намерих малко инфо по въпроса..жалко, че е на енглиш..
Harmonics
Using a specific finger placement, harmonics allow you to obtain a very high sound in comparison with the played note.
A harmonic is indicated by a little diamond (full or empty) before a note on the tablature. A symbol (for example "N.H" for an natural harmonic) is added on the tablature. On the standard notation, the head of the note is changed to a diamond.
Several harmonics are available:
Natural Harmonic
The natural harmonic consists of playing the string open while you lightly touch it with the left hand (for a right-handed person) above a fret. The left hand finger has to be taken off at the same time that the right hand plays it. 5th, 7th and 12th frets harmonics are very commonly used, while the others are quite difficult to obtain.
Artificial Harmonic (+5/+7/+12)
For the artificial harmonic, the left hand finger presses the string like a normal note. It is the forefinger of the right hand that lightly touches the string 5,7 or 12 (octavado) frets higher. The right hand has to play the note too, so it may be difficult. - това нещо не си го преставям как ще стане
Tapped Harmonic
The tapped harmonic is an artificial harmonic obtained by tapping quickly on the string 12 frets higher.
Pitch Harmonic
The pitch harmonic is done with a pick, and consists in playing the string by letting the thumb that holds the pick lightly touch the string. This harmonic is best obtained with distortion effect.
Semi Harmonic
The semi harmonic is similar the pitch harmonic, except you keep the natural resonance of the string in addition to the harmonic.