Another tuning method for the guitar besides using fretted notes is to use harmonics. Harmonics are created by very lightly touching a string directly above the fret wire, and plucking the string. This creates a very high and clear sounding tone. For tuning purposes, we will use harmonics found on the fifth and seventh frets, and in one case, the fourth fret.
As with the fretted note method of tuning, you will need to use an external reference pitch for tuning the 6th string.
The colored triangles in the diagram represent the location of the harmonic pairs you will use to tune the remaining strings.
• Pluck the harmonic on the fifth fret of the 6th string.
• Allow the harmonic to ring while you then pluck the
harmonic on the seventh fret of the 5th string.
• Both harmonics should sound identical. The pitches will
conflict with one another if they are not in tune.
• Adjust the 5th string so that the harmonic is in tune with
the harmonic on the 6th string.
• Repeat this procedure for the pairs on the 5th & 4th
strings, and the 4th & 3rd strings.
• Tuning the 2nd string breaks the pattern used in the previous strings. Here you will use
a harmonic on the fourth fret of the 3rd string. Pluck the harmonic. This one is a little harder
to sound than the others.
• Pluck a harmonic on the fifth fret of the 2nd string, and compare it to the harmonic on the
3rd string.
• Adjust the 2nd string accordingly.
• Notice that you will use the same harmonic on the 2nd string to tune the 1st string.
• Pluck the fifth fret harmonic on the 2nd string.
• Pluck the harmonic on the seventh fret of the 1st string and compare the two.
• Make the necessary adjustment to get the 1st string in tune.
I find this method to be more accurate than using the fretted note approach. Once you get the hang of producing the harmonics, it is easier to hear any fluctuations between the two strings since they produce more pure and clearer sounding tones for comparison. I recommend using this method with a clean setting on your amp (no distortion).