[wrench68]

Originally Posted by charles Tauber

Depending upon how well-trained are one's ears, tuning a guitar can be either very simple or not so simple. In the end, it does come down to what your ears tell you.

Without getting into it, although using the 5th fret harmonic on one string to tune the 7th fret harmonic on the next string is a popular method of tuning, it is one that I don't recommend. You are better off choosing from a variety of other methods.

The short answer is that the fretted notes produce pitches belong to a mathematical system called equal temperament while the harmonics produce pitches that do not. The only place where they are the same is octaves and unisons. This theoretically rules out comparing 5th fret harmonics with 7th fret harmonics. The harmonics may be in tune, but the fretted notes won't.

Tuning and intonation, now THAT is a deep, dark rabbit hole.

+1 and Amen.