is a technique commonly referred to as pinched harmonics. This technique allows you to create artificial harmonics at any point on the fret board and is used to generate those high pitched squeals rock guitarist love to use.

This technique is achieved by using picking the string with the plectrum but using the side of the thumb to dig in and brush the string at a node point to create a harmonic. This is a fairly difficult technique to describe but fairly easy to execute. Try aiming around 12 frets above the note you are trying to play to find the sweet spot. It will take a fair bit of trial and error to really find the right spot.

Distortion and vibrato are two great ways to intensify the sound of this type of harmonic which is why they are so well associated with rock and metal guitar styles.