Guitarists often begin to tune-up in the following way: first tune the 4th harmonic of the low E string, the 3rd of the A string and the top E all to the same note. The figure at right shows the harmonic series on the two lowest strings.



 Guitar tuning by harmonics. 
(These are real pitches: guitar music is usually transposed up an octave.)


Next they tune the B string (B3) to the 3rd harmonic of the first (E2); then tune the 4th harmonic of the A string to the 3rd of the D string. This method cannot be extended succesfully to the G string because it is usually too thick and stiff, so it is better tuned by octaves, using the frets. For several reasons, this method of tuning is only approximate, and one needs to retune the octaves afterwards. The best tuning is usually a compromise that must be made after considering what chords you will be playing and where you are playing on the fingerboard.


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