Recently I was informed that the 5th fret/7th fret technique that a lot of people use does produce a guitar that is slightly out of tune. I use this technique myself and didnt quite believe it, so ill put simple theory behind it. Even though the notes of the strings are a 5th apart (excluding the 5th string), using the circle of fifths starting at 3o'clock we get E, then travelling a FOURTH back, we get A, D, G...etc..actually tuning harmonicly in fourths..which is not what we want. The real way to test this is to try tuning tuning a Piano with this harmonic method. You will notice that after about 12-15 strings we are a half step off. By the end we will be a full 4-5 steps off.
In actuality you will end up with a guitar that is about 1/4 off...If you wanted to use a correct 5th harmonic method:
Tune the high E. Now tune the harmonic at the 12th fret of the B to the 7th fret of the high E, the 12th fret harmonic of the G to the 3rd fret of the high E, the 12th fret harmonic of the D to the 3rd fret of the B, the 12th fret harmonic of the A to the 2nd fret of the G, and the 12th fret harmonic of the low E to the 2nd fret of the D.
This will produce a guitar that is 100% in tune.
Mai Zure - So overdriven, he sh*ts distortion