String harmonic

Playing string harmonics produces high pitched tones, often compared in timbre to a whistle or flute.

[1][2] Overtones can be isolated "by lightly touching the string with the finger instead of pressing it down" against the fingerboard (without stopping).

[2] For some instruments this is a fundamental technique, such as the Chinese guqin, where it is known as fan yin (泛音, lit.

(Resulting harmonic sound: two octaves and a major third above the first finger or new fundamental.

This results in a high-pitched sound which is particularly discernible on an electrically amplified guitar as a "squeal".

The note is fretted as usual, but instead of striking the string the excitation energy required to sound the note is achieved by tapping at a harmonic nodal point.

The open string technique can be extended to artificial harmonics.

This technique is used by effect devices producing a magnetic field that can agitate fundamentals and harmonics of steel strings.

Playing a harmonic on a string. Here, "+7" indicates that the string is held down at the position for raising the pitch by 7 semitones.
Table of harmonics, indicating in colors on which positions the same overtones occur
Artificial harmonics on a G fundamental, as written (below) and as sounding (top). The round note (below) is pressed with one finger, and the square note is lightly touched with another one. Play ⓘ
Natural versus artificial harmonic
The fundamental and the double- and triple-frequency overtones of a guitar string.
Pinch harmonics performed on an acoustic guitar