Natural Harmonics on the Guitar

what is a harmonic ?

• On a mathematical / physical plan, it's a multiple Hertz frequencies of a given fundamental frequency.
• On a Musical plan, it is a crystal clear sound producible at different intervals of a given note.

To simplify: when you strum a string, you produce a sound wave made with a superposition of elementary sounds called harmonics.
 

How to make a natural harmonic on the guitar ?

A natural harmonic is obtained by touching lightly a vibrating string at the fret level, at specific locations of the fretboard. The natural harmonics are marked 'NH' (natural harmonic) on a tab.
 

     NH
D|--(12)--

As shown above, the best known and easiest to make it ring is apparently the octave harmonic, it's that one we'll use in our case study:

1. Strum the D string (open)

2. As the string vibrates, touch it lightly with the index of the right hand at the 12th fret. Do not press at all (even lightly), otherwise the harmonic will not ring! If you are successful, the simple fact of touching the string in vibration should have caused a change in tone and produce a crystal clear sound: it is the harmonic.

There are different types of harmonics but the most common are located at frets 5 (octave), 7 (diminished), 9 (third), 12 (octave).

Note that you do not have to play the open string before creating a harmonic, you can touch directly the corresponding fret and pick it.

It is also possible to tune his guitar using the natural harmonics, comparing the harmonics produced by the frets 3 (upper string) and 5 (lower string) (instead of the notes fret 5 and open string, like the traditional way).