The term “harmonics” refers to a technique that allows you produce a chime-like sound from your guitar. The pitches that you produce using the technique will be higher than those normally heard at the fret that you are playing and will have a distinctly different quality of sound than the one you are used to getting from your guitar. It may take a little experimentation to learn to produce the sound, but it is not difficult and it will open up some interesting possibilities in your playing, so it’s worth investigating!
Harmonics that are played using open strings (often called natural harmonics) will be found at specific mathematical divisions of the string length. Begin by learning to produce a harmonic at the 12th fret, which is half the string length. Very lightly touch (don’t press!) your left index finger over the 12th fret of the first string. (You will not touch between the frets, as you usually do when you play, but instead, you will touch directly over the fret itself.) Next, use your right hand to strike the string and immediately remove your left finger from its position over the fret. The timing will be so close that it may feel like your right and left hand move at the same time.
You should hear a very pure, ringing sound that is an octave higher than the one that would be produced if you fretted a note at the 12th fret. You might not get the sound the first time or two you try, but just experiment until you discover the way you need to touch the string. Check that your left hand finger is directly over the fret and try slightly more or less pressure. You may also need to experiment with the timing. After you are able to produce the sound at the 12th fret, try it at the 7th fret, which is 1/3 the string length and at the 5th fret, which is ¼ the string length. When you are comfortable with those, try it on different strings and using different fingers on your left hand.
Using Harmonics to Tune
Because the sound is so pure and rings out for an extended time, many people choose to use harmonics when they are tuning by ear. The following method for tuning with harmonics is similar to the relative tuning method described on this page.
First, establish the note for the sixth string (E). Then, play the harmonic at the 5th fret of that string followed by the harmonic at the 7th fret of the fifth string. Compare the sounds and, if necessary, adjust the fifth string until the pitch matches that of the sixth.
Repeat this process with the next two sets of strings, comparing the 5th fret of the fifth string with the 7th fret of the fourth string and the 5th fret of the fourth string with the 7th fret of the third string.
Because the interval is different between strings two and three, you will not be able to use the same method, but you can find the pitch of the open second string by playing the harmonic on the 7th fret of the sixth string. Find the correct pitch of the first string in the same manner you did for strings 3 – 6: compare the 5th fret of the second string to the first string, 7th fret.